Our study concludes that both Cases and DDD of dispensed respiratory drugs could be useful for epidemiological surveillance of air pollutant health effects. Further investigation may routinely allow health and economics considerations, producing a stimulating new tool for health policy makers.

The definition of specific drug use patterns by individual can provide prevalence measures that are broad proxies for varying categories of respiratory disease. However, a very high proportion of people who receive respiratory drugs do so for one-off or very infrequent episodes of illness. Analysis of the infrequent and more regular users of respiratory drugs may be useful for comparative research.

Air pollution, although still frequently high and relevant to the health of the population, is not easily recognizable on a small scale, such as a single hospital, and does not affect daily Accident and Emergency activities.