Long Island's Smoke Clears, Air Quality Improves for Friday.

Smoke from out-of-control wildfires in Canada has caused air quality to remain at "unhealthy levels" on Long Island, forcing cancellations of activities and irritating throats for a second day. The Belmont Stakes may be cancelled on Saturday if air quality remains poor. While air quality improved slightly on Thursday, it remained "unhealthy" for everyone. Schools cancelled Friday outdoor events and moved school recess inside. Health experts warned that the smoky air could trigger asthma attacks and heart attacks in some vulnerable populations.