Health effects of a sulphur dioxide air pollution episode.

Background: A sulphur dioxide (SO(2)) episode occurred in the United Kingdom in 1998. The worst affected area was the city of Nottingham.

Methods: Emergency hospital admissions in Nottingham in the episode week were compared with those in the previous week.

Results: A statistically significant increase in admissions for all respiratory diseases occurred in the episode week (odds ratio (OR) = 1.40, 95 per cent confidence interval (CI) = 1.00-1.94). Ten of the 25 excess admissions were for asthma, although the excess for asthma alone was not statistically significant (OR = 1.90, 95 per cent CI = 0.87-4.15).

Conclusions: The excess admissions for respiratory diseases could have been caused by exposure to SO(2), to other pollutants present in increased concentrations during the pollution episode, or by seasonal variations in the frequency of asthma symptoms, or prevailing weather conditions. This study shows how simple analyses of routinely collected health data can be used to assess public health impacts of pollution episodes.