imating PAH Dry Deposition by Measuring Gas and Particle Phase Concentrations in Ambient Air

Abstract

Concentrations of the total polycyclic aromatic hydrocarbons (PAHs) in both the gas-phase and particle-phase were measured simultaneously in industrial, urban and suburban areas, and were 1652, 1185, and 834 ng/m 3 , respectively. PAHs with two to four-ring were distributed more than 94% in the gas-phase of all sampling sites. Meanwhile, for PAHs with five to seven-ring, less than 70% were distributed in the gas-phase of the three sites. Approximately two-thirds of the three most hazardous PAHs (BbF + BaP + DBA) were distributed in the gas-phase at the TIP and NCHU, and only one-third of BbF + BaP + DBA were distributed in the gas-phase at the THU.Total dry deposition flux was mainly contributed, with a proportion of between 53.3% and 63.4%, by PAHs with three to four-ring at the three sites. For LMW PAHs, the gas-phase PAHs contribute over 87% to the dry deposition flux at the three sites. Meanwhile, the particle-phase PAHs contribute more than 86% and 99% to the dry deposition flux of the MMW and HMW PAHs, respectively. The mean dry deposition velocities were 0.01, 0.24, 0.47, 0.76, 0.84 and 0.88 cm/s for two to seven-ring PAH homologue. Notably, the dry deposition velocity of the HMW PAHs was significantly higher than that of the LMW PAHs at the three sampling sites. The dry deposition velocities of BbF + BaP + DBA PAHs were 0.8, 0.64 and 1.02 cm/s at the TIP, NCHU and THU, respectively. Accordingly, hazardous PAHs with high dry deposition velocities are threatening to human health by dry deposition.

Particle-associated polycyclic aromatic hydrocarbons and their dry deposition fluxes from a bus-station in the Rio de Janeiro metropolitan area, Brazil

“…Deposition velocity, V d, may vary 1-2 orders of magnitude 8,71-73 due either to particle size, climatic or physical conditions in the atmosphere Even considering those uncertainties, the particulate matter dry deposition flux calculations help to better understand PAHs removal mechanisms. Indeed, some authors, such as Vardar et al 71 and Chang et al, 8 have modeled V d and they have found results comparable to those from Sheu et al 72 In this study PAH particle dry depositions were calculated using V d as stated on the latter cited study as shown in Table 4.…”

“…Accordingly, breathing PAHs may represent a health hazard for humans. [8][9][10] The risk associated with human exposure to atmospheric PAHs is higher in urban environments 8 where high vehicle density and the dispersion of atmospheric pollutants contribute to the increase of their concentrations. Indeed, in urban areas, exhaust from diesel and gasoline vehicles play an important role on PAH emissions.…”

Quantification and source identification of atmospheric particulate polycyclic aromatic hydrocarbons and their dry deposition fluxes at three sites in Salvador Basin, Brazil, impacted by mobile and stationary sources

“…In these cases, deposition velocity can vary 1-2 orders of magnitude. [61][62][63][64] Even keeping in mind these uncertainties, the particulate matter dry deposition flux calculations bring broad but very helpful insights in order to better understand PAH removal mechanisms. Indeed, some authors have modeled V d , 62,65 and they have found results comparable to those from Sheu et al 62 Therefore, in this study PAH particle dry depositions were calculated by using the V d stated in the latter study, as observed in Table 5 The apparent dry deposition fluxes from Table 5 take into account both the geometric averaged concentration level of an individual PAH sorbed on to particulate matter and dry deposition velocity.…”

Traffic Air Pollution and Risk of Death from Ovarian Cancer in Taiwan: Fine Particulate Matter (PM2.5) as a Proxy Marker

“…In Taiwan, the major source of PAH is traffic exhaust emissions (Chang et al 2003). PAH may be present in particulate or gaseous phase.…”