Ozone Position Paper Final version Prepared by the Ad-Hoc Working Group on Ozone Directive and Reduction Strategy Development July 1999 This document has been prepared by the working group. Any views expressed in this report do not necessarily reflect the views of the European Commission. Luxembourg: Office for Official Publications of the European Communities, 1999 2 Table of contents EXECUTIVE SUMMARY .................................................................................................................... 6 1. INTRODUCTION....................................................................................................................... 13 1.1. BACKGROUND ........................................................................................................................... 13 1.1.1. Introduction .................................................................................................................... 13 1.1.2. Air pollution by ozone..................................................................................................... 14 1.1.3. The Current Directive 92/72/EEC................................................................................... 15 1.2. EMISSIONS OF PRECURSORS........................................................................................................ 16 1.2.1. Global emissions............................................................................................................. 16 1.2.2. EU and national emissions.............................................................................................. 17 1.2.2.1. Sources of ozone precursors ......................................................................................................17 1.2.2.2. Emission projections.................................................................................................................21 1.3. OZONE IN THE TROPOSPHERE ..................................................................................................... 22 1.3.1. Atmospheric processes.................................................................................................... 22 1.3.1.1. Chemistry.................................................................................................................................22 1.3.1.2. Transport and deposition...........................................................................................................23 1.3.2. Distribution of ozone and source contributions ............................................................... 24 1.3.2.1. Spatial scales............................................................................................................................24 1.3.2.2. Temporal scales........................................................................................................................29 1.3.3. Observed concentrations................................................................................................. 29 1.3.3.1. Exceedance of the Directive 92/72/EEC thresholds ...................................................................29 1.3.3.2. Exceedances of the WHO guidelines.........................................................................................30 1.3.3.3. Trend, inter-annual variability ..................................................................................................30 REFERENCES..................................................................................................................................... 33 2. BASIC LEGISLATIVE CONCEPT FOR AN OZONE DAUGHTER DIRECTIVE............... 36 2.1. INTRODUCTION ......................................................................................................................... 36 2.2. POTENTIALLY RELEVANT DEFINITIONS IN THE FRAMEWORK DIRECTIVE ...................................... 36 2.2.1. The Limit Value............................................................................................................... 36 2.2.2. The Margin of Tolerance................................................................................................. 37 2.2.3. The Target Value ............................................................................................................37 2.2.4. Upper and Lower Assessment Level................................................................................. 38 2.3. PROPOSAL OF ATWO-LEVEL OBJECTIVE FOR OZONE ................................................................. 38 2.4. CONSEQUENCES OF A TARGET VALUE (TV) EXCEEDANCE........................................................... 41 2.4.1. Role of the TV................................................................................................................. 41 2.4.2. Linking the TV to Relevant FWD Provisions.................................................................... 41 2.5. CONSEQUENCES OF A LTO EXCEEDANCE ................................................................................... 42 2.6. THE ALERT THRESHOLD AND SHORT-TERM ACTION PLANS ........................................................ 43 2.6.1. Health-Related Information Release in the FWD and the Current Ozone Directive 92/7243 2.6.2. Short-Term Action Plans................................................................................................. 44 REFERENCES.................................................................................................................................... 48 3. RISK ASSESSMENT.................................................................................................................. 49 3.1. RISK FROM OZONE..................................................................................................................... 49 3.1.1. Health Effects ................................................................................................................. 49 3.1.1.1. Effects on Laboratory Animals..................................................................................................49 3.1.1.2. Effects on Humans....................................................................................................................50 3.1.1.3. Ozone and Asthma....................................................................................................................51 3.1.1.4. Health Impact Considerations ...................................................................................................52 3.1.2. Risks to Vegetation.......................................................................................................... 53 3.1.3. Effects on Materials........................................................................................................54 3.1.3.1. Direct Effects............................................................................................................................55 3.1.3.2. Multi-pollutant Effects..............................................................................................................55 3.2. WHO RECOMMENDATIONS........................................................................................................ 56 3.2.1. Health Guideline............................................................................................................. 56 3.2.2. Ecosystem Guidelines ..................................................................................................... 58 3 3.3. EXCEEDANCE OF THE WHO GUIDELINES .................................................................................... 61 3.3.1. Number of Exceedances of 120 µg/m3 and AOT60 - Human Health................................ 62 3.3.2. AOT40 - Crops and Semi-Natural Vegetation.................................................................. 63 3.3.3. AOT40 – Forests.............................................................................................................64 3.4. EXISTING EU THRESHOLDS ....................................................................................................... 65 3.5. EXISTING STANDARDS IN MEMBER STATES ................................................................................ 66 3.6. STANDARDS IN COUNTRIES OUTSIDE THE EUROPEAN UNION ........................................................ 69 3.7. VALUES TO BE TAKEN AS STARTING POINTS FOR SETTING EU AIR QUALITY THRESHOLDS ........... 69 3.7.1. Long-term objective and target value for the protection of vegetation............................. 74 3.7.2. Objectives for materials.................................................................................................. 80 3.7.3. Alert and information thresholds..................................................................................... 81 REFERENCES..................................................................................................................................... 84 4. MONITORING AND ASSESSMENT STRATEGY ................................................................. 88 4.1. INTRODUCTION ......................................................................................................................... 88 4.2. MONITORING AND ASSESSMENT UNDER THE CURRENT DIRECTIVE 92/72/EEC.............................. 88 4.2.1. The Council Directive on air pollution by ozone ............................................................. 88 4.2.2. Monitoring requirements................................................................................................. 88 4.2.3. Assessment of exposure, risk and effects in relation to network