Air quality simulations for London using a coupled regional-to-local modelling system
<p>A coupled regional-to-local modelling system comprising a regional chemistry–climate model with 5 km horizontal resolution (EMEP4UK) and an urban dispersion and chemistry model with explicit road source emissions (ADMS-Urban) has been used to simulate air quality in 2012 acros...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-08-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/18/11221/2018/acp-18-11221-2018.pdf |
| Summary: | <p>A coupled regional-to-local modelling system comprising a
regional chemistry–climate model with 5 km horizontal resolution (EMEP4UK)
and an urban dispersion and chemistry model with explicit road source
emissions (ADMS-Urban) has been used to simulate air quality in 2012 across
London. The study makes use of emission factors for NO<sub><i>x</i></sub> and
NO<sub>2</sub> and non-exhaust emission rates of PM<sub>10</sub> and PM<sub>2.5</sub> which
have been adjusted compared to standard factors to reflect real-world
emissions, with increases in total emissions of around 30 % for these
species. The performance of the coupled model and each of the two component
models is assessed against measurements from background and near-road sites
in London using a range of metrics concerning annual averages, high hourly
average concentrations and diurnal cycles. The regional model shows good
performance compared to measurements for background sites for these metrics,
but under-predicts concentrations of all pollutants except O<sub>3</sub> at
near-road sites due to the low resolution of input emissions and
calculations. The coupled model shows good performance at both background and
near-road sites, which is broadly comparable with that of the urban model that uses
measured concentrations as regional background, except for PM<sub>2.5</sub> where
the under-prediction of the regional model causes the coupled model to also
under-predict concentrations. Using the coupled model, it is estimated that
13 % of the area of London exceeded the EU limit value of
40 µg m<sup>−3</sup> for annual average NO<sub>2</sub> in 2012, whilst
areas of exceedances of the annual average limit values of 40 and
25 µg m<sup>−3</sup> for PM<sub>10</sub> and PM<sub>2.5</sub> respectively were
negligible.</p> |
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| ISSN: | 1680-7316 1680-7324 |