On-line Measurement of the Surface Area Concentration of Aerosols in Yokohama, Japan, using the Diffusion Charging Method

Abstract

Numerous researchers have proposed that surface area is a more appropriate indicator than mass for evaluating pulmonary inflammatory responses caused by exposure to fine and ultrafine particles. In this study, measurements of surface area concentrations of aerosols were conducted in Yokohama, Japan, using the diffusion charging method. PM 2.5 mass concentration and black carbon concentration in PM 2.5 were also measured. The 24-hour continuous measurement campaigns were conducted 39 times from March to November, 2014. The surface area concentration was more closely correlated with the black carbon concentration than with the PM 2.5 mass concentration. It is considered that the abundance of black carbon particles significantly affects the surface area concentration of PM 2.5 . The strength of the correlation between the surface area and black carbon concentrations varied considerably among the measurement campaigns. A relatively weaker afternoon correlation was observed compared with the other time zones (morning, evening, and night). We consider that these phenomena are due to the transportation/formation of the particles other than black carbon that affects surface area concentration and/or the variation of the surface condition of the black carbon particles.

Monthly and Diurnal Variation of the Concentrations of Aerosol Surface Area in Fukuoka, Japan, Measured by Diffusion Charging Method

“…Table 1 shows the mean values of the concentrations of aerosol surface area, PM 2.5 mass, BC, sulfate, and particle number measured in this study. The mean concentrations of surface area and other variables measured in this study were not so different from those presented in several previous papers [18,[23][24][25]30]. The diurnal variations of each variable were analyzed to investigate the effect of diurnal human activity on the concentration of aerosol surface area ( Figure 3).…”

“…The NSAM can measure reliable LDSA of the particles between the ranges of 20 and 400 nm [26]. The procedure for the conversion from LDSA (the actual NSAM reading) to aerosol surface area has already been described elsewhere [18], but is briefly summarized here. The calibration constant is determined with passing monodisperse aerosols simultaneously through the scanning mobility particle sizer (SMPS) and the NSAM by the manufacturer (TSI Inc.).…”

Monthly and Diurnal Variation of the Concentrations of Aerosol Surface Area in Fukuoka, Japan, Measured by Diffusion Charging Method

“…Table 1 shows the mean values of the concentrations of aerosol surface area, PM2.5 mass, BC, sulfate, and particle number measured in this study. The mean concentrations of surface area and other variables measured in this study were not so different from those presented in several previous papers [17,[22][23][24]29]. The diurnal variations of each variable were analyzed to investigate the effect of diurnal human activity on the concentration of aerosol surface area ( Figure 3).…”

“…The NSAM has a cyclone with a 50% cut-off of 1 μm at the inlet; thus, the quantity the NSAM measures is actually the surface area concentration of PM1.0. The procedure for the conversion from LDSA (the actual NSAM reading) to aerosol surface area has already been described elsewhere [17,22], but is briefly summarized here. The calibration constant is determined with passing monodisperse aerosols simultaneously through the scanning mobility particle sizer (SMPS) and the NSAM by the manufacturer (TSI.…”

A parameterization of the heterogeneous hydrolysis of N<sub>2</sub>O<sub>5</sub> for mass-based aerosol models: improvement of particulate nitrate prediction

“…A value 11 m 2 g −1 was used for SA fine , considering recently reported values of 11.9 and 10.2 m 2 g −1 from laboratory studies (Okuda, 2013) and measurements in Japanese urban regions (Hatoya et al, 2016). A value of 1.2 m 2 g −1 was used for SA coarse (Okuda, 2013).…”