Smoke from fires in southwestern Oregon drifted over much of Oregon in this true color image from late September 2009. The associated aerosol image reveals that the smoke reached as far east as eastern Montana and central Canada, illustrating that pollution travels long distances.
Simulations of air pollution from the GOCART model help show how much skies have cleared over Europe and North America even as they have darkened over Asia in the last decade.
In the weeks before India’s monsoon rains, dust, smoke, and haze build over the Ganges River Plain. This image provides a profile of the atmosphere during one of those pollution periods.
Solid particles and liquid droplets in the air come in a range of sizes, but those smaller than 2.5 micrometers pose the greatest risk to human health.
Thick haze hung over northern India and Bangladesh in January 2013. Over the past decade, large cities in India have seen some of the world's fastest-rising levels of air pollution.