Air quality expert group - Fine particulate matter (PM2.5) in ... - Defra

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Modelling PM2.5 and the future therefore not clear whether SOA levels will remain constant in the future if manmade emissions change significantly. This issue should be the subject of further research. 58. The semi-volatile components of organic aerosols and ammonium salts comprise a substantial fraction of PM2.5 and present a substantial modelling and measurement issue. Other components, such as sea salt, rural and urban dusts, and water content, must be accounted for in order to explain total PM2.5 concentrations and achieve mass closure. These still make a substantial contribution to overall concentrations and exposure for the finer PM2.5 fraction, albeit not as large a contribution as for PM10. Further work is required to investigate these other contributions and how they may be represented in modelling, including, for example, the response of the water content associated with the PM2.5 fraction to reductions in pollutant emissions. 59. In common with other species, the model evaluation of PM2.5 can be frustrated by lack of information or accuracy concerning emissions inventories, the chemical and physical processes involved and the availability of reliable measurements. There is a need for more extensive and consistent evaluation of PM2.5 models in the UK, considering for example, similar time periods and the speciated components of PM2.5. Such an evaluation should also consider the temporal and spatial characteristics of the key components of PM2.5. Furthermore, the evaluation would provide a more robust assessment of model performance beyond meeting the Air Quality Directive requirements (see Chapter 1) for model performance. Verification of models, particularly source attribution, remains challenging largely because of the lack of availability of chemically-speciated measurements. There is also a need to develop methodologies for quantifying uncertainties in modelled values. 145
PM2.5 in the UK Annex 2: PM modelling in the UK 146 A2.1: Applications of CMAQ to PM-related projects at AEA 1. CMAQ is one of the tools used to produce the UK daily air quality forecast on behalf of Defra. 48-Hour forecasts for PM10 and PM2.5 are produced using CMAQ at 10 km resolution. Figure A2.1.1 gives examples of the forecasts over a period of elevated particulate matter (PM) at the end of April 2011. The classification of PM air quality is based on a 24-hour average. The yellow areas of the daily average plots in Figure A2.1.1 identify areas where moderate air quality was predicted (see http://uk-air.defra.gov.uk/air-pollution/daqi for the air pollution health bandings used in the daily forecasts; see also Table 5.2 in Chapter 5). CMAQ tends to underestimate PM10, particularly when dust and resuspension are contributing factors. The maximum hourly plots demonstrate areas where PM was elevated but not sufficiently so to be classed as moderate on the 24-hour average. Further analysis of the PM components could be used to identify the major contributors. Daily Average PM10 Maximum Hourly PM10
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AIR QUALITY EXPERT GROUP Fine Parti
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This is a report from the Air Quali
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II Membership Chair Professor Paul
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IV Acknowledgements The Air Quality
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VI 2.5 Summary 39 2.5.1 What does t
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VIII 5.4 Components of PM2.5 and so
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PM2.5 in the UK 2 Air Quality Direc
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PM2.5 in the UK 4 I.2.1 Concentrati
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PM2.5 in the UK 6 • PM2.5 emissio
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PM2.5 in the UK 8 I.4.1 Modelling r
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PM2.5 in the UK 10 4. In broad term
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PM2.5 in the UK Table 1.2: National
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PM2.5 in the UK 14 17. Dry depositi
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PM2.5 in the UK 16 in ozone in the
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PM2.5 in the UK 18
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PM2.5 in the UK 20 5. The exact for
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PM2.5 in the UK 22 12. These diffic
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PM2.5 in the UK 24 2.3 Methods used
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PM2.5 in the UK 26 (e) During the
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PM2.5 in the UK 28 2.3.3 The Partis
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PM2.5 in the UK 30 35. For non-auto
