Assessment of Air Emissions Martin Marietta Materials Facilities on Highway 34, Weld County, Colorado Project No.:

Transcription

1 April 1, 2015 Mr. James Sharn Church Ranch Way, Suite 201 Westminster, Colorado Subject: Assessment of Air Emissions Facilities on Highway 34, Weld County, Colorado Project No.: Dear Mr. Sharn: is pleased to provide the enclosed performed at Facilities, U.S. Highway 34, Weld County, Colorado. Results of our assessment are described in the report. We appreciate the opportunity to be of service and look forward to working with you in the future. If you have any questions or comments relative to this report, please contact our office. Sincerely, STEWART ENVIRONMENTAL CONSULTANTS, LLC David R. Stewart President and CEO Enc Automation Way, Suite 200 Fort Collins, Colorado T: F: W: stewartenv.com Consulting Engineers and Scientists

2 performed at Martin Marietta Facilities U.S. Highway 34, Weld County, Colorado Prepared for: Prepared by: Consulting Engineers and Scientists Fort Collins, Colorado April Automation Way, Suite 200 Fort Collins, Colorado T: F: W: stewartenv.com Consulting Engineers and Scientists

3 Table of Contents 1.0 INTRODUCTION Background Overview of MMM Site Operations Asphalt Plant Ready Mix Plant Asphalt Recycling REVIEW OF EMISSION ESTIMATES Asphalt Plant Emissions Ready Mix Plant Emissions Asphalt Recycling Emissions Facility Wide Emissions DISPERSION MODELING AND RELATED HEALTH EFFECTS Dispersion Model Modeling CO Dispersion from Asphalt Plant and Asphalt Recycling Modeling HAP Dispersion from Asphalt Plant and Asphalt Recycling SUMMARY & CONCLUSIONS...12 Page FIGURES Figure 1: Site Location U.S. Highway 34 Facilities Page 3 of 14

4 1.0 INTRODUCTION 1.1 Background (MMM) is planning the operation of a hot mix asphalt plant, a concrete ready mix plant, and asphalt recycling (Highway 34 Facility) just outside the community of Kelim, Colorado, located in Weld County. The site is located to the southeast of the intersection of U.S. Highway 34 and Weld County Road 13. The Highway 34 Facilities will also contain a rail unloading facility, AC storage, a wash plant, aggregate sales, and a portable recycle plant. MMM has requested the services of (Stewart) to assess the estimated air pollution from the proposed facilities. Stewart has been assigned the following work, which is documented in this technical report. Review Air Emissions Inventory Review Air Dispersion Modeling Assess Potential Public Health Impacts of Criteria Pollutant and Hazardous Air Pollutant (HAP) Emissions Summarize Findings in a Technical Report 1.2 Overview of MMM Site Operations The area immediately surrounding the Highway 34 Facility is semi-rural in character, with a few residences surrounding the property and a residential housing development located to the northeast. An image of the site from Google Earth is shown in Figure Asphalt Plant The asphalt plant is a parallel-flow drum mix plant fired on natural gas with a maximum capacity of 450,000 tons/year. The asphalt plant produces warm mix asphalt, which is a combination of liquid asphalt cement, aggregate, sand, asphalt binder, and recycled asphalt pavement (RAP). A warm mix plant operates at temperatures of less than 300 degrees F, which is degrees F cooler than a more conventional hot mix plant. The warm mix plant consumes about 20 percent less fuel Ready Mix Plant Ready mix refers to concrete that is batched for delivery from a central plant instead of being mixed on the job site. Each batch of ready mixed concrete is tailor-made according to the specifics of the contractor and is delivered to the contractor in a plastic condition, usually in the cement mixers. Ready mixed concrete is particularly advantageous when small quantities of concrete or intermittent placing of concrete are required. Ready mixed concrete is also ideal for large jobs where space is limited and there is little room for a mixing plant and aggregate stockpiles. Ready-mixed concrete is often remixed once it arrives at the jobsite to ensure that the proper slump is obtained. However, concrete that has been remixed tends to set more rapidly than concrete mixed only once. Materials, such as water and some varieties of admixtures, are often added to the concrete at the jobsite after it has been batched to ensure that the specified properties are attained before placement. The ready mix plant has a maximum capacity of 325,000 cubic yards per year. U.S. Highway 34 Facilities Page 4 of 14

