What effect non-road heavy-duty diesel engines have on air quality.

All diesel engines emit particulates (PM10), nitrogen oxides (NOx), carbon monoxide (CO) and volatile organic compounds. These pollutants can affect human health and contribute to the formation of ground level ozone. In 2000 it was estimated that, for the UK, diesel engined off-road vehicles and machinery >50kW used in construction, mining and quarrying accounted for only 0.88% of NOx emissions, 0.71% of PM10 emissions and 0.1% of CO emissions. In specific areas with mining, quarrying and construction activity the contribution of these sources to local air quality will be higher. Local authorities are required to carry out regular reviews and assessments of air quality within their areas, and where an air quality objective is unlikely to be met by the relevant attainment date, to declare an Air Quality Management Area. All Scottish local authorities in Scotland have completed the first stage of the review and assessment process and no authority has indicated any possible exceedence of the air quality objectives in areas with mining, quarrying or construction activity. A further review and assessment exercise will begin in early 2003.