Using synchrotron based ATR-FTIR, EXAFS, and XRF to characterize the chemical compositions of TSP in industrial estate area

In Thailand, the Map Ta Phut Industrial Estate (MTPIE), a prominent industrial hub, has substantial environmental and health issues caused by industrial pollution. This study uses advanced synchrotron-based techniques, such as Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR), Extended X-ray Absorption Fine Structure (EXAFS), and X-ray Fluorescence (XRF), to fully examine the chemical make-up of total suspended particulate (TSP) in the given area. Notable findings include the detection of remarkably high enrichment factors for magnesium and sulfur, indicating the presence of industrial operations. Additionally, we found that magnetite, which accounts for an average of 40 % of the total iron oxides in the samples, is the main iron oxide. The study also highlights about how calcium carbonate and different organic functional groups are found in large amounts, which shows that industrial emissions and natural sources are connected in a complex way. The findings underscore the susceptibility of children to TSP exposure, revealing increased rates of inhalation and significant health hazards. In order to safeguard public health in industrial areas such as MTPIE, it is imperative to implement more sophisticated pollution control techniques and maintain ongoing environmental monitoring.

Vertical variation of source-apportioned PM2.5 and selected volatile organic compounds near an elevated expressway in an urban area

Fine particulate matter (PM2.5) and volatile organic compounds (VOCs) are associated with adverse health effects and show spatial variation in three dimensions. The present study attempted to evaluate source contributions of PM2.5 and toxic VOCs in a metropolitan area focusing on the associated vertical variations. A special emphasis is put on the effects of the elevated expressway on the vertical variability of contribution estimates of the identified sources. Nine source factors, i.e., soil dust, sea salt/oil combustion, secondary nitrate, industrial emission, aged VOCs/secondary aerosol, traffic-related I, solvent use/industrial process, secondary sulfate, and traffic-related II, were identified using positive matrix factorization (PMF). The main contributors to PM2.5 were secondary sulfate (19.1%) and traffic-related emissions (traffic-related I and II, 16.1%), whereas the largest contributors to VOCs were traffic-related emissions (37.6%). The influence of the elevated expressway is suggested to be particularly critical on vertical variations of traffic-related emissions, including aging and secondary formation of locally accumulated air pollutants near roads. Increasing the building porosity under the viaduct could reduce the accumulation of air pollutants caused by the shelter effect. Additionally, in-street barriers would be beneficial in reducing population exposure to traffic-related emissions by altering the airflows near roads.

Source appointment and health risk assessment of polycyclic aromatic hydrocarbons in paddy grain from Thailand and Laos

Rice is a staple meal for the majority of Asians. However, human exposure to polycyclic aromatic hydrocarbons from paddy grain is largely unknown in Thailand and Laos. Therefore, information on the quantitative measurement and assessment of the health problems caused by PAHs was analyzed. The results showed that the concentrations of total PAHs in paddy grain in Thailand and Laos were 38.86 ± 5.13 and 11.35 ± 1.96 ng g^-1, respectively. The highest concentration of PAHs in Thailand was B[k]F, whereas D[a,h]A was found to be the highest in Laos. A p-value less than 0.05 was defined, which showed B[b]F and B[k]F from Thailand and Laos were significant, which indicated that they could be from a different pollutant source. The main finding of this study, which was supported by the diagnostic ratios of PAHs and HCA, was that the primary source of PAHs was assumed to be incomplete combustion of petroleum products, which was caused by the burning of industrial fuels or vehicle exhausts, as well as open burning. The findings suggest that these two nations have similar PAH origins. Agricultural waste burning and transportation emissions are well-known sources of PAHs in Thailand and Laos. The cancer risk assessment method was based on the accumulation of PAHs from paddy grains. An ILCR of 1.0E-06 to 1.0E-04 was considered a tolerable limit of cancer risk, while a risk > 1.0E-04 was considered a concern in terms of cancer risk. The findings indicated that while PAH emissions exist, their contribution to global toxicity may be anticipated to be low in inhalation exposure. The higher values of ingestion and dermal risk estimated were regarded as the tolerable limit of cancer risk in children and adults from both countries, indicating that cancer risk in both nations falls within the "acceptable level" range.

