Ambient Air Monitoring Network Assessment of the South Saskatchewan Region

Transcription

1 Ambient Air Monitoring Network Assessment of the South Saskatchewan Region Final Report Prepared for Alberta Ministry of Environment and Sustainable Resource Development Calgary, Alberta January 2014

2 Environment and Sustainable Resource Development FOREWORD Contract Name: Ambient Air Monitoring Network Assessment of Alberta s South Saskatchewan Region Consultant Name: Sonoma Technology Inc. (STi) A number of different organizations - including Alberta Environment and Sustainable Resource Development (ESRD), Calgary Region Airshed Zone (CRAZ), Palliser Airshed Society (PAS), Parkland Airshed Management Zone (PAMZ), and local industry - conduct air quality monitoring within the SSR, but there has never been a monitoring network assessment of the region as a whole. ESRD contracted Sonoma Technology, Inc. (STI) to perform a network assessment to identify the strengths and weaknesses of the existing SSR ambient air monitoring network and evaluate its ability to meet its current monitoring objectives. This document recommends improvements to the current SSR monitoring network and will facilitate the implementation of the draft South Saskatchewan Region Air Quality Management Framework. STI developed a conceptual model of network strengths and weakness based on a brief consolidation of past work in the region, current monitoring locations, wind roses, population centres, and emissions information. The assessment considered the following substances: sulphur dioxide (SO 2 ), nitrogen dioxide (NO 2 ), ozone (O 3 ), ammonia (NH 3 ), hydrogen sulphide (H 2 S) and fine particulate matter (PM 2.5 ).The conceptual model was tested using four analyses: measured concentrations, population/emissions/area representativeness, suitability modelling, and additional monitor analysis. The results from those analyses were used to modify the conceptual model and develop a set of recommendations to help the network better meet the stated monitoring objectives for ambient air quality monitoring in Alberta s South Saskatchewan Region as a whole. Recommendations from this network assessment report did not take into account other considerations, such as; resource constraints, the historical objectives of the monitoring site, jurisdictional boundaries, compliance requirements, and other pollutants monitored at these sites, and monitoring objectives not included for this assessment. These and other unstated considerations may influence which, if any, of the recommendations that may be implemented in the future. This report has been completed in accordance with the contract issued by ESRD. ESRD has closed this project and considers this report final. ESRD does not necessarily endorse all of the contents of this report, nor does the report necessarily represent the views or opinions of ESRD or the stakeholders. The conclusions and recommendations contained within this report are those of the consultant, and have neither been accepted nor rejected by ESRD. Until such time as ESRD issues correspondence confirmed acceptance, rejection, or non-consensus regarding the conclusions and recommendations contained in this report, they should be regarded as information only.

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4 Ambient Air Monitoring Network Assessment of the South Saskatchewan Region Final Report STI FR2 Prepared by Michael C. McCarthy Bryan M. Penfold Angela L. Ekstrand Theresa E. O Brien Sonoma Technology, Inc N. McDowell Blvd., Suite D Petaluma, CA Ph F sonomatech.com Prepared for Alberta Ministry of Environment and Sustainable Resource Development January 27, 2014 Cover graphic illustrates Thiessen polygons for a proposed continuous network with new sites at Airdrie, Okotoks, Cochrane, Strathmore, and Brooks. For more information, see Section 4.1.

5 Table of Contents Table of Contents Section Page List of Figures... v List of Tables... vii Glossary... viii Executive Summary... ES-1 1. Introduction South Saskatchewan Region Overview Monitoring Objectives Network Evaluation Approach Overview of This Report Monitoring Network Overview and Conceptual Model Monitoring Network Description Conceptual Model Emissions Sources Population Meteorology and Climatology Pollutants of Interest Network Strengths and Weaknesses Network Strengths Network Weaknesses Methods Area, Emissions, and Population Served Analysis Measured Concentration Analysis Suitability Analysis Additional Monitor Analysis Analysis Results Area, Emissions, and Population Served (Thiessen Polygons) Concentrations Measured Suitability Analysis New Monitor Analysis Summary and Recommendations A Review of the Monitoring Objectives Monitor as Required for Compliance to AAAQOs, EPEA Approvals and for reporting to CWS, Forthcoming CAAQS, and the NAPS Implement and Review Alberta s Cumulative Effects Management System in the SSR Evaluate the Spatial Distribution of Monitored Pollutants in the Region (NO 2, Ozone, PM 2.5, SO 2, H 2 S, and NH 3 ) Identify Regional Air Quality Trends and Emerging Issues Characterize Specific Geographic Locations or Sources Provide Appropriate Information to Evaluate Potential Population Exposure to Ambient Air Quality iii

6 Table of Contents Provide Information Required to Understand Air Quality Impacts on the Health of the Environment Improve the Ability to Identify and Apportion Sources of Pollution for the Purpose of Air Quality Management Provide Suitable Input and Validation Information for Dispersion Modeling Conduct Monitoring Using the Best Available Technology Economically Achievable Recommendations Other Considerations References iv

7 List of Figures List of Figures Figure Page 1-1. Map of the South Saskatchewan Region and ongoing monitoring within the region General framework for performing a network evaluation Map of NO x emissions sources and areas in the SSR Map of SO 2 and SO x emissions sources and areas in the SSR Map of direct PM 2.5 emissions sources and areas in the SSR Map of VOC emissions sources and areas in the SSR Total emissions of VOCs, PM 2.5, SO x /SO 2, and NO x /NO 2 in the SSR for large facilities, small upstream sources, and area/mobile emissions Population subdivisions from the 2011 Statistics Canada census for the SSR Wind roses for data at each of the monitoring sites with at least one complete year of monitoring data Steps of the Area Served analysis Instructions for interpreting notched box-whisker plots (SYSTAT software) Conceptual approach used to develop a suitability model Thiessen polygons indicating the population and area served for the current continuous monitoring network for PM Thiessen polygons indicating the facility and upstream emissions and area served for the current continuous monitoring network for SO Thiessen polygons indicating the population and area served for the passive monitoring network for NO 2, SO 2, and ozone Thiessen polygons indicating the emissions and area served for the passive monitoring network for SO Notched box-whisker plots showing two concentration distributions for 1-hr PM 2.5 in units of µg/m 3, 1-hr NO 2 in units of ppb, 8-hr daily maximum ozone in units of ppb, and 1-hr SO 2 in units of ppb Interpolation maps of 2012 annual mean values of SO 2, NO 2, and ozone concentrations in ppb from the SSR passive monitoring network Suitability map for the Optimal Network scenario v

8 List of Figures Figure Page 4-8. Suitability map for the New Monitor scenario Suitability map for the Source-Oriented scenario Suitability map for the Spatial Coverage scenario Proposed locations of new monitoring sites for the continuous monitoring network, along with Thiessen polygons indicating the 2011 population representativeness if these changes occur Locations of proposed additional passive monitors for the SSR, along with Thiessen polygons representing the area and population coverage of current and proposed monitoring sites vi

9 List of Tables List of Tables Table Page 2-1. Monitoring sites and pollutants monitored in References reviewed during the development of the conceptual model Suitability analysis weighting scheme for the four scenarios Site key for Figures 4-1, 4-2, and Site key for Figures 4-3, 4-4, and vii

