The Health Risks of Airborne Polycyclic Aromatic Hydrocarbons (PAHs): Upper North Thailand

Decadal Trends in Ambient Air Pollutants and Their Association with COPD and Lung Cancer in Upper Northern Thailand: 2013-2022

Air pollution in upper northern Thailand raises health concerns. This study examined trends and associations between air pollutants and respiratory diseases, focusing on COPD and lung cancer during haze (December-May) and non-haze (June-November) seasons in upper northern Thailand from 2013 to 2022. This study utilized data from the Pollution Control Department and Chiang Mai Provincial Public Health. The key air pollutants included PM10, PM2.5, SO2, NO2, CO, and O3. Respiratory disease data included fatality rates for lung cancer and COPD and the re-admission rate for COPD. Results indicated peak air pollutant levels and COPD re-admission rates in March, with PM2.5 concentrations exceeding air quality standards from January to April. During haze periods, COPD fatality and re-admission rates significantly increased (mean difference: 0.43 and 4.23 per 1000-case population, respectively; p < 0.001), while lung cancer fatality rates were higher without statistical significance. Pearson correlation analysis found positive correlations between PM10, PM2.5, O3, and NO2 concentrations and COPD re-admission and fatality rates at 0-1 month lag times, with a declining trend observed at subsequent lag intervals of 2 to 3 months. Overall, this study highlights the predictable pattern of air pollution in the region, correlating with higher COPD fatality and re-admission rates.

Experimental determination of the partitioning of representative organic pollutants to the air-water interface

Using glancing-angle laser-induced fluorescence (GALIF) spectroscopy as a probe, the partitioning of naphthalene, fluoranthene, pyrene, umbelliferone, phenol red, and bisphenol A from bulk solution to the air-water interface was examined in both pure water and aqueous solutions of 6 mM octanol. Previous studies provided similar Langmuir adsorption isotherms for anthracene and imidazole 2-carboxaldehyde. The surface partitioning behaviour of each compound in both environments was well described using a Langmuir adsorption model; partitioning coefficients were derived from the fits to such isotherms. Only the PAH molecules, naphthalene, fluoranthene and pyrene, saw an enhancement in the surface partitioning in octanol solution compared to pure water. The surface partitioning to pure water surfaces could be fairly well described using a one parameter linear free energy relationship based on either solubility or KOW.

Unveiling the Aftermath: Exploring Residue Profiles of Insecticides, Herbicides, and Fungicides in Rice Straw, Soils, and Air Post-Mixed Pesticide-Contaminated Biomass Burning

This study delved into the impact of open biomass burning on the distribution of pesticide and polycyclic aromatic hydrocarbon (PAH) residues across soil, rice straw, total suspended particulates (TSP), particulate matter with aerodynamic diameter ≤ 10 µm (PM10), and aerosols. A combination of herbicides atrazine (ATZ) and diuron (DIU), fungicide carbendazim (CBD), and insecticide chlorpyriphos (CPF) was applied to biomass before burning. Post-burning, the primary soil pesticide shifted from propyzamide (67.6%) to chlorpyriphos (94.8%). Raw straw biomass retained residues from all pesticide groups, with chlorpyriphos notably dominating (79.7%). Ash residue analysis unveiled significant alterations, with elevated concentrations of chlorpyriphos and terbuthylazine, alongside the emergence of atrazine-desethyl and triadimenol. Pre-burning TSP analysis identified 15 pesticides, with linuron as the primary compound (51.8%). Post-burning, all 21 pesticides were detected, showing significant increases in metobromuron, atrazine-desethyl, and cyanazine concentrations. PM10 composition mirrored TSP but exhibited additional compounds and heightened concentrations, particularly for atrazine, linuron, and cyanazine. Aerosol analysis post-burning indicated a substantial 39.2-fold increase in atrazine concentration, accompanied by the presence of sebuthylazine, formothion, and propyzamide. Carcinogenic PAHs exhibited noteworthy post-burning increases, contributing around 90.1 and 86.9% of all detected PAHs in TSP and PM10, respectively. These insights advance understanding of pesticide dynamics in burning processes, crucial for implementing sustainable agricultural practices and safeguarding environmental and human health.

Ocean Stratification Impacts on Dissolved Polycyclic Aromatic Hydrocarbons (PAHs): From Global Observation to Deep Learning

Ocean stratification plays a crucial role in many biogeochemical processes of dissolved matter, but our understanding of its impact on widespread organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs), remains limited. By analyzing dissolved PAHs collected from global oceans and marginal seas, we found different patterns in vertical distributions of PAHs in relation to ocean primary productivity and stratification index. Notably, a significant positive logarithmic relationship (R2 = 0.50, p < 0.05) was observed between the stratification index and the PAH stock. To further investigate the impact of ocean stratification on PAHs, we developed a deep learning neural network model. This model incorporated input variables determining the state of the seawater or the stock of PAHs. The modeled PAH stocks displayed substantial agreement with the observed values (R2 ≥ 0.92), suggesting that intensified stratification could prompt the accumulation of PAHs in the water column. Given the amplified effect of global warming, it is imperative to give more attention to increased ocean stratification and its impact on the environmental fate of organic pollutants.

