Environmental Science & Technology Letters Environ.最新文献

Dust backflow, a secondary pollution process following dust storms, has unclear mechanisms for affecting key redox-active components, oxidative potential (OP), and environmentally persistent free radicals (EPFRs) in dust particulate matter (PM). This study found that dust backflow increased PM’s OP and EPFRs concentrations to 9.7- and 4.2-fold of original dust levels. Dust backflow PM was strongly associated with nonaccidental hospitalizations (0.85%, 95% CIs: 0.50%, 1.21%) with each 10 μg/m³ increase in PM₁₀. During the original dust stage, OP and EPFRs, primarily dominated by PM₁₀, mainly originate from the physical migration of natural mineral components (e.g., metal oxides) in the dust, with their oxidative activity linked to coarse PM’s transport. However, during dust backflow, PM_2.5 becomes the main carrier of OP and EPFRs, and their concentration surge is attributed to the mixing of dust with anthropogenic pollutants (such as sulfates and nitrates) during long-distance transport. Meteorological factors such as rising temperatures and weak winds enhance oxidation reactions, leading to redox-active substance accumulation. This study is the first to reveal the characteristics and health risks of dust backflow PM through natural-anthropogenic synergy, providing a scientific basis for health risk warnings about dust pollution and the coordinated control of fine PM during dust backflow.

Disinfection byproducts (DBPs) form when chemical disinfectants, such as chlorine or chloramine, react with natural organic matter and halides in drinking water. Accurate DBP analysis requires quenching of residual disinfectants and pH adjustment. Ascorbic acid (AA) and sulfuric acid (H₂SO₄) are commonly used for these purposes, particularly for organic DBPs, yet no standardized guidance exists on their use. This study evaluated the impact of AA and H₂SO₄ premixing on the quenching of DBP samples under both controlled laboratory and field sampling conditions. Results showed premixing of these reagents prior to sampling substantially increased the formation of haloacetaldehydes (HALs), particularly dichloroacetaldehyde (DCAL) and trichloroacetaldehyde (TCAL) under chlorination, due to acid-catalyzed degradation of AA and subsequent formation of reactive aldehydic intermediates. This effect is magnified in the presence of elevated bromide, leading to higher levels of brominated HALs that are among the most cytotoxic DBPs. Field data from four treatment plants confirmed the laboratory findings and demonstrated that premixing introduced substantial bias into HAL measurements. To prevent overestimation of DBP levels, premixing of AA and H₂SO₄ should be avoided; AA should be added at the time of sampling, followed immediately by pH adjustment with H₂SO₄.

p-Phenylenediamines (PPDs), widely utilized as antioxidants in rubber products, have emerged as contaminants of environmental concern, yet their fate and associated health risks in rubber manufacturing environments remain poorly characterized. This study quantified the occurrence and estimated worker exposure based on settled dust concentrations of PPDs and their quinone derivatives (PPD-Qs) in two representative rubber manufacturing sectors, i.e., tire and seal factories, and the surrounding areas. Results showed that median concentrations of ∑PPDs (114 μg/g) and ∑PPD-Qs (354 μg/g) in indoor workshops far exceeded the levels in industrial park road dust (∑PPDs: 1.84 μg/g; ∑PPD-Qs: 0.410 μg/g) and surrounding road dust (∑PPDs: 219 ng/g; ∑PPD-Qs: 217 ng/g) in tire rubber factories. In addition, PPD and PPD-Q concentrations exhibited interfactory disparities (tire factories exceeding seal factories by 397-fold and 227-fold, respectively) and intrafactory variations (peaking in high-temperature/abrasion workshops), highlighting the necessity for targeted ventilation and protection. Distribution patterns differed by facility type, with concentrations halving within 0.3 km of plant boundaries. This study identifies rubber manufacturing, particularly large rubber tire plants, as a major source of PPDs and PPD-Qs, emphasizes the need for targeted worker protection and chemical management in high-emission zones such as mixing and vulcanizing workshops, and provides production-specific contamination profiles to guide effective regulatory and mitigation strategies.

