Monday, 14 August 2017

Real-time air quality monitoring: Why would you want anything less?

Here we go again Kamloops. Wood smoke pollution is starting to build rapidly yet government sensors are slow off the mark once again. Our community and all communities deserve real-time and not averaged and lagged indicators for air pollution. The government hates these low-cost devices because they erode their control over access to information and individuals/alternative interpretations of risk.

A diesel truck example of PM2.5 emissions

Here's what happens when one very dirty diesel water delivery truck drives past a PurpleAir sensor. Note the spike and relatively higher level of PM2.5 compared to other sensors in the area. The increase in pollution is still a fraction of what wood burning stoves and fireplaces generate, and the diesel pollution dropped in a few minutes. We still need to work on replacing such polluters since air quality is the biggest environmental health risk of our times. Air pollution is also the main and likely only driver of climate change.

Tuesday, 8 August 2017

The AQHI downplays exposures from particulate pollution

How much is a human life worth? If you live in rural British Columbia or in resource-based communities like Kamloops you may be surprised to learn that your life is worth far less than someone from Vancouver or Victoria.

Recent forest fires in the interior of BC, and the massive amounts of wood smoke produced, demonstrate how risk communication tools like the Air Quality Health Index (AQHI) are designed to treat differentially exposures across populations.

The AQHI is a scale used in Canada to weigh the relative contribution of three air pollutants; namely, particulate matter in the 2.5 micron range (PM2.5), ground level ozone, and nitrogen dioxide. It normally ranges between 1-10 or from “low” to “very high” health risk but can reach numbers like 49 as was recorded on August 3, 2017, in Kamloops.

The formula used for calculating the AQHI is straightforward and it involves using a three-hour average for these pollutants in micrograms/m3 for PM2.5, and parts-per-billion (ppb) for ozone and nitrogen dioxide. A weight is assigned to each of these pollutants based on observed adverse health outcomes.

In BC, the air quality objective for PM2.5 (24-hour average) is 25 micrograms/m3. With recent forest fires, numbers have been in the 150-200 range for several consecutive weeks.

The AQHI is mathematically flawed and out of line with these objectives. It downplays the significance of PM2.5 exposures and it generates low AQHI levels when air pollution risks from PM2.5 are actually high.

For example, a community exposed to no nitrogen dioxide, no ozone, and 100 micrograms/m3 of PM2.5 pollution yields an AQHI of 5, or “moderate risk.”  This is actually a staggering amount of pollution yet the risk messaging is tempered and muted. It would take 400 micrograms/m3 of PM2.5 with this scenario to hit a 10 on the AQHI. China issues “red alert” warnings when 24-hour averages exceed 150 micrograms/m3.

The AQHI poorly protects people in rural and resource-based communities from particulate pollution, and it seems designed more for urban environments where ozone and nitrogen dioxide pollution are more common. As a result, this tool exposes us to higher levels of risk.

Michael D. Mehta, Ph.D. (August 8, 2017) 

Monday, 7 August 2017

Should industrial polluters be shut down during forest fires?

The following commentary is from Gabriola Island Clean Air Society director Dr. Michael Mehta. Dr. Mehta is a Professor of Geography and Environmental Studies at Thompson Rivers University and an expert on health and environmental risk issues.

In cities like Beijing, when a "red alert" day is called due to high air pollution levels, many restrictions come into effect including a shutdown of industrial operations that may exacerbate the problem.
With the extremely high pollution levels in Kamloops over the past month, the following questions arise: To what extent do current industrial operations like those engaged in by the Domtar Pulp Mill contribute to these high levels, and do their operations makes thing worse during emergency situations like this?
This is a very difficult question to answer completely, and without full access to provincial air quality data I can only make some inferences and educated guesses.
Here's what I have seen, and this suggests that a lot more work is needed on these questions.
First, we began seeing a spike in PM2.5 levels around July 8 in Kamloops. PM2.5 levels can come from a variety of sources including pulp operations, traffic, residential wood burning practices, slash burning, and of course forest fires. In the past, the PurpleAir network that I setup in Kamloops showed very big spikes in PM2.5 levels that coincided with visible pollution from Domtar plus notable sulphur smells that come from its processing operations. There is no doubt that Domtar can rapidly spike PM2.5 levels in Kamloops, and provincial air pollution readings for Total Reduced Sulphur confirm that this is primarily (if not exclusively) from this polluter.
Second, Total Reduced Sulphur emissions are not associated (as far as I can see in the literature) with forest fires themselves. They come from industrial processes and also from municipal sewers and sewage treatment plants as well as swamps, bogs and marshes. 
Preliminary analysis [based on Kamloops Federal Building Air Monitoring Station: "Contains information licensed under the Open Government Licence – British Columbia."
If we look at PM2.5 (hourly averaged) data from July 31-August 7 and Total Reduced Sulphur (hourly averaged) data for the same time period, it seems clear to me that the contribution of Domtar to the current pollution situation from forest fires is significant.
The peaks on August 3, 5, 6 and 7 overlap almost perfectly with little latency between PM2.5 levels and Total Reduced Sulphur. Since Domtar is likely emitting PM2.5 at the same time as Total Reduced Sulphur, it is reasonable to conclude that these very high levels (especially the unprecedented spike on August 3) are a combination of Domtar emissions and forest fires.

If so, it only makes sense to immediately shutdown such industrial operations to avoid creating a compounded problem."