Determination of Particle Effective Density in Urban Environments with a Differential Mobility Analyzer and Aerosol Particle Mass Analyzer

Abstract

Effective densities of atmospheric aerosols in various locations 53-4507-0482 and 53-4507-7721 to the University of Southern California. The research described herein has not been subjected to the agency's required peer and policy review and therefore does not necessarily reflect the views of the agency, and no official endorsement should be inferred. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.Address correspondence to Constantinos Sioutas, University of Southern California, Department of Civil and Environmental Engineering, 3620 S. Vermont Avenue, Los Angeles, CA 90089, USA. E-mail: sioutas@usc.edu CA-110 (D f = 2.54) aerosols, presumably due to the influence of vehicular combustion emission on these sites. By contrast, average fractal dimensions at USC, Riverside and Coast were found to be 2.79, 2.83, and 2.92, respectively. High fractal dimensions at these sites may be the effects of aging, moisture absorption and/or organic vapor condensation on the particles, which fills void space and makes particles more spherical.

Insight into winter haze formation mechanisms based on aerosol hygroscopicity and effective density measurements

“…The size dependency of particle effective density varied in the literature. Hu et al (2012) and Yin et al (2015) reported that effective density of the particles increased as particle size increased while a opposite trend was observed by Geller et al (2006) and Spencer et al (2007). The different trends were attributable to the variable fraction of lower-density mode particles (ρ eff < 1.0 g cm −3 ).…”

Uncertainty Budget of the SMPS–APS System in the Measurement of PM1, PM2.5, and PM10

“…Using on-line measurement techniques based on mobility-aerodynamic sizing for density estimation, it is difficult to separate the combined effect of bulk density and shape factor (Schmid et al 2007). To this purpose, an effective particle density was introduced (McMurry et al 2002;Geller et al 2006;De Carlo et al 2004;Khlystov et al 2004) as a parameter involving both bulk density and shape factor. An elegant method to measure effective particle density was developed by McMurry et al (2002) through the mass-mobility relationship.…”

Aerosol Density Determined Using Micro-orifice Uniform Deposit Impactor and Aerosol Dust Monitors Data at Seoul

“…또한 아마존 지역에서 발생한 산불에서 배출된 연기 (smoke) 입자의 밀도는 1.35 g/cm 3 (Reid and Hobbs, 1998), 도시 대기 중 50~202 nm 범위의 입자에 대 한 밀도는 1.20~1.55 g/cm 3 로 평가되었다 (Geller et al, 2006). 미국 텍사스의 Big Bend 국립공원에서 측 정한 PM 2.5 의 평균 밀도는 1.56±0.12 g/cm 3 였으며, 이 지역은 주로 멕시코 및 텍사스 동부 지역과 치우 아후안 사막에 인접해 있으며 시정(visibility)이 가 장 좋지 않은 지역 중 하나이다 (Hand and Kreidenweis, 2002 et al, 1993).…”