10 Glossary Glossary Term AAADMS AAAQO AMSP AQHI CAAQS CASA CH 4 CO CRAZ CWS EPA EPEA ESRD Esri GIS H 2 S NAPS NH 3 NMHC NO NO 2 NO x PAHs PAMZ PAS PM PM 2.5 SO 2 SSR STI THC VOCs Definition Alberta Ambient Air Data Management System, more commonly known as the Clean Air Strategic Alliance s (CASA) data warehouse Alberta s Ambient Air Quality Objectives Alberta Monitoring Strategic Plan Air Quality Health Index Canadian ambient air quality standards Clean Air Strategic Alliance methane carbon monoxide Calgary Region Airshed Zone Canada-Wide Standards U.S. Environmental Protection Agency Alberta s Environmental Protection and Enhancement Act Alberta Environment and Sustainable Resource Development Environmental Systems Research Institute geographic information system hydrogen sulfide National Air Pollution Surveillance Program ammonia non-methane hydrocarbon nitrogen oxide nitrogen dioxide nitrogen oxides polycyclic aromatic hydrocarbons Parkland Airshed Management Zone Palliser Airshed Society particulate matter particulate matter less than 2.5 microns in diameter sulfur dioxide South Saskatchewan Region Sonoma Technology, Inc. total hydrocarbons volatile organic compounds viii

11 Executive Summary Executive Summary Overview Alberta s South Saskatchewan Region (SSR) is a vast area covering over 80,000 square kilometres, which is approximately 12.6% of Alberta s land area. Municipalities with over 20,000 residents are Calgary (Canada s third largest city 1 ), Lethbridge, Medicine Hat, Airdrie, and Okotoks. A few other municipalities in the region have over 10,000 residents, including Cochrane, Chestermere, Brooks, High River, Strathmore, and Canmore. The SSR includes mountains, foothills, rivers, and plains. Major land uses include forestry, oil and gas extraction, tourism, outdoor recreation, residential housing, farming, ranching, and agricultural production. Additionally, seven First Nation communities are located in the SSR. A number of different organizations including Alberta Environment and Sustainable Resource Development (ESRD), Calgary Region Airshed Zone (CRAZ), Palliser Airshed Society (PAS), Parkland Airshed Management Zone (PAMZ), and local industry conduct air quality monitoring within the SSR, but there has never been a monitoring network assessment of the region as a whole. Sonoma Technology, Inc. (STI) performed a network assessment to identify the strengths and weaknesses of the existing SSR ambient air monitoring network and evaluate its ability to meet its monitoring objectives. This document recommends improvements to the current SSR monitoring network and will facilitate the implementation of the draft South Saskatchewan Region Air Quality Management Framework. STI uses a general framework for performing network evaluations as described in the U.S. Environmental Protection Agency s (EPA) network evaluation guidance document (Raffuse et al., 2007). The steps in the framework are (1) examining the sites and monitoring objectives, (2) developing a conceptual model of network strengths and weaknesses, (3) testing the conceptual model by performing analyses, (4) developing recommendations for modifying the network, (5) taking other technical and non-technical considerations into account, and (6) implementing changes to the monitoring network. This document describes the first four steps of the network evaluation; after considering additional political, jurisdictional, and budget issues, the local, regional, and provincial stakeholders are responsible for deciding what changes to the network are implemented. For this network assessment, the monitoring objectives focused on a regional approach to monitoring, primarily for the purpose of air quality management using the cumulative effects management system. ESRD and other stakeholders defined the monitoring objectives for the network. The monitoring objectives for this regional monitoring network are to: Monitor as required for compliance to Alberta Ambient Air Quality Objectives (AAAQOs) and Environmental Protection and Enhancement Act (EPEA) approvals and reporting for Canada-wide Standards (CWS), forthcoming Canadian Ambient Air Quality Standards (CAAQS), and the National Air Pollution Surveillance Program (NAPS). 1 Tableau.cfm?LANG=Eng&T=301&S=3&O=D. ES-1

12 Executive Summary Implement and review Alberta s cumulative effects management system in the SSR. Assess ambient air quality in relation to triggers and limits identified in the draft SSR Air Quality Management Framework. Evaluate the spatial distribution of monitored pollutants in the region (i.e., NO 2, ozone, PM 2.5, SO 2, H 2 S, and NH 3 ). Identify regional air quality trends and emerging issues. Characterize specific geographic locations or sources. Provide appropriate information to evaluate potential population exposure to ambient air quality. Provide information required to understand air quality impacts on the health of the environment. Improve the ability to identify and apportion pollutant sources for the purpose of air quality management. Provide suitable input and validation information for dispersion modeling. Conduct monitoring using the best available technology economically achievable. STI developed a conceptual model of network strengths and weakness based on a brief consolidation of past work in the region, current monitoring locations, wind roses, population centres, and emissions information. The conceptual model was tested using four analyses: measured concentrations, population/emissions/area representativeness, suitability modeling, and additional monitor analysis. The results from those analyses were used to modify the conceptual model and develop a set of recommendations to help the network better meet the stated monitoring objectives. Implementing recommendations is based on a number of considerations that are not addressed in the technical network evaluation. These include resource constraints, historical objectives of monitoring sites, jurisdictional issues, other measurements made at the sites (such as speciated Particulate Matter or volatile organic compounds (VOCs), and compliance requirements. The following recommendations are based on a network evaluation of the technical merits of the monitoring objectives for SO 2, NO 2, ozone, H 2 S, NH 3, and PM 2.5 and do not account for these external considerations. The stakeholders implementing changes to the network should take these other considerations into account when choosing which recommendations to implement. Recommendations The following recommendations are listed in priority order based on the results of the network assessment. Recommendations and opinions expressed in this report are those of STI and may not be representative of the views of ESRD or other SSR stakeholders. Add a north-south axis of monitoring stations around Calgary in Airdrie and Okotoks to improve spatial coverage, identify gradients in concentrations upwind and downwind of Calgary, enhance population representativeness, and ensure Air Quality Health Index (AQHI) monitoring. Airdrie and Okotoks are the two largest population centres in the SSR that do not have AQHI monitoring. ES-2

13 Executive Summary Add (or move existing) passive monitors to the southwest portion of the SSR to better assess spatial gradients in NO 2 and SO 2 in areas with no current passive measurements. Move the Calgary Central site away from its urban canyon location. The urban canyon is likely to channel and divert winds in complicated ways that may result in reduced spatial representativeness of the monitoring site. Add meteorological measurements to help identify and apportion sources. Over the longer term, add an east-west axis of monitoring stations around Calgary, with a site located west of Calgary in Cochrane and a site located east of Calgary between Chestermere and Strathmore, to improve regional spatial coverage, provide AQHI for communities with populations of 20,000 or more, and help assess gradients in pollution across the region and in the Calgary metropolitan area. Over the longer term, add a monitoring site in Brooks to improve network spatial coverage, provide representative AQHI values for residents in the northeastern portion of the SSR, and assess local impacts of industrial and upstream sources in the area. Use temporary ozone stations (or short-term passive samplers during peak ozone season) north of Calgary to help locate where ozone concentrations are highest. Conduct additional temporary monitoring (e.g., using mobile monitoring laboratory, portable monitors, low-cost sensors) to characterize specific sources and locations. This may be a cost-effective approach to help fill in the spatial coverage of pollutants that cannot be measured using passive techniques. Collocate passive measurement sites with at least a few continuous stations (e.g., Calgary sites, Lethbridge) for quality assurance to ensure that the two methods provide the same values for monthly average concentrations of ozone, NO 2, and SO 2. ES-3

