NABEL. National Air Pollution Monitoring Network. The network Monitoring stations Principal results

Transcription

1 NABEL National Air Pollution Monitoring Network The network Monitoring stations Principal results

2 Contents 3 Introduction 4 NABEL measures air pollution 6 Organisation of the data acquisition network, measurement programme 7 Location of NABEL monitoring stations 8 Types of NABEL site 1 Operation of the data acquisition network 12 NABEL results 18 Application of the results 2 Air quality in Switzerland at a glance 21 The aim: clean and healthy air 22 Further information

3 Introduction The air is invisible, and mostly we don t notice it. And it seems that air always stays the same, but is this really so? We may recall the pleasant smell of resin from summer walks through the woods, but equally the stench of diesel fumes in the city! Like our noses, the NABEL measuring instruments are extremely sensitive to air pollution, and using them, we can detect pollutant concentrations of only a few micrograms per cubic meter of air. But whereas our noses can detect only a few pollutants, modern measuring instruments are sensitive to a wide range of substances. It may seem surprising that we take the trouble to measure these pollutants at all, but the problem is that certain atmospheric pollutants are toxic even at very low concentrations. Their effects range from inflammation of the mucous membranes and the eyes, and increased susceptibility to diseases of the respiratory tract, to cardiovascular diseases and death. Also, plants and buildings are affected by air pollutants reason enough to strive towards cleaner air. By means of intensive research, a large body of knowledge has been built up on air pollutants. Using this, so-called 'ambient air quality standards' have been set for numerous air pollutants. By comparing the NABEL data with these standards, the quality of the air can be assessed. The data acquisition network therefore serves to measure and evaluate air quality, indicate trends, and point to any possible need for action. It also enables the effectiveness of measures to be assessed at national and international levels. In addition, the data are used in numerous scientific programmes. As head of the data acquisition network, I should like here to express my warm appreciation to the entire NABEL team for its excellent work, and for the high quality with which data measurement and assessment are performed. Of course the data acquisition network does not of itself guarantee clean air. However, the measurement and assessment of air quality, coupled with the dissemination of the resulting information to the authorities and to the public, are important steps in this direction. Urs Nyffeler Head of Basic Studies Section Air Pollution Control Division, SAEFL The NABEL team comprising members from SAEFL and EMPA NABEL 3

4 What are the causes of air pollution? The emission of air pollutants has risen sharply since the beginning of the 195s as a result of rapid industrial growth and the heavy increase in road traffic. Natural sources of air pollution such as volcanic eruptions, forest fires and erosion have never caused such severe air pollution as human activity has. Today, the air we breathe is more or less heavily polluted depending on the area, and can affect not only our health but also the environment. NABEL measures air pollution Three processes are responsible for the presence of air pollutants: emission (pollutant release at source) transmission (spreading and in some cases transformation of pollutants in the air) impact (concentration of the pollutant at the point of exposure, or deposition) emission impact transmission emission impact In air pollution control, emissions are defined as those processes in which substances not previously present, or present only at low concentrations, are released to the atmosphere. Human activities such as running cars and using heating appliances, as well as industrial and agricultural activities, lead to the emission of sulphur dioxide (SO 2 ), nitrogen oxides (NO x ), carbon monoxide (CO), volatile organic compounds (VOC), dust and heavy metals (e.g. lead and cadmium). In addition to emissions from human activities (anthropogenic emissions), emissions also arise from natural sources. Natural emissions of SO 2, NO x and CO make up less than 2 per cent of total emissions of those substances in Switzerland. For VOC, natural emissions comprise about 25 per cent of total emissions. Anthropogenic emissions thus exceed natural emissions in Switzerland by a wide margin. 4 NABEL

