Good Morning from Indiana. I have just read your post again and I’ve been going over your paper this week, many times. I am not a scientist or a data specialist but part of a local (and increasingly national), concerned group of amateurs. We are loaning monitors from the EPA and using them to measure the density of PM2.5 particles in the air, surrounding sand and gravel pits. I have some questions and forgive me if they display any ignorance or naivety on my part;
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Why does the Alt PM 2.5 figure, which I am persuaded to use, show lower figures, when it is counting so many more of the very tinniest of the PM2.5 particles? Is it just a hidden characteristic of the CF1 algorithm that overestimates the stat by almost 100%?
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Why do you think the EPA has not adoped your algorithm? I believe their conversion is currently based on the work of Barkjohn. However, these figures seem to be midway between the ATM and the ALT PM2.5 stats. This is very confusing and makes direct comparisons difficult.
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Is there any reason why I should consider one of the other stats, when I know I am dealing mainly with tiny, abraded parts of silica dust , as well as the combustion of some vehiclular traffic, chiefly diesel. Of course its natural for me to want my figures to be higher, but accuracy is the most important criteria.
Many thanks.