14 Introduction 1. Introduction Alberta s South Saskatchewan Region (SSR) is a vast area covering over 80,000 square kilometres, which is approximately 12.6% of Alberta s land area. A number of different organizations including the Alberta Ministry of Environment and Sustainable Resource Development (ESRD), Calgary Region Airshed Zone (CRAZ), Palliser Airshed Society (PAS), Parkland Airshed Management Zone (PAMZ), and local industry conduct air quality monitoring within the SSR (Figure 1-1), but there has never been a monitoring network assessment of the region as a whole. A network assessment is needed to identify the strengths and weaknesses of the SSR monitoring network and evaluate its ability to meet monitoring objectives. This network evaluation will provide recommendations for improving the current SSR monitoring network and will facilitate the implementation of the draft South Saskatchewan Region Air Quality Management Framework. Figure 1-1. Map of the South Saskatchewan Region and ongoing monitoring within the region. Continuous monitoring sites are shown as a blue cross, passive sites are shown as a green diamond, and industrial monitors are denoted as a black X. 1-1

15 Introduction 1.1 South Saskatchewan Region Overview The SSR boundaries are defined to the south by the Canadian-U.S. border and to the east by the Saskatchewan border. The Rocky Mountains make up the western boundary and the Municipal District of Bighorn the northern boundary. Major land uses include forestry, oil and gas extraction, tourism, outdoor recreation, residential housing, farming, ranching, and agricultural production. While accounting for only 12.6% of Alberta s area, the SSR contains approximately 45% of Alberta s population. The SSR emission mix is complex, including emissions from (1) transportation sources, such as cars, trucks, buses, planes, and rail; (2) industrial sources, such as electrical generating units and gas plants; (3) agricultural sources, such as concentrated feeding operations, and (4) miscellaneous sources, such as biogenic emissions, upstream oil and gas extraction, and natural gas use and processing. Historically, the continuous monitoring network consisted of population-oriented monitoring, with three sites in Calgary and single sites in Medicine Hat and Lethbridge. Passive monitoring sites for ozone, SO 2, and NO 2 were deployed in the CRAZ, PAS, and PAMZ portions of the airshed. Additional industrial facilities with compliance monitors (continuous and passive) operated throughout the region, primarily monitoring for SO 2 and H 2 S. Additionally, a mobile monitoring laboratory is available in the PAS for characterizing specific sources and locations. At present, ambient air quality monitoring plays a role in triggering air quality management activities and assessing the efficacy of those activities. At the same time, stakeholders in the SSR are interested in emerging local issues, such as regional development due to population growth, ozone and PM 2.5 management, and non-point source emissions management. The historical monitoring locations may not be adequate to meet these evolving needs. Therefore, ESRD has requested a network evaluation and recommendations for improving the monitoring network to better meet the evolving needs of its stakeholders. As with any monitoring network, resources are constrained and should be allocated to focus on best meeting monitoring objectives. The technical working group prepared a set of new monitoring objectives and emerging issues with which to guide this monitoring network evaluation. These monitoring objectives are described in the following section. 1.2 Monitoring Objectives ESRD wishes to maximize the informational value of the monitoring network in a cost-effective and sustainable way, with the following objectives for the SSR ambient air quality monitoring network: Monitor as required for compliance to Alberta Ambient Air Quality Objectives (AAAQOs) and Environmental Protection and Enhancement Act (EPEA) approvals and reporting for Canada-wide Standards (CWS), forthcoming Canadian Ambient Air Quality Standards (CAAQS), and the National Air Pollution Surveillance Program (NAPS). 1-2

16 Introduction Implement and review Alberta s cumulative effects management system in the SSR. Assess ambient air quality in relation to triggers and limits identified in the draft SSR Air Quality Management Framework. Evaluate the spatial distribution of monitored pollutants in the region (i.e., NO 2, ozone, PM 2.5, SO 2, H 2 S, and NH 3 ). Identify regional air quality trends and emerging issues. Characterize specific geographic locations or sources. Provide appropriate information to evaluate potential population exposure to ambient air quality. Provide information required to understand air quality impacts on the health of the environment. Improve the ability to identify and apportion pollutant sources for purpose of air quality management. Provide suitable input and validation information for dispersion modeling. Conduct monitoring using the best available technology economically achievable. Some of these monitoring objectives have not been explicit goals of the monitoring network in previous years, although others have been implicitly recognized in guiding the monitoring network design. For example, historical trends in air quality have been tracked at multiple sites in the region for more than 10 years. Air quality measurements in the form of the Air Quality Health Index (AQHI) are reported in Calgary, Lethbridge, and Medicine Hat. 1.3 Network Evaluation Approach STI uses a general framework for performing network evaluations as described in the U.S. Environmental Protection Agency s (EPA) network evaluation guidance document (Raffuse et al., 2007). A flowchart describing the general evaluation approach is shown in Figure 1-2. This report contains the draft recommendations for modifying the network and includes revised copies of webinars used to present findings during the project. The network assessment recommendations were made to be as feasible and scientifically justified as possible, but did not take into account other considerations as listed in Step 5. These include the historical objectives of the monitoring sites, jurisdictional boundaries, available monitoring resources, other pollutants monitored at these sites, and monitoring objectives not included for this assessment. These and other unstated considerations may influence which, if any, of the recommendations should be implemented by regional stakeholders in Step

17 Introduction Figure 1-2. General framework for performing a network evaluation. 1.4 Overview of This Report This report is organized into sections that mirror the general framework outlined above. Section 1 provides a summary of the network evaluation approach, an overview of the region and a summary of the monitoring objectives. Section 2 provides an overview of the existing monitoring network and a description of the conceptual model of air pollution in the region, as well as a list of the references consulted. Section 3 describes the analysis methods used in the network evaluation. Section 4 contains the results of the analyses. Section 5 summarizes the performance of the monitoring network relative to its monitoring objectives, and includes a list of recommendations for better meeting these objectives. Section 6 contains references cited in this report. 1-4