5 What are the effects of air pollution? Our knowledge about the effects of air pollution on human health has increased considerably in recent years. It is now known that air pollution may affect human health, not only in extreme situations (e.g. with smog), but also in normal daily life. Air pollutants come into contact with the body mainly via the respiratory tract, so that this tends to be the most frequently affected part of the body. Ozone, nitrogen dioxide and sulphur dioxide, as well as fine particulates and smoke, lead to inflammation of the mucous membranes. This causes reddening of the eyes, inflammation of the pharynx and throat, reduced lung function, and reduced resistance to disease, which in their turn lead to respiratory infections. Existing illnesses can worsen, resulting in an increase in emergency consultations and hospital admissions for respiratory problems, and to premature deaths. Not only the respiratory tract, but other organs, too, are affected by air pollution. Thus volatile hydrocarbons and carbon monoxide are transported to the brain and heart via the blood. Symptoms such as headaches, giddiness, nausea and pounding of the heart are the first indications of excessive exposure. Lead and cadmium enter the blood partly via the lungs and are deposited in the bones, teeth, liver and kidneys. Even at low concentrations, lead causes developmental retardation in children. What is NABEL's aim? In Switzerland, the concentration of pollutants in the ambient air has been measured systematically since the mid-196s, the emphasis at that time being on sulphur dioxide and dust. From 1968 onwards, Switzerland participated in international measurement programmes with two of its monitoring stations. The outcome of this was the National Air Pollution Monitoring Network (NABEL), which was established in The Ordinance on Air Pollution Control (OAPC) of 16 December 1985 obliges the authorities to measure air pollution. The Swiss Agency for the Environment, Forests and Landscape (SAEFL) is responsible for this task at national level, and uses NABEL to obtain high quality data. NABEL also represents an important control instrument for the enforcement of the OAPC, since the long-term measurement series provided by it showing whether the measures taken to reduce air pollution are meeting with success, and whether air pollution has declined. Damage to buildings and monuments caused by acids (formed from NO 2 and SO 2 ) transported in gaseous form by the rain, or attached to dust particles. How is air pollution assessed? Air pollution contributes significantly to the weakening and destabilisation of forest ecosystems, damages agricultural crops and reduces their yield. Air pollution is assessed with the ambient air quality standards laid down in the Ordinance on Air Pollution Control (OAPC). In general, pollutant concentrations below the prescribed levels have no detrimental effects on human health or the environment. However, people sensitive to ozone may experience inflammation of the eyes and the respiratory tract if the level is only slightly exceeded. The higher the concentration, the greater the number of persons affected, and the more serious the complaints and functional disorders become. In the NABEL programme, air pollutants of national relevance are measured. The pollutants in question are emitted in considerable quantities from various sources throughout the country. In addition to the NABEL monitoring stations, another 1 stations that measure several air pollutants continuously are operated by the cantons and cities. NABEL 5

6 Organisation of the data acquisition network The NABEL data acquisition network comprises the data centre together with 16 monitoring stations distributed over the whole country. The monitoring stations are operated by the Swiss Federal Laboratories for Materials Testing and Research (EMPA) in Dübendorf under the supervision of the Swiss Agency for the Environment, Forests and Landscape (SAEFL). EMPA is responsible for the operation and maintenance of the monitoring stations, for quality assurance and data control. The data centre and database are located at SAEFL in Ittigen. SAEFL is responsible for the operation of the centre and network design, and also for data management, assessment and publication. In normal operation, the centre automatically retrieves data from the monitoring stations every six hours via modem and telephone line, and stores these in the database. The data are then evaluated at the centre and the results published at regular intervals (see pages 18 and 19). Measured data SAEFL: data centre Data eva u l ation NABEL monitoring stations Operation and maintenance Data validation database Data publication: reports, teletext, Internet,...; data provision Assessment of air quality EMPA: Operating of monitoring stations, quality control Measurement Programme Gaseous pollutants Suspended particulates and dust fallout Volatile organic compounds (VOC) Ozone (O 3 ), nitric oxide (NO), nitrogen dioxide (NO 2 ), oxides of nitrogen (NO x ), sulphur dioxide (SO 2 ), carbon monoxide (CO) Respirable particulate matter (PM1), dust fallout (total), heavy metals in PM1 (lead and cadmium) and in dust fallout (lead, cadmium, thallium and zinc), sulphur in particulate matter and nitrogen aerosols Total VOC, non-methane VOC, methane, specific VOC components Wet deposition Meteorological data Traffic counters ph, conductivity, sulphate, nitrate, chloride, ammonium, sodium, potassium, magnesium and calcium Wind direction and speed, peak wind speeds, temperature, air humidity, global radiation, net radiation, precipitation, air pressure Number of vehicles 6 NABEL

