Environmental Science & Technology Letters Environ.最新文献

Nitrogen-containingorganic compounds (NOCs) are key characteristiccomponents in particulate matter (PM) from household solid fuel combustion,yet their personal exposure and class-dependent toxicity remain poorlycharacterized. We compared size-resolved personal exposure to particulatenitrated phenols (NPs) and nitro-PAHs (n-PAHs) among rural users ofclean coal (CC), raw coal chunk (RCC), and biomass (BB), and evaluatedrepresentative compounds in A549 cells. Biomass users had the highestPM_2.5-bound n-PAH exposure (up to 11.5-fold above cleancoal), while NPs varied little across fuel groups (≤1.3-fold);CC and RCC users showed comparable PM_2.5-bound NPs concentrations(64.0 ± 12.1 vs 57.4 ± 25.8 ng m^–3, P = 0.545). n-PAHs exhibited greater cytotoxicity with lowerIC₅₀ values, whereas NPs produced stronger NF-κBactivation by larger increases in p-IκB-α and COX-2 expression.Physicochemical descriptor analysis and molecular docking suggestedthat divergent biological responses may be partly attributable todiffering hydrophobicity and protein interaction modes: hydrophobiccontacts for n-PAHs, polar and hydrogen-bonding interactions for NPs.These results demonstrate clean heating transitions better mitigaten-PAH than NP exposure. NPs and n-PAHs differ substantially in cytotoxicityand NF-κB-mediated inflammation, providing a case study linkingreal-world personal exposure monitoring to molecular toxicology forhealth-risk-based prioritization of combustion-derived PM constituents.

Nitrate is a major inorganic component of fine particulatematter,yet simulating it via chemical transport models (CTMs) is computationallyintensive. Deep learning surrogates have emerged as efficient toolsfor approximating CTMs. Here, we developed a Temporal-Context U-Net(TC-U-Net) model to emulate hourly surface-layer nitrate from theCommunity Multiscale Air Quality (CMAQ) model over China in July andDecember (2011–2020). Built on an attention-integrated architecture,TC-U-Net uses inputs from the target and preceding 2 h to capturerapid atmospheric changes and summarizes the preceding 96 h to representmultiday accumulation and dispersion. Incorporating temporal contextsenabled TC-U-Net to reproduce the spatiotemporal variations of CMAQnitrate and improve high-concentration simulations, yielding higheraccuracy than the common baseline models. Emission-reduction experimentscaptured the national-mean nitrate decreases in July but underestimatedmagnitudes, while agreement was limited for January NO_x responses outside the model-development months.Diagnosis of TC-U-Net prediction residuals revealed statistical associationswith other CMAQ outputs, including gaseous NH₃ and particle-phaseH⁺ mass concentration. Adding these variables improvedprediction accuracy in exploratory tests, suggesting potential benefitsfrom additional information on atmospheric chemical conditions. Thesefindings motivate future development using explicit chemical constraintsand diverse CMAQ emission-reduction training scenarios.

Bioassays have proven their use in water quality monitoring.Thisstudy presents a novel framework for deploying bioassays to enablecompliance screening in relation to regulatory threshold values. Bioanalyticalequivalent concentrations for chemicals are derived from bioactivitydata to calculate for each bioassay response the Bioanalytical RiskQuotient percentage (BRQ_%): the percentage of chemicalspotentially surpassing their quality standard (QS). If the bioassayresponse indicates BRQ₀, none of the individual chemicalswith known bioactivity in the bioassay surpass their QS. Should thebioassay response indicate potential QS exceedance by some candidates,the magnitude of that exceedance is a guide to prioritize chemicalsfor confirmation by instrumental analyses. Multiple bioassays arerequired to cover compliance for all relevant chemicals. As a proofof concept, compliance with the Dutch Drinking Water Regulation wasevaluated for 100 surface water monitoring events by derivation ofBRQ_% values for a battery of six bioassays. Full compliancecould not be guaranteed for any of the water samples, with a medianpotential noncompliance for 13% of chemicals. The presented frameworkhas potential for broader application, such as compliance testingrelated to QS for human health or the environment in a variety ofmatrices or for specific permits.