18 Overview and Conceptual Model 2. Monitoring Network Overview and Conceptual Model 2.1 Monitoring Network Description The 2012 regional monitoring network consists of continuous (i.e., typically reported as hourly duration) monitoring sites with measurements of at least one of ozone, PM 2.5, NO 2, and/or SO 2. The monitoring site names and pollutants monitored in 2012 are listed in Table 2-1 (locations shown in Figure 1-1). STI acquired data for all these sites in July and August 2013 from the Alberta Ambient Air Data Management System (AAADMS), more commonly known as the Clean Air Strategic Alliance s (CASA) data warehouse (Clean Air Strategic Alliance, 2012), or from ESRD for data not available in the data warehouse. The existing monitoring network design is based on population monitoring sites originally funded by ESRD. In recent years, the individual airsheds (CRAZ, PAS, PAMZ), their resources, and individual airshed objectives have taken priority rather than a regional monitoring approach. Continuous monitoring stations in Calgary, Lethbridge, and Medicine Hat are the primary resources, with passive monitoring providing spatial coverage for SO 2, NO 2, and ozone on a monthly average basis. Industrial monitoring sites are currently providing compliance monitoring for EPEA approvals, but they are not integrated into the regional network. Table 2-1. Monitoring sites and pollutants monitored in Airshed Station CH 4 CO H 2 S NH 3 NMHC NO, NO 2, NO x O 3 PM 10 PM 2.5 SO 2 THC 1 CRAZ CRAZ CRAZ PAS PAS PAS Lethbridge X X X X X X X X X X Calgary Central Calgary Southeast Calgary Northwest Crescent Heights X X X X X X X X X X X X X X X X X X X X X X X X X X X X X Portable Taber 2 X X X Portable Hays 2 X X X 1 Lethbridge is not within an Airshed. 2 The portable monitoring station was located in Hays in 2011 and Taber in

19 Overview and Conceptual Model 2.2 Conceptual Model A conceptual model is a mental model used to represent Sonoma Technology, Inc. s (STI s) understanding of the network. The conceptual model forms the basis for the network recommendations, which are provided in the Summary and Recommendations section of this report (Section 5). A conceptual model of a monitoring network needs to consider emissions sources, population density, meteorology and climatology, pollutants of interest, existing monitoring network locations, and monitoring objectives. Our conceptual model is based on an examination of the current monitoring network and a review of work done in the SSR over the last five years as listed in Table 2-2. We discuss our conceptual model of each of these considerations in the subsections below, with the exception of monitoring objectives and locations, which were discussed in Sections 1.2 and 2.1, respectively. Figures representing each of these areas are available in the Analysis Results section (Section 4). Table 2-2. References reviewed during the development of the conceptual model. Full citations are provided in Section 6. Year Title Authors Air Quality Modelling Exercise using Community Multiscale Air Quality (CMAQ) model for South Saskatchewan Regional Plan Summary Report Air Quality Modelling Exercise using CMAQ model to Support South Saskatchewan Regional Planning Technical Report ENVIRON Canada and Novus Environmental (2013) Novus Environmental (2013) 2013 Alberta Ambient Air Quality Objectives Alberta Environment (2013) 2012 CRAZ Annual Report Calgary Region Airshed Zone (2012) 2012 Clearing the Air Alberta s Renewed Clean Air Strategy Government of Alberta (2012) 2012 A Year in the Palliser Airshed 2012 Annual Report Palliser Airshed Society (2012) 2009 Air Issues Scoping Study for the Alberta South Saskatchewan Land-Use Planning Region Stantec Consulting Ltd. (2009) 2009 Ambient Air Quality Trends in Alberta 2008 Alberta Environment (2009) 2009 Ambient Air Monitoring Strategy for Alberta AMSP Project Team (2009) 2009 Profile of the South Saskatchewan Region Government of Alberta (2009) 2008 CRAZ Particulate Matter and Ozone Management Plan Calgary Region Airshed Zone (2008) Emissions Sources The SSR is unlike most of Alberta in its mix of emissions sources. While there are industrial facilities that generate emissions of SO 2, NO 2, PM, and volatile organic compounds (VOCs) in the SSR, these sources are not as large or as numerous as in other regions of Alberta. The 2-2

20 Overview and Conceptual Model larger population of the SSR generates increased emissions from transportation and area sources, such as motor vehicles, small commercial buildings, and light industry. These emissions primarily occur within the populated areas of the region. Small upstream emissions caused by oil and gas extraction activities are also an important source of emissions in some portions of the SSR. Emissions source locations for nitrogen oxides (NO x ), SO 2, direct emissions sources of PM 2.5, and VOCs (precursors of secondary ozone and PM 2.5 ) were mapped to identify emissions source areas. Examples are shown in Figure 2-1 for NO x, Figure 2-2 for SO 2, Figure 2-3 for PM 2.5, and Figure 2-4 for VOCs, indicating stationary source locations from the National Pollutant Release Inventory (NPRI) 2011, area and mobile source emissions (by populated area) from the 2008 ESRD inventory, and small upstream emissions (oil and gas extraction) from the 2008 Energy Resources Conservation Board (ERCB, now AER) inventory and 2008 South Saskatchewan Regional Plan modeling locations (we note there was very little difference in upstream locations, but emissions estimates were notably different for SO x /SO 2 and NO x /NO 2 ). Additionally, monitoring locations for the pollutant of interest are shown as green squares for continuous monitors. Total emissions within the SSR are shown in Figure 2-5 for VOCs, PM 2.5, SO X /SO 2, and NO x /NO 2. Area and mobile emissions are the predominant source of VOCs, direct PM 2.5 emissions, and NO x. Facilities dominate SO x /SO 2 emissions and contribute significantly to NO x emissions. Upstream sources contribute significantly to both VOC and NO x emissions. Figure 2-1. Map of NO x emissions sources and areas in the SSR. 2-3

21 Overview and Conceptual Model Figure 2-2. Map of SO 2 and SO x emissions sources and areas in the SSR. Figure 2-3. Map of direct PM 2.5 emissions sources and areas in the SSR. 2-4

22 Overview and Conceptual Model Figure 2-4. Map of VOC emissions sources and areas in the SSR. Emissions (tons/yr) Facility (NPRI 2011) 2008 Small Upstream (ERCB, now AER) Area/Mobile (2008 ESRD) VOC PM2.5 SOx & SO2 NOx & NO2 Figure 2-5. Total emissions of VOCs, PM 2.5, SO x /SO 2, and NO x /NO 2 in the SSR for large facilities, small upstream sources, and area/mobile emissions. 2-5

23 Overview and Conceptual Model Population The SSR is anchored by Calgary, Alberta s largest city. The 2011 census reported approximately million residents in the greater metropolitan region; of these residents, the city of Calgary accounts for million. Estimates from the 2013 municipal census put the city population at 1.15 million, or a growth rate of more than 2.5% per year. Other large municipalities and their 2011 census populations include Lethbridge (83,517), Medicine Hat (61,180), Airdrie (42,564), Okotoks (24,511), Cochrane (17,580), Chestermere (14,824), Brooks (13,676), High River (12,920), Strathmore (12,305), and Canmore (12,288). Some of the municipalities around Calgary, such as Airdrie, Okotoks, Cochrane, and Chestermere, are experiencing extraordinary rates of population growth much higher than that of Calgary. For example, the 2013 municipal census in Airdrie counted a population of 49,560 16% greater than the 2011 estimate. Figure 2-6 shows the major population subdivision centres for the SSR. Other maps of population density indicate that municipal districts with total populations above 5,000 (e.g., Rocky View and Foothills) are sparsely populated. Only the major towns and cities have population densities greater than 500 people per square kilometre. Figure 2-6. Population subdivisions from the 2011 Statistics Canada census for the SSR. 2-6

