MONITORING IN THE UK BY ENVIRO TECHOLOGY SERVICES GROUP.

John is holding the Met One Instruments' AEROCET-531S Monitor

http://www.standard.co.uk/news/uk/revealed-top-tories-constituencies-suffer-blight-of-toxic-air-a3534236.html

"Scientific engineer Lewis John, who carried out the study by Enviro Technology Services, said: “These are only brief snapshots of air pollution, but we observed spikes of over 100μg/m3 in several locations.

“These findings could benefit from further investigation.”