5 1.2.3 Asphalt Recycling Similar to the asphalt plant, 90,000 tons/yr of recycled asphalt will be processed on site. Approximately 20 percent of the recycled asphalt will be fed to the warm mix asphalt plant. The emissions for the recycled asphalt facility are calculated separate from the asphalt plant emissions, as the recycle plant will not be run at the same frequency. 2.0 REVIEW OF EMISSION ESTIMATES The Clean Air Act requires the U.S. Environmental Protection Agency (EPA) to set National Ambient Air Quality Standards (NAAQS) for pollutants considered harmful to public health and the environment above certain limits. EPA has set NAAQS for six principal pollutants, which are called criteria pollutants: carbon monoxide, lead, nitrogen dioxide, ozone, particle pollution, and sulfur dioxide. The criteria pollutants of concern from the MMM Highway 34 Facilities are carbon monoxide, nitrogen dioxide, volatile organic compounds, particle pollution, and sulfur dioxide. Hazardous air pollutants (HAP), also known as toxic air pollutants or air toxics, are those pollutants that cause or may cause cancer or other serious health effects, such as reproductive effects or birth defects, or adverse environmental and ecological effects above certain limits. EPA is required to control 187 hazardous air pollutants. The sources of HAPs from the Highway 34 Facility is the asphalt plant and the recycled asphalt plant. Emissions from the Highway 34 Facility were estimated using in part using emission factors. The EPA document titled, AP-42, Compilation of Air Pollutant Emission Factors, is the primary compilation of EPA's emission factor information. It contains emission factors and process information for more than 200 air pollution source categories. A source category is a specific industry sector or group of similar emitting sources. The emission factors have been developed and compiled from source test data, material balance studies, and engineering estimates. 2.1 Asphalt Plant Emissions Emissions from asphalt plants are generally divided into ducted production emissions, pre-production fugitive dust emissions, and other production-related fugitive emissions. The asphalt plant is a parallel-flow drum mix plant fired on natural gas. The most significant ducted source of emissions from this type of plant is the rotary drum dryer. Emissions from the drum consist of water, PM, products of combustion; CO; and small amounts of organic compounds of various species (including VOC, CH4, and HAP). Pre-production fugitive dust sources associated with asphalt plants include vehicular traffic generating fugitive dust on paved and unpaved roads, aggregate material handling, and other aggregate processing operations. Production related fugitive emission sources include the transport and handling of the asphalt from the drum mixer to the storage silo and also from the load-out operations to the delivery trucks. Since the drum process is continuous, these plants have surge bins or storage silos. Table 1 summarizes the estimated criteria pollutant emissions from the asphalt plant as estimated using the appropriate emission factor from AP-42 and the plant maximum production rate of 450,000 tons/yr. An emission U.S. Highway 34 Facilities Page 5 of 14