Assessment of health burden due to the emissions of fine particulate matter from motor vehicles: A case of Nakhon Ratchasima province, Thailand

Air pollution, owing to the ever-increasing transport vehicle fleet, and adverse health effects are increasing in provinces of Thailand. The study estimated that the vehicle fleet size of Nakhon Ratchasima (NR) province of Thailand will grow to 2 million vehicles by 2030, which was 1.36 million in 2021. In NR, the PM2.5 and PM10 concentrations already surpassed both WHO and NAAQS guidelines in 2019-2021. Using Pollution Control Department (PCD) approved Tier I and II Methodology of EMEP/EEA, this research estimated that the total tailpipe emission load will be 1039 tons of PM2.5, 16,630 tons of NO₂, 20,623 tons of CO, 195 tons NH₃, and 249 tons of SO₂ in NR during 2030. The emission load will increase to 1752 tons of PM2.5, 21,126 tons of NO2, 25,559 tons of CO, 361 tons of NH3 and 9344 tons of SO₂ during 2030 if upstream emissions are considered. This study has developed five control scenarios in line with the directives of PCD to mitigate the adverse health from vehicle-led air pollution in NR and implementation during 2024-2030. According to the study, different control scenarios to be implemented during 2024-2030, will be able to keep the fleet size of vehicles in the NR under control. The results show that the control scenarios will keep the annual tailpipe emission of PM2.5 at 604 tons in 2030, a 42 % reduction over the 2030 Business-As-Usual scenario (BAU). The health damage in the range of 6941 to 11,625 disability-adjusted life years (DALYs) under the 2030 BAU scenario in NR due to tailpipe and upstream emissions can be reduced to 4162-7318 DALYs with the implementation of different control scenarios. The control scenarios will also provide significant economic benefits ranging from 4465 to 6718 million THB during 2024-2030 through reduced DALYs and associated costs.

Summertime Characteristics of Atmospheric Polycyclic Aromatic Hydrocarbons in a Coastal City of Northern Poland

Parent polycyclic aromatic hydrocarbons (PAHs) in the gas and particle fraction were measured between May and August 2021 at a coastal urban site in Poland, to examine their chemical characteristics, distribution, sources, deposition fluxes and interactions with basic meteorological drivers. The mean concentration of PAHs in the gas phase was significantly higher (26.26 ± 15.83 ng m^-3) than levels measured in the particle phase (1.77 ± 1.26 ng m^-3). The highest concentration in the gas phase was found for phenanthrene (Phe), followed by fluoranthene (Flt), acenaphthene (Ace) and naphthalene (Naph). The contribution from each group of PAHs to the total particulate phase accounted for 50%, 25%, 14% and 12% for 3-, 4-, 5- and 6-ring compounds, respectively. The mean ΣPAH deposition flux was 59 ± 24 ng m^-2 day^-1. During the whole field campaign, the efficient removal of PM-bound PAHs was typically observed after precipitation events. Based on statistical analysis, it was found that 4-ring PAHs were less effectively removed (25%) by daily precipitation as compared to 5- and 6-ring components, whose fluxes decreased by 32% and 53%, respectively. This study revealed local urban sources such as vehicular emissions, coal-fired power plants, shipping activities, docks/ports infrastructure and municipal solid waste recycling units as predominant contributors to PM-bound and gas-phase PAHs.

Polycyclic aromatic hydrocarbons in coarse particles (PM10) over the coastal urban region in Poland: Distribution, source analysis and human health risk implications

In this study, the results of PM10-bound PAH measurements were subjected to positive matrix factorization (PMF) approach and diagnostic ratios to investigate their levels, seasonal variability, impact of primary anthropogenic sources, and human health risk via the inhalation route. Daily ground-based observations were carried out at a representative coastal site in Gdynia (northern Poland), from April to December 2019. The concentrations of Σ13PAHs in PM10 varied between 0.45 ng m-3 and 54.02 ng m-3, with a mean of 5.22 ± 8.67 ng m-3. A clear seasonality and distribution profiles of PM10-bound PAHs were observed as a result of local/remote sources and meteorological conditions. The highest Σ13PAH concentration was found in December (18.56 ± 16.45 ng m-3) and the lowest values were observed between June and September (3.89 ± 0.52 ng m-3). The PMF-based analysis revealed five factors, suggesting the importance of primary anthropogenic sources of PAHs, i.e. coal combustion, biomass burning, gasoline/diesel vehicles, industrial and shipping activities as well as natural gas combustion. In summer, PAH levels were mostly controlled by local shipping emissions as well as traffic-related and non-combustion sources such as photochemical decomposition. The winter PAH maxima were attributed to a strong increase in residential coal combustion. A Spearman's rank correlation and multilinear regression analysis showed that ambient temperature and NO× had a significant impact on intra-annual variability in PM10-bound PAH transformation in this region. PAH congeners in coarse-size fraction were positively correlated with SO2, indicating their shared anthropogenic sources. The annual mean of epidemiologically based ILCR value was 6.6 × 10-5. This work indicates a potential carcinogenic risk for the local population and a significant difference in BaPeq levels between the individual seasons in this region.

