SAPE1 (San Pedro Parks, NM, Lat. 36.0139, Long. -106.8446, Alt. 2919)      

2 year and 5 month aerosol data are available in San Pedro Parks during the sampling period of 1997 - 2002. As shown in Figure 1, the overall average total light extinction coefficient (Bext) is 22.0 Mm-1 (Visual Range ~ 177 Km; Deciview ~ 7.9). The average PM2.5 mass concentration is 3.2 mg/m3. The average contributions of the major aerosol components to San Pedro Parks haze are particulate sulfate 21.9%, nitrate 5.4%, organic matter (OMC) 14.5%, elemental carbon (light absorbing carbon, LAC) 4.4%, fine soil 3.2% and coarse mass (CM) 5.3%. 

Bext = 22.0 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 22.7 Mm-1, which is about 5.4 times of the value of 4.2 Mm-1 during the 20% best days and 2.1 times of the value of 10.9 Mm-1 during the middle 60% days. Sulfate and Nitrate are two of the largest contributors to aerosol light extinction, with a contribution of 35% and 32% in the 20% worst days.

Figure 3 suggests that the highest occurrence of the 20% worst days happened in August, in which ~ 60% of the sampling days are the 20% haziest days at San Pedro Parks. As shown in Figure 4, Sulfate is the largest aerosol contributor to haze in August, with a contribution of ~ 32%. OMC also contributes 21% to haze in August. Sulfate and OMC are the two largest aerosol contributors to haze in the 20% worst days most of the year. Occasionally, nitrate or CM may be responsible for the 20% haziest days in the winter. 

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)