Take good, clean air away and what else matters? Not much. That’s why it’s so important for us to be able to measure and judge the quality of the air throughout the province – and pass that information on to you.
We’ve talked a lot before about Alberta’s Air Quality Health Index – that’s the AQHI. Many Albertans now know they can use this tool when they need to know how air quality is changing (due to weather, forest fire, industry, and human activity) and how it may impact their health. But in an effort to make things easy to understand, what we don’t talk about much is how the numbers in the index are produced – how we monitor Alberta’s air quality.
We’ve heard from a few concerned Albertans recently about a third-party study on air quality that was done in the Industrial Heartland. We understand this concern, and we want to make sure that it’s easy to understand how our monitoring works – both in the heartland, and across the province.
What makes for good monitoring?
The goal of air quality monitoring is simple: we want to be able to measure pollutants caused by industrial activity, forest fire, and
other factors – and take action when they reach levels that might impact human or ecosystem health. But because pollutants will have different concentrations in different areas – in particular, they’ll be most concentrated at their sources – we need to make sure we measure widely, and measure often.
Although we pay particular attention to areas where people live and work, we sample a wide range of sites throughout the entire province – with about 160 air quality stations in all. These include:
- Five stations operated by our department
- 56 stations operated by independent, non-profit partner organizations
- 100 facility-specific stations, funded and operated by industry. Government receives info from these stations monthly and annually – and companies are responsible for alerting government immediately if pollutant concentrations hit certain limits. All Albertans can check out the operating requirements of any facility right here.
The importance of setting limits: finding signal in noise
Our stations monitor more than 30 compounds – many on an hourly basis. Once we have the numbers, we need some way to judge whether the pollutant levels we’ve measured are acceptable – that’s where the limits we’ve set come into play. The presence of small amounts of pollutants in the atmosphere is expected, and pretty much unavoidable. If we didn’t have these limits, our monitoring numbers would be meaningless – we wouldn’t know what our data meant.
Crunching the numbers
Let’s take an example that there’s been quite a bit of discussion about lately – benzene. Here’s how we get the info we need:
- We have established ‘objectives’ (or limits) for both the average benzene concentration we tend to see over an hour, and how those concentrations average out over the course of a whole year. The average hourly concentration limit tends to be higher than the annual limit; it’s produced from a smaller sample size, so numbers that are way out of the ordinary make a bigger difference. You can find a (pretty technical) overview of our ambient air quality objectives here.
- Our one hour average benzene objective is 30 micrograms per cubic metre. Our annual average benzene concentration is 3 micrograms per cubic metre.
- Benezene is monitored in the heartland at the Scotford station (as well as at several sites in Edmonton and Calgary). From 2011 to today, our hourly benzene limit was only exceeded once, and levels were well below our annual average limits for both 2011 and 2012.
The numbers behind the AQHI
The AQHI shows how our monitoring results compare with the limits we’ve set for pollutants with the greatest impact on human health. If actual pollutant levels are well below maximums, the AQHI assigns its lowest-risk rating. Communities in Alberta receive this rating 94 per cent of the time – and when limits are exceeded, or an exceptional event (like the June flood) poses an exceptional risk, we take action – targeting the source of pollutants. When we need to, we can also add more monitoring, so we have more information about what we’re dealing with.
Need more info? Please get in touch
The bottom line: we want you to breathe easy. If you have concerns or questions about the way your air is monitored, you can get in touch with us – in the comments, on Twitter, or by calling us at 310-ESRD (3773) – and we’ll get you the info you need.