Author(s)

D. M. Elsom

Abstract

In addition to permanent measures to reduce emissions from pollution sources, short-term measures may be implemented to improve air quality. Short-term measures may be introduced to help attain air quality standards that are defined by short-term averaging concentrations as these may be particularly sensitive to the frequency of pollution episodes. Short-term measures may also be introduced to support permanent emission-reduction measures to ensure compliance with limit values (EU) or say, air quality objectives (UK), where a maximum number of permitted exceedances of a short-term averaging standard are specified. For some pollutants it may even be cost effective to apply short-term measures instead of permanent ones to ensure the number of permitted exceedances is not exceeded. In addition, EU, national or local legislation may specify threshold pollution concentrations (alerts) when short-term actions to reduce emissions are required during pollution episodes. This paper considers the types and effectiveness of short- term measures aimed at reducing emissions from motor vehicles, industrial sources, businesses and residential areas. 1 Justification for short-term air quality management There are several reasons for implementing short-term measures to reduce emissions [1,2,3,4]: 1.1 Ensuring air quality standards are met Short-term averaging air quality standards (15-minute, 1-hour, 8-hour and 24-hour) may be particularly sensitive to the frequency of pollution episodes. Permanent

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