How to keep safe as wildfire smoke chokes eastern US skies

Exposure to smoke can trigger an array of health problems, experts say, but there are ways residents can stay safe

Air quality alerts were in place for 110 million US residents on Wednesday as smoke from Canadian wildfires choked the skies.

New York, Washington DC, Delaware and Pennsylvania had the worst air quality in the nation on Wednesday morning, EPA data showed. Levels in central New York were deemed hazardous" - the worst level on the EPA's index for air quality reporting - while Philadelphia was placed under a code red" as the air quality index soared to its highest level since 2008.