Trends in Ozone Across Europe: Influences and Implications

1. TRENDS IN OZONE ACROSS EUROPE: INFLUENCES AND IMPLICATIONS Dick Derwent rdscientific, Newbury, United Kingdom Anne Hjellbrekke CCC, NILU, Norway 13th Meeting of Task Force on Measurement and Modelling Tuesday 17th April 2012 Malta This study was supported as part of the SSNIP research programme of ALE Defra under contract AQ0902

2. SCOPE OF THE PRESENTATION Trends presented address variations in space across Europe and with time since 1990. Aims: To provide a national contribution to the evaluation of the improvement in air quality resulting from the Gothenburg Protocol. To provide a consistent analysis of trends across Europe for the evaluation of photochemical models.

3. DIFFICULTIES PRESENTED BY OZONE TRENDS Ozone trends are metric dependent episodic peak ozone concentrations annual or monthly mean concentrations Ozone trends are site dependent local influences of motor vehicle traffic surface vs mountain-top sites maritime vs rural sites There is significant year-on-year variability Use EMEP ozone database for rural and remote sites only

4. HUMAN HEALTH IMPACTS OF OZONE World Health Organisation Air Quality Guidelines Global Updates 2005 document focusses on : highest 8-hour rolling mean ozone concentration in each year sets guideline of 50 ppb as air quality target for highest 8-hour mean Provides an excellent metric for assessing ozone trends across Europe.

5. DISTRIBUTION OF EPISODIC PEAK OZONE ACROSS EUROPE EMEP ozone database calculate highest 8-hour rolling mean concentration for each site and year accept only sites and years with >75% data capture take average of 10 values for each year from 2000 – 2009 and reject if any year is missing 78 sites have complete coverage for 2000 – 2009 period

6. 2000 – 2009 AVERAGE HIGHEST 8-HOUR MEAN OZONE DE0003R 95.3 ppb Schauinsland 1205 m IT0001R 92.0 Montelibretti 48 CH0005R 91.9 Rigi 1031 BE0032R 90.9 Eupen 295 CH0004R 89.0 Chaumont 1137 SI0032R 88.9 Krvavec 1740 DE0008R 88.8 Schmucke 937 BE0035R 88.2 Vezin 160 AT0032R 86.2 Sulzberg 1020 CH0003R 85.9 Tanikon 539 AT0041R 85.7 Haunsberg 730 AT0005R 85.0 Vorrhegg 1020

7. 2000 – 2009 AVERAGE HIGHEST 8-HOUR MEAN OZONE 13. FR0009R 85.0 ppb Revin 390 m AT0046R 84.7 Gansemdorf 161 DE0002R 84.5 Langenbrugge 74 AT0038R 84.3 Gerlitzen 1895 AT0002R 84.2 Illmitz 117 AT0042R 84.0 Heidenreichstein 570 AT0047R 83.9 Stixneusiedl 240 BE0001R 83.8 Offagne 430 AT0030R 83.7 Pillersdorf bei Retz 315 SI0033R 83.2 Kovk 600 PL0003R 83.1 Sniezka 1603 GB0038R 83.1 Lullington Heath 120 SI0008R 83.1 Iskrba 520

8. 2000 – 2009 AVERAGE HIGHEST 8-HOUR MEAN OZONE 65. FI0037R 66.9 ppb Ahtari II 180 m 66. NO0039R 66.8 Karvatn 210 67. NO0015R 66.6 Tustervatn 439 68. FI0022R 66.6 Oulanka 310 69. ES0008R 66.0 Niembro 134 70. SE0013R 65.9 Esrange 475 71. NO0055R 64.2 Karasjok 333 72. NO0001R 63.9 Birkenes 190 73. IE0031R 63.9 Mace Head 15 74. SE0035R 63.8 Vindeln 225 75. GB0002R 63.1 Eskdalemuir 243 76. CH0001G 62.9 Jungfraujoch 3578 77. GB0033R 61.8 Bush Estate 180 78. NO0042G 55.0 Zeppelinfjell 474

9. 2000 – 2009 average DECADAL AVERAGE HIGHEST 8-HOUR MEAN OZONE ALONG A SOUTH-NORTH TRANSECT THROUGH CENTRAL EUROPE

10. 2000 – 2009 average DECADAL AVERAGE HIGHEST 8-HOUR MEAN OZONE ALONG A WEST-EAST TRANSECT THROUGH CENTRAL EUROPE

11. CONCLUSIONS CONCERNING 2000 – 2009 DECADAL AVERAGE HIGHEST 8-HOUR MEAN OZONE there is an ‘ozone maximum region’ encompassing Belgium, Germany, Switzerland, Italy and Slovenia based on 8 stations with decadal average values >90 ppb there is a surrounding region covering Austria, Czech Republic, France, Poland, United Kingdom, Netherlands and Spain there are 25 stations with decadal average values in the range 80.3 – 86.2 ppb decadal values are lowest at NO0042G Zeppelinfjell at 55 ppb all 78 EMEP monitoring stations had decadal average highest 8-hour mean ozone levels in excess of the WHO air quality guideline of 50 ppb

