When It Comes to Air Pollution, the Tiniest Particles Might Be the Worst
by Patrick J. Kiger (HowStuffWorks) … But in recent years, scientists have found increasing evidence of health risks from a part of air pollution that we don’t see, and that isn’t yet regulated under federal air quality standards. In addition to visible emissions, the burning of fossil fuels and other types of combustions create vast quantities of ultrafine particles — somewhere around a thousandth of the width of a human hair — that we inhale without even realizing it.
Lots of Sources
Ultrafine particles come from an array of sources, according to Bart Ostro, former chief of air pollution epidemiology for the California Environmental Protection Agency, and currently a researcher at University of California, Davis. They’re emitted from vehicles, especially ones that burn diesel fuel, as well as smaller gasoline-burning engines, such as the ones in lawn mowers and leaf blowers. But other types of burning — wood fires, burning leaves, secondhand smoke from cigarettes, for example — also produce ultrafine particles. So does cooking meat on the stove in your kitchen.
It may seem strange that something so small could be dangerous. But because of their size, ultrafine particles have an easier time getting into lung tissue and causing inflammation, as detailed in this 2003 animal study. Even a brief amount of ultrafine particle exposure can increase the allergic inflammation that makes asthma worse, according to this study published July 5, 2010 by UCLA researchers.
But that’s not the only worry. Ultrafine particles are so tiny that they can penetrate the blood-brain barrier and be absorbed into brain tissue. READ MORE
Thank you for this great explanation… (Urban Air Initiative)