December 5-9, 1952. A massive layer of smoke and fog descended on the city of London, England, born of the smelters, factories, and coal furnaces that powered the industry and heated the homes of the region. In its wake, it left perhaps 12,000 people dead, taking its slow toll for months to come after the haze had lifted.1

The Lethal London Smog of 1952, as it is known now, 50 years later, was hardly the first time the air itself turned deadly. Twenty-two years earlier, in 1930, in the Meuse Valley in Belgium, 60 people had also died in December. And, in 1948, a weather inversion had trapped the exhausts of factories, coke ovens and refineries in tiny Donora, Pennsylvania. Although it only killed 20 people, 17 died on one day in October. As would happen four years later in London, undertakers in Donora ran out of caskets.2

Each of these three cases sounded a warning to the world about the deadly threat of airborne pollution and helped usher in the modern environmental movement.3 Then, in the mid 1990s, new scientific studies demonstrated that the threat remained: air pollution in the form of tiny, invisible particles, was still quietly, but effectively killing tens of thousands of Americans every year.

Particle pollution refers to a combination of fine solids and aerosols that are suspended in the air we breathe. The particles are especially small, some so small they can only be seen with an electron microscope. Particle pollution is all around us ? sometimes in high concentrations. However, particle pollution can trigger reactions ranging from coughing and wheezing to heart attacks and death. Because of their size, you can?t see the individual particles. You can only see the haze that forms when millions of particles blur the spread of sunlight in an area. You can?t tell when you?re breathing particle pollution. And yet it is so dangerous it can take years off your life.4

This is the first time the American Lung Association has included assessments of particle pollution in the American Lung Association State of the Air. This report provides the first specific county-level information on the presence of particle pollution now available to us through a new monitoring network first set up in the late 1990s. The years covered by this report, 2000 to 2002, mark the first time three complete years of monitoring data were available nationwide from this network.

Particle pollution ranges in size from the tiny to the microscopic. Our built-in respiratory protection system is designed to filter and get rid of the larger particles, those that are larger than 10 microns in diameter. For comparison, a human hair is about 75 microns in diameter. However, the smaller particles get trapped in the lungs, while the smallest are so tiny they pass through the lungs into the blood stream, along with the essential oxygen molecules. Researchers categorize particles according to size, grouping them as coarse particles and fine particles. Coarse particles fall between 2.5 microns and 10 microns in diameter and are called PM10-2.5. Fine particles are 2.5 microns in diameter or smaller and are called PM2.5. Both coarse and fine particles are harmful to your health.

Click here to view a Quicktime annimation on how partical pollution effects the lungs.  You must have Quicktime installed on your computer to play our movie. Quicktime installation is easy! Just visit their website: http://www.quicktime.com and download.

 Health Effects continued...