Heat dome plus wildfire smoke degrade NYC-area air to "Unhealthy"

On July 17, 2026, a heat dome — a stubborn high-pressure lid trapping heat — pushed NYC temperatures past 90°F as Canadian wildfire smoke settled over the city. Long Island's AQI for fine particles reached 195, a level where everyone, not just sensitive groups, faces health risks. Mayor Zohran Mamdani urged residents indoors; the city distributed free KN95 masks.