Why you should be wearing an N95 mask today in Ottawa

When the level of fine particulate in the air reaches 60 micrograms per cubic metre, Environment Canada issues an air quality warning. Ottawa reached higher than 260 this morning.

Under a sinister grey-orange sky, Ottawa's air quality readings hit levels more commonly seen in some of the most polluted cities in the world Tuesday as smoke from forest fires created widespread health risks.

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"It is terrible. I have lived in Ottawa since 1996 and I have never seen a day like this," said Dr. Shawn Aaron, a respirologist at The Ottawa Hospital.

Aaron said emergency departments across the city would likely see a spike in visits in the coming days related to the extremely poor air quality, which can increase the risk of heart and lung problems, especially in the elderly, very young children and those with chronic illnesses. Studies around the world have linked wildfire smoke with an increase in health risks and even deaths.

Health officials were advising people to wear N95 masks when outside, to limit their times outdoors and to keep their windows closed and air conditioning on.

"If you must spend time outdoors, a well-fitted N95 mask can help reduce your exposure," said Monica Vaswani, a warning preparedness meteorologist with Environment and Climate Change Canada. "A mask would be your best defence if you do have to be outdoors."

Ottawa has been under a special air quality advisory since Monday because of smoke from forest fires in Quebec, Ontario and elsewhere. Early on Tuesday, the risk level spiked as one of the key measures of poor air quality hit levels more commonly seen in some of the most polluted parts of the world.

The amount of fine particulate matter (known as PM2.5) in Ottawa's air is usually measured in the range of four to 11 micrograms per cubic metre. When that reading hit 60 earlier this week, Environment and Climate Change Canada issued an air quality warning.

Early Tuesday, that number more than quadrupled to upwards of 260 micrograms per cubic metre. A reading at that level is considered very unhealthy. It came down later in the day.

Beijing, which in the past has had some of the worst air quality in the world, was registering a moderate 61 on Tuesday. In parts of India, though, PM2.5 readings were over 900 — considered hazardous to health. The World Health Organization recommends levels of 15 or less.

The fine particulate matter found in smoke can go deeply into a person's lungs and blood stream. It is linked to a number of negative health impacts, including headaches, watery eyes and coughs, but also, less commonly, premature death, heart attacks and stroke.

Those most at risk include seniors, pregnant people, infants, young children, those who work outdoors or do strenuous outdoor exercise, and people with existing conditions such as lung or heart conditions, cancer or diabetes.

Dr. Tom Kovesi, a pediatric respirologist at CHEO, said the air quality in Ottawa is a risk to everyone.

"This is extraordinary. I looked out the window this morning and the air was yellow. It was bright yellow. This does affect potentially everybody."

Aaron said the fine particles could get deep into people's lungs and bloodstream and cause inflammation.

People with asthma, COPD (chronic obstructive pulmonary disease) or other chronic lung diseases are at increased risk of additional inflammation and may become wheezy or short of breath, Aaron said.

The fine particulate matter can also cause inflammation throughout the body that can trigger things like blood clot formation, angina and heart attacks in people at risk.

Some studies have also linked premature births and increased mortality with exposure to forest fire smoke.

Aaron said fine particulate matter readings were something he normally didn't think about.

"In a city like Ottawa, which has a lot cleaner air than a place like Beijing, we don't even pay attention to this. But, on a day like today, it becomes important for lung physicians. It is going to explain why we are going to see people getting sick."

Birgit Isernhagen, a member of the healthy environments team at Ottawa Public Health, said public health supported people wearing masks outdoors when air quality was poor. She added that people should listen to their bodies.

"We are so used to super clean air that we are shocked by these numbers. The reality is, there are places around the world that see these kinds of numbers a lot and people take precautions like wearing masks and staying home."

The poor air quality is forecast to continue throughout the week and could worsen on Wednesday. Kovesi said this week would be a good time for people to "dust off the exercise bike in the basement" and avoid going out as much as possible.

And he said people should think carefully about what was contributing to forest fires and reduced air quality.

"We have to think as a society about what we are doing to this planet. Waking up and seeing the air outside is yellow is an important reminder for all of us."

Why is the sky so hazy in Ottawa?

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