6 factor for PM2.5 is not directly listed in AP-42, but AP-42 gives a PM2.5 fraction of 5.5% for the uncontrolled emissions. Table 1 - Estimated Criteria Pollutant Emissions from Asphalt Plant Criteria Pollutant Emissions from Drum Dryer (tpy) Emissions from Truck Load-out (tpy) Emission from Silo Filling (tpy) PM PM PM CO NOx SO VOC Total Emissions (tpy) Table 2 summarizes the estimated HAP emissions from the asphalt plant. Please note that HAP emissions are reported in pounds whereas the other pollutant emissions are listed in tons. The HAP emissions were calculated using the maximum production rate of 450,000 tons/yr and the appropriate AP-42 emission factors. Table 2 - Estimated HAP Emissions from Asphalt Plant HAP Emissions from Drum Dryer (lb/yr) Benzene 140 Ethylbenzene 86 Formaldehyde 1,116 Hexane 331 Toluene 54 Xylene Ready Mix Plant Emissions The primary pollutant of concern from ready mix plants is particulate matter, consisting primarily of cement and pozzolan dust but includes some aggregate and sand dust emissions. Emissions of select metals are associated with this particulate matter. All but one of the emission points are fugitive in nature. The only point sources are the transfer of cement and pozzolan material to silos, and these are usually vented to a fabric filter. Fugitive sources include the transfer of sand and aggregate, truck loading, mixer loading, vehicle traffic, and wind erosion from sand and aggregate storage piles. The amount of fugitive emissions generated during the transfer of sand and aggregate depends primarily on the surface moisture content of these materials. Table 3 summarizes the estimated emissions from the ready mix plant as estimated using the appropriate emission factors from AP-42 and the plant maximum production rate of 325,000 cubic yards per year. The emissions were calculated using the AP-42 emission factors for plant wide emissions for central mix concrete. U.S. Highway 34 Facilities Page 6 of 14

7 Table 3 - Estimated Criteria Pollutant Emissions from Ready Mix Plant Source Emission Type Controlled - AP-42 Emission Factor (lb/ton) Controlled - AP-42 Emissions (tpy) PM PM10 PM PM10 Aggregate transfer fugitive Sand transfer fugitive Cement unloading to silo point Cement supplement unloading to silo point Weigh hopper loading fugitive Mixer loading fugitive Fugitive (tpy) Point (tpy) Total (tpy) The values provided in Table 3 summarize the emissions generated from the ready mix operations; truck traffic is not accounted for. Wind erosion has not been factored in at this time. 2.3 Asphalt Recycling Emissions As previously discussed, emissions from asphalt plants are generally divided into ducted production emissions, preproduction fugitive dust emissions, and other production-related fugitive emissions. When the recycled material is processed, the emissions from the drum will also consist of water, organics, combustion byproducts, CO, and PM. The pre-production fugitive dust sources will include vehicular traffic and material handling. Other process fugitive emissions will result from transport and handling of the recycled material. Table 4 illustrates the anticipated emissions from the recycling of asphalt, when assuming that 20 percent of the 450,000 tons/year of recycled material will be re-processed through the warm mix asphalt plant. The same AP-42 emission factors were used to calculate these emissions. Table 4 - Estimated Criteria Pollutant Emissions from Asphalt Recycling Criteria Pollutant Emissions from Drum Dryer (tpy) Emissions from Truck Load-out (tpy) Emission from Silo Filling (tpy) PM PM PM CO NOx SO VOC Total Emissions (tpy) Table 5 lists the estimated HAP emissions from the recycled asphalt operations. These emissions were calculated assuming maximum throughput of 90,000 tons/year and the appropriate AP-42 emission factors. U.S. Highway 34 Facilities Page 7 of 14

8 Table 5 - Estimated HAP Emissions from Asphalt Recycling HAP Emissions from Drum Dryer (lb/yr) Benzene 35.1 Ethylbenzene 21.6 Formaldehyde Hexane 82.8 Toluene 13.5 Xylene Facility Wide Emissions The total estimated emissions from the Highway 34 Facility are summarized in Table 6 and Table 7. Table 6 - Estimated Criteria Pollutant Emissions from Highway 34 Facility Criteria Pollutant Asphalt Plant (tpy) Asphalt Recycling (tpy) Ready Mix Plant (tpy) Total Emissions (tpy) Total PM Total PM PM n/a 1.02 CO n/a NOx n/a 5.85 SO n/a 0.77 VOC n/a 7.20 Table 7 - Estimated HAP Emissions from Highway 34 Facility HAP Asphalt Plant (lb/yr) Asphalt Recycling (lb/yr) Total Emissions (lb/yr) Benzene Ethylbenzene Formaldehyde Hexane Toluene Xylene U.S. Highway 34 Facilities Page 8 of 14