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PM2.5 in the UK 32 43. Ratification
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PM2.5 in the UK 34 49. Many of the
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PM2.5 in the UK 36 57. Black carbon
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PM2.5 in the UK 38 2.4.4 PM2.5 elem
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PM2.5 in the UK 40 average of 93.6%
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PM2.5 in the UK Annex 1 - PM2.5 mon
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PM2.5 in the UK 44
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PM2.5 in the UK 46 3.2.1 Diurnal va
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PM2.5 in the UK 48 PM2.5/µgm -3 20
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PM2.5 in the UK 50 3.2.4 Seasonal v
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PM2.5 in the UK 52 12. Results are
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PM2.5 in the UK 54 3.4.2 Relationsh
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PM2.5 in the UK 56 Correlation 0.8
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PM2.5 in the UK Figure 3.11: Polar
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PM2.5 in the UK 60 south. Further a
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PM2.5 in the UK 62 3.7 PM2.5 episod
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PM2.5 in the UK 64 secondary ammoni
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PM2.5 in the UK 66 3.8 PM2.5 concen
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PM2.5 in the UK 68 3.9 Composition
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PM2.5 in the UK 70 43. The UK has i
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PM2.5 in the UK 72 NO 3 6 4 2 2000
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PM2.5 in the UK 74 54. PM ammonium
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PM2.5 in the UK 76 58. Data from th
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PM2.5 in the UK 78 (k) Road traffic
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PM2.5 in the UK 80 provided by spec
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PM2.5 in the UK 82 14. The London L
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PM2.5 in the UK Table 4.1: UK emiss
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PM2.5 in the UK 86 24. National inv
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PM2.5 in the UK 88 Figure 4.5: Spat
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PM2.5 in the UK 90 either nanoparti
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PM2.5 in the UK 92 37. Further cons
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Page 115 and 116: PM2.5 in the UK 104 4.5.2 Quantifyi
Page 117 and 118: PM2.5 in the UK 106 77. Early effor
Page 119 and 120: PM2.5 in the UK 108 4.6.1 Receptor
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Page 123 and 124: PM2.5 in the UK 112 PM2.5 contribut
Page 125 and 126: PM2.5 in the UK 114 inorganic parti
Page 127 and 128: PM2.5 in the UK 116 93. While there
Page 129 and 130: PM2.5 in the UK 118 100% 90% 80% 70
Page 131 and 132: PM2.5 in the UK 120 105. Receptor m
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Page 135 and 136: PM2.5 in the UK 124 5. At the regio
Page 137 and 138: PM2.5 in the UK 126 15. Some of the
Page 139 and 140: PM2.5 in the UK 128 Figure 5.2: Tot
Page 141 and 142: PM2.5 in the UK 130 µgm -3 160 140
Page 143 and 144: PM2.5 in the UK 132 PM component (
Page 145 and 146: PM2.5 in the UK 134 with larger dev
Page 147 and 148: PM2.5 in the UK 136 Figure 5.8: UKI
Page 149 and 150: PM2.5 in the UK Figure 5.9: Compari
Page 151 and 152: PM2.5 in the UK 140 PM2.5 concentra
Page 153 and 154: PM2.5 in the UK 142 the North Sea (
Page 155: PM2.5 in the UK 144 53. Modelling r
Page 159 and 160: PM2.5 in the UK 148 2. Figure A2.1.
Page 161 and 162: PM2.5 in the UK 150 6. The non-line
Page 163 and 164: PM2.5 in the UK 152 Model 50 45 40
Page 165 and 166: PM2.5 in the UK 154 (a) (b) modPM 2
Page 167 and 168: PM2.5 in the UK 156 NO3 - concentra
Page 169 and 170: PM2.5 in the UK 158 26. This was in
Page 171 and 172: PM2.5 in the UK 160 SIA components
Page 173 and 174: PM2.5 in the UK 162 x 50 km grid fo
Page 175 and 176: PM2.5 in the UK 164 A2.6: Photochem
Page 177 and 178: PM2.5 in the UK 166 PM2.5 Emission
Page 179 and 180: PM2.5 in the UK 168 A2.8: PCM PM mo
Page 181 and 182: PM2.5 in the UK 170 illustrated by
Page 183 and 184: PM2.5 in the UK 172 trajectory mode
Page 187 and 188: PM2.5 in the UK 176 4. The delivery
Page 189 and 190: PM2.5 in the UK 178 12. With respec
Page 193 and 194: PM2.5 in the UK Chapter 2: Measurin
Page 195 and 196: PM2.5 in the UK RoTAP (2012). Revie
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Page 199 and 200: PM2.5 in the UK Chapter 5 Modelling
Page 201 and 202: PM2.5 in the UK Jones A.M., Harriso
Page 203: PB13837 Nobel House 17 Smith Square
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