An Application of Artificial Neural Network to Evaluate the Influence of Weather Conditions on the Variation of PM2.5-Bound Carbonaceous Compositions and Water-Soluble Ionic Species

Previous studies have determined biomass burning as a major source of air pollutants in the ambient air in Thailand. To analyse the impacts of meteorological parameters on the variation of carbonaceous aerosols and water-soluble ionic species (WSIS), numerous statistical models, including a source apportionment analysis with the assistance of principal component analysis (PCA), hierarchical cluster analysis (HCA), and artificial neural networks (ANNs), were employed in this study. A total of 191 sets of PM2.5 samples were collected from the three monitoring stations in Chiang-Mai, Bangkok, and Phuket from July 2020 to June 2021. Hotspot numbers and other meteorological parameters were obtained using NOAA-20 weather satellites coupled with the Global Land Data Assimilation System. Although PCA revealed that crop residue burning and wildfires are the two main sources of PM2.5, ANNs highlighted the importance of wet deposition as the main depletion mechanism of particulate WSIS and carbonaceous aerosols. Additionally, Mg2+ and Ca2+ were deeply connected with albedo, plausibly owing to their strong hygroscopicity as the CCNs responsible for cloud formation.

An application of aromatic compounds as alternative tracers of tsunami backwash deposits

This manuscript provides some comprehensive technical insights regarding the application of polycyclic aromatic hydrocarbons (PAHs) characterized by using Gas-Chromatography Mass Spectrometry. Although numerous chemical species such as water soluble ionic species (e.g. Na+, K+, Cl-, Ca2+, Mg2+) and acid leachable heavy metal fractions (e.g. Fe, Cd, Al, Mo, Sb, As, Cu, Zn, Pb, and Mn) can be used to characterize tsunami deposits, the knowledge of PAH congeners as alternative chemical species for identifying tsunami backwash deposits is strictly limited. This manuscript is exclusive because it aims to find some alternative chemical proxies in order to distinguish tsunami backwash deposits from typical marine sediments. A wide range of diagnostic binary ratios of PAH congeners have been selected in order to characterize Typical Marine Sediments (TMS), Tsunami backwash deposits (TBD), Onshore Tsunami Deposits (OTD) and Coastal Zone Soils (CZS). The state of the art and future perspectives coupled with both advantages and disadvantages of above mentioned chemical tracers will be critically reviewed and further discussed.

Distribution, sources, risks, and vitro DNA oxidative damage of PM2.5-bound atmospheric polycyclic aromatic hydrocarbons in Urumqi, NW China

Research has focused on the impacts of polycyclic aromatic hydrocarbons (PAHs) in the atmosphere due to their potential carcinogenicity. In this study, we investigated the seasonal variation, sources, incremental lifetime cancer risks (ILCR_S), and vitro DNA oxidative damage of PAHs in Urumqi in NW China. A total of 72 atmospheric samples from Urumqi were collected over a year (September 2017-September 2018) and were analyzed for 16 PAHs that are specifically prioritized by the U.S Environmental Protection Agency (U·S EPA). The highest PAHs concentrations were in winter (1032.66 ng m^-3) and lowest in spring (146.00 ng m^-3). Middle molecular weight PAHs with four rings were the most abundant species (45.28-61.19% of the total). The results of the diagnostic ratio and positive matrix factorization inferred that the major sources of atmospheric PAHs in Urumqi were biomass burning, coking, and petrogenic sources (52.9%), traffic (30.1%), coal combustion (8.9%), and the plastics recycling industry (8.1%). ILCR_S assessment and Monte Carlo simulations suggested that for all age groups PAHs cancer risks were mainly associated with ingestion and dermal contact and inhalation was negligible. The plasmid scission assay results showed a positive dose-response relationship between PAHs concentrations and DNA damage rates, demonstrating that toxic PAHs was the primary cause for PM_2.5-induced DNA damage in the air of Urumqi.

