Special to The Explorer
Tucson’s “winter” is approaching, and there is a change in the air, according to the Pima County Department of Environmental Quality.
Air quality is closely linked to solar influences and meteorological conditions.
“When we move from summer to winter, changes in the sun’s intensity, its morning arrival time, and air temperature all contribute to changes in visibility and air pollution levels,” the department said in a release. “Actions that we take on a daily basis can help reduce levels of air pollutants to keep our mountain views and our air healthy to breathe during the winter months.”
Why do winter mornings look hazy? It’s because of the meteorological phenomenon known as a temperature inversion, when the air temperature is inverted because cooler air is trapped closer to the surface by warmer air aloft.
“During the summer, the sun comes up early and the sun-warmed air rises freely, carrying air pollution with it as it circulates above our community,” the release said. “In the winter, the sun rises over the mountains later in the morning, so overnight and early-morning air pollution we create is trapped in the cool, dry, concentrated layer.”
Pollutants remain until the surrounding air is warmed enough to begin rising, which helps dilute the pollutants. “Since the nights in the wintertime are much longer than nights during the summertime, surface inversions are stronger and more common during the winter months,” the release said.
What we can do to reduce winter air pollution levels
Drive less. Walk, carpool, bike, or take the bus instead. Combine errands into one trip.
Avoid idling. Save gas and reduce engine wear by limiting idling to less than a minute.
Reduce fireplace use. Heating by fireplace is a very inefficient form of heat. If you have an option, choose electric, natural gas, solar, or an EPA-certified wood stove to heat your home.
Keep your car well maintained and check your tire pressure monthly. Save money on gas and reduce emissions associated with poorly maintained vehicles.
For more information on local air pollution levels, call Pima County Department of Environmental Quality’s air pollution hotline at 882-4AIR (882-4347) or click on www.AirInfoNow.org.



