Death by pollution

Ozone is being wrongly blamed for many of the deaths during hot weather spells, finds a new UCL (

) study. UCL scientists warn that amidst all the concerns over air pollution, the more basic health message of ‘staying cool when the weather is hot' may be being forgotten.

The study, published online in the journal Environmental Research, modelled the daily mortality rate of people over 65 (who suffer most of the heat-related deaths) in Greater London from 1991 to 2002. The model included daily temperatures, humidity, sunshine and wind and assessed any effects of atmospheric ozone, particulates and sulphur dioxide. UCL researchers then analysed general mortality trends for days when mean air temperatures exceeded 18oC.

The team found that when temperatures topped 18oC, mortality rates in the plus-65 group rose progressively as the days grew hotter. They also found that mortality rose more with temperature rises in early summer than in late summer when people had adjusted to heat. High levels of ozone and particulates tended to be associated with sunshine, and high particulates and sulphur dioxide with low wind, both of which can increase heat stress.