Soaring summer temperatures can be a godsend for people with asthma but only if pollution levels are low, a Queensland University of Technology public health study has found.
PhD student Cizao (Shezow) Ren, with Associate Professor Shilu Tong, studied the interaction between temperature and air pollution and its effect on hospital admissions in Brisbane city and surrounding suburbs.
The findings will be presented at the International Symposium on Environmental Health, Climate Change and Sustainability at QUT tomorrow.
Mr Ren found that the number of respiratory and cardiovascular hospital admissions for both breathing and heart problems was linked to daily air pollution levels and temperatures.
He found that when the temperature went above 25 degrees, the number of respiratory hospital admissions for conditions such as asthma and pneumonia fell.
"However, high air pollution negates the beneficial effects of higher temperatures on respiratory hospital admissions," Mr Ren said.
"While my study looked at the association of these three factors, not the causes, the effect on respiratory admissions could have something to do with high pollution exacerbating allergies and respiratory diseases."
With cardiovascular admissions, he found high temperature and high pollution were a deadly mix.
"We found that heart attacks and stroke admissions go up when the temperature rises above 24 degrees.
"When high temperatures are combined with high levels of air pollution it is particularly dangerous for people who have heart or vascular conditions - more deaths occur when these two factors are both high.
"But when we have high temperatures and low pollution, the effect of temperature is less strong on cardiovascular mortality."
Mr Ren said it was largely unknown what caused the association between pollution and temperature and cardiovascular hospital admissions.
"It could be that the physiological stress caused by high temperatures makes people more susceptible to air pollution or it could be that the body has to cope with the extra load of two physiological stresses at once - the high temperature and the pollution."
Mr Ren said Tuesdays, Wednesdays and Thursdays tended to be peak pollution days in cities and people with health problems should aim to lower their exposure to air pollution on these days.
These findings have just been published in the International Journal of Meteorology, and Mr Ren will report these results in the upcoming International Symposium on Environmental Health, Climate Change and Sustainability which will be held at QUT's Kelvin Grove Campus, 21-22 November 2006.
Media contact: Niki Widdowson, QUT media officer, 07 3138 1841 or n.widdowson@qut.edu.au.
