Light scattering from sea-salt aerosols at Interagency Monitoring of Protected Visual Environments (IMPROVE) sites.
A method is described to estimate light scattering (Bsp) by sea-salt aerosols at coastal locations in the Interagency Monitoring of Protected Visual Environments (IMPROVE) network. Dry mass scattering efficiencies for fine and coarse sea-salt particles were based on previously measured dry sea-salt size distributions. Enhancement of sea-salt particle scattering by hygroscopic growth was based on NaCl water activity data. Sea-salt aerosol mass at the IMPROVE site in the Virgin Islands (VIIS) was estimated from strontium (Sr) concentrations in IMPROVE aerosol samples. Estimated Bsp, including contributions from sea-salt mass based on Sr, agreed well with measured Bsp at the VIIS IMPROVE site. On average, sea salt accounted for 52% of estimated Bsp at this site. Sea-salt aerosol mass cannot be reliably estimated from Sr unless its crustal enrichment factor exceeds 10. Sodium (Na) concentrations are not accurately determined by X-ray fluorescence analysis in IMPROVE samples. It is recommended that Na be measured in the fine and coarse modes by a more appropriate method, such as atomic absorption spectroscopy or ion chromatography, to account for scattering by sea-salt particles at IMPROVE sites where such contributions may be significant.
Lowenthal
Douglas
D
Desert Research Institute, Reno, NV 89512, USA. Doug.Lowenthal@dri.edu
Kumar
Naresh
N
D000336:Aerosols / Q000032:analysis; D004784:Environmental Monitoring; D006813:Humidity; D008027:Light; D008962:Models, Theoretical; D012542:Scattering, Radiation; D012623:Seawater; D012964:Sodium / Q000032:analysis*; D012965:Sodium Chloride / Q000032:analysis*; D013324:Strontium / Q000032:analysis
D000336:Aerosols; D012965:Sodium Chloride; D012964:Sodium; D013324:Strontium