Air quality risk 'off the charts' in Ottawa because of smoke

Ottawa's air quality was so bad that it cracked through the top of a risk scale on Tuesday morning, as Environment Canada warns that forest fires may keep the air dangerous to human health through most of the week.

The city was officially at a 10+ on Environment Canada's Air Quality Health Index Tuesday morning, which is the highest level possible, placing Ottawa the highest among Canada's major cities.

This means the general public should reduce or reschedule strenuous outdoor activities and people at risk of serious health problems from pollution — including seniors, young children and pregnant people — should avoid these types of activities.

By early afternoon, it lowered to 10, which is still high.

Monica Vaswani, warning preparedness meteorologist for Environment and Climate Change Canada, said the air quality index maxes out at 10 for forecasting purposes. Ottawa's readings actually hit as high as 14 on an internal scale on Tuesday, double the benchmark for the ministry to issue an air quality statement.

"That just gives you an idea that it is definitely, in some ways, off the charts," said Vaswani.

Don't expect a return to normal anytime soon. Vaswani said winds from the north and northeast will push plumes of smoke from Quebec toward Ottawa. There's also little sign of significant rainfall in the forecast and the forest fires might actually prevent rain from forming, she said.

"Unless the forest fires themselves reduce in some fashion, the weather is not going to change," she said. "So more likely than not the air quality is going to remain ... bad."

Air quality to remain bad for days

Vaswani said forest fires are unpredictable, which means it's difficult to tell how air quality will change in the coming days. There could be brief spells of relief, though she doesn't expect the index to go below the "high risk" threshold.

"It will still be considered dangerous, especially for vulnerable populations to be outdoors for extended periods of time," she said.

Environment Canada still has smog warnings for areas north and east of Gatineau and special air quality statements for the rest of eastern Ontario and western Quebec.

Vaswani said the poor air quality in Ottawa is driven by high levels of fine particulate matter in the air from the forest fires. As of Tuesday at 8 a.m., Ontario's Ministry of Environment, Concentration and Parks reported levels of that pollutant in excess of healthy levels. Concentrations of fine particulate matter were 267 micrograms per cubic metre.

That's more than twice the average level in Delhi, India, a city known for bad air pollution, based on statistics from India's Central Pollution Control Board.

What you can do

Birgit Isernhagen, the extreme weather lead with Ottawa Public Health (OPH), said people working outside should take breaks and make sure they're drinking enough fluids.

Anyone with pre-existing conditions such as asthma should use their puffer regularly, she added.

"If you're doing lots of activity outside and you're noticing that you're dizzy or you can't breathe, stop what you're doing, go into a space that has closed windows and has air conditioning," she said.

Environment Canada's Tuesday special air quality statement also issued guidelines for residents to keep safe. It said wildfire smoke can be harmful to health even at low concentrations and advised people to reduce exposure.

"People respond differently to smoke. Mild irritation and discomfort are common, and usually disappear when the smoke clears. Drinking lots of water can help your body cope with the smoke."

It also said people can run fans and HEPA filters at home, keep doors and windows closed as much as possible and try not to encourage indoor air pollution by vacuuming, frying foods or burning candles.

Respirator face masks such as N95s can help filter out particles in smoke, but not gases.