7 Location of NABEL monitoring stations Basel Lägeren Zürich Härkingen Tänikon Dübendorf Chaumont Rigi Bern Payerne Davos Lausanne Jungfraujoch Sion Magadino Lugano Reproduced with the permission of the Federal Office of Topography (BA2574) GIS cartography: SAEFL, Research and Environmental Observation Section In Switzerland, there are large differences in the spatial distribution of pollutants depending primarily on the type of site and the emission sources present. The monitoring stations are therefore classified according to the type of site. The NABEL sites at which air pollution is measured are representative of all levels of pollution, i.e. from very low to very high. Pollution at different types of site Pollutant Urban, near a main road Urban, in a park Suburban Rural, near a motorway Rural, below 1 m altitude Rural, above 1 m altitude High-altitude NO 2 SO 2 CO O 3 PM1 Legend: Ambient air quality standards frequently/greatly exceeded Ambient air quality standards sometimes exceeded Ambient air quality standards almost always complied with NABEL 7

8 Types of NABEL site Urban, near a main road NO 2 SO 2 CO O 3 PM1 Bern, Bollwerk Lausanne, Bibliothèque Pour Tous area Urban, in a park NO 2 SO 2 CO O 3 PM1 Lugano, Ospedale Civico Park Zurich, Zeughaushof Barracks Suburban NO 2 SO 2 CO O 3 PM1 Basel Binningen, park in Astronomical Institute precinct of the University of Basel Dübendorf, EMPA area Rural, near a motorway NO 2 SO 2 CO O 3 PM1 Härkingen, agricultural area Sion airfield, within airfield perimeter 8 NABEL

9 Rural, below 1 m altitude NO 2 SO 2 CO O 3 PM1 Lägeren, wooded site Magadino, Agricultural Research Institute precinct in Cadenazzo Payerne, Station Aérologique, SMA MeteoSchweiz Tänikon, Agricultural Research Institute Rural, above 1 m altitude NO 2 SO 2 CO O 3 PM1 Chaumont, 114 m altitude, extensively cultivated agricultural area in upland Jura Davos, 164 m altitude, Alpine wooded site south-east of Lake Davos Rigi, Seebodenalp, 13 m altitude, extensively cultivated agricultural area on north-facing incline High-altitude NO 2 SO 2 CO O 3 PM1 Jungfraujoch, 358 m altitude, Alpine With its extremely low level of air pollution, the Jungfraujoch monitoring station takes on special significance in within NABEL network. In combination with two other mountain stations, namely the Zugspitze in Germany and the Hohenpeissenberg in Austria, it serves as 'background' station for the lower free troposphere in the central European region. The Jungfraujoch station has been an integral part of international measurement programmes for many years now. NABEL 9