24 Overview and Conceptual Model Meteorology and Climatology Meteorological measurements were available at four of the five continuous monitoring sites; Calgary Central did not have meteorological measurements. The Calgary Northwest and East sites had distinctly different wind patterns. Calgary Northwest showed winds dominantly from the northwest, while Calgary East showed winds predominantly from the southwest. Lethbridge and Crescent Heights both showed strong flows from the southwest as well. However, further investigation of meteorology measurements from the Calgary Airport, Strathmore, and Brooks indicated that predominant flow patterns on the east side of Calgary are more north-south oriented. Additionally, the Springbank station west of Calgary showed northwest and southsoutheast flow very similar to that observed at Calgary Northwest. It is plausible that the continuous air quality monitoring stations are more influenced by local river valleys and topographical features like Nose Hill. This is consistent with chemical transport model results showing downwind concentrations of ozone to be highest northeast of Calgary. Figure 2-7 shows wind roses for for air quality monitoring sites with meteorological measurements in the SSR. Wind roses for other sites in Calgary region can be generated at windfinder.com, 2 but cannot be reprinted here due to copyright restrictions. Figure 2-7. Wind roses for data at each of the monitoring sites with at least one complete year of monitoring data. 2 See, for example, 2-7

25 Overview and Conceptual Model Pollutants of Interest The pollutants of interest in this monitoring network are those which can help inform the monitoring objectives. Among currently monitored pollutants, the focus of the continuous monitoring network is on SO 2, ozone, NO 2, NH 3, PM 2.5, CO, total hydrocarbons (THC), non-methane hydrocarbons (NMHC), CH 4, and H 2 S. Additional pollutants, such as speciated VOCs, polycyclic aromatic hydrocarbons (PAHs), and speciated PM 2.5, are monitored at the Calgary Central site, but were not considered for this network assessment. 2.3 Network Strengths and Weaknesses Network Strengths Some of the continuous sites have been operating and collecting measurements over the long term for target pollutants; these sites should be adequate for examining trends. Continuous network sites measure AQHI pollutants, providing appropriate information to evaluate population exposure to key pollutants. Passive monitoring provides spatial coverage for northern, northwestern, and eastern portions of the SSR for NO 2, SO 2, and ozone. Speciation data at the Calgary Central site provides useful information for understanding the components of PM mass, and may provide useful information on the emissions sources most important for ozone formation and PM mass Network Weaknesses There are insufficient continuous and passive monitoring stations for the SSR for the following reasons: There are only six continuous monitors to cover a population of over 1.65 million residents. In comparison, Edmonton s capital region, with a population of approximately 1.16 million, has nine continuous AQHI monitors. The Peace Airshed Zone Association (PAZA) has three AQHI monitors for a population of approximately 110,000 residents. Airdrie and Okotoks both have populations greater than 20,000, which meet the criteria for permanent AQHI monitoring stations under the 2009 Ambient Air Monitoring Strategic Plan (AMSP Project Team, 2009). Cochrane only needs approximately 1,000 more residents to meet this threshold, which will occur in 2015 at current growth rates. There are no upwind or downwind continuous monitoring sites around Calgary for assessing spatial gradients or identifying locations of maximum ozone concentrations. The southwestern portion of the SSR is not covered by the passive network and leaves a spatial void in assessments of gradients of ozone, SO 2, and NO

26 Overview and Conceptual Model The SSR boundary is based on the regional watershed and may not be appropriate under southerly wind conditions, which will transport Calgary and Airdrie emissions northward into the Red Deer Region. The Calgary Central site is in an urban canyon and has no meteorological measurements, despite its wide array of speciated measurements of VOCs, PAHs, and PM. Wind flows are likely to be trapped and redirected by the surrounding large buildings. The Calgary Central and East sites have been moved or are being moved, causing discontinuous trend records that are confounded by spatial differences. Network coverage is overly focused on facility emissions at the expense of spatial coverage and population representativeness. Hydrogen sulfide measurements were temporarily suspended while the Calgary East site was relocated. The complex topography and meteorology around Calgary as it transitions from foothills to prairie may result in complicated spatial variability patterns in concentrations. This may necessitate a larger number of monitors to assess concentration gradients than would be necessary for a city with fewer topographical features. 2-9

27 Methods 3. Methods STI performed a series of analyses to test the conceptual model and preliminary network recommendations. These analyses were either quantitative or qualitative. The goal of each analysis was to improve our conceptual model and refine or change preliminary recommendations on the basis of our improved understanding. Techniques for assessing technical qualities of monitoring networks may be grouped into three broad categories: site-by-site comparisons, bottom-up methods, and network optimization. Site-by-site comparisons rank individual monitors according to specific monitoring objectives. Bottom-up analyses examine data other than monitoring data (e.g., emissions or population information) to assess optimal placement of monitors to meet monitoring objectives. Network optimization analyses evaluate proposed network design scenarios. A thorough description of each method type is provided in Raffuse et al. (2007). Four analysis methods were used to assess the regional monitoring network. Because not all analysis methods address all objectives, a suite of analyses was performed to meet the project scope. The remainder of this section describes the network assessment analyses performed. 3.1 Area, Emissions, and Population Served Analysis The purpose of the area, emissions, and population served analysis is to determine the spatial, emissions, and population coverage of each monitoring site to identify spatial gaps or redundancies in the overall monitoring network. The first step in an area served analysis is to map the air quality sites using geographic information system (GIS) software. Maps were generated in a Canada Albers Equal Area Conic projection centred on the SSR. The next step involves creating Thiessen polygons (also called Voronoi diagrams) within the GIS software. Thiessen polygons are applied as a standard technique in geography to assign a zone of influence or representativeness to the area around a given point; in this case, a monitoring site. Calculating Thiessen polygons is one of the simplest quantitative methods for determining an area of representation around sites. Most monitoring sites outside the SSR were not included in the area served analysis; a few passive stations outside the SSR boundaries were included. Figure 3-1 is a graphical representation of the steps involved in the area served analysis taken from a previous network assessment for the Fort Air Partnership. Using Thiessen polygons is a quantitative analysis that provides area values. Because the Thiessen polygon approach does not consider surface wind speed and direction, surface wind pattern information should be assessed when evaluating the area represented by each site. 3-1

28 Methods Figure 3-1. Steps of the Area Served analysis. The map on the left depicts the monitoring sites (black dots). The middle map shows Thiessen polygons (black lines) surrounding each monitoring site. The last map shows color-coded Thiessen polygons in which large geographic areas are represented by darker blue. The purpose of the population served analysis was to determine the population coverage represented by each monitoring site. Sites representing the greatest population numbers ranked highest in this analysis. Population data were acquired from the Statistics Canada 2011 census at the dissemination block level. The population served analysis was used to identify populations likely to be represented poorly for exposure to the most important criteria air contaminants. The population density values were imposed on the area served polygons (from the previous analysis) and the number of people living in each polygon was calculated. This quantitative analysis identifies which monitors represent the largest populations, based on proximity. Population density relative to existing monitor locations was also investigated as part of this analysis. The purpose of the emissions served analysis was to determine the emissions coverage for each monitoring site. Sites representing the greatest magnitude of facility and upstream emissions are ranked highest. This exercise identifies sites that may be particularly valuable for characterizing concentrations near large emissions sources. 3.2 Measured Concentration Analysis The purpose of the measured concentration analysis was to identify sites within the monitoring network that measure the highest pollutant concentrations. Sites that measure high pollutant concentrations are important for assessing compliance and population exposure, and for performing air quality model evaluations. Conversely, sites with relatively low concentrations are candidates for relocation or removal. Notched box-whisker plots were created for pollutants measured in the continuous monitoring network. Figure 3-2 illustrates how to interpret notched box-whisker plots. Additionally, 3-2