N,N′-Disubstituted p-phenylenediamines (PPDs) and their oxidized derivatives(PPD-Qs) are widely used as rubber antioxidants, but their atmosphericsources remain incompletely characterized. Here we systematicallyinvestigate solid waste burning as a previously overlooked sourceof atmospheric PPDs and PPD-Qs. Field measurements of uncontrolledopen burning and controlled incineration, combined with suspect screeningand targeted analysis, revealed distinct emission profiles. Suspectscreening detected and annotated 47 PPD-related features (20 confirmed,five tentatively identified, and 22 provisionally annotated), withmore features detected in open burning PM_2.5 (n = 43) than in incineration PM_2.5 (n =27). Quantitative analysis showed that open burning predominantlyemitted parent PPDs at higher concentrations (median: 11.54 μg/gPM_2.5), whereas incineration was characterized by a higherrelative abundance of PPD-Qs (median: 2.50 μg/g PM_2.5). In a screening-level esimate for China, open burning accountedfor more than 99.7% of the estimated emissions of the 10 targeted∑(PPDs + PPD-Qs) from solid waste burning in China. These findingssuggest that solid waste burning is an overlooked source of atmosphericPPDs and PPD-Qs, indicating the need to incorporate waste disposalinto emission inventories and targeted emission control strategies.

India, which experiences some of the highest levels ofambientair pollution and associated premature mortality worldwide, launchedthe National Clean Air Program (NCAP) to reduce ambient PM_2.5 and PM₁₀ concentrations by 20–30% across 131 citiesbetween 2017 and 2024, with a subsequent 40% target announced overan additional 2 year period. We present the first comprehensive evaluationof NCAP using high-resolution satellite-based PM_2.5 andPM₁₀ concentration fields together with surface measurementsand apply the latest Global Burden of Disease (GBD) dose–responsefunctions to estimate avoided premature mortality under the proposedreduction scenarios. Satellite-derived data show limited attainmentof NCAP goals: 44 cities met the 20% PM_2.5 target and onemet the PM₁₀ target; six cities achieved the 30% PM_2.5 target and one met the 40% target. Average improvementswere 12% (8.2 μg m^–3) for PM_2.5 and 4.9% (5.7 μg m^–3) for PM₁₀. Monitoring data indicate similarly modest progress: 7 of 29 citiesmet the 20% PM_2.5 target and 43 of 96 met the PM₁₀ target. Achieving a 40% PM_2.5 reduction across NCAP citieswould avert ∼36000 annual premature mortalities. Overall, despitemodest progress in some NCAP cities, stronger interventions are necessaryto achieve widespread air quality and health benefits nationwide.

Roadway runoff is the major source of N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine-quinone(6PPDQ), a tire rubber-derived transformation product that causesacute mortality in some salmonid species. Despite its widespread occurrence,little data exist for watersheds that are Endangered Species Act (ESA)listed as critical habitat for populations of coho salmon (Oncorhynchus kisutch) and coastal rainbow trout (Oncorhynchus mykiss irideus) that are acutely susceptibleto 6PPDQ. Here, we quantified 6PPDQ during a storm event across high-risk,roadway-impacted watersheds in Central California, sampling six roadwayoutfalls, fourteen creeks or rivers, and two estuaries. Median 6PPDQconcentrations in outfall (n = 9), creek (n = 48), and estuary (n = 2) samples were350, 62, and 1.9 ng/L, respectively. 6PPDQ was detected in 98% ofsamples, with 78% of storm samples exceeding the EPA Acute AquaticLife Screening value (11 ng/L) and 69% exceeding 24-h LC₅₀ values for juvenile coho salmon. Concentrations peaked early duringthe storm and correlated significantly with traffic intensity (R² = 0.50, p < 0.005), highlighting thechemical loading potential of busy roads. These data document highand sustained concentrations of 6PPDQ within multiple ESA-listed criticalhabitats, underscoring the need for improved source control to preventpossible mortalities of susceptible species within these watersheds.

