CRMO1 (Craters of the Moon NM, ID, Lat. 43.4605, Long. -113.5551, Alt. 1817)

2 and a half years aerosol data are available in Craters of the Moon NM during the sampling period of 1997 - 2002. As shown in Figure 1, the overall average total light extinction coefficient (Bext) is 28.0 Mm-1 (Visual Range ~  139 Km; Deciview ~ 10.3). The average PM2.5 mass concentration is 3.3 mg/m3. The average contributions of the major aerosol components to Craters of the Moon NM haze are particulate sulfate 15.1%, nitrate 19.6%, organic matter (OMC) 15.8%, elemental carbon (light absorbing carbon, LAC) 4.4%, fine soil 2.4% and coarse mass (CM) 7.0%. 

Bext = 28.0 Mm-1

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 5.8 times of the value of 6.5 Mm-1 during the 20% best days and 2.5 times of the value of 15.1 Mm-1 during the middle 60% days. Nitrate is the largest contributor to aerosol light extinction during the 20% worst days, and the contribution of nitrate to aerosol light extinction is  ~ 43% in worst days.

Figure 3 suggests that the highest occurrence of the 20% worst days happened in the winter time, in which ~30-40% of the sampling days are the 20% haziest days at Craters of the Moon NM. As shown in Figure 4, nitrate is the largest aerosol contributor to haze in the winter, with a contribution of ~50%. In the summer, OMC is the largest aerosol contributor to haze, and its contribution is about 50% in July and August.

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)