Intergewestelijke Cel voor het Leefmilieu (IRCEL) Cellule Interrégionale de l’Environnement (CELINE) Belgian Interregional Environment Agency (IRCEL-CELINE) ANNUAL REPORT Air Quality in Belgium 2015 This report is the result of the collective effort of all the colleagues of the Belgian Interregional Environment Agency (IRCEL-CELINE) Air: Frans Fierens Charlotte Vanpoucke Elke Trimpeneers Olav Peeters Stijn Quidé Thierri de Vos Philippe Maetz Virginie Hutsemékers Acknowledgements This report is based on air quality and meteorological data collected from the monitoring networks in the three Regions. IRCEL-CELINE would therefore like to thank all staff of the Flemish Environment Agency (VMM), the Public Service Scientific Institute (ISSeP) and the Walloon Air and Climate Agency (AWAC) and of the Brussels Environment Agency (IBGE-BIM). Table of Contents List of Abbreviations and Glossary .....................................................................................................1 Summary ............................................................................................................................................3 Introduction ........................................................................................................................................7 1 European Regulations ............................................................................................................... 13 1.1 History ................................................................................................................................... 13 1.2 European Directive (2008) ...................................................................................................... 13 1.3 Review of European Directive 2008/50/EC ............................................................................. 17 2 Periods with increased air pollution (smog episodes) in 2015..................................................... 19 2.1 Winter and spring smog .......................................................................................................... 20 2.2 Summer smog......................................................................................................................... 21 3 Particulate matter ...................................................................................................................... 23 3.1 PM10 ....................................................................................................................................... 24 3.1.1 PM10 monitoring stations............................................................................................ 24 3.1.2 PM10 annual mean concentration ................................................................................ 25 3.1.3 PM10 daily mean concentration................................................................................... 29 3.2 PM2.5 ...................................................................................................................................... 35 3.2.1 PM2.5 monitoring stations ........................................................................................... 35 3.2.2 PM2.5 annual mean concentration ............................................................................... 35 3.2.3 Average Exposure Index (AEI) .................................................................................. 39 3.3 Black Carbon (BC) ................................................................................................................. 41 3.3.1 BC monitoring stations .............................................................................................. 41 3.3.2 BC annual concentrations ........................................................................................... 41 4 Nitrogen oxides ......................................................................................................................... 43 4.1 NO2 monitoring stations ......................................................................................................... 44 4.2 NO2 annual mean .................................................................................................................... 44 4.3 NO2 hourly values .................................................................................................................. 49 5 Ozone ....................................................................................................................................... 52 5.1 Ozone monitoring stations ...................................................................................................... 53 5.2 Ozone and population ............................................................................................................. 54 5.2.1 NET60 ....................................................................................................................... 54 5.2.2 AOT60 ...................................................................................................................... 58 5.3 Ozone and vegetation ............................................................................................................. 59 5.3.1 AOT40 for vegetation ................................................................................................ 60 i 5.3.2 AOT40 for forests ...................................................................................................... 62 5.4 O3 annual mean ...................................................................................................................... 64 5.5 Evolution of trend in O3 concentration classes......................................................................... 67 6 Sulphur oxide ............................................................................................................................ 69 6.1 SO2 monitoring stations .......................................................................................................... 69 6.2 SO2 hourly mean values .......................................................................................................... 70 6.3 SO2 daily mean values ............................................................................................................ 72 6.4 SO2 annual mean values ......................................................................................................... 74 Prospect: improvement of the RIO interpolation technique ................................................................ 75 Conclusion........................................................................................................................................ 76 References ........................................................................................................................................ 77 Annex A: Monitoring stations ........................................................................................................... 79 Annex C: Interpreting box plots ........................................................................................................ 88 Annex D: Uncertainty maps .............................................................................................................. 89 PM10 .................................................................................................................................................. 90 PM2,5.................................................................................................................................................. 93 BC ..................................................................................................................................................... 94 NO2 ................................................................................................................................................... 95 O3 ...................................................................................................................................................... 97 ii List of Abbreviations and Glossary AEI Average Exposure Index: national indicator that is calculated as the three-year running annual mean PM2.5 concentration observed at urban background stations. AOD Aerosol optical depth: a measure for the transparency of aerosols in the atmosphere. AOT40 forests Accumulated Ozone Exposure above a Threshold of 40 ppb (=80 µg/m³): The difference between the hourly mean above 80 µg/m³ and 80 µg/m³ for all hourly values between 8 a.m. and 8 p.m. CET in the months of April to September. Indicator for the protection of forests. AOT40 vegetation Accumulated Ozone Exposure above a Threshold of 40 ppb (=80 µg/m³): The difference between the hourly mean above 80 µg/m³ and 80 µg/m³ for all hourly values between 8 a.m. and 8 p.m. CET in the months of May, June and July (growth season). Indicator for the protection of crops and (semi-)natural vegetation. AOT60 Accumulated Ozone Exposure above a Threshold of 60 ppb (= 120 µg/m³): The difference between the daily maximum 8-hour mean concentration above 120 µg/m³ and 120 µg/m³, accumulated over a calendar year. BC Black Carbon or soot. This is a component of particulate matter and originates primarily from diesel vehicles and biomass burning. LTO Long-term objective MTO Medium-term objective NET60 Number of Exceedances above a Threshold of 60 ppb (= 120 µg/m³): Number of days the daily maximum 8-hour mean ozone concentration exceeded 120 µg/m³. NOx Generic term for a gas mixture consisting of nitrogen monoxide (NO) and nitrogen dioxide (NO2). O3 Ozone: highly