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

Enhanced light absorption due to the mixing state of black carbon in fresh biomass burning emissions

lack of information on the radiative effects of refractory black carbon (rBC) emitted from biomass burning is a significant gap in our understanding of climate change. A custom-made combustion chamber was used to simulate the open burning of crop residues and investigate the impacts of rBC size and mixing state on the particles' optical properties. Average rBC mass median diameters ranged from 141 to 162 nm for the rBC produced from different types of crop residues. The number fraction of thickly-coated rBC varied from 53 to 64%, suggesting that a majority of the freshly emitted rBC were internally mixed. By comparing the result of observed mass absorption cross-section to that calculated with Mie theory, large light absorption enhancement factors (1.7-1.9) were found for coated particles relative to uncoated cores. These effects were strongly positively correlated with the percentage of coated particles but independent of rBC core size. We suggest that rBC from open biomass burning may have strong impact on air pollution and radiative forcing immediately after their production

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

Hazard Quotients, Hazard Indexes, and Cancer Risks of Toxic Metals in PM10 during Firework Displays

Bonfire night is a worldwide phenomenon given to numerous annual celebrations characterised by bonfires and fireworks. Since Thailand has no national ambient air quality standards for metal particulates, it is important to investigate the impacts of particulate injections on elevations of air pollutants and the ecological health impacts resulting from firework displays. In this investigation, Pb and Ba were considered potential firework tracers because their concentrations were significantly higher during the episode, and lower than/comparable with minimum detection limits during other periods, indicating that their elevated concentrations were principally due to pyrotechnic displays. Pb/Ca, Pb/Al, Pb/Mg, and Pb/Cu can be used to pin-point emissions from firework displays. Air mass backward trajectories (72 h) from the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model indicated that areas east and north-east of the study site were the main sources of the airborne particles. Although the combined risk associated with levels of Pb, Cr, Co., Ni, Zn, As, Cd, V, and Mn was far below the standards mentioned in international guidelines, the lifetime cancer risks associated with As and Cr levels exceeded US-EPA guidelines, and may expose inhabitants of surrounding areas of Bangkok to an elevated cancer risk

Ecological and health risks of polycyclic aromatic hydrocarbons in the sediment core of Phayao Lake, Thailand

Polycyclic aromatic hydrocarbons (PAHs) in sediment cores from Phayao Lake were investigated in terms of their concentration, distribution, and potential effects on the environment and human health. The concentration of Σ16PAHs ranged from 77.6 to 1251.1 ng g-1. Additionally, low molecular weight PAHs (two or three fused aromatic rings) were dominant, indicating that the main source of PAHs is the incomplete combustion of organic sources. The toxic equivalent quantities (TEQs) of 16 PAHs varied from 2.67 to 155.09 ng g-1, with an average of 38.29 ± 46.69 ng g-1. Furthermore, the TEQs of 9 known carcinogenic PAHs averaged 20.77 ± 30.63 ng g-1. B[a]P had the highest TEQ, followed by D[a,h]A and B[k]F, with values of 16.93 ± 25.49, 13.89 ± 15.37 and 2.12 ± 3.64, respectively. The RQ(NCs) of ΣPAHs (RQΣPAHs(NCs)) ranged from 1.65 × 10-4 to 6.27 × 10-1 with an average value of 1.18 × 100 ± 1.52 × 100. Moreover, RQ(NCs) was less than 1 for individual PAHs, indicating a minor risk. However, RQ(MPCs) was less than 1 for individual PAHs, indicating a moderate risk. The results showed a significant incremental lifetime cancer risk (ILCR) from sediment-bound PAHs with dermal absorption, followed by ingestion and inhalation, as the prevalent route of exposure. The measured ILCR values of all PAHs were less than 10-6 for both adults and children, which were lower than the baseline value, indicating that each PAH poses a low risk of cancer to humans. This study provides information for control and preventive actions to limit future PAH pollution in Phayao Lake

Effect of agricultural waste burning season on PM2.5-bound polycyclicaromatic hydrocarbon (PAH) levels in Northern Thailand