29 Methods summary statistics of the median, mean, 75 th, 90 th, 95 th, and 98 th percentile concentrations observed from 2010 through 2012 at each site were compiled. The median, mean, and 98 th percentile statistics were used to rank order sites from highest to lowest concentrations. How to Interpret Notched Box-Whisker Plots A notched box-whisker plot illustrates the distribution of concentrations. The notch is centered on the median concentration, widening to the size of the box to illustrate the 95% confidence interval in the median concentration value. The edges of the box illustrate the 25th and 75th percentile concentrations. The whiskers indicate values that are 1.5 times the interquartile range (IQR). Star outliers fall between 1.5 and 3 times the IQR. Circle outliers are greater than 3 times the IQR. outlier more than 3 times IQR from the mean (extreme outlier) outlier more than 1.5 times the IQR * 75 th percentile median 25 th percentile box indicates the IQR whisker ends = 1.5 times the IQR The notch and extents of the notch indicates the 95% confidence interval; when comparing notched box-whisker plots, if the notch of one box does not overlap with the notch of another box, the median values are statistically significantly different at the 95% confidence interval. If the notches overlap, the median values are not statistically significantly different. Figure 3-2. Instructions for interpreting notched box-whisker plots (SYSTAT software). Note that mean concentrations are also included as red dots in our plots. 3.3 Suitability Analysis Suitability modeling is a method of identifying appropriate monitoring locations based on specific criteria. For example, suitability modeling can be used to determine possible locations for new air quality monitoring sites based on criteria such as emissions source influence, proximity to populated areas, urban or rural land use, and site accessibility. That being said, it is important to remember that suitability modeling is considered a qualitative analysis and is designed to refine monitoring location selection. A more detailed and localized approach would be needed to determine final site selection; such an approach would include logistics information such as power and road accessibility. Map layers representing important criteria can be compiled and merged to develop a composite map representing the combination of important criteria for a defined area. Furthermore, each map layer input can be assigned a weighting factor based on the relative importance of each layer in the overall suitability model. For example, when determining suitable locations for placing a new air quality monitor, each criterion can be prioritized in terms of its relative importance. If the monitoring objective is to measure air quality in densely populated areas, a map layer representing population density would be given priority and a correspondingly high 3-3

30 Methods weighting factor in the overall model. The resulting suitability map output would favour areas of high population density. The Environmental Systems Research Institute s (Esri) ArcGIS software, Spatial Analyst, was used for this analysis. Spatial Analyst is raster-based software that provides a platform for developing and manipulating gridded data. Spatial Analyst can be used to develop suitability models that produce maps highlighting suitable geographic areas based on defined model criteria. The map calculator within the Esri Spatial Analyst extension was used to weight and combine the map layers and produce suitability models. Equation 1 shows an example of a map calculator expression: ([Layer_1]*.40 + [Layer_2]*.12 + [Layer_3]*.09 ) In this example, Layer_1, Layer_2, and Layer_3 represent individual map layers, and decimal values are the weighting factors applied to each layer. Layer 1 is weighted most heavily because it should have the most influence in the model. Figure 3-3 illustrates a conceptual approach used to develop a suitability model. Figure 3-3. Conceptual approach used to develop a suitability model. 3-4

31 Methods For this analysis, modeling scenarios were developed to: 1. Identify optimal locations for monitoring stations based on proximity to emissions, population, and land cover; 2. Identify locations for new monitoring stations using the same criteria, but adding layers to reduce suitability around existing monitors; 3. Identify areas most likely to be affected by emissions; and 4. Identify areas furthest from current monitors that might be suitable locations for new monitors. Modeling scenario weights for individual suitability layers are shown in Table 3-1. Layers used in this analysis included a 10-km buffer around existing monitors, distance to industrial point sources and active oil/gas wells, distance to major roads (i.e., highways), distance to roads with heavy-duty traffic, distance to small roads, distance to other transportation facilities, distance to concentrated feeding operations, population density, census subdivision population, population centres with more than 20,000 residents that do not have an AQHI monitor, distance to existing monitors, and land cover classification. Table 3-1. Suitability analysis weighting scheme for the four scenarios. Layers Optimal New Monitor Source Oriented Spatial Coverage Existing continuous monitors 20% 5% 10% Point sources 20% 16% 40% 18% Major roads (volume) 10% 8% 12% 9% Heavy-duty roads (volume) 3% 2% 4% 2% Small roads (no volume) 2% 1% 3% 1% Rail lines 3% 2% 4% 2% Population 15% 12% 5% 10% Concentrated feeding operations 5% 4% 8% 5% Airports 2% 1% 1% 1% Land cover 15% 9% 13% 10% Census subdivision categories 15% 9% 7% Population centres without AQHI 10% 6% 5% Distance from existing monitor 10% 5% 20% 3-5

32 Methods 3.4 Additional Monitor Analysis In this analysis, the effect of adding monitors to the existing network was quantified using area and population served analysis. The Thiessen polygon technique was used in the same way as described in Section 3.1. However, the polygons were applied to existing monitoring sites and the locations of proposed continuous or passive monitoring sites to assess how the network would be affected by the addition of monitoring. These maps were used to illustrate how making proposed changes to the network would affect the SSR. 3-6

33 Analysis Results 4. Analysis Results The following results document the analyses performed to test the conceptual model and better characterize existing concentrations across the regional monitoring network. Methods for each of the analyses are documented in the Methods section (Section 3). Results for each analysis are described individually, with a short summary of the implications for the monitoring network described at the beginning of each subsection. Analyses performed include: 1. Area, emissions, and population served (discussed in Section 4.1). 2. Concentrations measured (discussed in Section 4.2). 3. Suitability analysis (discussed in Section 4.3). 4. New monitor analysis (discussed in Section 4.4). 4.1 Area, Emissions, and Population Served (Thiessen Polygons) The results from this analysis are that: The continuous monitors all serve populations of at least 100,000 people, with the Calgary monitors serving over 400,000 residents. The area covered by most of the continuous monitors is very large. Locating the monitors in populated areas will result in overestimation of concentrations for areas outside of the urban centres. The emissions coverage for continuous monitors is likely appropriate for monitoring area/mobile emissions, but is less suitable for characterizing facility emissions. Passive monitoring provides excellent spatial coverage of the northern and eastern portions of the region, but does not cover the southwestern portion of the region. The observed spatial distribution of industrial emissions of SO 2 and NO 2 may not require the current density of passive monitoring to assess spatial gradients. This is further addressed in Section 4.2. Maps were generated using the Thiessen polygon analysis technique in GIS for each of the four pollutants. Population numbers within a polygon were calculated from 2011 census dissemination block level information. Areas were calculated using the GIS software based on the Thiessen polygons algorithm within the SSR boundary. Figures 4-1 and 4-2 show maps of the current continuous monitoring network for PM 2.5 population representativeness and SO 2 emissions representativeness, respectively. Both maps can also be used to characterize area representativeness. The ozone and NO 2 continuous networks are in the same locations as the SO 2 network, but we should note that site 5, Taber, is a portable monitor for the PAS that will be monitoring in other locations in future years. Site numbers and letters on the map are defined in Table 4-1. Given the sparse continuous monitoring network, the population and areas represented by each monitor are quite large compared to other regional monitoring networks in Alberta. In the Capital Region, the highest population represented by a single PM 2.5 monitor was less than 330,000, which will be reduced 4-1

