20100923 globalairqualitynasamap600
A Global satellite-derived map showing the level of "health-sapping particles," also known as PM2.5, averaged over 2001 to 2006. - 

Air pollution has been a killer since the dawn of the industrial age, yet until recently scientists didn't know just how dirty the air was in most of the world.

New maps using satellite images and computer modeling are finally giving researchers a clearer view of the global problem of air pollution. These maps illustrate small particulate matter spread across the globe. The problematic particles are impossible to see, and in large amounts the microscopic dust can get into our lungs and bloodstreams -- causing health issues like asthma and cardiovascular disease. The American Heart Association estimates that in the United States, this particulate matter causes around 60,000 deaths a year.

These new maps don't rely just on satellite imagery alone. When you are looking down on the atmosphere from the perspective of a satellite, it's sort of like looking down through a glass of dirty water. The satellite is taking a picture of what it sees at the top -- but actually what you want to know is how the dirt is distributed in the entire column. So researchers used computer modeling to figure out how much particular matter had settled out in the air that we all actually breath.

"Now, with this map and dataset in hand, epidemiologists can start to look more closely at how long-term exposure to particulate matter in rarely studied parts of the world -- such as Asia's fast-growing cities or areas in North Africa with quantities of dust in the air -- affect human health." NASA writes on its website.

Until now, developing countries haven't had the tools to measure air pollution levels. The new information may also be useful in parts of the United States or Western Europe. Currently, air quality is measured using a small number of surface monitors. NASA is hoping the maps will be a good first step in helping to further understand airborne particles and their impact on our public health.

We talk with two researchers who built these maps -- Randall Martin, a professor at Dalhousie University in Halifax, and Michael Brauer, a professor of public health at the University of British Columbia.