Murky Vermont Weather Is Also Polluted

A murky, somewhat polluted winter day last February in 
St. Albans, Vermont beneath a temperature inversion.
Another inversion is causing some air quality concerns
in Vermont overnight. 

 We have suffered through quite a few days in Vermont so far this month with thick, low overcast, fog, haze and whatnot. 

When you get these calm, dank, depressing spells, sometimes you get another problem. Air pollution, believe it or not. And that's a bit of a problem tonight. 

Much of southern Vermont is under an air quality alert through around 11 a.m. tomorrow.

When there's a temperature inversion, stuff that comes out of tailpipes, chimneys and such gets stuck without being able to blow away.  That's especially true when winds are light, like today.

Remember, a temperature inversion is a layer of warmer air overhead. It's called an inversion because normally it gets colder with height, not warmer. 

Anyway, the inversion acts like a lid, keeping pollutants and fog and stuff trapped beneath that layer of warm air. 

Most of the pollution when there's a Vermont air quality alert in the winter consists of tiny particles that come out of chimneys, wood stoves and the like when we burn wood. 

As today's air quality alert states:

"Children and older adults, as well as people with heart or lung disease, should reduce prolonged or heavy exertion. Exposure to elevated levels of fine particles such as wood smoke can increase the likelihood of respiratory symptoms in sensitive individuals and aggravate heart or lung disease."

These types of air quality alerts happen almost every winter in Vermont, as this is the time of year when inversions tend to persist.   The strong, high sun in the spring and summer tends to easily break up inversions. The sun is still at a low angle now, and not as strong as it will be in a few months. 

The Rutland area is especially prone to this type of air quality problem because the valley is shaped somewhat like a bowl. An inversion puts a lid on this bowl and everybody's wood smoke gets trapped. 

The air quality alert is not in effect for Vermont north of Rutland and Windsor counties. Still, the air quality in the rest of Green Mountain State is not great this evening, so it literally won't kill people who have health problems to take it easy tonight and tomorrow morning. 

As of this evening, air quality was sort of borderline.  An air quality index of over 101 calls for caution among sensitive people. Both Rutland and Burlington were in the low 90s for an AQI as of 5 p.m. today.

Winds will begin to stir during the day Friday, which will likely improve the air quality.