querry: back-half of particulate samplers

[ttweed@wildrockies.org (Tony Tweedale)]

can anyone tell me or the list if requiring the back-half of the impinger
in particulate samplers to be part of the reported concentration of PM is
standard practice in regulations, and the logic of why or not (MT plans to
make it discretionary)?  I wouldn't mind an explanation of how the sampling
train works, and why these are called the condensible emissions.  Do the
new PM2.5 samplers operate on the same principles as PM10 samplers, and how
do PM10 samplers fraction out PM2.5--and what is the effect on partitioning
of pollutants of the various configuarations (to be on-topic, you could use
O-Cl's as an example)?

Tony Tweedale

Causality is a concept not subject to empirical demonstration. -David Hume
(1711-'76)

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