AGTI1 (Agua Tibia, CA Lat. 33.4636, Long. -116.9706, Alt. 507) Print-Friendly Version Print-Friendly Version (B&W)
2 years aerosol data are available in Agua Tibia during the sampling period of 1997 - 2002. As shown in Figure 1, the overall average total light extinction coefficient (Bext) is 62.6 Mm-1 (Visual Range ~ 62 Km; Deciview ~ 18.4). The average PM2.5 mass concentration is 8.1 mg/m3. The average contributions of the major aerosol components to Agua Tibia haze are particulate sulfate 29.3%, nitrate 24.0%, organic matter (OMC) 13.3%, elemental carbon (light absorbing carbon, LAC) 6.2%, fine soil 1.5% and coarse mass (CM) 9.8%.
Figure 1 Average contributions of major aerosol chemical components to light extinction (1997-2002) (B&W)
Figure 2 Average contributions of major aerosol chemical components to light extinction in 20% best, middle 60% and 20% worst days (1997-2002) (Data Table) (B&W)
As Figure 2 indicates, the average aerosol light extinction coefficient (Bext – Rayleigh Scattering (10 Mm-1)) during the 20% worst days is 92.2 Mm-1, which is about 5.1 times of the value of 17.9 Mm-1 during the 20% best days and 1.8 times of the value of 50.1 Mm-1 during the middle 60% days. Particulate sulfate is the largest contributor to aerosol light extinction during the 20% worst days, and the contribution of particulate sulfate to aerosol light extinction is ~ 35.8% in worst days. Nitrate is also responsible for 31.9% of the aerosol light extinction in the 20% worst days.
Figure 3 suggests that the highest occurrence of the 20% worst days happened in August and October, in which ~40% of the sampling days are the 20% haziest days at Agua Tibia. During the winter season, nitrate particle is the largest aerosol contributor to haze, and contributes 40-60% to haze during the 20% worst days in January to March as shown in Figure 4. While, in the summer, Sulfate dominates the aerosol light extinction and contributes more than 40% to haze during the 20% worst days. Both sulfate and nitrate are important to haze in the mild month as April, May, October and November.
Figure 3 Percentage of sampling days that are 20% worst days in each month (1997-2002) (Data Table) (B&W)
Figure 4 Average contributions of major aerosol chemical components to light extinction during 20% worst days in each month (1997-2002) (Data Table) (B&W)
