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| Fort Peck |
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| Chemical components
responsible for haze |
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| At the Fort Peck tribal
monitoring site, the average PM2.5 mass
concentration during 6/2002-12/2003 is 3.8 mg/m3,
and the average total light extinction coefficient (Bext) is 34 Mm-1
(Visual Range ~ 115 Km; Deciview ~ 12). Sulfate is the largest contributor to
haze, with an average contribution of 26%. |
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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 February and
August, in which ~50-60% of the sampling days are the 20% haziest days at
Fort Peck. Sulfate and nitrate contribute in average ~37% and 32% to light
extinction in the 20% worst days during February 2003. In August, OMC is the
largest contributor to light extinction in 20% worst days, with a
contribution of 32%. CM and sulfate each contributes ~20% in the 20% worst
days of August. |
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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 Fort Peck site consult the
aerosol description web page. |
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Last updated 20 May 2005
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