_PERMIT FILE - M1981302 ‎(25)‎

• Permit No: M1981302
• IBM Index Class Name: Permit File
• Doc Name: AIR QUALITY
• Media Type: D
• Archive: No

rise to above background levels when winds are such as to
transport automotive and other pollutants from Boulder or
the Front Range Metropolitan area. These instances of
moderate particulate or gaseous pollution are rare however,
and annual averages of air pollution at the site are low.
Dustfall and Suspended Particulate. All solid matter in
the air (dust, pollen, combustion products , etc. ) are re-
ferred to as particulate matter, as distinguished from
gaseous pollutants such as sulfur dioxide, carbon monoxide,
hydrocarbons, etc. Particulate pollution is usually sub-
divided into "dustfall" , which consists of generally
• large particles that settle out of the air and are
measured by their rate of collection on the ground or in
a collection pan, and "suspended particulate" , which as
it' s name implies is made up of particles so small that they
remain suspended in the air for long periods. Suspended
particulate is normally measured by a high-volume sampler
that draws air through filter paper on which the particles
are collected. Suspended particulate is ultimately re-
moved from the air naturally by precipitation, impaction
of particles on vegetation, and combination of small
• " particles into larger ones which fall out by gravitational
settling.
C• G-3