How can we measure air quality?

With this summer’s huge fires in California that spew their smoke and ashes eastwards into Utah, measuring or at least knowing what air quality is all about has never been so important. 

The problem is where can we get some good information. Ideally, I like a system that has as many air sensors as possible, as close to my home as possible of course, but also that offers a great coverage everywhere else, not just in North America, but also in the world, that is as precise as possible and that can be accessed both reliably and conveniently. 

The next thing is to know what is being measured, for instance most systems and air quality indexes are based on measurement of particulate matter (PM2.5 and PM10), Ozone (O3), Nitrogen Dioxide (NO2), Sulfur Dioxide (SO2) and Carbon Monoxide (CO) emissions. Usually and most systems have stations that are monitoring both PM2.5 and PM10 data, but there are few exceptions where only PM10 is available.

Since last year, we’ve used PurpleAir as a source. This is a Utah company, that manufactures low-cost air monitors and sells them all over the world. I also know of another company that rendered a similar service worldwide, IQAir, a Swiss air quality technology company, that also sells air quality monitoring and air cleaning devices. From what I’ve been told however, IQAir’s sensors seem to show less accuracy and besides their website doesn’t provide for easy, fast and convenient reading. 

There’s also the World Quality Index (WQI), that uses the so-called GAIA air quality monitoring stations for its input, using high-tech laser particle sensors to measure in real-time PM2.5 pollution, one of the most harmful air pollutants. Its map is pretty good but it seems to have far less stations than PurpleAir, at least as far as the US is concerned. 

In 2018, AirNow was launched; it’s an air quality website that’s a government consortium between the US, Canada and Mexico, and is only available for us to see how bad (or good) the air is in North America. 

Based on my research, not only PurpleAir offers worldwide coverage, but it provides a denser coverage and also real time readings. Some assert that it might be less accurate than AirNow. 

I just don’t agree with that, especially when I look outside, see the air filled with smoke, and simultaneously compare readings from the three systems, I found that AirNow is getting half the readings of what IQAir and PurpleAir are registering. 

So for the time being, I’m gonna trust PurpleAir over World Air Quality Index, that is as long as I don’t die of smoke inhalation by the end of the year!