The concept of regulatory capture has been extensively studied in academic literature, primarily within the social sciences. This phenomenon has been increasingly discussed in the environmental sciences as the impacts of regulatory capture on human and ecosystem health have become increasingly apparent. Regulatory capture is just one tactic employed by vested interests in the strategy of delaying, weakening, or abolishing policies designed to protect the public interest. Here, we define capture strategies as ‘the act of influencing individuals, organizations, or governments to prioritize corporate interests over those of human and ecosystem health’. Similar to the evolution of terms like whitewashing and greenwashing into the broader concept of colorwashing, this new definition expands the scope of capture to include a wide range of targets, such as individuals, educational institutions, nongovernmental organizations, media, and local, national, and intergovernmental organizations. By broadening the definition, we anticipate that researchers, policymakers, and civil society will find it easier to identify and prevent such nefarious activities. This paper illustrates how ‘capture strategies’ have played, and (unless kept in check) will continue to play, an instrumental role in obstructing efforts to address the triple planetary crises of climate change, biodiversity loss, and chemical pollution.

Benzothiazoles (BTHs) are an important class of emerging organic pollutants from volatile chemical product emissions which have been detected in atmospheric environments due to their extensive use, especially as vulcanization accelerators in tire production. However, studies of the atmospheric photochemical oxidation of BTHs remain very limited, hindering the assessment of their atmospheric impacts. Herein, we systematically investigated the reaction kinetics and yields of secondary organic aerosol (SOA) from benzothiazole (BTH, the parent compound of BTHs) photo-oxidation under various experimental conditions using an oxidation flow reactor. The rate constant for BTH reacting with OH radicals, (3.14 ± 0.20) × 10^–12 cm³ molecule^–1 s^–1, was similar to that of single-ring aromatics like toluene, yet its SOA yield was comparable to that of bicyclic aromatics like naphthalene. Furthermore, we found that while NOx suppressed the BTH-derived SOA production, relative humidity enhanced its production. Further field measurements revealed significant SOA formation potential from BTH photo-oxidation in typical urban areas, comparable to that of well-known benzene or naphthalene. Gaseous BTH in an offshore atmosphere was also detected, indicating its potential impacts on marine environments. Our results elucidate the atmospheric photochemical processes of BTH, revealing its important but previously overlooked contribution to ambient SOA formation.

Exposure to organophosphate esters (OPEs), used as flame retardants and plasticizers, is highly variable in the general population, and limited data exist on exposures in young children. This study evaluated the use of silicone ankle bands to assess OPE exposure in infants under 18 months of age. Infants (n = 21) wore silicone ankle bands for three consecutive days, and spot urine samples were collected using either pediatric urine collection bags or toddler training toilets. Ankle bands were analyzed for 20 OPEs; seven were detected in >70% of samples. TDCIPP and TPHP were the most abundant compounds on bands (medians = 57.5 and 53.0 ng/g, respectively). All targeted urinary metabolites were detected in most samples, with BDCIPP being the most abundant biomarker (median = 3.7 ng/mL SG-corrected), 2.5 times higher than DPHP. Significant positive correlations were observed between urinary metabolites and parent compounds on the ankle bands (r_s = 0.40–0.73, p < 0.05), suggesting that silicone samplers reliably capture exposure trends. These findings support ankle bands as a practical, noninvasive tool for assessing OPE exposures in infants, offering an alternative to urine-based biomonitoring.

In Canada, cold heavy oil production with sand (CHOPS) has a high methane emissions intensity. This study uses TROPOMI satellite observations and mass balance modeling to estimate multiyear (2019–2023) methane emissions rates for a key CHOPS region spanning Alberta and Saskatchewan. The iterative 3-year mean emissions estimates were found to be ∼4.5 times higher than industry-reported data but show a notable downward trend, with a 71 ± 34% reduction over the study period. The methane emissions intensity decreased by 63 ± 31%, reaching 0.69 ± 0.25 gCH₄/MJ, but remains substantially higher than that of other oil production basins globally. Although the TROPOMI-based emission reductions were found higher than the industry-reported reductions, our emission estimates remain notably higher than the industry-reported emissions. Deficient industry reporting makes identifying root causes difficult, underscoring the need for robust measurement systems to benchmark and drive performance improvements. Potential drivers for the observed reductions include regulatory efforts targeting vent gas and fugitive emissions, an increased use of solution gas combustors, and a 19% decline in production during the period. While the exact causes remain uncertain, the measurable reductions demonstrate progress toward lowering methane emissions in the region.

