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

PM2.5 in the UK
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60. At a local level, direct emissions of PM2.5 from non-exhaust traffic sources will
dominate exhaust emissions overall, assuming control measures such as diesel
particulate filters are effective. There needs to be a consolidated effort to reduce
the uncertainty in methods for quantifying emissions from tyre and brake wear
and other non-exhaust processes for use in national and local inventories.
61. Inventories have not traditionally provided much, if any, detail on the
component parts of PM2.5. This situation is improving with the availability of
some information on the fractions of organic and elemental carbon in emissions
from combustion sources, but there is much more that needs to be done to
improve understanding of the chemical composition of particulate matter
emissions from different sources.
62. Section 4.2 listed several sources which are not included in the NAEI. For
modelling PM2.5, it is necessary to look beyond this and consider areas where
primary PM2.5 emissions and emissions of its precursors are most uncertain and
further work is needed to improve methods for quantifying them in a manner
suitable for air quality models. In the following list we highlight key sources (in
order of importance), selected because of their contribution to total primary
PM2.5 emissions in the inventory and/or their levels of uncertainty and because
of their potential influence on PM2.5 concentrations locally or at certain times;
we also identify specific areas of uncertainty for further work:
• non-exhaust vehicle emissions including tyre and brake wear, road abrasion
and road dust resuspension;
• fugitive dust emissions from construction, demolition, quarrying, mineral
handling and industrial and agricultural processes and methods for
quantifying them nationally and locally;
• PM2.5 emissions from domestic and commercial cooking;
• small-scale waste burning and bonfires;
• wood burning and the effectiveness of control measures;
• biogenic emissions of NMVOCs, for which a definitive inventory or
estimation method is required;
• emissions of NH3 from agriculture, their temporal variability and methods
for control;
• emissions of SO2 and NOx from shipping, in particular their spatial
distribution around ports and harbours, their temporal variability and future
emissions;
• exhaust emissions from off-road machinery used in construction and
industry; and
• exhaust emissions from diesel vehicles under real world driving conditions
and the factors and technologies affecting them.