I am comparing NO2 and PM2.5 levels in the pre-2020 Jan-April and 2020 Jan-April (representing air quality during lockdown and under no-lockdown conditions).
The data was from the aqicn website (https://aqicn.org/data-platform/covid19/). The data is not raw concentrations, it is converted into the US EPA standard, which I believe is represented as AQI values.
Can someone please explain why with PM2.5, the data reaches from 'Good' to 'Hazardous', whereas the NO2 is only within the 'Good' bracket. I'm hoping it is because PM2.5 is more harmful than NO2?
But if it is because I should be using a different scale for NO2 (e.g., 0-10 = Good, 10-20 = Moderate, etc.) I'd like to know - I haven't been able to find different AQI scales for different pollutants.