Air quality rated hazardous from wildfires, as Detroit ranks worst in world: What you need to know

Published July 16, 2026 8:11 AM EDT

Air quality continues to be a concern Thursday with the haze, smell and breathing conditions at dangerous levels for those spending long periods of time outdoors.

By the numbers:

The Air Quality Index is explained as the bigger the number, the more particles are in the air. The AQI marks anything more than 310 as hazardous - with Detroit current scoring 474 thanks to the smoke from Canadian wildfires.

Other cities with the worst conditions in the world Thursday morning are Minneapolis at 421, Oak Park at 427 and Ypsilanti with 293.

The Air Quality Index score ratings are:

0-50 GOOD — Little to no risk

51-100 — MODERATE — A small number of unusually sensitive people may have health concerns

101-150 —  UNHEALTHY FOR SOME — People with heart/lung disease, older adults and children should limit outdoor activities

151-200 — UNHEALTHY — Everyone should limit outdoor activities, unusually sensitive people should remain indoors.

201-300 — VERY UNHEALTHY — Everyone should remain indoors as much as possible.

Any score beyond 301 is HAZARDOUS.

When it comes to global conditions, Toronto is scoring at 360 unsurprisingly given its vicinity to the wildfires with other scores paling in comparison to the other highest non-US cities, like Kinshasa, Democratic Republic of Congo (161) and Delhi, India (146) according to the website IQAir.

Safety guidelines:

It is recommended that, when possible, you avoid strenuous outdoor activities, especially those with heart disease and respiratory conditions like asthma.

Watch for symptoms including wheezing, coughing, chest tightness, dizziness, or burning in nose, throat, and
eyes.

You can help reduce air pollution by limiting activities, such as outdoor burning and use of residential wood burning devices.

Tips for households: Keep windows closed overnight to prevent smoke from getting indoors and, if possible, run central air conditioning with MERV-13 or higher rated filters.

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Tower cam view of the Mackinac Bridge

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