Qualité de l’air à Ottawa

Is Ottawa a city with clean air quality?

Ottawa is the capital city of Canada, situated in the southern region of the country next to the Ottawa river and part of southern Ontario. It is home to an estimated one million citizens, and holds the title of being the fourth largest city in Canada. It is home to a large number of higher education centers, and boasts the highest amount of educated citizens countrywide. It finds itself renowned for a good quality of life, having clean air and low unemployment rates, as well as being home to many economic powerhouses and industries revolving around telecommunication, environmental technology and the development of electronics and software.

Looking at its PM2.5 average taken over the course of 2019, Ottawa came in with a reading of 7.3 μg/m³. This is a very respectable reading for a yearly average and one that is strong enough to put it into the World Health Organizations (WHO's) target goal of 10 μg/m³ or less, for the best quality of air, with the closer the reading is to 0 of course being the most optimal.

This reading of 7.3 μg/m³ placed Ottawa into 3683^rd place out of all cities ranked around the world, a very good placing by any means, as well as 64^th place out of all cities ranked in Canada. Of note is that Canada itself as a country came in at 90^th place out of all countries ranked worldwide, out of 98 countries registered, meaning that it was very close to being one of the cleanest in the world, and as one would expect, many of its cities have an extremely good quality of air, albeit with a month or two here and there that rise slightly in their PM2.5 ratings.

What are the main causes of pollution in Ottawa?

The main causes of pollution in Ottawa would be ones that are very similar to many countries throughout the world, but on a significantly smaller scale due to the cleanliness of the air. These main causes would include ones such as the ever present and encroaching threat of vehicular fumes and emissions, with a growing population correlating with a larger amount of vehicles and thus more pollution arising from them. There are numerous personal vehicles inhabiting the roads in Ottawa, among them cars and motorbikes, and beyond this there would be a sizeable amount of more heavy duty vehicles, ones above a certain size and weight such as trucks, lorries, buses and even snowplow trucks.

Other causes would be gases and air contaminants generated by the agriculture industry, as well as the construction industry, the burning of wood (which sees a rise in the winter months due to ingrained practices amongst the population, coupled with the extremes of cold that the country is subject to) as well as factory and industrial area emissions.

When is the air at its cleanest its Ottawa?

Observing the data taken over 2019 as the best indicator to go by, Ottawa saw 11 months of its year falling into the WHO's target bracket for the best quality of air at 10 μg/m³ or under. As well as this, there were no clear cut patterns that so often emerge in major cities as to when the worst levels of pollution were. Heightened readings of PM2.5 often correlate directly with the winter months, but this was not so overtly the case here, although it was present and detectable.

To highlight the disparity between pollution readings, the months that came in with the best readings of PM2.5 over the course of the year were April, May, September and October. These four months came in with readings of 4.9 μg/m³, 5.2 μg/m³, 5 μg/m³ and 5.3 μg/m³ respectively, making April the cleanest month out of the entire year.

Whilst this time frame, with the exception of a rather large jump in pollution during the month of July, it can be said that the period of time between April and October is when the air was at its cleanest, before some slight depreciations in air quality are witnessed.

When is the air quality at its most polluted in Ottawa?

In contrast to the previous question, as well as in direct continuation of it, as mentioned, the PM2.5 readings took a slight turn for the worse towards the end of the year, typically when the colder months start to set in. October came in with a very fine reading of 5.3 μg/m³, which then jumped up somewhat to 8.7 μg/m³ in November. Whilst this is not a significant jump by any means, and when compared to more polluted cities around the world, represents a very minute change, it is still a move in a more polluted direction, and these ‘higher’ readings continued into December with a reading of 9.3 μg/m³, showing that the pollution levels had gone up further.

This continued until March of the following year, with the months of January through to March all coming in with readings of 6.7 μg/m³, 7.6 μg/m³ and 8/8 μg/m³, before settling back down to lower readings as mentioned in the previous question (with 4.9 μg/m³ reappearing in April, making it the cleanest month of the year). Of note is that the anomaly witnessed was that July saw the highest reading of the entire year with a PM2.5 number of 13.5 μg/m³, nearly three times higher than the lowest reading and a whole three ratings brackets up in the ‘moderate’ grouping.

What are some of the airborne pollutants found in Ottawa?

With much of its pollution stemming from vehicular use, factory emissions as well as the burning of fossil fuels and organic matter, Ottawa would have chemicals such as nitrogen dioxide (NO₂) as well as sulfur dioxide (SO₂) in the air, with nitrogen dioxide being one of the chief culprits in its release from vehicles, particularly those that have older engines or run off of fossil fuels such as diesel.

Other pollutants would be ones such as black carbon and volatile organic compounds (VOC's), both of which find their release from the incomplete combustion of both organic matter such as wood, or fossil fuels. As such, they would both be present from the burning of woods as well as released from cars and industrial areas.