http://www.guardian.co.uk/environment/2013/jul/12/air-pollution-deaths-climate-change

More than 2 million deaths occur globally each year as a direct result of air pollution from human activity, a team of international scientists has said.

But climate change has only made a small contribution to the lethal effects, according to the study published on Friday in the journal Environmental Research Letters.

It suggests that 2.1 million people die after inhaling fine sooty particles called PM2.5s generated by diesel engines, power plants and coal fires.

Another 470,000 are thought to be killed by high levels of ozone, created when vehicle exhaust gases react with oxygen.

Dr Jason West from the University of North Carolina said: "Our estimates make outdoor air pollution among the most important environmental risk factors for health.

"Many of these deaths are estimated to occur in east Asia and south Asia, where population is high and air pollution is severe."

Climate change since 1850 has only led to 1,500 extra deaths from ozone and 2,200 from PM2.5 particulates, according to the research.

The scientists used climate computer models to simulate concentrations of ozone and PM2.5s in the years 2000 and 1850. Epidemiological studies were then used to assess how the levels related to worldwide death rates.