Concentrations of Atmospheric Polycyclic Aromatic Hydrocarbons in Particulate Matter and the Gaseous Phase at Roadside Sites in Hanoi, Vietnam

Abstract

We analyzed the concentrations of polycyclic aromatic hydrocarbons (PAHs) in both particulate matter (PM) and the gaseous phase at 10 roadside sites in Hanoi, Vietnam. The average concentrations of 47 PAHs ( summation 47PAHs) were 63 +/- 82 ng m(-3) in PM and 480 +/- 300 ng m(-3) in the gaseous phase. The PAHs mainly originated from motorcycles without catalytic converters. The highest concentrations of summation 47PAHs in both PM and the gaseous phase were observed at a terminal for buses and trucks. The operation of large commercial vehicles led to increased PAH pollution at the terminal site.

Evaluation of a Compact Sampler Designed for the Simultaneous Collection of Atmospheric Polycyclic Aromatic Hydrocarbons in Size-fractionated Particulate Matter and the Gaseous Phase

“…Investigated --Twenty-eight PAH compounds were examined, classified into five categories based on the number of aromatic rings in the molecule: 3 rings: fluorene, phenanthrene (Ph), anthracene (Ant), 1-, 2-, 3-, 4-, 9-methylphenanthrene (1-, 2-, 3-, 4-, 9-MePh) and 2-, 9-methylanthracene (2-, 9-MeAnt); 8,9) Sampling Apparatus -- Figure 1 shows a schematic diagram of the proposed compact sampler. The sampler combines a MCI sampler with a three-stage cascade impactor (Tokyo Dylec Co., Tokyo, Japan) 23) and holders for PUF plugs and a filter (Special order, GL Science Inc., Tokyo, Japan).…”

“…Cor-d 12 ) was separately spiked on QFF(s) and the PUF plugs prior to extraction in order to correct for the recoveries of the different PAHs throughout the extraction and clean-up procedures. For the pretreatment of QFFs, we employed a simplified version of the method described by Kishida et al [8][9][10] PAHs were extracted from QFFs using sonication with DCM for 10 min, repeated three times. The extract was concentrated into 1 ml using a rotary evaporator with the water bath kept at approximately 30 • C, using a hexane solvent.…”

“…In contrast, low-molecular-weight (LMW) PAHs (e.g., phenanthrene and pyrene), which are considered to be less mutagenic and carcinogenic compared with HMW PAHs, occur mainly in the gaseous phase, where they react with other pollutants such as ozone and NO x to form more toxic compounds. [8][9][10][11] Therefore, it is important to understand the gas-particle and particle-size distributions of atmospheric PAHs.…”

“…Many previous studies have focused on the particle-size [3][4][5][6][7]12) and gas-particle [8][9][10][11][13][14][15][16][17][18][19][20] distributions of PAHs. Size-fractionated PM is gener-ally collected using a high-or low-volume cascade impactor.…”

“…In addition, a high-volume air sampler equipped with an XAD-4 resin column has been developed for the collection of PAHs and their nitro compounds in the atmosphere. 22) Elsewhere, a compact sampler for particulate and gaseous PAHs has been applied to the collection of gas-particle PAHs, [8][9][10] including studies of atmospheric PAHs in Hanoi, Vietnam 8,9) and Kathmandu, Nepal, 10) where such investigations had not been previously performed. However, no studies would have employed a compact system for the simultaneous sampling of PAHs in fine particles and the gaseous phase.…”