Vertical distribution of source apportioned PM2.5 using particulate-bound elements and polycyclic aromatic hydrocarbons in an urban area

Receptor models have been widely used for identifying and quantifying source-specific contributions from mixtures of air pollutants. Nonetheless, our knowledge is still limited on how various components of air pollution are vertically distributed and the sources of such pollutants. In this study, we collected 135 samples of PM_2.5 (particles with aerodynamic diameter less than or equal to 2.5 µm) from building balconies at three altitudes in the metropolis of Taipei (Taiwan) and analyzed the samples for elements and polycyclic aromatic hydrocarbons that could be used to identify the sources of those pollutants. We used positive matrix factorization (PMF) to identify seven likely sources, including combustion, sulfur-rich aerosol, fresh traffic, industry/Cr-rich, oil combustion/vehicle, dust, and traffic. Although PM_2.5 mass differed significantly between low-level and mid-level sites, the largest contributor to PM_2.5 mass (sulfur-rich aerosol, 35.2%) showed nonsignificant variation in the vertical distribution. In contrast, oil combustion/vehicle, which exhibited significant difference between mid-level sites and the other two altitudes, might be a determinant in the vertical variation of PM_2.5. We also observed negative trends with sampling height for combustion and traffic emissions.

The traffic signature on the vertical PM profile: Environmental and health risks within an urban roadside environment

In an attempt to investigate the traffic-impacted vertical aerosols profile and its relationship with potential carcinogenicity and/or mutagenicity, samples of different sized airborne particles were collected in parallel at the 1st and 5th floor of a 19 m high building located next to one of the busiest roads of Athens. The maximum daily concentrations were 65.9, 42.5 and 38.5 μg/m³, for PM₁₀, PM_2.5 and PM₁, respectively. The vertical concentration ratio decreased with increasing height verifying the role of the characteristics of the area (1st/5th floor: 1.21, 1.13, 1.09 for PM₁₀, PM_2.5 and PM₁, respectively). Chemically, strengthening the previous hypothesis, the collected particles were mainly carbonaceous (68%-93%) with the maximum budget of the polyaromatic hydrocarbons being recorded near the surface (1st/5th floor: 1.84, 1.07, 1.15 for PM₁₀, PM_2.5 and PM₁, respectively). The detected PM-bound PAHs along with the elements as well as the carbonaceous and ionic constituents were used in a source apportionment study. Exhaust and non-exhaust emissions, a mixed source of biomass burning and high temperature combustion processes (natural gas, gasoline/diesel engines), sea salt, secondary and soil particles were identified as the major contributing sources to the PM pollution of the investigated area. With respect to the health hazards, the calculation of the Benzo[a]Pyrene toxicity equivalency factors underlined the importance of the height of residence in buildings for the level of the exposure (1st/5th floor: B[a]P_TEQ: 1.82, 1.12, 1.10, B[a]P_MEQ: 1.85, 1.13, 1.09 for PM₁₀, PM_2.5 and PM₁, respectively). Finally, despite its verified significance as a surrogate compound for the mixture of the hydrocarbons (its contribution up to 72%, 79% on the level of the 1st and 5th floor, respectively), the importance of the incorporation of PAH species in addition to B[a]P when assessing PAH toxicity was clearly documented.

