KALM1 (Kalmiopsis, OR, Lat. 42.5519, Long. -124.0587, Alt. 90)
2 year and 10 month aerosol data are available in Kalmiopsis during the sampling period of 1997 - 2002. As shown in Figure 1, the overall average total light extinction coefficient (Bext) is 38.8 Mm-1 (Visual Range ~ 100 Km; Deciview ~ 13.6). The average PM2.5 mass concentration is 3.9 mg/m3. The average contributions of the major aerosol components to Kalmiopsis haze are particulate sulfate 18.9%, nitrate 5.6%, organic matter (OMC) 35.4%, elemental carbon (light absorbing carbon, LAC) 9.3%, fine soil 0.6% and coarse mass (CM) 4.4%.
Figure 1 Average contributions of major aerosol chemical components to light extinction (1997-2002)
Figure 2 Average contributions of major aerosol chemical components to light extinction in 20% best, middle 60% and 20% worst days (1997-2002)
As Figure 2 indicates, the average aerosol light extinction coefficient (Bext – Rayleigh Scattering (10 Mm-1)) during the 20% worst days is 83.7 Mm-1, which is about 12.0 times of the value of 7.0 Mm-1 during the 20% best days and 4.8 times of the value of 17.4 Mm-1 during the middle 60% days. OMC is the largest contributor to aerosol light extinction during the 20% worst days, and the contribution of OMC to aerosol light extinction is ~ 60% in worst days. LAC also contributes ~ 15% to aerosol light extinction in the worst days.
Figure 3 suggests that the highest occurrence of the 20% worst days happened in August, in which more than ~50% of the sampling days are the 20% haziest days at Kalmiopsis. As shown in Figure 4, very high light extinction coefficients are found in the 20% worst days in August. OMC is the largest aerosol contributor to haze in August, with a contribution of ~ 66%. LAC also contributes ~ 18% to haze at the same time period. Extremely high OC / EC loadings suggest that specific pollution events such as forest fires may be the major reason for the 20% haziest days in August.
Figure 3 Percentage of sampling days that are 20% worst days in each month (1997-2002)
Figure 4 Average contributions of major aerosol chemical components to light extinction during 20% worst days in each month (1997-2002)