Smoke from agricultural waste burning causes hazardous haze pollution in Southeast Asian countries every year. Besides traces of a few toxic gases several persistent organic pollutants, natural, and anthropogenic emissions are released, resulting in adverse health effects. The study focuses on identification of sources of PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) during the non-haze and haze seasons and investigates the concentration and toxicity of fine particulate matter, especially in the middle of biomass burning period. Totally, 12 fine particulate PAH congeners were selected and analysed at air quality observatory sites located in nine administrative provinces of Northern Thailand during four different sampling periods from 7th December 2012 to 27th March 2015. Nisbet and Lagoy's toxicity equivalent concentration (TEQ) equation revealed that the B[a]PEquivalent value for 2014–2015 roughly surpassed the value of 2012–2013 by a factor of 17. This can be attributed to the significant rise in five-to six-ring PAHs levels in the past two years. Diagnostic binary ratios and linear regression analysis highlight the roles of vehicular exhausts and biomass burning as two major contributors of PM2.5-bound PAHs. Interestingly, principal component analysis (PCA) reveals similar loading patterns for PC1 during the non-haze and haze periods, indicating that agricultural waste burning cannot be considered as the sole contributor of particulate PAHs in Northern Thailand

Estimation of Gas-Particle Partitioning Coefficients (K-p) of Carcinogenic Polycyclic Aromatic Hydrocarbons in Carbonaceous Aerosols Collected at Chiang-Mai, Bangkok and Hat-Yai, Thailand

To assess environmental contamination with carcinogens, carbonaceous compounds, water-soluble ionic species and trace gaseous species were identified and quantified every three hours for three days at three different atmospheric layers at the heart of Chiang-Mai, Bangkok and Hat-Yai from December 2006 to February 2007. A DRI Model 2001 Thermal/Optical Carbon Analyzer with the IMPROVE thermal/optical reflectance (TOR) protocol was used to quantify the organic carbon (OC) and elemental carbon (EC) contents in PM10. Diurnal and vertical variability was also carefully investigated. In general, OC and EC mass concentration showed the highest values at the monitoring period of 21.00-00.00 as consequences of human activities at night bazaar coupled with reduction of mixing layer, decreased wind speed and termination of photolysis at nighttime. Morning peaks of carbonaceous compounds were observed during the sampling period of 06:00-09:00, emphasizing the main contribution of traffic emission in the three cities. The estimation of incremental lifetime particulate matter exposure (ILPE) raises concern of high risk of carbonaceous accumulation over workers and residents living close to the observatory sites. The average values of incremental lifetime particulate matter exposure (ILPE) of total carbon at Baiyoke Suit Hotel and Baiyoke Sky Hotel are approximately ten times higher than those air samples collected at Prince of Songkla University Hat-Yai campus corpse incinerator and fish-can manufacturing factory but only slightly higher than those of rice straw burning in Songkla province. This indicates a high risk of developing lung cancer and other respiratory diseases across workers and residents living in high buildings located in Pratunam area. Using knowledge of carbonaceous fractions in PM10, one can estimate the gas-particle partitioning of polycyclic aromatic hydrocarbons (PAHs). Dachs-Eisenreich model highlights the crucial role of adsorption in gas-particle partitioning of low molecular weight PAHs, whereas both absorption and adsorption tend to account for gas-particle partitioning of high molecular weight PAHs in urban residential zones of Thailand. Interestingly, the absorption mode alone plays a minor role in gas-particle partitioning of PAHs in Chiang-Mai, Bangkok and Hat-Yai.</p

Can the improvement of individual well-being predict rural residents ‘choice of green cooking energy consumption? -- Evidence from CFPS 2016