10 Operation of the data acquisition network EMPA in Dübendorf is responsible for the operation of NABEL. The longterm acquisition of very large quantities of data confronts the network with challenging problems. The challenge is made even more demanding by the fact that highly consistent, continuous and uninterrupted data that comply with international standards are required. Careful attention must be paid to selecting the right measurement procedures, regular instrument tests, maintenance and calibration of the monitoring stations. The data must be validated, their international comparability assured, and finally the documentation prepared. Measurement procedures Air pollutants Sulphur dioxide (SO 2 ) Nitrogen oxides (NO / NO 2 ) Ozone (O 3 ) Carbon monoxide (CO) Non-methane VOC Suspended particulates Metals in suspended particulates (lead, cadmium) Sulphur in suspended particulates Dust fallout Metals in dust fallout (lead, cadmium, thallium and zinc) Wet deposition Nitrogen aerosols Sampling time 1 2 hour / day 1) 1 2 hour 1 2 hour 1 2 hour 1 2 hour day year day month year day day Measurement method UV fluorescence/absorption in H 2 O 2, sulphate determination by ion chromatography Chemiluminescence UV absorption Infrared absorption FID and ECD detectors Gravimetric determination Plasma mass spectrometry X-ray fluorescence Dust fallout using the Bergerhoff method Plasma mass spectrometry Ion chromatography Ion chromatography 1) Jungfraujoch Data control Data from the automatic measuring instruments are subjected to an initial daily plausibility check. If necessary, these are corrected using manual calibration. The data are then checked thoroughly according to the following criteria: Plausibility range Do the measured values lie within the station s maximum and minimum values? Time distribution Do the daily, weekly and yearly time distributions accord with what would be expected? Variability Is the variability (difference between successive values) realistic? Dependent measurements Is the time variation of the concentration of dependent substances (chemical reaction, same sources) consistent? Comparable sites Do sites behave similarly under comparable conditions (same pollution type, same weather conditions)? Completeness Do the data fit the measurement series before and after an interruption (due, for example, to initialisation of equipment)? 1 NABEL

11 To satisfy the high demands placed on long time-period air pollution measurements to determine non-compliance with air quality standards, and for trend analyses, comprehensive quality control is required in the areas: Maintenance The monitoring stations are serviced every two weeks based on a service sheet that lists the work required and the service intervals. All work carried out is documented. Calibration For continuous measurements, an automatic check is triggered every 25 hours, and the measuring instruments are calibrated manually on a 14-day cycle. Regular instrument tests All measuring instruments are subjected to tests prior to initial use, and thereafter at regular intervals. In the tests, reference values such as the calibration function (linearity), drift (stability), signal noise, setting time, detection limit, limit of determination, repeatability and selectivity (sensitivity to other substances) are recorded. Compliance with standards (traceability) To ensure national and international comparability, all measurements must comply with the standards (so-called traceability). NABEL uses a NIST (National Institute of Standards and Technology, USA) standard reference photometer as the measurement standard for ozone, and NIST reference gases as measurement standards for SO 2, NO and CO. Interlaboratory tests Interlaboratory tests are used to compare the results of different data acquisition network operators. NABEL regularly participates in national and international interlaboratory tests. Parallel measurements in the field On changing measurement methods or instrument types, controls are tightened by making supplementary parallel measurements in the field. Quality assurance Laboratory NABEL primary measurement standards for NO, SO 2, O 3, and CO Calibration Calibration rack (measuring instruments) Transfer measurement standard Monitoring station Comparison Transfer measurement standard manual calibration every 14 days automatic check of zero and span every 25 hours Measuring instruments Checking of measuring instruments against NABEL standards Calibration laboratory: Comparison of the measurement standards with the primary standards and performance of instrument tests NABEL 11

12 NABEL results The evaluation of NABEL data is carried out at the data centre at SAEFL, where the data are analysed and interpreted. The results are made available at regular intervals to professional bodies, the media and the public in the form of written and electronic publications. NABEL data are also provided to further interested parties such as research institutes and international organisations. Studies based on NABEL data provide an important foundation for the assessment of air pollution by comparison with ambient air quality standards, performance assessment, and the further development of air pollution control policy in Switzerland. A few statistics Based on the data obtained, statistical data in the form of average and percentile values are calculated. While the hourly and daily average values are characteristic of short-term pollution, the annual average values represent the long-term levels. Percentile values characterise the frequency distribution of the measured values. Thus for example the 98 percentile value (the value below which 98 per cent of the values lie) of the half-hourly values is a measure of the short-term peak level of pollution. Workplace at the NABEL data centre How are pollutant concentrations specified? The following units are used: mg/m 3 milligram per cubic meter, 1 mg = 1/1 gram µg/m 3 microgram per cubic meter, 1 µg = 1/1 gram ppm parts per million (by volume) ppb parts per billion (by volume) 12 NABEL

