Vancouver Air quality today

What pollutants cause poor air in Vancouver?

Metro Vancouver, the regional district, runs the air monitoring network from Horseshoe Bay to Hope ^[1]. It says two pollutants are most likely to trigger a regional air quality advisory ^[1]. One is ground-level ozone, or smog, made by a chemical reaction on hot and sunny days ^[1]. The other is fine particulate matter, called PM2.5, tiny particles from wildfire smoke, home wood smoke, vehicle exhaust and industrial processes ^[1].

PM2.5 particles are small enough to be breathed deep into the lungs, affecting the lungs and the heart and blood vessels ^[2]. Ozone can irritate the eyes, nose and throat and reduce lung function ^[2]. The BC Centre for Disease Control says PM2.5 is the part of wildfire smoke that poses the greatest risk to health ^[4].

Canada's Air Quality Health Index, or AQHI, shows how air quality can affect your health ^[1]. It runs from 1, low health risk, to 10 plus, very high risk, and is updated every hour ^[1]. In 2023, 97 to 99 percent of hours were rated low risk in each part of the region ^[1].

How does wildfire smoke reach Vancouver?

Wildfires can make large amounts of smoke that travels great distances ^[2]. In 2017, winds carried smoke from fires in the BC Interior to the coast, and a haze fell over the Lower Mainland ^[3]. Environment Canada issued a number of special air quality and weather advisories for Metro Vancouver and the Fraser Valley that summer ^[3].

In 2018, BC had one of its worst wildfire seasons, with the largest area burned ^[2]. Plumes from fires in Washington state added to the smoke, and the Lower Mainland was under health advisories for 22 days in a row ^[3].

In 2023, Canada had its worst wildfire season on record, with over 18 million hectares burned ^[1]. Metro Vancouver felt the biggest smoke impacts in August 2023, when smoke from fires across BC and Washington led to two multi-day advisories ^[1].

What happened in September 2020?

Fire activity in BC was well below average in 2020, but smoke came from wildfires in Washington, Oregon and California ^[2]. On September 8, 2020, Metro Vancouver issued an advisory for fine particles as the smoke moved in ^[2].

From September 11, every monitoring station in the region was above the 24-hour PM2.5 objective for nine straight days ^[2]. That objective is 25 micrograms per cubic metre ^[1]. The highest daily level was 200 micrograms in Hope on September 15, 2020, about 8 times the objective ^[2].

The 11-day advisory ended on September 19, 2020, when cleaner marine air flowed into the region ^[2]. Meteorologists noted that the smoke reached BC later than usual, and that it did not come from BC's own fires ^[3].

Why does ozone build up in the Fraser Valley?

Ground-level ozone forms when nitrogen oxides and volatile organic compounds react in the air during hot, sunny weather ^[1]. Most nitrogen oxides come from transport, while volatile organic compounds come from trees, cars, light trucks and solvents ^[2]. The highest ozone levels are measured in eastern Metro Vancouver and in the Fraser Valley ^[1].

On May 15, 2023, Metro Vancouver issued its earliest ozone advisory since its advisory program began in 1993 ^[1]. May 2023 was unusually warm, and hot, sunny weather led to ozone advisories in May, June and July that year ^[1]. The 2023 summary says average ozone levels have risen slightly, partly because more ozone formed outside Canada comes into the region ^[1].

Is Vancouver's air getting better or worse?

Metro Vancouver's 2023 summary says most pollutant levels improved over the decade, even as the population grew ^[1]. Levels of nitrogen dioxide, sulphur dioxide and carbon monoxide generally fell, as engine and fuel standards for vehicles, ships and machinery improved ^[1].

In 2023, PM2.5 went above the 24-hour objective at every station, with wildfire smoke behind the high readings in June and August ^[1]. No station went above the annual objective ^[1]. Climate projections suggest hotter, drier summers, and a warming climate will likely bring wildfire smoke more often and for longer ^[1]. Metro Vancouver is updating its regional ozone strategy to account for hotter weather and wildfires ^[1].

How to protect yourself in Vancouver

The BC Centre for Disease Control says everyone can be affected by wildfire smoke and should act to reduce their exposure ^[4]. People at higher risk include those with asthma, COPD, heart disease or diabetes, pregnant people, infants and small children, and older people ^[4]. Check the AQHI to see local air quality ^[4].

To cut exposure, filter the air in one area of your home with a portable HEPA air cleaner or a do-it-yourself air cleaner ^[4]. Public spaces such as community centres, libraries and malls tend to have cleaner, cooler indoor air ^[4]. Limit outdoor exercise on smoky days, because the harder you breathe, the more smoke you inhale ^[4].

If you need to be outdoors, consider a well-fitted N95, KN95 or KF94 respirator ^[4]. On hot days, keep your cleaner air space cool, because overheating can cause serious health problems ^[4]. People with a chronic condition should make a plan for smoky days with their health care provider ^[4].