9 3.0 DISPERSION MODELING AND RELATED HEALTH EFFECTS 3.1 Dispersion Model The EPA AERSCREEN model is the recommended screening model for air pollutant dispersion estimations. The model produces estimates of "worst-case" 1-hour concentrations for a single source and includes conversion factors to estimate "worst-case" 3-hour, 8-hour, 24-hour, and annual concentrations. Stewart conducted air quality dispersion modeling using the AERSCREEN model (Version 11126). The AERSCREEN model was run using a unit emission rate of 1.0 grams per second. This allowed the results were then adjusted to the actual emission rate by multiplying the AERSCREEN output by the emission rate in grams per second. This accounts for the relationship in the model that pollutant concentrations are linearly proportional to the emissions rate. The AERSCREEN output files will be provided upon request. 3.2 Modeling CO Dispersion from Asphalt Plant and Asphalt Recycling AERSCREEN was modeled by using a unit emission rate (1.0 grams per second). The modeling results were then adjusted to the actual CO emission rate by multiplying the AERSCREEN model output by the emission rate in grams per second. The CO emission rate was determined by multiplying the maximum capacity and the applicable emission factor. This methodology accounts for the known relationship in the model that concentrations are linearly proportional to the emissions rate. The AERSCREEN modeling result was then added to a background concentration, which accounts for ambient concentrations attributable any regional pollutant sources not explicitly included in the modeling. Ambient monitoring data collected over the period at a Greeley monitor ( th Avenue) was used to determine the background. The model results are compared to the NAAQS in Table 8. Impact Adjusted AERSCREEN Concentration from Asphalt Plant (ug/ m3 ) Table 8 AERSCREEN CO Estimates and NAAQS Values Adjusted AERSCREEN Concentration from Asphalt Recycling Background Concentration Total Concentration NAAQS 1-hour 1, ,941 5,016 40,000 8-hour 1, ,500 4,367 10,000 The dispersion modeling results shows that the predicted CO concentration using AERSCREEN complies with the NAAQS. There is ample conservatism in the modeling analysis such that there is high confidence that the NAAQS would not be exceeded. U.S. Highway 34 Facilities Page 9 of 14

