Wildfire smoke is expected on Long Island Thursday: Here's what to know

Smoke from Canadian wildfires is once again bringing hazy skies and unhealthy air quality to Long Island and New York City.

The state first issued an air quality health advisory for Wednesday. Then, Thursday, as the smoke is expected to enter downstate New York, the state said the air will be unhealthy for certain groups with chronic medical problems.

Here is what you need to know:

Why are wildfires in Canada impacting air in New York?

About 112 wildfires are currently burning in Quebec, the Canadian Interagency Forest Fire Centre reported Wednesday. In all, 474 active fires are burning across Canada. The smoke has drifted throughout parts of the United States and has even been detected in Europe.

Why is smoke from the wildfires dangerous?

Smoke from these fires releases particles and chemicals. Particulate matter can get inside a person’s lungs, causing difficulty breathing. Short-term health effects include irritation to the eyes, nose and throat, coughing, sneezing and runny nose.

For people who already have lung or heart disease as well as children and the elderly, the health impacts can be even more serious.

How is air quality measured?

The U.S. Department of Environmental Protection sets standards for air quality and measures the level of several major pollutants but in the case of wildfire smoke, scientists usually focus on the level of particulate matter known as PM 2.5.

An air quality index of 0-50 for PM 2.5 is described as “good” air quality while 51-100 is considered “moderate.” An index above 101 indicates the air quality is unhealthy for certain groups, such as people with asthma and heart conditions. A level of 151-200 is “unhealthy” followed by 201-300 as “very unhealthy.” Finally, an air quality index above 301 is considered to be “hazardous.”

What should I do when the air quality is considered unhealthy or worse?

Limit your time outdoors and stay inside with the windows closed. If you have a window air conditioner, only use it if you can close the outdoor damper, the EPA advises and make sure the space between the air conditioner and the window is tight. For those with central air, the EPA recommends closing the fresh air intake, turning it to recirculate mode and making sure the filter is in good condition. 

When do I need to use a mask?

If you are spending any time outdoors when the air is unhealthy, experts recommend wearing a N95 or KN95 mask. Gov. Kathy Hochul said free masks are available at several locations including Jamaica Station, Grand Central Terminal and Penn Station.

How can I keep track of the air quality in my neighborhood?

The New York State Department of Environmental Conservation publishes the Air Quality Index Forecast on its website. The national site AirNow.gov — run by the U.S. EPA, NOAA and other agencies — provides real time updates. Users can view maps or enter ZIP codes to check current air quality.

New Yorkers will also receive emergency call phone alerts if the air quality index exceeds the 200 threshold for 'Very Unhealthy' air and sustained for longer than an hour, Hochul announced on Wednesday.

Newsday also has an air quality map at its website.

By Lisa L. Colangelo

lisa.colangelo@newsday.com@lisalcolangelo

Lisa joined Newsday as a staff writer in 2019. She previously worked at amNewYork, the New York Daily News and the Asbury Park Press covering politics, government and general assignment.