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

3.9 Composition 68
3.9.1 Overall composition of PM2.5 68
3.9.2 Individual constituents of PM2.5 69
3.9.3 Seasonal pattern of nitrate and sulphate 70
3.9.4 Trends in nitrate, sulphate, ammonium, black smoke
and black carbon 71
3.10 Summary and recommendations 77
3.10.1 Key points from measurements 77
3.10.2 Recommendations 78
Chapter 4: PM2.5 emissions and receptor modelling 79
4.1 Introduction 79
4.2 Emissions and sources of primary PM2.5 79
4.2.1 Quantifying the emissions of all primary PM2.5 components and
their spatial distribution 79
4.2.2 Inventory uncertainties and gaps 88
4.3 Quantifying the emissions of PM2.5 precursor gases, their conversion to
particles and their spatial distribution 92
4.3.1 Primary versus secondary PM 97
4.4 A critical assessment of emission inventories for modelling
of PM2.5 concentrations 98
4.5 Receptor modelling to estimate the source apportionment of PM2.5 101
4.5.1 Markers of primary sources 102
4.5.2 Quantifying the secondary inorganic contribution 104
4.5.3 Estimation of the secondary organic aerosol contribution 104
4.5.4 Aerosol dynamics 105
4.6 Receptor modelling sources of PM2.5 in the UK 107
4.6.1 Receptor modelling of particulate matter in the UK 108
4.6.2 Comparison of receptor modelling results with output
from the PCM model 113
4.6.3 Use of carbon-14 as a tracer of contemporary carbon 116
4.7 Summary 119
Chapter 5: Modelling PM2.5 and the future 123
5.1 Introduction 123
5.2 What is modelling? What can models do? 123
5.3 What do models predict across the UK? 126
5.3.1 PM2.5 modelling for public information and forecasts 129
5.3.2 Transects in PM2.5 across London 130
VII