13 Nitrogen dioxide: annual average values 1999 [µg/m 3 ] Bern Lausanne Zürich Lugano Basel Nitrogen dioxide: annual average values [µg/m 3 ] 8 Ambient air quality standard 3 Dübendorf Härkingen Sion Urban, road Suburban Alpine foothills, Jura Payerne Tänikon Ambient air quality standard Magadino Lägeren Chaumont Urban, park Rural Alps Rigi Davos Jungfraujoch Nitrogen oxides Nitrogen oxides (NO x ), especially nitric oxide (NO) and nitrogen dioxide (NO 2 ), are produced in all combustion processes. Motor traffic is the principal emitter of nitrogen oxides. Therefore it is not surprising that exposure to nitrogen dioxide still exceeds the limit for the annual average (3 µg/m 3 ), particularly in the large cities and along main roads. The situation in suburban areas is somewhat better, while NO 2 levels are well under the limit in the countryside at a distance from the roads. Pollution from nitrogen oxides has declined in recent years, and this can mainly be attributed to technical measures, especially to catalytic converters. From the end of the 198s till about 1994, ambient concentrations of NO 2 declined, but since then, the decrease has been very slight Volatile organic compounds (VOC) Non-methane VOC: levels over the period [mg/m 3 ],25 The group of substances known as VOC (volatile organic compounds) comprises a variety of volatile substances. Some of these are themselves hazardous (e.g. benzene, which is carcinogenic), and most are precursor substances in the formation of ozone. VOC are measured at selected NABEL stations both as individual substances and as total non-methane VOC.,2,15,1,5 Dübendorf Zürich, NABEL 13

14 Ozone At ground level, the short-term peak values for ozone are very significant from the point of view of health. For this reason, the ambient air quality standards in the Ordinance on Air Pollution Control are specified not in terms of the annual average but of the maximum hourly average over the year, and of the 98 percentile value over one month. Both of these limits are considerably exceeded every year at all stations Number of hours at which the 1h ambient air quality standard of 12 µg/m 3 is exceeded South of the Alps Alpine foothills, Jura Rural Suburban Urban, park Alps Ozone is formed in complex photochemical reactions from the precursor substances, NO x and VOC, whereby solar radiation and the transport of pollutants from the city to the countryside play an important role. High ozone concentrations occur mainly during fine summer weather and like the weather vary considerably from one year to another. As a result of the more intensive solar radiation in the Canton of Ticino and its proximity to the conurbation of greater Milan, the ozone values are considerably higher there than to the north of the Alps. At high-altitude Alpine sites, the ozone values are much lower. Short-term peak ozone pollution: 98 percentile values of the month with the highest ozone concentration, 1999 [µg/m 3 ] Ambient air quality standard 5 Zürich Lugano Basel Dübendorf Magadino Payerne Tänikon Lägeren Chaumont Rigi Davos Jungfraujoch Over the last decade, ozone pollution has declined less markedly than its precursor substances. Especially the peak values have declined. To reduce the overall ambient concentrations of ozone to the values required by current pollution control regulations, today s NO x and VOC emissions need to be halved again. 14 NABEL