10 3.3 Modeling HAP Dispersion from Asphalt Plant and Asphalt Recycling Stewart conducted an assessment of the public health impacts associated with the reported HAP emissions from the asphalt plant and asphalt recycling. The HAP modeling analysis was conducted using the modeling results from the AERSCREEN model. The results for each HAP of interest were determined using the unit emissions rate modeling by multiplying the AERSCREEN modeling results by the appropriate emissions data for the HAP pollutant of interest. Stewart s analysis reports emissions for the following HAPs: benzene, ethylbenzene, formaldehyde, hexane, toluene, and xylene. The HAP modeling was conducted for two receptors near the Highway 34 Facility where people are known to live and/or congregate. The locations are the Highway 34 Facility boundary and the nearest home within the Indianhead Estates neighborhood (south of U.S. 34 and west of Weld County Road 15). The HAP modeling analysis considered both acute (short-term) and chronic (long-term) health effects of the pollutants of interest for both locations. For the acute effects analysis, Stewart estimated the maximum 1-hour concentration of each HAP and for the chronic effects analysis Stewart estimated the maximum annual average concentrations for each HAP. The emission estimates at each location were compared to the EPA Safe Concentration Thresholds and Reference Exposure Levels (RELs) for the State of California s Office of Environmental Health Hazard Assessment (OEHHA). California has instituted the most stringent emission policies in the country, and the Highway 34 Facility complies with and is well below those levels. Table 9 shows that the estimated HAP emissions near the property boundary are within both the EPA Safe Concentration Thresholds and the OEHHA RELs. The combined asphalt plant and recycled asphalt plant emissions show acute and chronic impacts well below the safe concentration thresholds. When above the EPA acute and chronic threshold concentrations of 1300 ug/m 3 and 7.8 ug/m 3, respectively, benzene has been linked to damage of the hematologic and nervous system and has also been shown to hinder development. The maximum acute and chronic impacts of benzene near the property boundary were found to be 1.78 ug/m 3 and 0.18 ug/m 3 respectively. Therefore, the level of benzene emissions is not an issue from an environmental compliance standpoint. The maximum impact of ethlybenzene emissions were also found to be substantially lower than both the EPA safe concentration thresholds and the OEHHA RELs. These acute and chronic emissions were estimated at 1.10 and 0.11 ug/m 3, which are well below the EPA safe concentration thresholds of 140,000 and 2.5 ug/m 3. When above the REL, ethylbenzene has been linked to kidney, liver, endocrine system, and developmental issues. However, the modeled ethylbenzene emissions are more than 20 times below this permissible level. Therefore, the level of ethlybenzene emissions is not an issue from an environmental compliance standpoint. The calculated formaldehyde maximum acute and chronic impacts were found to be ug/m 3 and 1.41 ug/m 3. These values are significantly less than the EPA acute and chronic thresholds of 55 ug/m 3 and 13 ug/m 3. These values are also substantially less than the OEHHA RELs. Therefore, the level of formaldehyde emissions is not an issue from an environmental compliance standpoint. Acute and chronic maximum impacts of hexane were found to be 4.20 ug/m 3 and 0.42 ug/m 3. The chronic value is orders of magnitude less than the OEHHA REL of 7,000 ug/m 3. Therefore, the level of hexane emissions is not an issue from an environmental compliance standpoint. U.S. Highway 34 Facilities Page 10 of 14

11 The maximum acute and chronic impacts of toluene were calculated to be 0.68 ug/m 3 and 0.07 ug/m 3. The EPA safe acute and chronic safe concentrations are set at 37,000 ug/m 3 and 5000 ug/m 3. The impacts calculated are much lower than the OEHHA RELs of 37,000 ug/m 3 and 300 ug/m 3. Therefore, the level of toluene emissions is not an issue from an environmental compliance standpoint. The model estimated acute and chronic xylene maximum impacts of 0.91 ug/m 3 and 0.09 ug/m 3. OEHHA set acute and chronic RELs at 22,000 ug/m 3 and 700 ug/m 3. The predicted impacts are well below both exposure limits. Therefore, the level of xylene emissions is not an issue from an environmental compliance standpoint. Table 9: Impacts at Facility Property Boundary Pollutant Calculated Max 1-hr Impact (Highway 34 Site) Acute Impacts EPA Safe Concentration Threshold California OEHHA REL Calculated Max Annual Impact (Highway 34 Site) Chronic Impacts EPA Safe Concentration Threshold California OEHHA REL Benzene Ethylbenzene Formaldehyde Hexane Toluene Xylene Table 10 shows that the estimated HAP emissions at the nearest residence in Indianhead Estates are within both the EPA Safe Concentration Thresholds and the OEHHA RELs. The maximum acute and chronic impacts of benzene near Indianhead Estates were found to be 1.40 ug/m 3 and 0.14 ug/m 3 respectively. Therefore, the level of benzene emissions is not an issue from an environmental compliance standpoint. These acute and chronic emissions of ethylbenzene were estimated at 0.86 and 0.09 ug/m 3, which are well below the EPA safe concentration thresholds of 140,000 and 2.5 ug/m 3. Therefore, the level of ethylbenzene emissions is not an issue from an environmental compliance standpoint. The calculated formaldehyde maximum acute and chronic impacts were found to be ug/m 3 and 1.11 ug/m 3. These values are significantly less than the EPA acute and chronic thresholds of 55 ug/m 3 and 13 ug/m 3. These values are also substantially less than the OEHHA RELs. Therefore, the level of formaldehyde emissions is not an issue from an environmental compliance standpoint. Acute and chronic maximum impacts of hexane were found to be 3.30 ug/m 3 and 0.33 ug/m 3. The chronic value is orders of magnitude less than the OEHHA REL of 7,000 ug/m 3. Therefore, the level of hexane emissions is not an issue from an environmental compliance standpoint. U.S. Highway 34 Facilities Page 11 of 14

