101 Notes on Air Pollution Monitoring

During a question and answer session in Delhi late last year, I was asked this question “Since Diwali, the Delhi government has installed 20 continuous monitoring stations. Despite that, why are the pollution levels still so high?”. The simple answer to this is that monitoring is a diagnostic tool to assess levels of air pollution and in and off itself does not reduce any air pollution. What it does do, is provide a starting point for understanding the air pollution problem and a direction for addressing pollution control options.

This however got me thinking. Having worked on air pollution related research for my entire career, I have to constantly remind myself of a cognitive bias while communicating on matters related to air pollution. This means that I (unknowingly) assume that others also understand the concepts related to air pollution as I understand them. This type of bias tends to be reinforced when speaking to other “experts” and the only way to break out of this bias is to communicate as clearly as possible to people. There are several topics within air pollution that I would like to speak about – such as source apportionment, dispersion modelling, emissions inventory, etc. However, in this discussion I will focus solely on “air pollution monitoring”.

This note is my attempt to explain air pollution monitoring – What purpose does it serve? Is ambient monitoring the same as emissions monitoring? How does one monitor? How do “low-cost” monitors fit in? These are some of the questions, I will try to answer in this brief (all the references used in this piece are from India, but the notes is relevant for other countries as well).

Direct link to the note