15 Suspended particulates Prior to 1997, NABEL measured suspended particulates in the form of total suspended particulates (TSP), but since 1997, respirable particulate matter (PM1) has been measured. Since 1998, the ambient air quality standards in the Ordinance on Air Pollution Control have also been based on PM1. In recent years, levels of suspended particulates have declined. However, the measured PM1 values for 1999 exceed the air quality standards almost everywhere. Especially at locations affected by traffic, and also in urban and suburban areas, the annual average air quality standard for PM1 is still significantly exceeded. In the countryside, the values lie in the region of the limit, but strict compliance is only achieved above 1 m altitude Suspended particulates (TSP until 1996, PM1 from 1997) for the period [µg/m 3 ] Urban, road Urban, park Suburban Rural Alpine foothills, Jura Ambient air quality standard Respirable fine particulates (PM1): annual average values 1999 [µg/m 3 ] Ambient air quality standard Bern Zürich Lugano Basel Dübendorf Magadino Härkingen Sion Payerne Tänikon Chaumont Rigi Peak values for fine particle pollution occurring during winter temperature inversions with fog and light winds are shown in the figure below (Dübendorf monitoring station, 1998). The daily average air quality standard for PM1 (5 µg/m 3 ) is frequently exceeded. 15 Respirable fine particulates (PM1): daily average values 1998 [µg/m 3 ] 1 5 Ambient air quality standard Jan Feb Mar Mär Apr Mai May Jun Jul Aug Sept Okt Oct Nov Dez Dec Pocket guide to suspended particulates TSP: total suspended particulates PM1 (particulate matter <1 µm): respirable fine particulate matter, i.e. dust particles with an aerodynamic diameter less than 1 µm (1 µm = 1/1 millimetre) NABEL 15

16 Sulphur dioxide Contrary to the problem air pollutants oxides of nitrogen, respirable particulate matter and ozone, for which the ambient air quality standards continue to be exceeded, the levels of other pollutants are now well within the standards. Examples of these are sulphur dioxide, carbon monoxide and heavy metals (particularly lead and cadmium in suspended particulates and dust fallout) Sulphur dioxide: levels for the period [µg/m 3 ] Ambient air quality standard Urban Suburban Rural Alpine foothills, Jura Alps In the 197s and 198s, sulphur dioxide was still a problem pollutant. As a result of the measures taken, and especially the change to natural gas and low-sulphur heating oil, sulphur dioxide pollution levels declined to a quarter of their values at the beginning of the 198s, and today, they lie significantly below the standard levels Lead in suspended particulates [ng/m 3 ] Lead in dust fallout [µg/(m 2 day)] Heavy metals ,5 1,25 1,,75,5,25 Cadmium in suspended particulates [ng/m 3 ] Cadmium in dust fallout [µg/(m 2 day)] 2, 1,5 1,,5 Legend: Urban, road Urban, park Suburban Land Alpine foothills, Jura Alps Ambient air quality standard, Among the principal atmospheric pollutants, the levels of lead have declined most markedly. The reduction is attributable particularly to the introduction of unleaded petrol. Cadmium levels have declined significantly owing to reduced emissions. 16 NABEL

17 NABEL also records the weather Ozone concentration [µg/m 3 ] Ozone concentration Solar radiation Ozone formation in comparison to solar radiation (6 summer days in July 1999, Basel NABEL monitoring station): during periods of fine weather, increasing quantities of ozone are formed during the day. Decomposition of ozone takes place at night and during bad weather : 12: : 12: : 12: : 12: : 12: 3.7. : 12: : In addition to the atmospheric pollutants, all NABEL stations also measure the principal meteorological data (wind, temperature, air humidity, solar radiation, precipitation and air pressure). Meteorological data are important for an understanding of atmospheric pollution. Thus the formation of ozone is strongly dependent on solar radiation, rainfall causes pollutants to be washed out from the atmosphere, the wind determines where pollutants are borne, and temperature inversions can lead to high pollutant concentrations. Rain-borne pollutants 1,2 1,,8,6,4 Dübendorf Payerne,3,2 Dübendorf Payerne,2, Solar radiation [W/m 2 ] Sulphate in rainwater: annual average values [mg S/I] Nitrate in rainwater: annual average values for [mg N/I],6,5,4 At several of the NABEL stations, wet deposition is analysed (acids, sulphates, nitrates, etc.). This is important to determine the input of pollutants to the soil. NABEL measurements show that the levels of acids and nitrogen compounds have decreased. The quantities nevertheless remain too high for sensitive ecosystems. NABEL 17

