Scientists have long known about the life-threatening impact of air pollution -- but up until now, tracking it globally with any accuracy had been out of reach. With new satellite-based imaging, however, researchers are getting their first peek at how particulate matter is distributed around the world, and in places where air pollution had been difficult to measure with any accuracy before -- an important step towards better understanding of a problem that epidemiologists say contribute to millions of premature deaths every year.In the developed world, instruments on the ground are typically used to measure the levels of harmful fine particulate matter, which is 2.5 micrometers or less in diameter. Material around this size, say researchers, is small enough to become embedded deep with in the lungs, which can contribute to asthma and bronchitis, as well as other serious health problems. Unfortunately, many places in the developing world had no way of accurately measuring air quality.
Using satellites to measure pollution near the planet's surface is no easy task -- instead data is returned reflecting the amount of particulate matter in a column of atmosphere. With the information gathered from two NASA satellites, researchers Aaron van Donkelaar and Randall Martin from Canada's Dalhousie University used computer modeling to generate a map showing how fine particulate matter is distributed throughout the world.
While some of the particulate matter is naturally occurring, particularly in windy places where it is lifted into the air, human activities is largely responsible as well. Areas of dense urbanization, like in eastern China, show higher levels of air pollution. Burning coal, and diesel fuels are likely thought to be responsible for the spikes, though researchers are working on updating the map to reflect human-caused and naturally occurring air pollution.
"We still have plenty of work to do to refine this map, but it's a real step forward," says Martin. "We hope this data will be useful in areas that don't have access to robust ground-based measurements."
For more information and a closer look at the map, visit NASA.gov.
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