Part of my commute involves cycling from Wigan train station to my office in Leigh; the red line in the image below. The blue splodges are Air Quality Management Areas (AQMAs). In the smaller inset map you can see the Greater Manchester AQMA in the middle (lots of splodges), with the Liverpool AQMA to the west and Sheffield’s AQMA to the east.
The Manchester AQMA was created with air quality modelling software, so only those areas where the annual mean concentration is above a certain level are highlighted. You can see the various splodges that I cycled through in Wigan, with a few more at busier junctions all the way to Leigh.
I would have liked to have used the ‘clip’ function in QGIS to calculate exactly how far I cycle each day inside the AQMA, but my GPS route doesn’t have the required attributes to do the job. I’m sure there is a way of converting to the correct format, but my knowledge of GIS isn’t the best. My commute is just over 11 km, with approximately 1 km inside various sections of the Greater Manchester AQMA.
Most of my journey is busy with traffic, so I am probably exposed to quite high levels of pollution, but studies have shown that the exercise from cycling benefits me far more than the exposure.
As I near the end of my commute in Leigh, there is another splodge of AQMA right on top of the office where I work, quite apt for a bunch of air quality scientists.
The NO2 annual mean objective is 40 ug/m3 (micro grams per cubic meter), and as any good air quality scientist will tell you, if you are exposed to pollution concentrations above 40 you will die tomorrow, and less than 40 you will live forever. I’m joking of course, but this is why air quality is an objective and not a hard and fast ‘level’, which any city in the UK should be able to achieve, if it is a priority. Cars would appear to be more of a priority in most cities, especially between Wigan and Leigh.