What is an Inversion?
Have you ever experienced a wintertime inversion? Thick, fog-like air you can almost cut with a knife and taste in your mouth. It’s bad. With winter approaching we know an inversion is coming…but do you actually know why it occurs?
Inversions occur in colder months, usually between December and February, when normal atmospheric conditions become inverted and a dense layer of cold air becomes trapped under a layer of warm air. The warm layer acts as a lid, trapping the cold air and all of the pollutants it contains near the ground.
Inversions are common in areas that are surrounded by mountains. The mountains create a bowl keeping cold air stagnant.
When an inversion hangs around – which they often do – it can lead to high levels of fine particulate pollution, or PM 2.5. These particulates are small, 2.5 micrometers or less in diameter. It’s the size of fine particulate matter that makes it so dangerous – it can get past the nose and throat and make its way deep into the lungs.
According to the EPA, safe levels for PM 2.5 are 35 micrograms per cubic meter or less. During a strong inversion these PM 2.5 levels can reach up to 90 micrograms per cubic meter or more.
There will always be some fine particulate matter in the air. However, the majority is caused by sources such as vehicle emissions and wood burning stoves.
Here are some small changes you can make to reduce your negative impact on air quality during an inversion:
Check out the air quality levels in your area here: https://www.airnow.gov/