12. TRENDS IN ANNUAL HIGHEST 8-HOUR MEAN OZONE OVER THE PERIOD 1990 - 2009 Station Sens slope Intercept P Station name ppb per year in 1990, ppb IT0004R -2.3 ± 1.1 118 0.001 Ispra GB0013R -2.0 ± 1.4 104 0.01 Yarner Wood GB0038R -1.7 ± 1.1 104 0.01 Lullington Heath NL0010R -1.6 ± 1.1 104 0.05 Vredepeel AT0032R -0.7 ± 0.6 103 0.05 Sulzberg GB0036R -1.6 ± 1.2 100 0.05 Harwell AT0045R -0.9 ± 0.8 100 0.1 Dunkelsteinerwald GB0031R -1.3 ± 1.0 93 0.1 Aston Hill AT0002R -1.0 ± 0.7 93 0.1 Illmitz + further 31 stations, of which 7 showed significant trends AT0047R, SE0011R, GB0002R, NL0009R, NO0001R, GB0006R, GB0033R

13. TRENDS IN ANNUAL HIGHEST 8-HOUR MEAN OZONE OVER THE PERIOD 1993 - 2009 Station Sens slope Intercept P Station name ppb per year in 1990, ppb GB0039R -1.6 ± 1.4 101 0.1 Sibton DE0008R -0.7 ± 0.7 95 0.05 Schmucke CZ0001R -1.3 ± 1.3 92 0.05 Svratouch GB0014R -1.7 ± 1.5 91 0.01 High Muffles AT0042R -0.6 ± 0.6 87 0.1 Heidenreichstein DK0041R -1.0 ± 1.0 82 0.05 Lille Valby DE0009R -1.0 ± 0.7 81 0.05 Zingst + a further 22 stations that showed no statistically significant trends

14. WHY ARE THE DOWNWARDS TRENDS LARGEST FOR THE STATION WITH THE HIGHEST EPISODIC PEAK LEVELS ?

15. CONCLUSIONS CONCERNING TRENDS OVER THE 1990 – 2009 PERIOD IN HIGHEST 8-HOUR MEAN OZONE LEVELS 40 monitoring stations have suitable records over the 1990 – 2009 period and a further 29 over the 1993 – 2009 period statistically significant downwards trends were found at 23 out of the 69 stations downwards trends were larger for those stations with higher initial levels in 1990 those stations with the lowest initial levels showed no significant trends

16. WHAT HAVE BEEN THE MAIN INFLUENCES ON EPISODIC PEAK OZONE LEVELS DURING 2000 – 2009 ? Influences that have led to downwards trends: VOC and NOx emission reductions resulting from the fitting of exhaust gas catalysts and evaporative cannisters Influences that have led to upwards trends: increasing levels of hemispheric intercontinental transport of O3 from Asia and North America

17. HOW DOES EPISODIC PEAK OZONE RESPOND TO VOC AND NOx EMISSION REDUCTIONS ?

18. INTERCONTINENTAL SOURCE ATTRIBUTION OF THE OZONE OBSERVED AT GB0049R STATION DURING 2008

19. PTM model addressing baseline trends and precursor emission trends DO WE UNDERSTAND WHAT HAS DRIVEN THE OBSERVED DOWNWARDS TRENDS AT GB0036R FROM 1990 – 2009 ?

20. CONCLUSIONS The full implementation of the Gothenburg Protocol and the supporting EU Vehicle Emission Directives has led to a reduction in episodic peak ozone levels of between 15 – 40 ppb over the 1990 – 2009 period in the ‘ozone maximum region’ in central Europe. This reduction in episodic peak ozone has been partially offset by the increasing levels of intercontinental ozone transport particularly in the fringes of Europe. Policy actions are required on hemispheric ozone. Decadal averaged 2000 – 2009 highest 8-hour mean ozone levels at all EMEP monitoring stations exceeded the WHO 8-hour ozone Air Quality Guideline despite all the actions taken to reduce VOC and NOx emissions under the Gothenburg Protocol. Further actions are required in the future on European emissions.