"Strict curbs on soot and ozone air pollution would limit global warming by 0.5 degree Celsius (0.9 F) in a step toward achieving tough world climate goals, a U.N.-backed study showed on Friday.

Stricter limits on "black carbon" soot and tropospheric ozone -- a greenhouse gas that is a big component of smog -- would also clear the air and so reduce human deaths and improve crop yields, especially in Asia, it said."

Alister Doyle reports for Reuters Times February 21, 2011. [2]