This world is polluted with acronyms (and other things)! The strange thing is that in each little segment of life, the acronyms are as familiar as any other word. Outside of that segment, they’re meaningless. This one is pretty cool: AQI stands for Air Quality Index.

If we bet we can improve the air in the house by exchanging it with air outside, how can we know if that outside air is any good? There’s a app for that!

https://www.airnow.gov/about-airnow/

There’s a US AQI for five major pollutants that are regulated by the Clean Air Act: ozone, particle pollution (also called particulate matter), carbon monoxide, nitrogen dioxide and sulfur dioxide. The AQI for each pollutant is generally based on the health-based national ambient air quality standard for that pollutant and the scientific information that supports that standard.

Smoke is a big deal particularly if you are anywhere near the massive fires. I got a notice on the weather app on my phone that the sunset is going to be spectacular this evening because of the smoke — and I live on Cape Cod!

Residential ventilation systems rely on diluting the pollutants in the house with outside air. The majority of residential systems exhaust the air and that depressurizes the house and draws outside air in through the cracks and holes in the building envelope. And that’s great if the outside air is less polluted than the inside air. The exhaust strategy can be a problem if the humidity in the air moving through the cracks and holes strikes a surface that is below the dew point where the moisture will condense and cause mold and rot.

If you happen to be considering moving, you might want to check out the AQI for your new location before you design a new ventilation system. A positive pressure ventilation system might be a good choice if the AQI is consistently poor – anything over 100. A positive pressure system – the fan blowing into the house – will keep the bad air from leaking in.