Ambient air pollution and daily hospital admissions in Melbourne 1994-1997
This 2002 study found that air pollution in Melbourne is associated with increased hospital admissions for respiratory and cardiovascular disease. There is also a link with admissions for asthma in children.
Many overseas studies have shown links between air pollutants and increases in premature deaths and hospital admissions for people with existing heart and lung disease. These effects have been seen amongst the elderly, people with existing illnesses, asthmatics and children. These studies have focused attention on air quality standards and the action required to improve air quality.
EPA’s Melbourne mortality study (publication 709) from June 2000 was the first of a number of collaborative studies with researchers in Australia that investigated the effects of air pollution on our health. The hospital admissions study further investigated these effects.
The study was a collaboration with researchers from the University of the Sunshine Coast and University of Queensland. It investigated the association between air pollution and daily emergency admissions for respiratory and cardiovascular disease and asthma.
The study included admissions to all Melbourne hospitals between July 1994 and December 1997. The pollutants studied were fine particles, ozone, nitrogen dioxide and carbon monoxide. The analysis looked at the impact on people across all age groups, with a particular emphasis on the elderly and children.
Findings of the hospital admissions study
The results of the study showed that, after allowing for the effects of weather, all the pollutants were associated with increases in hospital admissions for respiratory and cardiovascular disease. The effects from carbon monoxide, nitrogen dioxide and particles were difficult to separate. This is not surprising, since the main sources of these pollutants are combustion processes such as in motor vehicle engines. The effects from ozone were independent of the other pollutants.
Hospital admissions for children with asthma were affected by air pollution, in particular fine particles and ozone. Admissions for the elderly with existing heart disease were strongly associated with carbon monoxide.
The results of this study were consistent with the findings of overseas studies. However, the links between particles and admissions of children for asthma were generally stronger than those seen overseas. This may be partly because Australia has the second-highest asthma rate in the world.
Comparison with the Melbourne mortality study
The Melbourne mortality study found that increases in daily mortality were linked with Melbourne’s air pollution levels . Except for ozone and nitrogen dioxide, the effects of individual pollutants were difficult to separate.
The effects of particles and carbon monoxide were weak compared with the findings of the hospital admissions study. This is not surprising, though, as hospital admissions are a more sensitive health indicator.