It’s not cloudy in Boston; that gray sky is the result of a smog blanketing the city caused by traveling pollutants from the Canadian wildfires. Boston’s air quality reached record highs this week, with the Boston Real-time Air Quality Index (AQI) exceeding 136 at points in the day.
To put that into context, a reading of 50 or below marks a healthy Air Quality Index number. Health officials recommend avoiding time outdoors if possible and wearing a mask to avoid breathing the toxic dust particles.
Indoors, they suggest keeping all windows closed until the air quality improves and using an air filter.
Air quality index levels
- 0–50 – Good: Air quality satisfactory
- 51–100 – Moderate: Air quality is acceptable; some concern for sensitive groups
- 101–150 – Unhealthy for Sensitive Groups: Members of sensitive groups (e.g., children, elderly, people with asthma or heart/lung conditions) may experience health impacts.
- 151–200 – Unhealthy: For general public.
- 201–300 – Very Unhealthy
- 301–500 – Hazardous
When will the air quality improve in Boston?
Wildfire season lasts through October in Canada. The Air Quality is expected to reach its worst on Monday and Tuesday. By Wednesday, August 6, the smog should slowly start clearing, with improved air quality levels expected for the weekend.
If you’re traveling, locations closer to Cananda, like northern Maine, currently have even worse air quality than Boston due to their proximity to the fires. To check the air quality in your neighborhood or travel destination, use AirNow.gov.