Hi does anyone know where I can find monthly data on PM 2.5 concentrations across counties in the US? I was looking at the EPA and CDC but am having trouble finding raw monthly data.
Thank you! 
This does not sound useful for the pandemic:
> These datasets include measurements beginning in 1990 and are updated twice a year. In June, the complete data for the previous year is updated, and in December the summer data is updated.
You can get daily PM2.5 concentrations, which can be aggregated, by monitor, but not every county has a monitor in it. You have to make assumptions based on nearby monitors. Download Files | AirData | US EPA
@Laszlo_Sandor_University_of_Luxembourg I’m sorry I’m a little confused, what do you mean by this? Will summer data not be updated till December?
I am not sure what @Sina_Unfolded and @Colton_Tousey recommend, to me the EPA data looks horribly lagging. You could scrape the real-time measurement from some API (of a third-party service) and most importantly, ask someone who already has been scraping it to turn over their logs. And that will be the raw monitor data only, as the aggregation the EPA daily stats have comes from their calculations much later. I’m actually surprised (if) this has not been solved by the public-access research community long ago.