WHRI1 (White River National Forest, CO, Lat. 39.1517, Long. -106.819, Alt. 3418) Print-Friendly Version Print-Friendly Version (B&W)
2 year and 10 month aerosol data are available in White River National Forest during the sampling period of 1997 - 2002. As shown in Figure 1, the overall average total light extinction coefficient (Bext) is 20.7 Mm-1 (Visual Range ~ 188 Km; Deciview ~ 7.3). The average PM2.5 mass concentration is 2.4 mg/m3. The average contributions of the major aerosol components to White River National Forest haze are particulate sulfate 17.9%, nitrate 4.7%, organic matter (OMC) 14.9%, elemental carbon (light absorbing carbon, LAC) 4.8%, fine soil 2.4% and coarse mass (CM) 6.9%.
Figure 1 Average contributions of major aerosol chemical components to light extinction (Based on data available in 1997-2002) (B&W)
Figure 2 Average contributions of major aerosol chemical components to light extinction in 20% best, middle 60% and 20% worst days (Based on data available in 1997-2002) (Data Table) (B&W)
As Figure 2 indicates, the average aerosol light extinction coefficient (Bext – Rayleigh Scattering (10 Mm-1)) during the 20% worst days is 22.2 Mm-1, which is about 6.6 times of the value of 3.3 Mm-1 during the 20% best days and 2.4 times of the value of 9.2 Mm-1 during the middle 60% days. OMC and sulfate are the largest contributors to aerosol light extinction, with a contribution of 36% and 28%, respectively in the 20% worst days.
Figure 3 suggests that the highest occurrence of the 20% worst days happened in May, in which ~ 46% of the sampling days are the 20% haziest days at White River National Forest. As shown in Figure 4, OMC is the largest aerosol contributor to haze during the 20% worst days in the summer, with a contribution of ~ 30 - 40%. Sulfate is the largest aerosol contributor to haze for the rest of the year, with a contribution of 20 - 40%. CM and fine soil each contributes ~16% in the 20% worst days in April.
Figure 3 Percentage of sampling days that are 20% worst days in each month (Based on data available in 1997-2002) (Data Table) (B&W)
Figure 4 Average contributions of major aerosol chemical components to light extinction during 20% worst days in each month (Based on data available in 1997-2002) (Data Table) (B&W)
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