Tracking CO2 is very useful for internal spaces.
And an Air purifier: https://www.amazon.com/Purifier-Display-Formaldehyde-Sterili...
Monitoring seems like it's interesting to do if you want to, but if you already know it's an issue, just start addressing it?
If you know you're in a polluted environment, why would you need instrumentation before taking action? To me it's like getting blood work done before you err on the side of exercising.
You need to keep enough ventilation going to ensure you don't exceed 800ppm CO2.
You also need to monitor the PM2.5 levels to ensure your air purifier is working.
An air quality monitoring device is an essential piece of equipment for anyone.
But if you don't have an air purifier, and you're concerned about air quality, surely you want to get one before you start worrying about whether or not it's working?
Or both at the same time, sure, my only point is that if there's already concern I don't see the point in monitoring before or without mitigating.