Dhaka, Aug. 3 -- Smoke from wildfires can travel vast distances and significantly deteriorate air quality far from the fire's source, posing health risks even in areas not directly affected by the flames.

Fires burning in one region can spread smoke across multiple states, and wildfires in Canada have also sent polluted air into U.S. cities. Here's what you need to know to stay safe when air quality worsens due to wildfire smoke:

Understanding bad air quality

The U.S. Environmental Protection Agency (EPA) uses the Air Quality Index (AQI) to rate air pollution. A lower AQI means better air quality:

0-50: Good

51-100: Moderate

101-150: Unhealthy for sensitive groups

Above 150: Unhealthy for all

Sensitive groups include individuals w...