Air pollution causes over 2 million deaths a year
West and his colleagues concluded that about 470,000 people die each year from ozone produced by human industrial activities. (Unlike ozone high in the atmosphere, which provides protection from the sun's rays, ground level ozone is mostly caused by chemical reactions in urban and suburban regions). Authors also concluded that an additional 2.1 million deaths were caused by fine particulate matter resulting from human activity. Such particles measure smaller than 2.5 microns in width and are called, PM 2.5. These particles have been linked to lung cancer and a variety of respiratory diseases.
The authors noted that climate change could affect air quality in a number of ways. Moist or wet regions, for example, might see less ozone production, while drier areas might see more. Different climate models provided widely differing forecasts, the researchers said, with some models estimating an overall decrease in mortality. When these models were averaged together, the effects of climate change were determined to be small.
"It cannot be clearly concluded that past climate change has increased air pollution mortality," the authors wrote.
Monte Morin