BAND1 (Bandelier Wilderness Area, NM, Lat. 35.7796, Long. -106.2663, Alt. 1987)

5 years aerosol data are available in Bandelier National Monument during the sampling period of 1997 - 2002. As shown in Figure 1, the overall average total light extinction coefficient (Bext) is 27.0 Mm-1 (Visual Range ~ 145 Km; Deciview ~ 9.9). The average PM2.5 mass concentration is 3.6 mg/m3. The average contributions of the major aerosol components to Bandelier National Monument haze are particulate sulfate 21.9%, nitrate 5.3%, organic matter (OMC) 18.4%, elemental carbon (light absorbing carbon, LAC) 6.7%, fine soil 2.3% and coarse mass (CM) 8.2%. 

Bext = 27.0 Mm-1

 

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 29.9 Mm-1, which is about 3.4 times of the value of 8.7 Mm-1 during the 20% best days and 2.0 times of the value of 15.3 Mm-1 during the middle 60% days. Organic matter and sulfate are two of the largest contributors to aerosol light extinction during the 20% worst days, and the contribution of OMC and sulfate to aerosol light extinction are  ~ 33.8% and 32.3%, respectively in worst days.

Figure 3 suggests that the highest occurrence of the 20% worst days happened in the summer from August to September, in which ~35% of the sampling days are the 20% haziest days at Bandelier National Monument. As shown in Figure 4, in the summer, sulfate dominates the aerosol light extinction, and contributes about 30% - 40% to haze during the 20% worst days. OMC is the second largest aerosol contributor with a contribution of ~15% - 30%. One big peak happened in May with very high OMC and LAC concentrations, which may due to special pollution events such as forest fires.

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Figure 3 Percentage of sampling days that are 20% worst days in each month (1997-2002)

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Figure 4 Average contributions of major aerosol chemical components to light extinction during 20% worst days in each month (1997-2002)