18 Application of the results Reports NABEL annual report NABEL monthly report Report on ambient concentrations Report on the air pollution control measures of the Confederation and the cantons Annual publication of results, from the NABEL data acquisition network with evaluations and assessments Monthly publication of results and evaluations from the NABEL data acquisition network Annual publication of results from NABEL, and from cantonal and municipal data acquisition networks Report of the Federal Council to the Swiss parliament Electronic publications Teletext Daily update of air pollution data on ozone, nitrogen dioxide and sulphur dioxide, and comparison with ambient air quality standards Internet Daily update of air pollution data on ozone, nitrogen dioxide and sulphur dioxide; long-term measurement series are available Cf. further information p NABEL

19 Data provision for scientific purposes (selection) Calculation and Mapping of Critical Thresholds in Europe, CCE Status Report 1997 Jungfraujoch: University studies Pollumet SAPALDIA Investigations on critical levels of pollution and deposition of air pollutants to sensitive ecosystems (forest soils, Alpine lakes, etc.) Investigations in the lower free troposphere on the photochemistry of ozone and exchange processes Air pollution and meteorology in Switzerland Swiss study on air pollution and lung diseases in adults SCARPOL Swiss surveillance program of childhood allergy and respiratory symptoms with respect to air pollution and climate Data provision (example): Euroairnet Annual provision of NABEL data to the European Environment Agency (EEA) database Exceedance of EC Ozone Threshold Values in Europe in 1998 Request for data Annual report of the European Environment Agency (EEA) on ozone pollution in Europe Approximately 1 requests are received per year for permission to use NABEL data NABEL 19

20 Air quality in Switzerland at a glance How have pollutant levels changed in recent years? % -1% -2% -3% -4% Sulphur dioxide nitrogen dioxide nitric oxide non-methane VOC PM1 suspended particulates lead in PM1 cadmium in PM1 dust fallout lead in dust fallout cadmium in dust fallout zinc in dust fallout chloride in rainwater nitrate in rainwater sulphate in rainwater ammonium in rainwater conductivity of rainwater carbon monoxide ozone Changes in pollutant levels between 1988 and 1999 (trends in annual average values; trends in maximum hourly values for ozone). The decline is most marked for sulphur dioxide and lead. -5% -6% -7% -8% -9% Are the ambient air quality standards met? Pollutant levels in 1999 compared to the ambient air quality standards given in the Ordinance on Air Pollution Control. The following values are given in black: the values for the individual stations (annual and maximum daily average values for carbon monoxide, and maximum hourly values for ozone), for all NABEL stations except the Alpine stations in Davos and at Jungfraujoch. This figure clearly shows the three problem pollutants nitrogen dioxide, ozone and PM1, for which the ambient air quality standards are exceeded at numerous stations. 25% 2% 15% 1% 5% % sulphur dioxide nitrogen dioxide PM1 suspended particulates lead in PM1 cadmium in PM1 dust fallout lead in dust fallout cadmium in dust fallout zinc in dust fallout carbon monoxide ozone 2 NABEL

21 The aim: clean and healthy air Thanks to the 16 monitoring stations spread over the whole of Switzerland, the NABEL data acquisition network affords a good overall view of air quality at different types of site. It is complemented by cantonal and municipal measurement stations. Taken as a whole, Switzerland disposes of a very dense network of measuring sites. Using the extended NABEL data acquisition network, which has been in operation for nine years (the 'oldest' stations have now been providing data for over 2 years), trends can be observed and the success of air pollution measures can be confirmed. The NABEL network supplies a whole range of chemical and meteorological data, and some stations provide other parameters such as traffic density as well. The measurement of pollutant concentrations at the exceedingly low levels present in the air is a demanding task. To ensure the reliability of the results, NABEL pays special attention to quality assurance. By comparing the results with air quality criteria (ambient air quality standards), existing problems may be pinpointed. This enables the need for action to be assessed and air pollution measures to be justified. The NABEL network is thus an important tool for air pollution control policy. With its help, the success of air pollution measures in Switzerland and neighbouring countries may be judged. The successes already achieved may be looked upon with some satisfaction, and this acts as a spur to solving the problems that remain. The quality of NABEL data is acknowledged worldwide. The data are distributed to the many interested parties using modern communication technologies such as Teletext and the Internet. In all our endeavours, we try to keep the central objective in mind to promote cleaner and healthier air for our own benefit and that of the environment. NABEL 21

