CONCORD, N.H. — Wildfires burning in Canada have led to air quality alerts issued across the Northeast.
But even as the smoke dissipates, experts warn that the conditions that lead to massive wildfires — heat and dryness — are becoming more common thanks to climate change. This summer wasn’t the first time air quality suffered as a result of wildfires, they say, and it won’t be the last.
Here’s what experts say you should know about how to protect yourself from smoke and what to expect moving forward.
Why is this happening?
Canada is having a dry season, which is part of why these wildfires have been so intense and so frequent, said David Healy, a senior scientist in the air resources division at New Hampshire’s Department of Environmental Services.
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“It’s only June 7 and I think there could be a long and hot fire season to come,” Healy said.
Will the issues with smoke and poor air quality persist?
It’s hard to predict whether the fires in Canada will lead to more air quality issues in New Hampshire. A high pressure system brought smoke from Nova Scotia to the region last week. This week, it was a low pressure system that brought smoke from Quebec.
Is there an air quality index, alerts, or a local smoke forecast?
New Hampshire Department of Environmental Services issues air quality alerts on its website and provides an air quality forecast.
NOAA publishes a map with current smoke density and provides an air quality forecast for up to 72 hours.
At AirNow.gov you can enter your zip code to see the air quality at your current location and a forecast.
How can people protect themselves?
Healy said the most important thing people can do is stay informed, and stay indoors if certain air quality alerts are issued. When a code orange alert was issued this week, that meant the air quality was unhealthy for sensitive groups including children, older adults, and people with existing lung conditions like asthma or bronchitis.
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The department’s advice is that those people limit prolonged or heavy outdoor exertion. The department doesn’t set a time limit, but generally speaking, the longer you’re outside, the more exposure you can have.
Keep the windows and doors closed to prevent particles from entering your home. Experts also recommend running air conditioning if you have central air.
Should I wear a mask? What kind?
Smoke contains very fine particles, which are called PM 2.5 because they measure less than 2.5 microns in diameter. That’s significantly less than the width of a human hair, so a typical over-the-counter mask will not protect you from breathing in those particles.
An N95 or equivalent mask can help reduce exposure, according to Peter DeCarlo, an air quality expert and associate professor of Environmental Health and Engineering at Johns Hopkins University.
It’s important to make sure the mask fits snugly, said Dr. Holly Mintz, chief medical officer of Elliot Ambulatory Care Services. “The challenge with N95 is they have to fit correctly,” she said. “If it doesn’t fit properly, it’s not going to make a difference.”
Cloth masks will not help, she said.
What about using an air filter indoors?
Using a HEPA filter indoors can help improve air quality inside the house, according to DeCarlo. HEPA stands for high efficiency particulate air filter, and it can remove dust, pollen, mold, bacteria, and airborne particles that are as small as .3 microns, according to the EPA.
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The EPA also has information on how to make a DIY portable air filter, using a fan and a filter. If you choose to purchase an HVAC filter, the EPA recommends buying one with a MERV 13 rating.
If you have central air, you can use that to stay cool — be sure to set it to recirculate the air that’s already in your house. If your HVAC system has a fresh air intake option, be sure to turn that off. And if you have a window unit, figure out how to close the outdoor air damper. If you can’t, you will want to use another way to stay cool.
Why are children at risk? considered more sensitive?
Mintz said it’s important to keep children away from smoke because their lungs are still developing. But she said she wouldn’t expect a healthy child to be affected more than an adult. The determining factor is whether they have an illness such as asthma.
“The challenge is usually for people who have underlying lung issues, if someone has asthma, or COPD (Chronic obstructive pulmonary disease), or emphysema,” she said. “It’s hard to measure the effects that the poor air quality from the fires has on the lungs.”
Amanda Gokee can be reached at amanda.gokee@globe.com. Follow her on Twitter @amanda_gokee.