Abstract Based on the data of CFPS2016, this paper used binary Logistic regression model and coefficient of variation weighting method to weight the subjective and objective dimensions of individual well-being, and discussed the impact of subjective and objective well-being of rural residents on green cooking energy consumption. The study found that:(1) The increase of Nagelkerke R2 reached 51.2% after adding the subjective and objective well-being variable, which indicates that well-being is of great significance in explaining rural residents ‘green cooking energy consumption behaviour.(2) The subjective well-being and objective well-being of rural populations have a significant positive predictive role in green cooking energy consumption.(3) The variation coefficient of rural residents’ subjective environmental attitudes is the highest, indicating that there is a large difference in the level of environmental attitudes among rural groups. Subsequent governments should take it as an important point to guide the improvement of the overall level of rural residents’ environmental attitudes.(4) The demographic factors, gender, age and region of rural residents have significant influence on the choice of green cooking energy consumption. The above research is helpful to understand the influencing factors of rural residents’ green cooking energy consumption behaviour from the perspective of consumers, enrich academic literature in related fields, and provide reference for other green energy consumption behaviours of rural residents in China

Data relating to carbonaceous components in Songkhla Lake sediments, Thailand

The focus of this research was to present a data article associated with organic carbon (OC) and elemental carbon (EC) preserved in lake sediments. Descriptive statistics were applied in this dataset. Sediment cores were sliced immediately at the following layers: 0–20; 20–40; 40–60; 60–80; 80–100; 100–120; 120–140; 140–160; 160–180; 180–200; 200–220; 220–240; 240–260; 260–280; 280–300; 300–320; 320–340; 340–360; 360–380; 380–400; 440–460; 460–480; 480–500; 500–520; 520–540; 540–560 and 560–580 mm of depth. Chemical analysis of OC (i.e. OC1, OC2, OC3, OC4), EC (i.e. EC1, EC2, EC3), and the pyrolyzed organic carbon (OP) (i.e. OP1, OP2, OP3, OP4, OP5, OP6, Char, Soot) contents was conducted by using a DRI Model 2001 Thermal/Optical Carbon Analyzer. The chemical characterization coupled with statistical analysis reveal that vehicle exhausts are the most prominent factor governing OC/EC data detected in core sediments. These data underline some noticeable concerns associated with ecotoxicology and environmental safety of residents surrounding the Songkhla Lake. Keywords: Organic carbon (OC), Elemental carbon (EC), Sediment cores, Songkhla lak

Impacts of Biomass Burning in Peninsular Southeast Asia on PM2.5 Concentration and Ozone Formation in Southern China During Springtime-A Case Study

Biomass burning (BB) affects fine particulate matter (PM2.5) concentration and ozone (O-3) formation by emitting gaseous precursors and primary aerosols. The Impacts of BB in peninsular Southeast Asia (BB-PSEA) on PM2.5 concentration and O-3 formation in southern China are evaluated using a source-oriented WRF-Chem model to simulate an air pollution episode from March 21 to March 25, 2015. The source-oriented model separates the emissions from BB-PSEA and other sources and can evaluate the effects of aerosol-radiation interactions (ARIs) and aerosol-photolysis interactions (APIs) from BB-PSEA. Comparisons with observations reveal that the model performs well in simulating the air pollution episode. Sensitivity experiments show that BB-PSEA increases PM2.5 concentrations on the regional average by 39.3 mu g m(-3) (68.0%) in Yunnan Province (YNP) and 8.4 mu g m(-3) (24.1%) in other downwind areas (ODAs) in southern China, including the provinces of Guizhou, Guangxi, Hunan, Guangdong, Jiangxi, Fujian, and Zhejiang. PM2.5 enhancement is mainly attributed to primary aerosols in YNP and to secondary aerosols in ODA. BB-PSEA increases O-3 concentrations by 18.1 mu g m(-3) (19.4%) in YNP and decreases O-3 concentrations by 3.7 mu g m(-3) (5.3%) in ODA. The O-3 increase in YNP is attributed to the gaseous emissions of BB-PSEA, and the O-3 decrease in ODA is caused by the effects of ARI and API from BB-PSEA. NH3 emissions from BB-PSEA play a key role in enhancing secondary inorganic aerosols in southern China and determining increases in PM2.5 concentrations in ODA