LAVO1 (Lassen Volcanic National Park, CA, Lat. 40.5402, Long. -121.5777, Alt. 1755)
6 years aerosol data are available in Lassen Volcanic National Park during the sampling period of 1997 - 2002. As shown in Figure 1, the overall average total light extinction coefficient (Bext) is 26.5 Mm-1 (Visual Range ~ 147 Km; Deciview ~ 9.7). The average PM2.5 mass concentration is 3.6 mg/m3. The average contributions of the major aerosol components to Lassen Volcanic National Park haze are particulate sulfate 16.4%, nitrate 5.7%, organic matter (OMC) 25.1%, elemental carbon (light absorbing carbon, LAC) 7.7%, fine soil 1.9% and coarse mass (CM) 5.4%.
Figure 1 Average contributions of major aerosol chemical components to light extinction (Based on data available in 1997-2002)
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)
As Figure 2 indicates, the average aerosol light extinction coefficient (Bext – Rayleigh Scattering (10 Mm-1)) during the 20% worst days is 37.8 Mm-1, which is about 9.2 times of the value of 4.1 Mm-1 during the 20% best days and 2.9 times of the value of 13.2 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 ~ 47.2% in worst days.
Figure 3 suggests that the highest occurrence of the 20% worst days happened in August and September, in which ~ 40% of the sampling days are the 20% haziest days at Lassen Volcanic National Park. As shown in Figure 4, OMC is the largest aerosol contributor to haze in August and September, with a contribution of ~ 45% in the worst days.
Figure 3 Percentage of sampling days that are 20% worst days in each month (Based on data available in 1997-2002)
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)