Demystifying Science | How do you protect yourself from smoke?

Each week, our journalist answers readers’ science questions.

How do we protect ourselves from wildfire smoke when it reaches Montreal?

John Bellerin

In addition to staying at home, the Federal Minister of Health, Jean-Yves Duclos, recently suggested on his Twitter account the installation of a HEPA filter to filter the air.

But according to US researchers who have published extensively on the issue, it is possible to use less expensive filters.

“We recommend using MERV13 or a higher quality filter,” he explained in an interview with Beth Hassett-Sipple and Amara Holder of the US Environmental Agency (EPA), who published an abstract of their studies in 2021 in the journal. The limits of public health. “Ideally, you should have several spare filters to replace if needed during smog episodes related to wildfires.”

A HEPA (High Efficiency Particulate Absorption) filter is equivalent to MERV17 quality, according to EPA professionals. “The higher the filtration level, the more powerful the fan you need,” they explain. So the air recirculation may be less frequent. »

In other words, with the same fan power, the air in your home is recirculated more quickly with a MERV13 filter than with a HEPA filter, which has more resistance to fan blowing.

Also, higher quality filters are more expensive. “It may be best to use MERV13 filters because they are easy to find, relatively inexpensive, and don’t obstruct the fan-forced airflow too much.”

home filter

You can easily make your own MERV13 air purifier using a fan sold in supermarkets and a MERV13 filter, explains the master.^I What is with you. To achieve this, all you need to do is get a square fan model that you can put on the ground and attach a filter to it. “It works very well, and many tests have been done with homemade MERV13 purifiers.”

I just posted, in review indoor aira study showing that these home purifiers cost less than $100 and have comparable efficiency to MERV13 filters used in ventilation systems.

The goal is to reduce the amount of particles with a diameter of less than 2.5 micrometers, 0.0025 mm.

“Of all the smoke pollutants from wildfires, PM2.5 poses the greatest danger,” explains Danny Doiron, research associate at the McGill University Health Center (MUHC) Research Institute. “They are inhaled deep into the lungs and cause inflammation that affects other parts of the body.”

In addition to exacerbating existing lung diseases, PM2.5 increases the risk of chronic diseases, including heart disease.

Many people feel protected by their air conditioning system, noted m^I What is with you. “But the air conditioner does not usually run continuously, so the air is not always purified.”

Should the MERV13 filter be used when there is simply smog, no wildfires? M says^I Hassett Seibel.