High ozone levels and thick summer pollution are being wrongly blamed for deaths caused by straightforward heat, according to academics. The summer sun, not pollution, is responsible for most heatwave deaths. A new study from University College London (UCL) claims that while air pollution in various guises might be responsible for part of the rising death toll associated with heat waves, a simple failure to keep cool is far more likely to be the problem. The study, published online in the journal Environmental Research, looked at daily death rates for London's over 65s between 1991 and 2002 to see what links could be made between mortality, the weather and other environmental factors.