Visibility in the southwest—An exploration of the historical data base

Visibility: Science and Regulation

“…These did not contradict the simple extinction/fine-mass proportionality reported by others. White, 115 White and Roberts, 86 Cass, 116 and Trijonis 117 were working with data from total filter samples collected at generally moderate ambient humidities. They used chemistry as an available proxy of particle size, employing this information to distinguish the predominantly secondary fine particles from the predominantly crustal coarse particles.…”

The Excellent but Deteriorating Air Quality in the Lake Powell Region

“…= and other fine particulates has caused visibility to decrease, is supported by the work of Trijonis, et a/., 5 in which decreased visibility in the southwest has been associated with increasing 'secondary' aerosols including SO 4 . Additionally, mean particle diameter decreased from 3.8 jum to 1.8 jitm in 1974.…”

Carbonaceous Particles and Regional Haze in the Western United States

“…together with smaller characteristic particle sizes, typically yields estimated sulfate scattering efficiencies below 5 m2/g (Macias et al, 1981;Ouimette et al, 1981;Trijonis, 1979). In the arid Southwest, the scattering efficiency of nonvolatile organics appears to be as great as that of sulfates and nitrate.…”