How do we measure the chemical levels in air pollution?

Question

How do we measure the chemical levels in air pollution?

Answer 1

there is a device or machine used

Answer 2

Can be done by three methods I know off. One of spectrometry, very common method. Different gases tend to absorb different wavelengths of light and hence by measuring the spectrum after it has passed through a gas, we can know the cases (we even predict things like what gases are these in sun or mars and things like using this technic). Then there are chemical sensors - they are specific to each gas, as different gases can do different stuff to different chemicals.

If you drop out the whole sensor thing, there are even cruder methods - for example, you can measure CO2 in air by taking like a liter of air in a container, have some lime water and measure the pH or something simiar (I can tell you more but you'll probably get bored) to measure how much Ca(OH)2 is converted to CaCO3 - similar thing can be done for many chemicals.