Characterisation of polycyclic aromatic hydrocarbons in atmospheric aerosols by gas chromatography–mass spectrometry

Environmental Levels, Sources, and Cancer Risk Assessment of PAHs Associated with PM2.5 and TSP in Monterrey Metropolitan Area

In this work, the content of polycyclic aromatic hydrocarbons (PAHs) in total suspended particles and particulate matter with an aerodynamic diameter ≤ 2.5 µm (PM_2.5) was analyzed using gas chromatography-mass spectrometry. In addition, a sequential chemical analysis of C-rich particles was performed through the parallel coupling of micro-Raman spectroscopy and scanning electron microscopy with X-ray scattering detection. Samples were collected at four sites in the Monterrey metropolitan area, Mexico. A total of 13 PAHs were quantified; indeno(1,2,3-cd)pyrene, chrysene, and benzo(a)anthracene were the most abundant. The total PAH concentrations at the four sampling sites ranged from 1.34 to 8.76 μg/m³. The diagnostic relation of the PAHs indicates that these compounds were emitted by the burning of gasoline and diesel and by the burning of charcoal and biomass. The sequential analysis correlated the morphology and the elemental/molecular composition of the C-rich particles, associated with the PAHs, with their possible emission sources. The estimated lifetime excess cancer risk for inhalation was higher than that established by the World Health Organization, which clearly makes this a potential health risk for the population.

Ambient air levels and health risk assessment of benzo(a)pyrene in atmospheric particulate matter samples from low-polluted areas: application of an optimized microwave extraction and HPLC-FL methodology

A new methodology involving a simple and fast pretreatment of the samples by microwave-assisted extraction and concentration by N2 stream, followed by HPLC with fluorescence detection, was used for determining the concentration of benzo(a)pyrene (BaP) in atmospheric particulate matter (PM10 fraction). Obtained LOD, 1.0 × 10(-3) ng/m(3), was adequate for the analysis of benzo(a)pyrene in the samples, and BaP recovery from PAH in Fine Dust (PM10-like) certified reference material was nearly quantitative (86%). The validated procedure was applied for analyzing 115 PM10 samples collected at different sampling locations in the low-polluted area of Extremadura (Southwest Spain) during a monitoring campaign carried out in 2011-2012. BaP spatial variations and seasonal variability were investigated as well as the influence of meteorological conditions and different air pollutants concentrations. A normalized protocol for health risk assessment was applied to estimate lifetime cancer risk due to BaP inhalation in the sampling areas, finding that around eight inhabitants per million people may develop lung cancer due to the exposition to BaP in atmospheric particulates emitted by the investigated sources.

Using comprehensive GC × GC to study PAHs and n-alkanes associated with PM2.5 in urban atmosphere

Comprehensive two-dimensional gas chromatography (GC × GC) utilizing a flow modulator was applied to study particulate polycyclic aromatic hydrocarbons (PAHs) and n-alkanes in the urban atmosphere. Samples were collected onto quartz fiber filters using a PM2.5 sampler at Megacity Shanghai, China. Sample preparation included extraction into n-hexane-dichloromethane mixture and cleanup on silver-impregnated silica column. Analyses were performed well with GC × GC-FID and GC × GC-TOFMS equipment. Average particulate PAHs and n-alkane concentrations were in the range of 40-100 ng/m(3) and 120-500 pg/m(3), respectively. It is alarming to note that PAHs and n-alkane concentrations were increasing with urban PM2.5 values and exceeded the air quality standards in many sampling events. Among them, 2-ring, 3-ring, and 4-ring PAHs accounted for the majority of total PAHs, and C10-15 accounted for the majority of particulate n-alkanes. Potential sources of PAHs in PM2.5 were identified using the diagnostic ratios between PAHs. Local emission sources such as combustion from gasoline and diesel engines were the main contributors of particulate-associated PAHs, while long-range transport had minor contribution to the particulate PAHs. Additionally, we determined the overall carcinogenicity of the samples based on PAH concentrations by a dose addition model and found that the overall carcinogenicity during polluted period was obviously higher than during good air quality period.

Atmospheric polycyclic aromatic hydrocarbons in an industrialized city, Kocaeli, Turkey: study of seasonal variations, influence of meteorological parameters and health risk estimation

Ambient gas and particle phase samples were collected during two sampling periods from a residential area of an industrialized city, Kocaeli, Turkey. The sampling occurred during winter months when structures were being heated, and summer months when structures were not being heated. Σ(13)PAH (gas + particle) concentrations ranged between 6.2 ng m(-3) (DahA) and 98.6 ng m(-3) (Phe) in the heating (winter) period and 3.0 ng m(-3) (BaA) and 35.1 ng m(-3) (Phe) in the non-heating (summer) period. Phe, Flt and Pyr were found to be at high concentrations in both sampling periods. Winter time to summer time concentration ratios for individual ambient PAH concentration ratios ranged between 1.2 (DahA) and 17.5 (Flu), indicating the effect of the emissions from residential heating on measured concentrations of PAHs, but great industrial plants and the only incinerator facility of Turkey are other important pollution sources around the city. Temperature dependence of gas phase PAHs was investigated using the Clausius-Clapeyron equation. A high slope obtained (5069.7) indicated the effect of the local sources on measured gas phase PAHs. Correlation of the supercooled vapor pressure (P) with the gas particle partitioning coefficient (K(p)) and particle phase fraction was also evaluated. The relationship between the meteorological parameters and individual PAH (gas + particle) concentrations was investigated further by multiple linear regression analysis. It was found that the temperature had a significant effect on all of the measured PAH concentrations, while the effects of the wind speed and direction were not significant on the individual PAHs. On the other hand, PAH concentrations showed a strong linear relationship with the ventilation coefficient (VC) which showed the influence of local sources on measured PAHs. Benzo[a]pyrene toxic equivalent (BaP(eq.)) concentrations were used for health risk assessment purposes. The winter period risk level (2.92 × 10(-3)) due to the respiratory exposure to PAHs was found to be almost 3 times higher than in the summer period (1.15 × 10(-3)).

Application of surfactants and microemulsions to the extraction of pyrene and phenanthrene from soil with three different extraction methods

In the present work, the use of surfactants and oil-in-water (O/W) microemulsions as alternative extractants in accelerated solvent extraction (ASE) for the extraction of polycyclic aromatic hydrocarbons (pyrene and phenanthrene) from soils was investigated. In particular, the effect of each individual component within the microemulsions, i.e., oil phase, surfactant and co-surfactant, and extraction conditions on the percentage recovery was systematically studied. When compared to the water and organic solvent, the important findings were that the common surfactant solutions at the concentrations above their critical micelle concentrations (CMC) were shown to enhance the percentage recovery at the lower extraction temperature. Moreover, the highest percentage recovery can be obtained using microemulsion as the extractant. The chemical component within the microemulsions and relative amounts of the oil phase appeared to play a much more significant role in ensuring high percentage recovery. Finally, an overall comparison between the percentage recoveries obtained with ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE) and ASE using organic solvents, surfactants and microemulsions as extractants was exhibited.