Metadata explained - where?

I’m an absolute newbie and I’ve been browsing the FAQ for a while in the search for documentation on the metadata of the .csv files in the archive, without success so far. I understand sensor_id, sensor_type, lat, lon, and timestamp. I didn’t find explanations of location, P1, durP1 (mostly empty), ratioP1 (mostly empty), P2, durP2 and ratioP2 (both mostly empty). My guess is that P1 is the PM10 particle mass per m³ and P2 is the PM2.5 particle mass per m³, is that correct? And are there more metadata on the stations available, like elevation, surrounding (traffic, chimneys, …), shielding, etc.? As a physicist I’m very fond of metadata to crosscheck the quality, validity and reliability of the data…
Sorry for the innocent question, for a stupid beginner it’s a bit difficult to find this most basic information.
Thanx for any help,

I have also been considering many of these questions. I can say that you are correct wrt P1 and P2 as this is how we use the information from our SDS011 sensors. I am not aware of other location information such as proximity to local sources of particulates, etc. which would be helpful, but I also do not understand what the location number means.
The data archives seem to be a valuable asset and I have asked if there has been any analysis made on the data, but I don’t think I have received a reply.
I have recently been comparing PM2.5 data across the city I live in and a town thirty miles away and found a reasonable agreement between the two. This begs the question of how we untangle local effects from the background. I will be following the replies to your questions with interest.