Seasonal variations and sources of atmospheric polycyclic aromatic hydrocarbons and organochlorine compounds in a high-altitude city: Evidence from four-year observations

Lijiang is a high-altitude city located on the eastern fringe of the Tibetan Plateau, with complex seasonal atmospheric circulations (i.e. westerly wind, Indian Monsoon, and East Asia Monsoon). Very few previous studies have focused on seasonal variations and sources of organic pollutants in Lijiang. In this study, a four-year air campaign from June 2009 to July 2013 was conducted to investigate the temporal trends and the sources of polycyclic aromatic hydrocarbons (PAHs) and organochlorine compounds [including organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs)]. The atmospheric PAH concentrations in winter are 2-3 times of those in summer, probably because of the combined result of enhanced local emission and long-range atmospheric transport (LRAT) during winter. Traffic pollution was the primary local source of PAHs, while biomass burning is the dominant LRAT source. OCPs and PCBs also mainly underwent LRAT to reach Lijiang. The peak concentrations of most of OCPs occurred in pre-monsoon season and winter, which were carried by air masses from Myanmar and India through westerly winds. As compared with other sites of the Tibetan Plateau, without the direct barrier of the Himalaya, Lijiang is easily contaminated by the incursion of polluted air masses.

Chemical characterization of polycyclic aromatic hydrocarbons (PAHs) in 2013 Rayong oil spill-affected coastal areas of Thailand

Among Southeast Asian countries, Thailand has gradually accustomed to extremely prompt urbanization, motorization, and industrialization. Chonburi and Rayong provinces are two provinces involved in "eastern seaboard" industrial zones, which is an emerging economic region that plays a key role in Thailand's economy. The 2013 Rayong oil spill did not only cause damages to the coastal and maritime environment, but also undermine trust in the overall safety system and negatively affect the investor confidence. In this study, 69 coastal soils collected around Koh Samed Island were chemically extracted and analyzed for 15 PAHs by using a Shimadzu GCMS-QP2010 Ultra system comprising a high-speed performance system with ASSP function. In this study, numerous diagnostic binary ratios were applied to identify potential sources of PAHs. Advanced statistical techniques such as hierarchical cluster analysis coupled with principal component analysis were also conducted for further investigations of source identifications.

Characterization of parent and oxygenated-polycyclic aromatic hydrocarbons (PAHs) in Xi'an, China during heating period: An investigation of spatial distribution and transformation

Polycyclic aromatic hydrocarbons (PAHs) and its oxygenated derivatives (OPAHs) are toxins in PM2.5. Little information has been known for their transformation in the ambient airs. In this study, PM2.5 samples were collected at 19 sampling sites in Xi'an, China during the heating period, which is classified into: urban residential, university, commercial area, suburban region, and industry. Organic compounds including PAHs, OPAHs, hopanes and cholestanes were quantified. The average of total quantified PAHs and OPAHs concentrations were 196.5 ng/m(3) and 29.4 ng/m(3), respectively, which were consistent with other northern cities in China. Statistical analyses showed that there were significant differences on the distributions of PAHs between urban and suburban regions. The industry also had distinguishable profiles compared with urban residential and commercial area for OPAHs. The greater diversity of OPAHs than PAHs might be due to different primary emission sources and transformation and degradation pathways. The ratios of OPAHs to the corresponding parent PAHs, including 9-fluorenone/fluorene, anthraquinone/anthracene, benz[a]anthracene-7,12-dione/benzo[a]anthracene were 6.2, 12.7, and 1.4, respectively, which were much higher than those for the fresh emissions from coal combustion and biomass burning. These prove the importance of secondary formation and transformation of OPAHs in the ambient airs. Biomarkers such as retene, cyclopenta[CD]pyrene and αα-homohopane were characterized for the source apportionment. With Positive Matrix Factorization (PMF) model analysis, biomass burning was recognized as the most dominant pollution sources for PAHs during the heading period, which accounted for a contribution of 37.1%. Vehicle emission (22.8%) and coal combustion (22.6%) were also contributors in Xi'an.

