After fires destroyed multiple neighborhoods across Los Angeles County, many residents looked up to find blue, smoke-free skies this week. The Air Quality Index (AQI) — which measures the ...

Add Yahoo as a preferred source to see more of our stories on Google. Wildfires in Canada are sending heavy smoke across the northern U.S., and New Jersey is experiencing some unhealthy air pollution.

Delhi’s air debate is dominated by numbers—daily AQI values, PM2.5 averages, counts of “good”, “poor”, and “severe” days.

A thick cloud of wildfire smoke is choking millions of Washington state residents due to 23 active wildfires in the state, in addition to the dozens of wildfires to the north in British Columbia.

Wildfires in Canada are sending heavy smoke across the northern U.S., and New Jersey is experiencing some unhealthy air pollution. The air quality has some Northeasterners wondering, what is the AQI, ...