Alberta’s Industrial Heartland region has seen some very cold weather in recent weeks, keeping even those who love wintertime bundled up and indoors. A drop into the deep freeze often restricts our activities, and it can also affect the quality of the outdoor air.
Most of the time, local air quality in this region is of low risk to health as indicated by the Air Quality Health Index (AQHI). However, the AQHI rating can rise to a medium or high health risk when there is an occurrence of a weather phenomenon called a temperature inversion.
Normally, warm air sits near the ground and air rises easily, carrying away polluting substances. During a temperature inversion, cold air is trapped near the ground by warm air several hundred meters above it. The warm air acts like a lid and polluting substances can’t rise and disperse as readily. This leads to a higher AQHI rating.
The AQHI is a tool that helps people understand what the local outside air quality means to their health. An outdoor activity recommendation corresponds to each risk category. Moderate to high AQHI ratings may lead to health problems for at risk populations, such as children, the elderly and those with pre-existing respiratory conditions.
Some sources of polluting substances, like industrial emissions and wetlands, stay fairly constant throughout the year no matter what the season. But in the winter, fireplaces, wood stoves, home heating and idling vehicles contribute to higher concentrations. A temperature inversion traps a build-up of these substances near the ground until wind, a snowstorm or some other weather change sweeps them away.
Fortunately, temperature inversions that cause high or very high AQHI ratings are rare. Fort Air Partnership, the organization that monitors the air people breathe in and around Alberta’s Industrial Heartland, reported only six hours of high or very high AQHI ratings throughout 2017.
What You Can Do
People can reduce their impact on air quality by not idling vehicles when parked, avoiding excessive fireplace or wood stove use, and using energy efficient products. People can also keep track of current and forecast local AQHI levels at fortair.org and, if levels are high, adjust their outdoor activities accordingly.