A massive N.J. wildfire is nearly contained. Here’s what to know about wildfire smoke

Wildfire smoke contains carbon monoxide and hazardous air pollutants. But the main component of wildfire smoke, according to the EPA, is particulate matter, a common air pollutant that’s also present in car exhaust and emissions from fossil fuel-fired power plants.

Some particulate matter is so small — a fraction of the width of a human hair — that it can travel deep inside your lungs and even enter your bloodstream.

“What this does is cause an inflammatory response,” said Dr. Kartik Shenoy, an expert on pulmonary critical care at Temple Health. “Your airways tend to narrow a little bit more and the narrower airways make it hard for you to perform gas exchange — breathing in and breathing out.”

Exposure to wildfire smoke can exacerbate asthma and other lung diseases and can increase the risk of cardiovascular issues, such as heart attacks and strokes.

“Somebody may experience wheezing, shortness of breath, chest heaviness or tightness or coughing,” Dr. Olajumoke Fadugba, chief of allergy and immunology at Penn Medicine, told WHYY News last summer. “Those are signs and symptoms that there’s something going on.”

Wildfire smoke frequently affects air quality in the Philadelphia region, just not to the degree that it did last summer, Wilkins said.

Sometimes the smoke sits higher up, above the layer of air that humans typically breathe, he said. In that case, it may look like a cloud — instead of the low-lying haze of last summer’s smoke.

To find out where wildfires are currently burning and how their smoke is affecting air quality on a large scale, residents can check the real-time fire and smoke map published by the federal government.

To check the day’s air quality forecast for the place you live, use the EPA’s Air Quality Index,

The Air Quality Index, or AQI, rates air pollution from 0 to 500, with 0 being the cleanest and 500 being the dirtiest air. It also uses colors to communicate health risks.

• Green (0-50) means air quality is good, and poses little or no health risk
• Yellow (51-100) and orange (101-150) indicate air quality is moderate or unhealthy for sensitive groups. People who are not sensitive to poor air quality will likely not be affected. During an orange day, sensitive groups should limit their outdoor activities, people with asthma should keep quick relief medicine nearby, and those with heart disease should watch out for symptoms such as fatigue, palpitations or shortness of breath
• Red (151-200) means air quality is unhealthy, and the risks become more serious for people who are sensitive to poor air quality. They’re advised to avoid intense outdoor activities, and consider rescheduling them or moving them indoors. At this level, even members of the general public can feel health effects, and should reduce long or intense activities outside
• Purple (201-300) and maroon (301-500) mean air quality is very unhealthy or hazardous, and pose a health risk to everyone. At the maroon level, which is considered an air quality emergency, everyone should avoid physical activity outdoors and those who are sensitive to poor air quality should limit their activity levels even indoors

Wilkins recommends getting in the habit of checking the AQI each morning, like you might check the weather forecast.

“You wouldn’t plan a picnic during a thunderstorm warning. You wouldn’t go travel somewhere that’s about to get hit by a tornado or hurricane,” he said. “I want people to start looking at pollution the same way. Your life is just as in danger, your family’s life, your kids, your elders, whoever.”

“When you wake up in the morning, same as you try to figure out if you need to put that jacket on or that umbrella — simply just check the air quality,” he added.

The people most vulnerable to poor air quality include elders, young children, pregnant people and those who already have conditions such as asthma, COPD or heart disease.

Air pollution from wildfire smoke builds on other pollution sources, such as highways and industrial facilities, which are not distributed evenly in the Philadelphia region.

In Philly, rates of childhood asthma hospitalization are highest in ZIP codes in North and West Philly. Black and Hispanic children in Philly experience asthma-related hospitalizations at much higher rates than white and Asian children.

When the air quality outside is hazardous, it’s a good idea to stay inside or limit your activity outside.

If you go outside, wear a mask — preferably a tight-fitting N95 respirator.

Inside your home, close windows and doors and consider using an air filter. If you have central air conditioning, set it to recirculate mode so it’s not pulling in smoky air.

If you have asthma, keep your rescue inhaler with you, and make sure you and family members are taking any prescribed medications.

Human-caused climate change is lengthening the fire season across much of the world, Gonzalez said.

In the U.S., climate change is increasing the risk of major wildfires even in places not usually thought of as wildfire territory.

The research nonprofit Climate Central found that the number of hot, dry, windy days — when weather conditions are favorable for wildfires to spread — is increasing in New Jersey. The group found that in the last five decades, North Jersey has gained around 10 days of fire weather, while South Jersey has gained around four days.

So far, climate change has led to wildfires burning a larger area in the Western U.S., while other factors — like timber harvesting and other local human actions — have increased the area burned in other places, Gonzalez said.

If climate change continues to worsen, it could mean a higher risk that hazardous smoke will make its way to Pennsylvania from fires in the western U.S. and Canada, he said.

“Of course, we have a lot of ways to prevent that,” he said. “Each of us can take meaningful action on climate change.”