Is it worthwhile getting an indoor PM2.5/PM10 air particle counter? If we have air filters running and the air smells clear is a $150+ air quality meter overkill?

For DIY particle counter builders, these look like good options: https://twitter.com/jostheim/status/1305719035808509952

Lowest budget DIY PM2.5 option: https://twitter.com/metaphdor/status/1305738218478866433

Following up on this thread: My CO2 and PM 2.5 sensor arrived today. AQI is better this week, but still elevated. Here's the particle count and CO2 level with the office windows open:

Here's the CO2 and particle count after a few minutes with the windows closed:

That CO2 is way too high, some studies see a 50% decrease in performance on cognitive tasks at that level: https://www.businessinsider.com/office-air-co2-levels-making-workers-tired-2017-11

Rigged up some cheap MERV 13 furnace filters in the windows to get lower CO2 and particle counts:

I think the result is a reasonable trade off between PM2.5 and CO2 (~1000ppm), we'll have to see what happens when the AQI goes higher: