I have a bit of experience in measuring PM2.5 (fine particles in the (ambient) air 2.5 micrometres or less in size) using PMS5003 sensor. This sensor uses laser, photodiode and the fact that the air flow through the sensor has constant speed due to applied fan.
However, this sensor can measure PM2.5 only in one location. I want a device which would be capable of measuring air quality (particulate matter or anything else) from distance. So, in order to make a map of pollutants in the city I wouldn't need to provide sensor for every x meters. I'd like to just locate the LiDAR-like sensor on some high tower and scan some area.
What should I use to build such a device?