The weekend’s storm cleared out Tooele Valley’s air, but by noon on Monday Tooele’s air quality again reached the “yellow” or moderate level.
At the yellow air quality level, unusually sensitive people are cautioned to consider reducing prolonged or heavy outdoor exertion. All individuals are asked to voluntarily not use solid fuel burning devices, including wood and coal burning stove and fireplaces; reduce/stop open burning, and reduce vehicle emissions by consolidating trips and using public transportation or working from home. Industries are asked to voluntarily optimize operations to minimize air pollution emissions, according to the Division of Air Quality.
Last week, an inversion, an atmospheric condition where a layer of cold air sits on top of a layer of warmer air — like a lid on a kitchen pot — trapped pollutants in the valley.
From Jan. 10-20, 2022, Tooele County logged nine days of yellow air quality and reached “orange” or “unhealthy for sensitive groups” on one day, according to data from the Environmental Protection agency.
It is not unusual for inversions to occur after snow storms, according to the DAQ.
One of the main components of pollution trapped in an inversion is PM2.5, according to the DAQ. PM2.5 refers to microscopic particles, or particulate matter, that have a diameter of less than 2.5 micrometers, about 40 times smaller than the diameter of a strand of hair.
Sources of PM2.5 include mobile sources like vehicles, trains and aircraft; small immobile sources such as home heating, smoke from wood burning, and emissions from small businesses like restaurants and dry cleaners; and point sources that include industrial and commercial facilities.
During an inversion, mobile sources account for 48% of the PM2.5 build up, while immobile sources account for 39% and stationary sources account for 13%, according to the DAQ.
In Tooele County, PM 2.5 not only peaks during winter time inversions, but also during summer months when heat and smoke from forest fires cause PM 2.5 to build up to unhealthy levels.
High levels of PM 2.5 can cause wheezing, coughing, chest tightness and difficulty breathing. Because of their small size, PM 2.5 particles can be inhaled deeply into the lungs and are tied with long term health problems like premature death from heart or lung disease, irregular heartbeat, decreased lung function, nonfatal heart attacks, and aggravated asthma, according to the Environmental Protection Agency.
The quality of air is divided into six levels; good or green, moderate or yellow, unhealthy for sensitive groups or orange, unhealthy or red, very unhealthy or purple, and hazardous or maroon.
The level of two major pollutants, PM 2.5 and ozone, are used to determine air quality.
For PM 2.5 alone, air quality turns from good to moderate when the 24-hour average level of PM 2.5 exceeds 12.0 µg/m³ [micrograms per cubic meter].
Air quality turns unhealthy for sensitive groups at PM 2.5 concentration levels greater than 35.4 µg/m³.
Unhealthy air quality starts when the PM 2.5 level reaches 55.5 µg/m³. At 150.5 µg/m³ PM 2.5 air quality is called very unhealthy and at 250.5 µg/m³ it is hazardous.
In 2021, the monthly average of the daily PM 2.5 level in Tooele County was at the green or good level for nine months. For three months in 2021 — June, July and August — the monthly daily average was at the yellow or moderate level.
There were five days of orange or unhealthy for sensitive groups air quality and three days of red or unhealthy air quality in Tooele County during 2021.
The 24-hour daily average PM 2.5 level in Tooele County for the entire 2021 year was 8.5 µg/m³.
The Transcript Bulletin reported in July and August 2021, that wildfire smoke moved into the state from California and the Pacific Northwest along with high temperatures causing local air quality to deteriorate.
To reduce air pollution, the DAQ recommends that vehicle owners keep their automobile well maintained by following the manufacturer’s recommendations on routine maintenance. Tire pressure and wheel alignment should also be regularly checked.
Avoid idling automobiles, the use of electric or hand-powered lawn tools, using a modern gas can that limits emitting fumes and spilling gasoline, running dishwashers and clothes washers only when full and using environmentally responsible home cleaners can also contribute to better air quality, according to the DAQ.