12 The maximum acute and chronic impacts of toluene were calculated to be 0.54 ug/m 3 and 0.05 ug/m 3. The EPA safe acute and chronic safe concentrations are set at 37,000 ug/m 3 and 5,000 ug/m 3. The impacts calculated are much lower than the OEHHA RELs of 37,000 ug/m 3 and 300 ug/m 3. Therefore, the level of toluene emissions is not an issue from an environmental compliance standpoint. The estimated acute and chronic xylene maximum impacts are 0.72 ug/m 3 and 0.07 ug/m 3. OEHHA set acute and chronic RELs at 22,000 ug/m 3 and 700 ug/m 3. The estimated impacts are well below both exposure limits. Therefore, the level of xylene emissions is not an issue from an environmental compliance standpoint. Table 10: Impacts at Nearest Residence in Indianhead Estates Pollutant Calculated Max 1-hr Impact (Highway 34 Site) Acute Impacts EPA Safe Concentration Threshold California OEHHA REL Calculated Max Annual Impact (Highway 34 Site) Chronic Impacts EPA Safe Concentration Threshold Benzene ,300 1, Ethylbenzene , ,000 Formaldehyde Hexane ,000 Toluene ,000 37, Xylene ,000 22, California OEHHA REL Table 9 and Table 10 show that the HAP concentrations at the property boundary and at the nearest residence in Indianhead Estates are within both the EPA Safe Concentration Threshold and RELs for the State of California s OEHHA. 4.0 SUMMARY & CONCLUSIONS MMM is planning the operation of a hot mix asphalt plant, a concrete ready mix plant and asphalt recycling in Weld County, Colorado to the southeast of the intersection of US Highway 34 and Weld County Road 13. The asphalt plant has a maximum production rate of 450,000 tpy, the ready mix plant has a maximum production rate of 325,000 yd 3 /yr, and approximately 90,000 tpy of asphalt will be recycled. The facility wide emissions from the Highway 34 Facility are presented in Table 6 and Table 7 of this report. Stewart conducted an assessment of the public health impacts associated with the reported HAP emissions from the asphalt plant and asphalt recycling. The HAP modeling analysis was conducted using the modeling results from the AERSCREEN model. Stewart s analysis reports emissions for the following HAPs: benzene, ethylbenzene, formaldehyde, hexane, toluene, and xylene. The HAP modeling was conducted for two receptors near the Highway 34 Facility where people are known to live and/or congregate. The locations are the Highway 34 Facility boundary and the nearest home within the Indianhead Estates neighborhood (south of U.S. Highway 34 and west of Weld County Road 15). The HAP modeling analysis prepared by Stewart considered both acute (short-term) and chronic (long-term) health effects of the pollutant of interest. For the acute effects analysis, Stewart estimated the maximum 1-hour U.S. Highway 34 Facilities Page 12 of 14

13 concentration of each HAP and for the chronic effects analysis Stewart estimated the maximum annual average concentrations for each HAP. As shown in Table 10 the HAP emissions included benzene, ethylbenzene, formaldehyde, hexane, toluene, and xylenes. The HAP values are well below both the EPA Safe Concentration Threshold and Reference Exposure Levels (RELs) for the State of California s Office of Environmental Health Hazard Assessment (OEHHA). California has instituted the most stringent emission policies in the country, and the Highway 34 Facility complies with those levels. Our conclusion is that this facility will not negatively impact the surrounding environment or affect human health as it will meet all environmental standards. U.S. Highway 34 Facilities Page 13 of 14

14 Figure 1 Site Location U.S. Highway 34 Facilities Page 14 of 14

15 miles km 1 1