How the monitoring works

Most of what we know about air pollution in our towns and cities comes from large static monitoring stations.  This has enabled us to know more about hotspots  and overall levels of pollution.  However,  we know very little about  how much  individuals  are exposed as they move around the city.  
That’s why we carried out air quality monitoring with  a cross section of Londoners,  in partnership with King’s College London. In 2019, we gave 10 individuals,  with different hobbies, occupations and travel routines,  portable  air pollution monitors to carry with them for  one week.  Read what we found: download the full report.
The monitors track black carbon (mcg/m³), which in an urban environment is most likely to be from traffic. Black carbon is a key component of particulate matter.  The amount of black carbon in the air correlates to overall PM 2.5 levels, so it  provides a good indication of people’s exposure to pollution. Read more about PM 2.5 here. 
The monitor works by sucking in air through a black tube. It then measures particles in the air. It detects particles that are the size of black carbon, and gives a reading every minute. 
Each monitor has a small filter that needs changing twice a week. You can tell a filter’s been used by the black dot on it (kind of gross when you realise that that black dot is what we’re breathing in!).
Curious to learn more about air quality monitoring? There’s many different types of monitors – read more about the pro’s and con’s of each kind based on what we’ve learnt.