22 Further information Swiss Agency for the Environment, Forests and Landscape Air Pollution Control Division CH-33 Bern, Switzerland Contact person: Dr. Paul Filliger Tel Fax paul.filliger@buwal.admin.ch Internet Teletext NABEL publications Publications on air pollution control in Switzerland Multimedia Home page of the Air Pollution Control Division at SAEFL. Up-to-date measurements, information about the data acquisition network under the keywords: Aktuell (latest) and Immissionen (ambient concentrations). NABEL pages at EMPA Home page of the Cercl Air and the Swiss air pollution agencies of the Confederation, the cantons and the towns. Pages 656/657 on SF DRS1 and pages 74/75 on SF DRS2: latest data. NABEL annual report: results of the National Air Pollution Monitoring Network. Published by SAEFL. Available in French and German (published annually). NABEL monthly report: measured data of the National Air Pollution Monitoring Network. Published by SAEFL. Available in French and German (published monthly). Technical report on the National Air Pollution Monitoring Network: 2, 164pp. Published by EMPA. Contact person: Dr. Brigitte Buchmann, Tel , brigitte.buchmann@empa.ch LuftPost: air pollution control in Switzerland. Popular brochure of the Cercl Air and the air pollution agencies of the Confederation, the cantons and the towns. 1996, 48 pp. Available in French, German and Italian. Obtainable from: cantonal agencies for air pollution control and SAEFL. Summer smog: the periodical for clean air. 1999, 32 pp. Published by SAEFL. Available in French, German and Italian. Air Pollution and Health: popular brochure of Doctors for Environmental Protection, Basel 1997, 84 pp. Obtainable from: AefU secretariat, PO Box 41, 413 Basel. The Environment in Switzerland 1997: facts, figures, perspectives. Environmental report of SAEFL and the Swiss Federal Statistical Office, Bern, 1997, 376 pp. Available in English, French, German and Italian. Obtainable from: EDMZ, 33 Bern. Ambient concentrations of air pollutants 1999: data from continuously operated fixed monitoring stations for air pollutants, prepared by the Swiss Association of Air Pollution Control Experts (Cercl Air) and SAEFL (electronic publication: keywords "Immissionen" and "Immissionsmesswerte Schweiz"). Published annually. Report on the air pollution control measures of the Confederation and the cantons: report of the Federal Council to the Swiss parliament, 23 June Obtainable from: EDMZ, 33 Bern. A!R: Multimedia CD on air and air pollution Obtainable from SAEFL. 22 NABEL

23 Published by: Swiss Agency for the Environment, Forests and Landscape (SAEFL) CH-33 Bern Switzerland Design, contents and editing: ARIAS Haudenschild and Bürgi, Luftreinhaltung und Umweltberatung, Bern, SAEFL, Air Pollution Control Division EMPA, Air Pollution / Environmental Technology Department Supervision SAEFL: Paul Filliger, Urs Nyffeler, Norbert Ledergerber Layout and production: Giger & Partner, Zurich Translated by: en-solar, Heimenschwand Key to illustrations: p. 2/3: EMPA; p. 4: PhotoDisc; p. 5: l. AFU St.Gallen, r. PhotoDisc; p. 8/9/11: EMPA; p. 12: Documenta Natura, Bern; p. 21: Incolor. Obtainable from: Swiss Agency for the Environment, Forests and Landscape, Documentation CH-33 Bern Switzerland Fax docu@buwal.admin.ch (or/f) Order number: DIV-511-E SAEFL 21 NABEL 23

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