Thursday, 24 November 2016

A comparison of weekly particulate levels across sample cities and towns

There are lots of ways to look at measurements for air pollution and different time frames that people and regulators look at. If we look at the weekly average for particulate at the PM 2.5 scale across several PurpleAir sensors, some interesting and troubling trends become evident.
Here are some 7 day averages from a sample of sensors in British Columbia and one wild card sensor - downtown Los Angeles near Dodger Stadium. LA is known around the world for the poor quality of its air.
Here's what we see. The worst weekly average in Canada can be found in Prince George BC with 16.06. Prince George has an active pulp and paper mill, other significant sources of industrial pollution, and lots of people who burn wood for residential heating.

In Parksville we see a weekly average of 10.85. This is mostly a retirement community on Vancouver Island and the readings from this sensor are likely due fully to wood smoke emissions from residential sources.


One of our sensors is Kamloops is 800m away from an active pulp and paper operation and its weekly average is 8.34. Based on a review of past data from this sensor there appears to be little residential wood burning in this area. Wood smoke has a very specific and identifiable signature.


Downtown Vancouver has a weekly average of 3.9. This is a city with 600,000 people, a fair amount of vehicular traffic, but wood burning is not commonly practiced at the residential level.


Our wildcard of LA had a weekly average of 12.88.


It should be clear that wood burning is a main driver of air pollution in many communities, and you may be surprised to see worse air pollution this time of year in small cities and towns in BC when compared to Vancouver and LA.

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