Foreign smog deadly to some locals, study finds

Migrating pollution estimated to lead to 380,000 premature deaths a year

Unseen and odorless, microscopic particles of air pollution wafting overseas and across continents kill some 380,000 people each year, according to a new study.

Exhaust from diesel engines, sulfur from coal-fired power plants, and desert dust swirl into an insidious cocktail of of tiny particles that can spend weeks airborne.

The most harmful are the smallest, less than 2.5 microns in diameter; when inhaled they can irritate the lungs or pass directly into the bloodstream and damage arteries.

Scientists and regulators know this is a major public health problem, especially in developing countries. But less clear is the effect that air pollution generated in regions like China and Southeast Asia has on far-off lands