Regular air filters of little use against wildfire smoke

Air quality advisory ends in Vancouver, but breathing issues on rise

As health impacts of the frequent air quality advisories in Metro Vancouver are starting to come to light, doctors and air filtration experts are warning that indoor air filters need to meet specific requirements to remove the tiny particles from the air, which are part of what health officials are warning about during the advisories.

Although the most recent air quality advisory ended on Monday, the wildfires that sent smoky air and fine particulate into the lower mainland continue, and scientists warn this could be more commonplace as climate change occurs.

Health professionals said August has seen a spike in those seeking treatment of smoke-related symptoms.

During air quality advisories, Dr. James Lu, a public health officer at Vancouver Coastal Health, recommends refraining from intense physical activity outside, and equipping homes and buildings with air filters that trap the fine particulate matter — brought in by the wildfires — that is known to irritate the lungs and cause breathing difficulties.

“The thing about air filters is that you need something that would actually take out the size of the smoke particles that are of concern,” he said.

The fine particulate matter emitted by the forest fires, is composed of minute solid particles and tiny liquid droplets that are suspended in the air, according Environment Canada. And, the particles, which are 2.5 microns or smaller, can only be trapped in furnace air filters with a rating of MERV13 (Minimum Efficiency Reporting Value) and higher, or HEPA-rated filters, Lu said.

In the summer months, without turning the heating on, people can turn on their furnace’s air circulation system, Lu explained. But unless the furnace filters are HEPA-rated or MERV 13 or higher, they won’t filter out the tiny particles.

According to Vern Milani, president of Milani Plumbing, Drainage & Heating, the standard home furnace typically has a MERV 8 rating, which filters particles that are 3 to 10 microns, and therefore don’t filter out the tiny particles health officials have been warning about. Furnace filters are square or rectangular, and vary in width, height and thickness.

MERV 8 filters aren’t only used in homes. Many commercial systems also use filters with this rating, Milani said. For example, the Vancouver Park Board says the filters at the city’s community centres generally use MERV 8 filters.

“Our filters in general are sort of designed to catch the midspectrum (particles) so they keep the air reasonably cleaned, but are not designed to catch these very, very tiny particles,” said Ian Harvey, manager of building operations.

Each community centre has about five to 10 filter stations installed throughout building, Harvey explained, and sometimes a station will have a prefilter in addition to the regular filter.

Harvey said the air quality inside community centres is generally better than the quality outdoors during air advisories, but the filters don’t address the fine particulate issue.

“We just simply were never designed for that. We haven’t come across this issue (of such poor air quality) before,” he said.

The impacts of the smoky air and its fine particulates can be seen at respiratory clinics, and is reflected in the lives of those with asthma. For example, the lung health clinic at St. Paul’s Hospital has seen a “sharp rise” in the number of calls from patients who were having worsening breathing issues,.