Objective-To examine the effect on hospital presentations for asthma of bri
ef exposures to sulphur dioxide (SO2) (within the range 0-8700 mu g/m(3)) e
manating from two point sources in a remote rural city of 25 000 people.
Methods-A time series analysis of SO2 concentrations and hospital presentat
ions for asthma was undertaken at Mount Isa where SO2 is released into the
atmosphere by a copper smelter and a lead smelter. The study examined 5 min
ute block mean SO2 concentrations and daily hospital presentations for asth
ma, wheeze, or shortness of breath. Generalised linear models and generalis
ed additive models based on a Poisson distribution were applied.
Results-There was no evidence of any positive relation between peak SO2 con
centrations and hospital presentations or admissions for asthma, wheeze, or
shortness of breath.
Conclusion-Brief exposures to high concentrations of SO2 emanating from poi
nt sources at Mount Isa do not cause sufficiently serious symptoms in asthm
atic people to require presentation to hospital.