34 Analysis Results further when the St. Albert site is operational. In contrast, each of the Calgary area monitoring sites was responsible for over 420,000 residents in Moreover, the Lethbridge and Medicine Hat monitors are each representing about the same number of residents that live in the entire PAZA Airshed, which operates a network of seven continuous monitoring sites. The emissions represented in Figure 4-2 illustrate the west-to-east gradient in SO 2 emissions facilities. It should be noted that the urban locations of the current continuous monitors are important for population exposure, but are probably less reliable for assessing emissions, given the wide area and diverse number of sources of SO 2 that could be responsible for ambient concentrations. Figure 4-3 shows the map of the current passive monitoring network locations for NO 2, SO 2, and ozone, and their respective population and area representativeness. Site numbers and names in the figure are defined in Table 4-2. Overall coverage spatially is very good for the northern and eastern portions of the region; only the southwestern section is lacking passive monitoring. In general, there is a good tradeoff between sites with high population representativeness covering a smaller area and sites with lower population representativeness covering a larger area. Figure 4-4 shows emissions representativeness of the passive monitoring locations for SO 2 emissions from facilities and upstream sources. In this figure, there is a high degree of variability in emissions representativeness that does not correlate with area or population representativeness. While the southwestern section is underrepresented by passive monitors for its emissions, a large number of monitors have essentially no industrial SO 2 emissions in their area. Table 4-1. Site key for Figures 4-1, 4-2, and Numbered sites are current monitors. Lettered sites are recommended or proposed locations. 4-2

35 Analysis Results Figure 4-1. Thiessen polygons indicating the population and area served for the current continuous monitoring network for PM 2.5. Figure 4-2. Thiessen polygons indicating the facility and upstream emissions and area served for the current continuous monitoring network for SO 2. Note that station 5 at Taber is a portable monitor. 4-3

36 Analysis Results Table 4-2. Site key for Figures 4-3, 4-4, and Numbered sites are current monitors. Lettered sites are recommended or proposed locations. 4-4

37 Analysis Results Figure 4-3. Thiessen polygons indicating the population and area served for the passive monitoring network for NO 2, SO 2, and ozone. Note that some passive monitors outside the SSR boundaries are still the most representative sites for a given area inside the SSR. 4-5

38 Analysis Results Figure 4-4. Thiessen polygons indicating the emissions and area served for the passive monitoring network for SO 2. Note that some passive monitors outside the SSR boundaries are still the most representative sites for a given area inside the SSR. 4.2 Concentrations Measured The results from this portion of the analyses are that: SO 2 concentrations are very low at all continuous sites, but there is significant variability (a difference of more than a factor of five in site-to-site annual mean concentrations) in the CRAZ Airshed of the SO 2 concentrations reported using passive measurements. NO 2 concentrations were highly variable across both the continuous and passive networks. Ozone concentrations were low at most sites. Mean and median PM 2.5 concentrations were highest in downtown Calgary, but the highest hourly concentrations occurred at the Lethbridge and Medicine Hat sites. Methane (CH 4 ) and CO concentrations showed low spatial variability. Ammonia (NH 3 ) was measured at Lethbridge and had no hourly values above the 1-hr AAAQO. Median concentrations for 2010 to 2012 ranged from 1 to 3 parts per billion (ppb). 4-6

39 Analysis Results Spatial variability of concentrations observed in the passive network do not warrant the density of passive monitors currently deployed for ozone, NO 2, or SO 2 in the western and northwestern areas of the region. Notched box-whisker plots were created for each pollutant for all sites using data for each year from Sites where high pollutant concentrations are measured are important for assessing compliance and population exposure, and for performing air quality model evaluations. Conversely, sites where relatively low concentrations are measured may be of less use, especially if they are in close proximity to other monitors or do not meet other monitoring objectives. Low concentrations may be important for characterizing spatial gradients, background concentrations, or for exposure modeling, but are considered less important in this analysis. Figure 4-5 shows notched box-whisker plots of concentrations of the four AQHI target pollutants for all continuous sites in the SSR and for the Caroline and Red Deer sites in the Red Deer region for Hourly PM 2.5 concentrations are somewhat variable across the network sites, with significantly higher mean and median values present at Calgary Central than at other sites. High outlier hourly values are not shown here, but there were a handful of hourly PM 2.5 observations over 100 µg/m 3 at both Lethbridge and Medicine Hat. The Calgary East site was not operational in Similarly, hourly average and median NO 2 concentrations were highest at the Calgary sites. In contrast, 8-hr average ozone concentrations were lowest at the Calgary sites and higher at the Caroline, Lethbridge, and Medicine Hat sites; this is likely due to the titration of ozone by NO in central Calgary. Finally, SO 2 concentrations were measured at a few continuous sites and the typical (median and mean) concentrations were below 0.5 ppb at both the Lethbridge and Medicine Hat sites; we note that reporting resolution of 0.1 ppb or less is needed to better characterize these low concentrations, rather than the current 1 ppb resolution. Figure 4-6 shows interpolated SO 2, NO 2, and ozone concentrations based on the 2012 annual mean values for the SSR passive network. Note that the southwestern section of the SSR interpolation is extrapolated and unreliable due to the lack of passive monitors; these extrapolated concentrations are highlighted with a red box. Gradients in observed concentrations of all three species are relatively shallow, with a few hot spots appearing for each of the pollutants in blue. Gradients for SO 2 clearly display higher western SO 2 than eastern SO 2 concentrations; this gradient is consistent with the gradient in SO x /SO 2 emissions shown in Figure 4-2. However, we note that the passive measurements from CRAZ and PAS are analyzed by different laboratories and this may potentially also introduce some difference in reported concentrations. The hot spot in SO 2 concentrations surrounding the Langdon site was investigated by CRAZ using mobile monitoring; no elevated concentrations of SO 2 or exceedances of the AAAQO were found in that investigation. As expected, NO 2 and ozone are inversely correlated. NO 2 concentrations are highest in and around populated urban areas, as expected for a pollutant that is predominantly associated with mobile and area emissions. Ozone concentrations are low where NO 2 concentrations are high as a result of the titration of ozone by emissions of NO. 4-7

