How smoke from distant wildfires can harm human health | Health News from the Healthiest Communities

Smoke from Forest fires burning across Canada has spread to North American cities far from the flames. New York and Detroit were both among the top five cities with the worst air quality in the world from the fires on June 7, 2023. The smoke has triggered air quality alerts in several states in recent weeks.

We asked Chris Migliacciotoxicologist at the University of Montana who studies the impact of wildfire smoke on human health, the health risks people may face when smoke comes from distant wildfires.

When we talk about air quality, we often talk about PM2.5. These are particles of 2.5 microns or less, small enough to penetrate deep into the lungs.

Exposure to PM2.5 from smoke or other air pollutants, such as vehicle emissions, can aggravate health conditions such as asthma and reduce lung function in ways that worsen existing respiratory problems and even heart disease.

But the term PM2.5 only tells you the size, not the composition – what burns can make a significant difference in the chemistry.

If you’ve ever been around a campfire and got a puff of smoke in your face, you’ve probably felt some irritation. If exposed to smoke from a wildfire, you may experience irritation of the nose and throat and possibly some inflammation. If you are in good health, your body will largely be able to handle it.

As with many things, the dose makes the poison – almost anything can be harmful in a certain dose.

Generally, cells in the lungs called alveolar macrophages will pick up particles and dispose of them – in reasonable doses. It’s when the system is overwhelmed that you may have a problem.

The stress of an inflammatory response can also exacerbate existing health issues. Being exposed to wood smoke will not independently cause a heart attack, but if it has underlying risk factors, such as heavy plaque buildup, the added stress may increase the risk.

Researchers have found that there appears to be a higher level of oxidation, so oxidants and free radicals are generated the longer the smoke is in the air. The specific health effects are not yet clear, but there are indications that greater exposure leads to greater health effects.

The assumption is that more free radicals are generated the longer the smoke is exposed to UV light, the greater the potential for health damage. A lot of it, again, comes down to dose.

Chances are, if you’re a healthy person, going for a bike ride or hike in light mist won’t be a big deal and your body will be able to recover.

However, if you do this every day for a month in the smoke of a wildfire, that raises more concerns. I worked on studies with residents of Seeley Lake, Montana who were exposed to dangerous levels of PM2.5 from wildfire smoke for 49 days in 2017. We found a decreased lung function one year later. No one was on oxygen, but there was a significant drop.

This is a relatively new area of ​​research, and we are still learning a lot, especially with the increase in wildfire activity as the planet warms.

If there is smoke in the air, you want to decrease your exposure.

Can you completely avoid the smoke? Unless you are in a hermetically sealed house. PM levels are not much different indoors and outdoors unless you have a very good HVAC system, such as those with MERV 15 filters or better. But going indoors decreases your activity, so your breathing rate is slower and the amount of smoke you inhale is likely lower.

We also tend to advise people that if you are part of a sensitive group, such as asthmatics, create a safe space at home and in the office with a high-level self-contained air filtration system to create a space with cleaner air. .

Some masks can help. It doesn’t hurt to have a high quality N95 mask. However, simply wearing a cloth mask won’t do much.