Another air quality alert is in effect Tuesday for NYC, western Long Island, the Hudson Valley, northwest New Jersey and southwest Connecticut.

Air quality alerts are in effect on Tuesday in 10 states as toxic smoke from hundreds of wildfires burning in Canada continues to waft into the United States, creating hazy, gray skies over major metropolitan areas, including New York City.

Air quality alerts are issued when pollution levels rise to unhealthy levels, warning the public, especially vulnerable groups, to limit outdoor exposure for health and safety.