Q&A: An air pollution expert on the dangers of wildfire smoke

Francesca Dominici

June 15, 2023Francesca Dominici, Clarence James Gamble Professor of Biostatistics, Population, and Data Science at Harvard T.H. Chan School of Public Health and co-director of the Harvard Data Science Initiative, is an expert on the short- and long-term health impacts linked with exposure to air pollution, and especially to wildfire smoke. In this Q&A—adapted from a June 9 Q&A on Harvard Chan School’s Instagram channel—Dominici answers questions about the smoke from Canadian wildfires that blanketed a large swath of the East Coast in early June, focusing on how smoke affects our health and how to stay safe on smoky days.

Why is the sky orange?

The sky is orange because of a very high level of particulate matter.

What should we do to stay safe?

Unfortunately right now the level of fine particulate matter in the air in the Northeast is extremely high, so the most important thing to stay safe is try to limit outdoor exposure to air pollution as much as possible, and a way to do that is to stay indoors, close your windows, activate air conditioning, and, if you have an air purifier, activate the air purifier. If you really have to go outside then wear an N99 mask [or other mask, such as an N95].

What are the immediate health concerns if you breathe in the air?

Our studies have shown that there are both short-term and long-term consequences of breathing a high level of fine particulate matter. We do know that being exposed to a high level of fine particulate matter can increase your risk of hospital admission either for cardiovascular respiratory disease on the same day, on the day after, or up to two or three weeks after. We also know that the long-term exposure to fine particulate matter has a chronic effect.

How do wildfires affect my health from thousands of miles away?

We can see with our naked eyes that wildfire smoke can travel very far. The general public may have been thinking that you just have to be careful if the wildfire is occurring across the street from you, but we are seeing now with satellite images … high levels of wildfire smoke in New York that originated in Canada. And, indeed, we also experience a high level of fine particulate matter on the East Coast when there are wildfires on the West Coast. So the bottom line is that wildfire smoke can travel really far and what is important is not so much where it’s coming from but the level of fine particulate matter that you are breathing right now.

Do we need to prepare for a greater threat from wildfires in the coming years?

Unfortunately, yes. Our studies have demonstrated by using an atmospheric chemistry model that even with moderate to aggressive climate change regulation in terms of targeting greenhouse gases, we are going to see a higher occurrence of wildfires. They will be both more common and more intense.

How can someone check the air quality where they live?

There is a website called AirNow.gov where you can see the level of fine particulate matter in your area by zip code. Also, there is an air quality index on your phone that you can check on a regular basis. These are very reliable data.

What symptoms might people experience as a result of the poor air quality?

The symptoms that we are experiencing are burning eyes, coughing, and sore throat. We could also experience more severe symptoms, such as heart failure or myocardial infarction.

What should those with asthma do to protect themselves?

They should limit exposure as much as possible. Stay indoors, close the windows, run an air purifier. I also think that they should call their doctors to see whether or not there are any preventative measures that they can take.

Will this last all summer? When can we expect this to end?

We know that this high level of fine particulate matter is going to persist for a few days as a result of the wildfires in Canada. Whether or not that’s going to occur again and for how long will really depend on whether or not there are more wildfires.

Karen Feldscher

Photo: Kent Dayton