Everyone knows air pollution is bad for you, your kids, trees, and the planet. Small particles of partially burned car and truck exhaust are particularly insidious, and can get into your lungs, your bloodstream, even your brain.

Now a new study suggests it can mess with your breathing while you sleep, too, and put you at higher risk for a host of serious health problems.

People exposed to high levels of "microparticle" pollution — mostly those living near roadways and/or in urban areas — can have higher rates of asthma and other lung afflictions, but they just as often show

no ill effects, even after years of exposure.

It isn't until researchers look at data from thousands of people across a whole city, or many cities, that patterns begin to emerge — high microparticle concentrations increase risk of high blood pressure, heart attack, and stroke.

Antonella Zanobetti of Harvard University and a team of researchers put a new twist on this type of work — they looked at whether air pollution could interfere with sleep. They matched a dataset of 6,000 people monitored for the Sleep Heart Health Study between 1995 and 1998 to air pollution measurements from the same time and locations.

The team found that "sleep disordered breathing," — a catch-all term for snoring and any other interference with normal breathing during sleep — increased 13 percent with elevated levels of pollution. Blood oxygen levels were depleted for 20 percent more time in people

sleeping in high-pollution environments, too. This was primarily seen during the summer, when high temperatures are known to exacerbate the effects of air pollution.

The researchers' work appears in American Journal of Respiratory and Critical Care Medicine. Zanobetti was quoted in an article on PhysOrg.com:

"Particles may influence sleep through effects on the central nervous system, as well as the upper airways," wrote Dr. Zanobetti. "…Poor sleep [associated with poor health outcomes] may disproportionately afflict poor urban populations. Our findings suggest that one mechanism for poor sleep and sleep health disparities may relate to environmental pollution levels."

Poor sleep habits have also been shown to increase risk of cardiovascular diseases, so this study presents a kind of double whammy. Not only are people exposed to high levels of microparticle pollution already at risk for heart attack, stroke, and the like, but the pollution is preventing them from sleeping well, exacting yet more punishment on their bodies.

As if we needed another reason to clean up air pollution, this is a pretty good one.

Source: American Thoracic Society, via PhysOrg

Image: Smog over Santiago, Chile via Skillig2008 on Flickr