Assessment of selected metals in the ambient air PM10 in urban sites of Bangkok (Thailand)

Estimating the atmospheric concentrations of PM10-bounded selected metals in urban air is crucial for evaluating adverse health impacts. In the current study, a combination of measurements and multivariate statistical tools was used to investigate the influence of anthropogenic activities on variations in the contents of 18 metals (i.e., Al, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Cd, Sb, Ba, La, Ce and Pb) in ambient air. The concentrations of PM10-bounded metals were measured simultaneously at eight air quality observatory sites during a half-year period at heavily trafficked roads and in urban residential zones in Bangkok, Thailand. Although the daily average concentrations of Al, V, Cr, Mn and Fe were almost equivalent to those of other urban cities around the world, the contents of the majority of the selected metals were much lower than the existing ambient air quality guidelines and standard limit values. The sequence of average values of selected metals followed the order of Al > Fe > Zn > Cu > Pb > Mn > Ba > V > Sb > Ni > As > Cr > Cd > Se > Ce > La > Co > Sc. The probability distribution function (PDF) plots showed sharp symmetrical bell-shaped curves in V and Cr, indicating that crustal emissions are the predominant sources of these two elements in PM10. The comparatively low coefficients of divergence (COD) that were found in the majority of samples highlight that site-specific effects are of minor importance. A principal component analysis (PCA) revealed that 37.74, 13.51 and 11.32 % of the total variances represent crustal emissions, vehicular exhausts and the wear and tear of brakes and tires, respectively.

Assessment of Reliability when Using Diagnostic Binary Ratios of Polycyclic Aromatic Hydrocarbons in Ambient Air PM10

The reliability of using diagnostic binary ratios of particulate carcinogenic polycyclic aromatic hydrocarbons (PAHs) as chemical tracers for source characterisation was assessed by collecting PM10 samples from various air quality observatory sites in Thailand. The major objectives of this research were to evaluate the effects of day and night on the alterations of six different PAH diagnostic binary ratios: An/(An + Phe), Fluo/(Fluo + Pyr), B[a]A/(B[a]A + Chry), B[a]P/(B[a]P + B[e]P), Ind/(Ind + B[g,h,i]P), and B[k]F/Ind, and to investigate the impacts of site-specific conditions on the alterations of PAH diagnostic binary ratios by applying the concept of the coefficient of divergence (COD). No significant differences between day and night were found for any of the diagnostic binary ratios of PAHs, which indicates that the photodecomposition process is of minor importance in terms of PAH reduction. Interestingly, comparatively high values of COD for An/(An + Phe) in PM10 collected from sites with heavy traffic and in residential zones underline the influence of heterogeneous reactions triggered by oxidising gaseous species from vehicular exhausts. Therefore, special attention must be paid when interpreting the data of these diagnostic binary ratios, particularly for cases of low-molecular-weight PAHs.

Assessment of polycyclic aromatic hydrocarbons in indoor and outdoor air of preschool environments (3-5 years old children)

This work characterizes levels of polycyclic aromatic hydrocarbons (PAHs) in indoor and outdoor air of preschool environments, and assesses the respective risks for 3-5-years old children. Eighteen gaseous and particulate (PM1 and PM2.5) PAHs were collected indoors and outdoors during 63 days at preschools in Portugal. Gaseous PAHs accounted for 94-98% of total concentration (ΣPAHs). PAHs with 5-6 rings were predominantly found in PM1 (54-74% particulate ΣPAHs). Lighter PAHs originated mainly from indoor sources whereas congeners with 4-6 rings resulted mostly from outdoor emissions penetration (motor vehicle, fuel burning). Total cancer risks of children were negligible according to USEPA, but exceeded (8-13 times) WHO health-based guideline. Carcinogenic risks due to indoor exposure were higher than for outdoors (4-18 times).

Assessing risks to adults and preschool children posed by PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) during a biomass burning episode in Northern Thailand

To investigate the potential cancer risk resulting from biomass burning, polycyclic aromatic hydrocarbons (PAHs) bound to fine particles (PM2.5) were assessed in nine administrative northern provinces (NNP) of Thailand, before (N-I) and after (N-II) a haze episode. The average values of Σ 3,4-ring PAHs and B[a] P Equivalent concentrations in world urban cities were significantly (p<0.05) much higher than those in samples collected from northern provinces during both sampling periods. Application of diagnostic binary ratios of PAHs underlined the predominant contribution of vehicular exhaust to PM2.5-bound PAH levels in NNP areas, even in the middle of the agricultural waste burning period. The proximity of N-I and N-II values in three-dimensional (3D) principal component analysis (PCA) plots also supports this conclusion. Although the excess cancer risk in NNP areas is much lower than those of other urban area and industrialized cities, there are nevertheless some concerns relating to adverse health impacts on preschool children due to non-dietary exposure to PAHs in home environments.

