MOOS1 (Moosehorn NWR, ME, Lat. 45.1259, Long. -67.2661, Alt. 77.75)
Based on the regional haze rule version 2, 5 years of complete aerosol data are available in Moosehorn NWR during the baseline period of 2000 - 2004. As shown in Figure 1, the overall average total light extinction coefficient (Bext) is 48.8 Mm-1 (Visual Range ~ 108 Km; Deciview ~ 14). The average PM2.5 mass concentration is 5.0 mg/m3. The average contributions of the major aerosol components to Moosehorn haze are particulate sulfate 45.7%, nitrate 6.5%, organic matter (OMC) 13.1%, elemental carbon (light absorbing carbon, LAC) 5.0%, fine soil 0.5%, sea salt 1.4%, and coarse mass (CM) 3.2%.
Figure 1 Average contributions of major aerosol chemical components to light extinction (Based on data available in 2000-2004)
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 2000-2004)
As Figure 2 indicates, the average light extinction coefficient during the 20% worst days is 96.6 Mm-1, which is about 3.8 times of the value of 25.3 Mm-1 during the 20% best days and 2.4 times of the value of 40.6 Mm-1 during the middle 60% days. Sulfate is the largest aerosol contributor to light extinction during the 20% worst days, with a contribution of ~ 61%.
Figure 3 suggests that the highest occurrence of the 20% worst days happened in July, in which ~ 45% of the sampling days are the 20% haziest days at Moosehorn. As shown in Figure 4, in the 20% worst visibility days, sulfate is the largest aerosol contributor to haze, with a contribution from ~40% in the winter to ~70% in the summer.
Figure 3 Percentage of sampling days that are 20% worst days in each month (Based on data available in 2000-2004)
Figure 4 Average contributions of major aerosol chemical components to light extinction during 20% worst days in each month (Based on data available in 2000-2004)
