Impacts of air pollutants on vegetation in developing countries

The predicted increases in emissions of primary pollutants in many rapidly industrializing countries may have severe consequences for the health and p roductivity of forest trees and agricultural crops. This paper presents a r eview of air pollution impacts on vegetation in developing countries by sum marising information describing the direct impacts to vegetation caused by a number of air pollutants (sulphur dioxide (SO2), nitrogen oxides (NOx), o zone (O-3) and Suspended Particulate Matter (SPM)). This information has be en collected by experts from a number of rapidly industrializing countries in Asia, Latin America and Africa and includes observations of visible inju ry in the field and the use of transect studies and controlled experimental investigations to ascribe damage to different pollutant concentrations. Th e ability to synthesise this information to define exposure-response relati onships and subsequent air quality guidelines similar to those established in North America and Europe is assessed. In addition, the use of regional a nd global models describing pollution concentrations is discussed with refe rence to assessing the extent of adverse impacts and identifying regions li kely to be most at risk from air pollution, both for the present day and in the future. The evidence summarised in the paper clearly shows that curren t pollutant concentrations experienced in many developing countries, partic ularly Asia, can result in severe damage to vegetation and that without app ropriate control measures such damage is likely to worsen in the future as pollutant emissions increase.