40 Analysis Results (a) 40 (b) 80 1-hr concentration (µg/m 3 ) hr concentration (ppb) Caroline Calgary Central 2 Crescent Heights Calgary Northwest Lethbridge Red Deer Riverside 0 Caroline Calgary Central 2 Crescent Heights Calgary Northwest Lethbridge Red Deer Riverside (c) 80 (d) 6 8-hr average concentration (ppb) hr concentration (ppb) Caroline Calgary Central 2 Crescent Heights Calgary Northwest Lethbridge Red Deer Riverside 0 Caroline Crescent Heights Lethbridge Red Deer Riverside Figure 4-5. Notched box-whisker plots showing two concentration distributions for (a) 1-hr PM 2.5 in units of µg/m 3, (b) 1-hr NO 2 in units of ppb, (c) 8-hr daily maximum ozone in units of ppb, and (d) 1-hr SO 2 in units of ppb. Note: to better identify differences in the central tendencies, very high outliers for PM 2.5 (>40 µg/m 3 ) and SO 2 (>6 ppb) are not shown. Red dots show mean concentrations; the centre of the notch shows the median concentration. Caroline and Red Deer Riverside are not in the SSR, but are included for spatial comparisons. 4-8

41 Analysis Results (a) (b) 4-9

42 Analysis Results (c) Figure 4-6. Interpolation maps of 2012 annual mean values of (a) SO 2, (b) NO 2, and (c) ozone concentrations in ppb from the SSR passive monitoring network. Areas in the red box are extrapolated concentrations and should not be considered valid since there are no passive monitors in the southwestern part of the SSR. 4.3 Suitability Analysis The results from this portion of the analyses are that: Current continuous monitors are located in highly suitable locations. The north-central portion of the Airshed (near Brooks) is suitable for improving spatial coverage and source-oriented monitoring. There are multiple areas that could be considered suitable for new monitor locations, including Airdrie, Okotoks, and Cochrane. Suitability maps were generated using the Esri ArcGIS Spatial Analyst software. Spatial Analyst can be used to develop suitability models that produce maps highlighting suitable geographic areas based on defined model criteria. For this analysis, five modeling scenarios were developed to 1. Identify optimal areas for placing monitors, regardless of current locations; 2. Identify places to put new monitors when considering the current locations of continuous monitors; 3. Identify areas and population centres most likely to be affected by emissions; and 4-10

43 Analysis Results 4. Identify areas and population centres most underrepresented by current continuous monitors. We illustrate a few of the key findings in Figures 4-7 through The Optimal Network scenario indicates where population and emissions are highest without regard to existing monitoring locations. It identifies suitable locations for monitors, focusing on monitoring areas with high population density, population centres with more than 20,000 residents and without AQHI monitors, and areas of high emissions. This Optimal Network scenario is useful for determining where monitors should be placed in an ideal network, regardless of the location of current monitors. The New Monitor scenario reduces the suitability around existing monitors because they are already providing representative measurements. The Source-Oriented scenario examines where emissions from industry may be highest. Finally, the Spatial Coverage scenario identifies areas that are least represented by current monitoring. We note that in the Optimal Network map shown in Figure 4-7, the current network has monitors in all the most suitable locations. This is a confirmation of the existing monitors relevance. Only a few other areas show up as highly suitable on this map, including Airdrie, Okotoks, and Cochrane. These areas also show up as highly suitable in Figure 4-8 under the New Monitor scenario, along with a large north-central section of the region. The foothills and mountains along the western boundary show up as less suitable locations because of the underlying land cover. Additionally, the southern portion of the SSR is deemed less suitable for ambient air monitoring because of its sparse population. Figure 4-7. Suitability map for the Optimal Network scenario. Black diamonds indicate the locations of current continuous monitoring sites for each pollutant. 4-11

44 Analysis Results Figure 4-8. Suitability map for the New Monitor scenario. Black diamonds indicate the locations of current continuous monitoring sites for each pollutant. Figures 4-9 and 4-10 both illustrate the lack of spatial coverage and the wealth of emissions sources in the north-central region of the SSR. Given the distance between existing continuous monitors and the number of emissions sources, this area is shown as suitable for improving the spatial and emissions coverage of the monitoring network. However, the low population does make it less suitable for improving population representativeness. Note that magnitudes of emissions are not included in this analysis, although facility emissions are weighted more highly than upstream sources. 4-12

45 Analysis Results Figure 4-9. Suitability map for the Source-Oriented scenario. Black diamonds indicate the locations of current continuous monitoring sites for each pollutant. 4-13

46 Analysis Results Figure Suitability map for the Spatial Coverage scenario. Black diamonds indicate the locations of current continuous monitoring sites for each pollutant. 4.4 New Monitor Analysis The results from this portion of the analyses are that: Adding additional continuous AQHI monitoring stations in the cities and towns around Calgary would improve the representativeness of concentrations measured for these communities, improve spatial coverage of the network, and meet strategic monitoring plan objectives. Additional continuous monitoring sites would also help assess plumes and gradients in concentration in and around the Calgary metropolitan area, which would aid in understanding the impacts of Calgary emissions on surrounding communities. Adding a site near Brooks would improve the spatial coverage of the continuous monitoring network for the region and reduce the area represented by the Medicine Hat and Lethbridge monitors. Repurposing industrial monitors near Cochrane, Brooks, and Okotoks as population monitors may be useful. Adding or moving five to six passive sites into the southwest portion of the region would help fill the current gap in passive spatial coverage for the SSR. 4-14

47 Analysis Results In this analysis, STI proposed a number of additional monitoring locations for continuous and passive monitoring sites. These sites were added to the existing monitoring network and Thiessen polygons were drawn to show how these proposed sites would affect the population and area representativeness of the existing and proposed network. In Figure 4-11, we show the locations of five proposed monitoring locations for the SSR. Each of these monitors would represent between 33,000 and 73,000 residents. Additionally, these monitoring sites would improve spatial coverage, better represent gradients in concentrations in the region, and capture the effects of Calgary emissions on surrounding and downwind communities. Moreover, these sites would better represent population exposure for residents of these communities and help characterize the impacts of the rapid population growth on concentrations in these bedroom communities. Of the proposed site locations, Airdrie is the highest priority, followed by Okotoks. After those two sites, a monitoring site in Cochrane, a second along the Strathmore/Chestermere corridor, and a third site around Brooks would improve area and population representativeness. Selecting among those three locations would depend on the prioritization of the monitoring objectives for the network between population exposure and better spatial coverage. Adding these monitoring resources to the region would help bring it in line with the monitoring resources devoted to air quality in other regions of the province of Alberta. Figure Proposed locations of new monitoring sites for the continuous monitoring network (shown as letters), along with Thiessen polygons indicating the 2011 population representativeness if these changes occur. 4-15

48 Analysis Results Due to the relatively good spatial coverage of the passive monitoring network, only a few additional monitoring locations are needed to cover the southwestern section of the SSR. Some candidate locations are shown in Figure These sites were selected to coincide with locations of towns and cities and to provide spatial coverage in the southwest. Existing industrial monitoring via passive sampling may be sufficient to provide some of this information, should the data be made publicly available. We also note that it is plausible to potentially redistribute existing monitoring locations within other portions of the SSR to cover the southwest. This could be achieved by moving a few sites from the CRAZ, PAMZ, or PAS airsheds to the southwest, assuming gradients in the other parts of the SSR are sufficiently captured. Figure Locations of proposed additional passive monitors (shown as letters) for the SSR, along with Thiessen polygons representing the area and population coverage of current and proposed monitoring sites. 4-16