Study on the mechanism of liver toxicity induced by acenaphthene in zebrafish

Acenaphthene is a polycyclic aromatic hydrocarbon (PAH) that is a widely distributed environmental pollutant that accumulates in organisms and leads to health risks in humans. Although acenaphthene is reported to be toxic to aquatic organisms, its effects of acenaphthene on the livers of these organisms have not been evaluated. Here, zebrafish were used as an experimental model. Zebrafish larvae were exposed to 4.5, 5.5, and 6.5 mg/L acenaphthene for 72 h while adult zebrafish were exposed to 1.5, 2, and 2.5 mg/L acenaphthene for 28 days. We investigated the mechanism by which acenaphthene causes liver toxicity in zebrafish. The results showed that acenaphthene affected the early development of zebrafish and led to mitochondrial damage by promoting the production of reactive oxygen species (ROS) resulting in oxidative stress. The expression of genes related to inflammation and apoptosis was analyzed, observing up-regulation of the pro-inflammatory factors IL-8, TNF-α, and IL-6. The pro-apoptotic genes p53, Caspase-3, and Bax and the Bax/Bcl-2 ratio were up-regulated, while the anti-apoptotic gene Bcl-2 was down-regulated. In addition, we investigated the effects of acenaphthene on liver metabolism. When exposed to acenaphthene, the glycogen content of the liver decreased, while lipid accumulation increased together with alterations in related indicators of liver metabolism. In conclusion, acenaphthene induced oxidative stress through ROS production, leading to mitochondrial damage and activation of pathways associated with inflammation and apoptosis, resulting in hepatotoxicity. This affects normal liver metabolism. Our results revealed the mechanism of hepatotoxicity in zebrafish acenaphthene, and provided new evidence for a more comprehensive understanding of the hepatotoxicity of acenaphthene.

Health Risk Assessment on Exposure to PM2.5-bound PAHs from an Urban-industrial Area in Rayong City, Thailand

BACKGROUND: A city's industrial area's air quality has become a major priority. PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) are one of the most common pollutants in urban-industrial area, and can be linked to health problems. AIM: This study aims to 1) investigate PM2.5 and PAHs emitted from roadside area (RS) and industrial estate (IE) in Rayong city 2) assess the inhalation of PM2.5 and PAHs on the human health of the age group. METHODS: PM2.5-bound PAHs were investigated and thier carcinogenic risk was evalued in this study. PM2.5 samples were collected on quartz filters contained in a mini-volume air sampler and analyzed for PAHs by GC-MS. RESULTS: The average PM2.5 concentrations at RS and IE were 43.3±26.8 and 40.4±21.7 µg/m3, while the values of total PAHs in both sites were 1.68±1.53 and 1.34±1.22 ng/m3, respectively. However, it was found that the PM2.5 and PAHs values were not significantly different (p>0.05). The results revealed that the individual lifetime cancer risk (Ric) of PM2.5 values for children and adults at both sites indicated acceptable cancer risk (10-6 to10-4). According to the incremental lifetime cancer risk (ILCR) values of PAHs for different age groups, exposure to PAHs in PM2.5 through the inhalation pathway was a negligible (<10-6). CONCLUSION: As a result, the PM2.5 concentrations have substantial implications for Rayong city’s environmental management and protection, relating to car emissions and coal combustion.

Global Cancer Risk From Unregulated Polycyclic Aromatic Hydrocarbons

In assessments of cancer risk from atmospheric polycyclic aromatic hydrocarbons (PAHs), scientists and regulators rarely consider the complex mixture of emitted compounds and degradation products, and they often represent the entire mixture using a single emitted compound-benzo[a]pyrene. Here, we show that benzo[a]pyrene is a poor indicator of PAH risk distribution and management: nearly 90% of cancer risk worldwide results from other PAHs, including unregulated degradation products of emitted PAHs. We develop and apply a global-scale atmospheric model and conduct health impact analyses to estimate human cancer risk from 16 PAHs and several of their N-PAH degradation products. We find that benzo[a]pyrene is a minor contributor to the total cancer risks of PAHs (11%); the remaining risk comes from other directly emitted PAHs (72%) and N-PAHs (17%). We show that assessment and policy-making that relies solely on benzo[a]pyrene exposure provides misleading estimates of risk distribution, the importance of chemical processes, and the prospects for risk mitigation. We conclude that researchers and decision-makers should consider additional PAHs as well as degradation products.