Application of binary diagnostic ratios of polycyclic aromatic hydrocarbons for identification of Tsunami 2004 backwash sediments in Khao Lak, Thailand

Identification of Tsunami deposits has long been a controversial issue among geologists. Although there are many identification criteria based on the sedimentary characteristics of unequivocal Tsunami deposits, the concept still remains ambiguous. Apart from relying on some conventional geological, sedimentological, and geoscientific records, geologists need some alternative “proxies” to identify the existence of Tsunami backwash in core sediments. Polycyclic aromatic hydrocarbons (PAHs) are a class of very stable organic molecules, which can usually be presented as complex mixtures of several hundred congeners; one can assume that the “Tsunami backwash deposits” possess different fingerprints of PAHs apart from those of “typical marine sediments.” In this study, three-dimensional plots of PAH binary ratios successfully identify the Tsunami backwash deposits in comparison with those of global marine sediments. The applications of binary ratios of PAHs coupled with HCA are the basis for developing site-specific Tsunami deposit identification criteria that can be applied in paleotsunami deposits investigations.

Risk assessment of the presence of polycyclic aromatic hydrocarbons (PAHs) in coastal areas of Thailand affected by the 2004 tsunami

The total concentrations of twelve, likely carcinogenic, polycyclic aromatic hydrocarbons (PAHs) (i.e., phenanthrene (Phe), anthracene (An), fluoranthene (Fluo), pyrene (Pyr), benz[a]anthracene (B[a]A), chrysene (Chry), benzo[b]fluoranthene (B[b]F), benzo[k]fluoranthene (B[k]F), benzo[a]pyrene (B[a]P), indeno[1,2,3-cd]pyrene (Ind), dibenz[a,h]anthracene (D[a,h]A), and benzo[g,h,i]perylene (B[g,h]P) in backwash deposits of the 2004 Khao Lak tsunami were carefully investigated and compared with the concentrations of world marine sediments (WMS). In general, ∑12PAHs in this study (i.e., 69.43 ± 70.67 ng g(-1)) were considerably lower than those values observed in marine sediments from Boston (54,253 ng g(-1)), coastal sediments from Barcelona Harbour (15,069 ng g(-1)), and riverine sediment from Guangzhou Channel (12,525 ng g(-1)), but were greater than values from coastal sediments in Rosas Bay (12 ng g(-1)), Santa Ponsa Bay (26 ng g(-1)) and Le Planier (34 ng g(-1)). The total toxic benzo[a]pyrene equivalent (TEQ(Carc)) values calculated for Khao Lak coastal sediments (KCS), Khao Lak terrestrial soils (KTS), and Songkhla Lake sediments (SLS) were 10.3 ± 12.2 ng g(-1), 16.0 ± 47.7 ng g(-1), and 5.67 ± 5.39 ng g(-1), respectively. Concentrations of PAHs at all study sites resulted in risk levels that fell into the "acceptable" range of the US EPA model and were much lower than those of other WMS. The cancer risk levels of PAH content in KCS ranged from 7.44 × 10(-8) to 2.90 × 10(-7), with an average of 1.64 × 10(-7) ± 8.01 × 10(-8); this value is 119 times lower than that of WMS. In addition, soil cleanup target levels (SCTLs) for both non-carcinogens (i.e., Phe, An, Fluo and Pyr) and carcinogens (i.e., B[a]A, Chry, B[b]F, B[k]F, B[a]P, Ind, D[a,h]A and B[g,h,i]P) in the KTS samples were estimated for all target groups, with an average value of 115,902 ± 197,229 ng g(-1).