Quantifying people’s exposure to wildfires is essential for assessing related health risks. While hydroxyl metabolites of polycyclic aromatic hydrocarbons (PAHs) are commonly used exposure biomarkers of combustion-originated air pollutants, methylated PAHs are more abundant in woodsmoke than other sources. Thus, urinary PAH carboxylic acids, which are metabolites of methylated PAHs, may serve as more sensitive biomarkers of wildfire exposure. In this exploratory study, we developed an LC-MS/MS method to simultaneously quantify hydroxylated and carboxylic metabolites of PAHs and methyl-PAHs in urine. This method was then applied to 56 urine samples collected from 8 campers before, during, and after a 4-h exposure to campfire. Campers also wore silicone wristbands to monitor ambient PAHs. We found that 1-pyrenecarboxylic acid (1-PYRCA) levels increased significantly at 4 h (96.9%, 95% CI: 2.60–101%), 6 h (96.8%, 95% CI: 5.85–107%), and 8 h (92.5%, 95% CI: 3.59–99.2%) and returned to baseline levels at 24 h. In contrast, the campfire exposure did not significantly increase other urinary PAH metabolites. Wristband PAHs also significantly increased during the 4-h exposure. These results support the use of urinary 1-PYRCA as a sensitive exposure biomarker for woodsmoke and potentially for assessing exposure to wildfires.

Aerosol surface composition plays a critical role in atmospheric chemistry but remains poorly characterized, especially for inorganic systems lacking organic surfactants. While bulk composition is typically measured, key interfacial processes, including heterogeneous reactions, water uptake, and cloud activation, occur at the surface. Here, we present the first depth-resolved, in-flight X-ray photoelectron spectroscopy (XPS) analysis of natural salt aerosols generated from hypersaline lake brines in the Qaidam Basin, a pristine region on the Qinghai-Tibet Plateau. These organic-poor aerosols offer a unique view of inorganic interfacial behavior. Using a synchrotron-based in-flight aerosol delivery system, we performed real-time, surface-specific analysis of freely suspended particles. Results reveal strong surface enrichment of minor ions such as Mg²⁺ and SO₄^2– and depletion of major bulk ions like Na⁺ and Cl^–. This divergence was consistent across aerosol types and confirmed by ion chromatography of the source brines. A simplified two-layer model indicates a subnanometer surface layer that substantially alters surface identity. Minor components, often overlooked in bulk analyses, dominate the interface and may influence reactivity and cloud activation potential. These findings underscore the need to further investigate the role of surface composition in atmospheric aerosol processes.

Behavioral ecotoxicology has emerged as a key research area, offering sensitive and ecologically meaningful endpoints for detecting contaminant effects. Much of this work has focused on pharmaceutical pollutants, now widely recognized as contaminants of emerging concern. Given the field’s rapid growth and increasing data availability, we synthesized four global databases to evaluate the environmental relevance of tested concentrations─using behavioral ecotoxicology and pharmaceuticals as a case study. We compared data from over 760 behavioral studies with more than 10 million pharmaceutical occurrence data in surface water and wastewater. On average, minimum tested concentrations were 43 times higher than median surface water levels and 10 times greater than median concentrations in wastewater. Roughly half of all compounds were never evaluated at concentrations below the upper end of wastewater detections (95th percentile). We found weak alignment between the pharmaceuticals most frequently tested and those most commonly detected in aquatic environments. These results reveal a mismatch between the experimental design and environmental exposure conditions. We recommend incorporating occurrence data into dose selection, prioritizing the inclusion of at least one environmentally realistic concentration─ideally near a measure of central tendency. For pharmaceuticals, we provide a consolidated database and an automated tool to support an environmentally informed study design.