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

PM2.5 in the UK
Table 4.1: UK emissions of primary PM2.5 from different sources from 1990-2009 and
projected to 2020 according to the NAEI (Passant et al., 2011). The projections are based on
assumptions about future levels of activities and changes in emission factors according to
current legislation (Wagner, 2010).
84
UK PM2.5 emissions (ktonnes)
Emission source 1990 1995 2000 2005 2009 2015 2020
combustion in the energy industries 33.6 20.2 12.2 6.6 4.8 3.9 5.4
combustion in industry 8.9 7.8 4.7 3.7 3.1 2.8 2.6
road transport (exhaust) 29.2 32.3 23.1 17.4 12.4 5.7 2.0
road transport (non-exhaust) 6.4 6.7 7.3 7.8 7.8 8.2 8.8
other transport (including rail,
national navigation and aviation
landing and take-off)
3.6 3.4 3.2 3.1 2.0 1.6 1.3
off-road transport 15.9 16.2 15.7 12.3 8.0 3.9 2.9
residential 19.3 11.7 10.0 7.4 9.8 8.3 7.9
quarrying and mining of minerals
other than coal
3.3 2.9 2.5 2.4 1.9 1.7 1.7
other mineral products 3.6 3.4 2.8 3.2 2.1 2.5 2.5
iron and steel production 3.1 3.1 3.0 2.2 2.5 2.2 2.2
agriculture 1.7 1.8 2.1 2.0 1.9 1.9 1.9
small-scale waste burning 4.1 4.1 4.1 4.1 4.1 4.1 4.1
other (combustion) 7.9 6.1 4.8 4.6 5.3 4.0 4.0
other (non-combustion) 17.0 13.2 7.6 6.8 5.0 5.8 5.8
TOTAL 157.6 132.8 103.1 83.6 70.5 56.8 53.0
22. As stated earlier, inventories for PM2.5 are generally calculated by applying
PM2.5 mass fractions to sector-specific emission factors for PM10 or TSP. To
demonstrate this, Figure 4.3 shows the PM2.5:PM10 ratio in emissions for a
number of key sectors in 2009. These have been back-calculated from detailed
inventories for both PM10 and PM2.5 using ratios for each individual sub-sector,
so they are in effect weighted averages of ratios for each key sector. The
figure demonstrates how emissions from combustion processes are generally
associated with high values of PM2.5:PM10 ratio (e.g. 0.95 for vehicle exhausts),
while PM emissions from more mechanical, non-combustion sources, such as
mining, quarrying and agriculture, are associated with smaller PM2.5:PM10 ratios
indicating that a higher proportion of the emitted PM mass is in the coarse
mode. The ratios for tyre wear, brake wear and road abrasion are 0.70, 0.40
and 0.54 respectively, giving a combined average of 0.55.