Temperature Inversions

My respiratory system has been feeling the effects of a temperature inversion in the Salt Lake Valley – a phenomenon that occurs frequently in the winter months here. Many of my studnets have been complaining of an exascerbation of their asthma symptoms.

In inversion occurs when a high pressure system develops and just sits over the area, trapping the smog and creating more polluted and still air until a storm comes along and blows it away.

Some days it gets so bad that people are asked not to drive or burn wood stoves.

They Department of Environmental Quality‘s website today reports that the air is “green” or “heatlhy”.

The site also has a page on 50 Steps You Can Take to Choose Clean Air, including tips of driving less and/or driving “smarter” and tips on what you can do at home and at work to promote cleaner air.

The past few days I have not been able to sleep well because of the congestion I have been experiencing. Along with this inversion is the onset of colder weather and the dryness from using the furnace. Tonight’s forcast is for rain and snow. I welcome anything to blow this stuff out of the valley.

What are temperature inversions? This is from the National Weather Service:

On most days, the temperature of air in the atmosphere is cooler the higher up in altitude you go. This is because most of the suns energy is converted to sensible heat at the ground, which in turn warms the air at the surface. The warm air rises in the atmosphere, where it expands and cools. Sometimes, however, the temperature of air actually increases with height. The situation of having warm air on top of cooler air is referred to as a temperature inversion, because the temperature profile of the atmosphere is “inverted” from its usual state. There are two types of temperature inversions: surface inversions that occur near the Earth’s surface, and aloft inversions that occur above the ground.

Surface temperature inversions play a major role in air quality, especially during the winter when these inversions are the strongest. The warm air above cooler air acts like a lid, suppressing vertical mixing and trapping the cooler air at the surface. As pollutants from vehicles, fireplaces, and industry are emitted into the air, the inversion traps these pollutants near the ground, leading to poor air quality. The strength and duration of the inversion will control AQI levels near the ground. A strong inversion will confine pollutants to a shallow vertical layer, leading to high AQI levels, while a weak inversion will lead to lower AQI levels. A large contributor to poor air quality during the winter is residential wood burning. Wood smoke contains much higher amounts of particulate pollution than smoke from oil- or gas-fired furnaces. In some areas of the country, local governments issue burn bans to curtail the use of woodstoves and fireplaces under certain weather and pollution conditions during the winter.