CONTRIBUTION FROM DIFFERENT VOC EMISSION SOURCES TO PHOTOCHEMICAL OZONE FORMATION IN EUROPE Dick Derwent rdscientific This work was supported by the UK Department for Environment Food and Rural Affairs under contract number EPG 1/3/200

AIM OF THE PRESENTATION To describe the contribution made by the different VOC emission sources to photochemical ozone formation over Europe.

UK PHOTOCHEMICAL TRAJECTORY MODEL Model description A single air parcel following a trajectory across Europe Emissions of SO 2, NO x, VOCs, CH 4, CO and isoprene From EMEP and UK NAEI inventories Master Chemical Mechanism

UK PHOTOCHEMICAL TRAJECTORY MODEL

MASTER CHEMICAL MECHANISM 137 emitted organic compounds 4,414 reaction products 12,871 chemical reactions Detailed explicit chemical mechanism to represent the contribution made by each individual VOC species. Developed by Michael Jenkin of Imperial College and Michael Pilling of University of Leeds and available at:

MASTER CHEMICAL MECHANISM Generates the same picture of regional ozone formation across Europe as other mechanisms Used here because it is the only mechanism that treats each emitted VOC species in explicit detail VOC source categories can only be treated explicitly with a chemical mechanism that treats each species in detail

COMPARISON OF MCMv3.1 WITH CBM4 MECHANISM

GRIDDED EMISSION INVENTORIES

VOC SPECIATION UK NAEI 248 emission source categories at the SNAP 3 level each has its own profile containing 667 VOC species 248 x 667 matrix UK Photochemical Trajectory Model 248 x 177 matrix of category x species 90% coverage of total VOC mass emissions fractional speciation held constant across Europe

EXPERIMENTAL DESIGN Base Case Experiment Run with year 2000 VOC, NO x, SO 2, CO, isoprene and CH 4 emissions and year 2000 VOC fractional speciation Ozone at arrival point 87.8 ppb 248 sensitivity cases Run with the emissions from each VOC emission source category increased fractionally Determine by difference the extra ozone formed

SENSITIVITY EXPERIMENTS An additional emission was added in turn from each VOC emission source category across Europe. The extra emission amounted to a 7.3% increase in VOC emissions. The speciation of the extra emission was given the same species profile as the emission source category. The increase in emission was applied everywhere across Europe

INCREMENTAL REACTIVITY OF A VOC EMISSION SOURCE CATEGORY This is the increase in ozone in ppb divided by the fractional increase in the emissions from that source category:  O  VOC VOC Incremental reactivities depend on the environmental conditions and are not geophysical quantities

INCREMENTAL REACTIVITIES Chemical waste incineration53.8 Blast furnaces_Coke-oven gas49.5 Iron & steel (Flaring)_Coke-oven gas49.0 Iron & steel industry_Coke-oven gas48.9 Other industrial combustion_Coke- oven gas48.9 Industrial coatings (drum)47.5 Printing (metal decorating)47.1 Printing (heatset web offset)47.0 Industrial coatings (marine)46.5 Railways (Freight)_Gas oil46.2 Road transport (rigid HGVs)_DERV46.2 Other industrial (off-road)_Gas oil46.0

CONTRIBUTION TO OZONE FORMATION Ozone formation = Incremental Reactivity x Fractional contribution to total VOC emissions

CONTRIBUTION TO OZONE FORMATION % incremental ozone emissions reactivity ppb Road transport (cars without catalysts)_Petrol Road transport (cars with catalysts)_Petrol Onshore loading of crude oil Chemical industry Offshore loading of crude oil Spirit manufacture (maturation) Refineries (process fugitives) Petrol stations (vehicle refuelling with unleaded petrol) Other solvent use Gas leakage Decorative paint (trade decorative) Industrial coatings (metal & plastic) Aerosols (cosmetics and toiletries) Decorative paint (retail decorative) Industrial adhesives

CONTRIBUTION TO OZONE FORMATION Each source category has a different incremental reactivity because of the contribution from the different VOCs that make up its species profile. Each source category makes a different contribution to ozone formation because of its different incremental reactivity and its different contribution to total emissions.

DOES IT MAKE ANY DIFFERENCE IF THE INFORMATION ABOUT THE INCREMENTAL REACTIVITIES IS USED IN CONTROL STRATEGIES ? Based on incremental reactivities for 248 source categories Base case 87.8 ppb 4 ppb

DOES IT STILL MAKE A DIFFERENCE AT THE HIGHLY AGGREGATED SNAP 1 LEVEL ? 1.9 ppb Based on incremental reactivities of 11 SNAP 1 source categories Road transport solvents Extraction & distribution of fossil fuels

CONCLUSIONS Incremental reactivities have been constructed for 248 VOC emission source categories. There is a factor of over 30 range in these incremental reactivities which is not represented in the EMEP/RAINS models. These variations in reactivity are caused by the different VOC species profiles for each source category. VOC control strategies targetting the most reactive source categories could be more cost-effective than currently estimated using the EMEP/RAINS models.