The impact of motor vehicles on air pollutant emissions and air quality in the UK - An overview

Abstract

This paper will attempt to summarise the contribution of motor vehicles to the emissions and air quality in terms of the more important air pollutants in the UK. It is important in this context to distinquish between primary pollutants which may affect a given target in the form in which they are emitted, and secondary pollutants which undergo or are formed by, reactions in the atmosphere between source and target. In the motor vehicle context one may list the more important primary pollutants as CO, CO2, NO, NO2, SO2, smoke and particulate material, lead and the range of organic compounds known generally as volatile organic compounds (VOCs). Secondary pollutants in this context are ozone, PAN (peroxyacetyl nitrate), NO2, sulphate and nitrate aerosols and the end products of atmospheric oxidation and rain chemistry H2 SO4 and HNO3 and others implicated in the "acid rain" issue. This paper will discuss the estimates of UK emissions of primary pollutants and the precursors of secondary pollutants (where data are available) and will give an indication of the methods used in their calculation. A brief discussion will be given of how vehicular contributions to measured air quality can be quantified using numerical modelling and air quality data and finally some indication of future trends in vehicle emissions will be given. © 1987.