Geology question....Please help?

Question

Fossil fuels: COAL

Environ problems: Sulfur, nitrogen causes acid rain, PM 10's, ......

What is PM 10's ?

Answer 1

im assming it has something to do with the acidic level, thats more of a chem question. the only involvment of geology is that it rained it lol

Answer 2

Just that no extra more word? it is a time or something.

Answer 3

Particulate Matter.  The notation PM10 is used to describe particles of 10 micrometers or less and PM2.5 represents particles less than 2.5 micrometers in aerodynamic diameter.

See here for a better explanation, as well as a scale:

http://en.wikipedia.org/wiki/Particulate

Answer 4

PM stands for particulate matter, and PM 10 (with 10 as a subscript) describes PM with diameters of 10 micrometers or less