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Jan 28, 2009 10:51 pm US/Central
Good Question: Is Cold Air Cleaner Than Warm Air?
(WCCO)
Take in a deep breath of cold, winter air and you'll probably feel invigorated, refreshed, even healthy. But is cold air cleaner than warm air?
"Just because its cold out doesn't mean that we don't have the pollution out there," said WCCO Morning and Noon meteorologist Mike Augustyniak.
In fact, small particulate levels were so high in the Southern portions of Minnesota, including St. Cloud and the Twin Cities, that the state Pollution Control Agency declared an Air Pollution Health Advisory.
What makes a winter day deserving of an air pollution advisory?
"In most cases it's a very fancy thing called a 'temperature inversion,'" said Augstyniak.
"You may not notice, but it is warmer at 5,000 feet than it is at the surface," he explained. "In general, its cooler in the upper atmosphere than it is on the ground. That allows air to mix, which dilutes the amount of pollution close to the surface.
"On inversion days it just doesn't happen," said Augustyniak, and the warm air aloft acts as a lid, "the proverbial meteorological class ceiling," trapping the pollution.
Small particulate pollution is generally caused by a complex reaction in the air between industrial and automotive exhaust gases, according to the
U.S. Environmental Protection Agency.
"It's crisp, that's for sure. It doesn't necessarily have to be cleaner," he explained.
So what about the health aspect of this? Didn't your mom tell you that breathing in that crisp air was good for you?
"Warm dry air, cold dry air, I don't think it's the temperature that matters," said M.D. Melissa Mark, a family practice physician with Fairview's Uptown Clinic in Minneapolis.
In fact, according to Mark, cold air can be a serious irritant to people with certain types of asthma.
"Some people have cold-induced asthma. They walk out the front door and start coughing after 30 seconds or so," said Mark.
She explained that the human face, tongue and throat have a dense amount of thermoreceptors. Those sensors detect cool temperatures and our bodies often translate that cool sensation as being fresh or clean.
"So it's not the temperature, it's what's in it," explained Mark.
(© MMIX, CBS Broadcasting Inc. All Rights Reserved.)
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