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| Flathead |
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| Chemical components
responsible for haze |
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At the Flathead monitoring site, the average PM2.5 mass
concentration during 6/2002-12/2003 is 4.1 mg/m3,
and the average total light extinction coefficient (Bext) is 31 Mm-1
(Visual Range ~ 126 Km; Deciview ~ 11). OMC is the largest contributor to haze,
with an average contribution of ~ 31%. |
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| Figure 1. Average
contributions of major aerosol chemical components to light extinction |
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| Figure 3 suggests that, in 2003, the
highest occurrence of the 20% worst days happened in August, in which ~80% of
the sampling days are the 20% haziest days at Flathead. OMC, which is most
likely from forest fires, contributes in average ~66% to light extinction in the
20% worst days during August 2003. |
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| Figure 3 Percentage of sampling days that
are 20% worst days in each month |
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| Figure 4 Average contributions of major
aerosol chemical components to light extinction during 20% worst days in each
month |
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| For a detailed examination of
the aerosol characteristics at the Flathead site consult the
aerosol description web page. |
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