Smoke from more than 430 active wildfires in Canada spread south last week and led to the worst pollution the New York and Washington regions have ever experienced. More than 75 million people in the eastern US were under air quality alerts as wildfire smoke shrouded major cities. Some flights were grounded, events were canceled, and millions of people breathed unhealthy air.
Much of the smoke has dissipated, but people still have questions. Do we need to be concerned about air quality? What are the short-term effects of wildfire smoke inhalation? Are there long-term consequences? And how can people prepare for future wildfires, which, according to the UN Environment Program, will be even more frequent and more severe going forward?
To guide us through these questions, I spoke with CNN Medical Analyst Dr. Leana Wen. Wen is an emergency physician and professor of health policy and management at the George Washington University Milken Institute School of Public Health. She previously served as Baltimore’s health commissioner.
CNN: How do people know if they are in the clear from wildfire smoke?
Dr. Leana Wen: The federal government has an excellent website, airnow.gov, where you can put in your city or zip code and see what the current air quality is in your area.
Just as the weather forecast in your area can change, so can the air quality. As we’ve seen from the spread of smoke from Canada’s wildfires, events hundreds of miles away can lead to pollution in another area. You can use this website to track air quality, and if necessary, change your plans and add precautions accordingly.
CNN: Are there people who should still be concerned about air quality due to the Canadian wildfires?
Wen: It depends on the air quality in their area and their underlying medical circumstances. The air quality in many parts of the country has gotten much better, returning to near normal, while other areas still have unhealthy levels of pollution.
Those most at risk during days with poor quality are young children, the elderly, pregnant individuals and people with underlying medical conditions, in particular chronic lung and heart conditions. Those people should be cautious, closely monitoring air quality in their area on a regular basis. If there are alerts and advisories, refrain from heavy exercise, stay indoors when possible and run air purifiers in indoor areas.
CNN: What are the short-term health effects of wildfire smoke inhalation?
Wen: During last week’s event, many people may have experienced adverse effects, such as throat irritation, hoarseness and cough. Some may have had worsening of their underlying asthma, bronchitis, COPD, which is short for chronic obstructive pulmonary disease, or other respiratory conditions. These are most pronounced in the initial days following smoke exposure. Studies have shown that exposure to wildfire smoke leads to an increase in emergency department visits and hospitalizations for respiratory disease in children and the elderly.
Studies have also demonstrated a more surprising link, which is the association between wildfire smoke exposure and serious cardiovascular events, including heart attacks and cardiac arrest. And there is research that has linked wildfire smoke exposure events to an increase in influenza months later, suggesting that there could be lagging effects.
It’s thought that many of these effects are due to microscopic particles called particulate matter that can enter deep into the lungs and even enter the bloodstream. These pollutants can induce inflammation and a stress response in the body, which can worsen existing medical conditions.
CNN: If people were exposed for a few days to bad air quality, should they be worried about long-term consequences?
Wen: There are people who live in parts of the world where exposure to hazardous amounts of particulate matter and other pollutants is an everyday reality. These populations are at risk for long-term consequences. Research has linked this type of chronic exposure to an increase in some cancers, for instance, and reduced lung capacity.
For most people, a one-time exposure event probably won’t cause major lasting problems. The worry is that these may not be one-time events going forward. Some people already live in areas prone to wildfires and could have exposure to events several times a year. And, as we have seen, wildfires from hundreds of miles away can cause such significant effects on air quality. With climate change, experts predict more frequent wildfires, which can lead to more days of hazardous air quality for all of us.
CNN: How can people prepare for future wildfires?
Wen: Invest in air purifiers for your home. Bad outdoor air leads to bad indoor air. Air purifiers can help remove smoke and those microscopic particles that are harmful to health.
Workplaces and schools can do this too, and also look to upgrade their ventilation system. Improving ventilation will also reduce virus transmission, including the spread of influenza and Covid-19.
People should optimize their medical health as much as possible. Those with lung disease especially should make sure to have an ample supply of inhalers and consult their physicians about whether there should be increased use in times of worse air quality.
Everyone should have a “go bag”— a bag of emergency supplies — to take with them when an emergency hits. That includes water, nonperishable food, prescription medications, flashlights, first aid kits and more.
Finally, we need to understand the intimate link between the environment and health, and work to prevent environmental hazards that can lead to many significant health problems, now and in the future.
Sign up for CNN’s Life, But Greener newsletter. Our limited newsletter series guides you on how to minimize your personal role in the climate crisis — and reduce your eco-anxiety.