Abstract. Meteorological hazards are usually considered to be tropical cyclones, droughts, hailstorms,
severe storms and their effects such as tsunamis, storm surges, wildfire, and floods. Urban
air pollution is not normally considered to be a meteorological hazard. This view has arisen because
the causes of urban air pollution – industrial and motor vehicle emissions – are not meteorological
in nature. Air pollution episodes, however, are sporadic in nature and their occurrence depends on a
particular combination of meteorological factors. This is true even in megacities such as Mexico City,
Manila, and Los Angeles that have acquired a reputation for polluted air. Analyses of air pollution
episodes and hospital admissions from many countries indicate that there is a significant increase
in morbidity and mortality as a result of such episodes. Time-series studies undertaken in Sydney
have shown that particulate matter, ozone and nitrogen dioxide are the pollutants that are primarily
responsible for adverse health effects in that city.
Air pollution, and in particular particulate matter, is believed to be responsible for just under
400 premature deaths per year in Sydney alone. This death rate is over twenty times larger than
deaths due to other meteorological hazards. Part of the reason for the low death rate for the more
traditional meteorological hazards is that the provision of high quality numerical weather prediction,
coupled with modern communications technology, has enabled emergency service personnel to take
appropriate action.
Air quality forecasting systems can play an important role in mitigating the adverse effects of air
pollution. The forecasts will affect the behaviour of susceptible individuals, and thus reduce adverse
health effects. The outputs from forecasting systems can also be used to provide improved estimates
of the total exposure to air pollutants of the inhabitants who are at risk. Such improved estimates can
then be used in conjunction with longitudinal studies of health effects to obtain better understanding
of the complex interaction between air quality and health.