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Smoke from wildfires burning in western Ontario and northeastern Minnesota pushed air quality across the Northeast into unhealthy territory on Thursday, July 16, prompting state agencies from Pennsylvania to Massachusetts to issue alerts. Pennsylvania's Department of Environmental Protection declared a Code Red air quality alert for Thursday, meaning pollution levels unhealthy for everyone. The Massachusetts Department of Environmental Protection issued alerts covering the entire state. An air quality advisory was in effect for all of New York State, and the New York State Department of Environmental Conservation forecast the New York City Metro region at an Air Quality Index (AQI) of 200 for fine particulate matter (PM2.5), the top of the Unhealthy band.
The category matters more than the number. At Unhealthy, spanning 151 to 200, the guidance stops being about sensitive groups. New York City Emergency Management (NYCEM) states that everyone may experience health effects and that all residents should take precautions. No one is immune to the health effects of wildfire smoke.
The guidance issued alongside the New York City advisory tracks what health departments across the region are telling residents. All residents should limit strenuous and prolonged outdoor activity, with prolonged defined as more than one hour, and sensitive people should avoid unnecessary outdoor activity. Windows and doors stay closed, and air conditioners and HVAC systems should be set to recirculate indoor air rather than draw in outside air. Outdoor workers should take frequent indoor breaks, and employers are urged to reschedule non-essential outdoor work.
Two items cut against common assumptions. On masks, a well-fitting KN95 or N95 offers protection, while cloth and surgical masks do not protect meaningfully against fine particulate matter. On the conflict between heat guidance and smoke guidance, one of which says open the windows while the other says seal the building, NYCEM is explicit that heat guidance takes precedence. Anyone without air conditioning whose home becomes uncomfortably warm should go to a cooling center, even during the smoke event.
Residents are advised to monitor conditions through AirNow and to watch for eye irritation, coughing, shortness of breath, and chest pain. Anyone with severe difficulty breathing or chest pain should call 911, and patients whose asthma or heart disease is worsening should contact their physician.