Atmospheric fine particulate matter (PM) poses substantialhealthrisks, largely through oxidative stress associated with particle-inducedreactive oxygen species (ROS). Although aqueous-phase reactions playan important role in the chemical aging of PM, the effects of theirsecondary organic products on cellular ROS responses remain poorlyunderstood. Here, we examine products formed from aqueous reactionsbetween α-dicarbonyls (glyoxal or methylglyoxal) and reducednitrogen species (ammonium sulfate or glycine) and evaluate theireffects on ROS production in A549 cells. High-resolution mass spectrometryshows that reactions involving ammonium predominantly yield imidazole-typenitrogen-heterocycle compounds, whereas reactions with glycine producea larger fraction of pyrrole-related species. These products inducelittle cellular ROS when tested alone but show contrasting effectswhen coexposed with 1,4-naphthoquinone, Cu²⁺, or both.Mixtures dominated by imidazole are associated with enhanced ROS responses,while mixtures with a higher pyrrole fraction tend to suppress ROSproduction. Complementary acellular assays suggest that these contrastingeffects likely reflect differences in redox interactions, includingpromotion or suppression of quinone cycling and metal-associated processes.Overall, these results indicate that aqueous-phase secondary organicproducts can influence oxidative stress through interactions withother redox-active PM components, underscoring the importance of molecularcomposition and mixture effects in PM health assessments.

Coal-fired power plants (CFPPs) are one of the largestcontributorsto anthropogenic mercury (Hg) emissions, which are regulated underthe Minamata Convention on Mercury. Bromine injectiontechnology has been recognized as an effective strategy for reducingmercury emissions. However, the comprehensive environmental impactsof potential bromine (Br) escape using this technology remain unexplored.This study evaluates the possible effects of using bromine injectiontechnology on Hg and Br emissions into the atmosphere, Hg cycle, andHg-related health effects. Our results indicate that this Hg controltechnology would increase Br emissions and consequently acceleratelocal Hg oxidation and deposition, thereby partially offsetting thehealth benefits from reduced Hg emissions. At bromine injection dosagesof 30–120 mg kg^–1 coal, CFPPs Hg emissionsdecrease by 101.9–188.8 Mg yr^–1, but bromineescape increases CFPPs Br emissions by 30.8–123.2 Gg yr^–1. At the highest dosage, the Br-escape-driven chemicaleffect yields a global increase of 2804 premature cardiovascular deathsand 7.48 × 10⁵ newborn IQ-point loss. Therefore, wehighlight that the substantial impacts of Br escape as well as itscontrol must be carefully considered before bromine-based Hg emissioncontrol technology is applied.

The tire rubber transformation productN-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine-quinone(6PPD-Q) is acutely toxic to select salmonids, yet current risk thresholdsare derived exclusively from constant-concentration exposure teststhat fail to represent the intermittent, rainfall-driven pulses patternsof urban runoff to surface waters. Here, we exposed rainbow troutto four 8-h pulses of 6PPD-Q at environmental relevant concentrations(0.125–1.95 μg/L), followed by a 14-d recovery period.The resulting multiple-pulsed LC₅₀ (0.28 μg/L) wassignificantly lower than thresholds from standard constant-exposurebioassays. Notably, substantial delayed mortality occurred duringrecovery, and environmental pulses of 6PPD-Q frequently reached orexceeded levels triggering such delayed mortality. Distinct lethalphenotypes were observed across the four successive pulses and therecovery period, suggesting differential disposition and/or toxicitypathways influence each stage. Furthermore, surviving fish exhibitedsignificant behavioral impairments even after the 14-d recovery period,indicating prolonged sublethal impacts. Collectively, our findingsdemonstrated that environmentally realistic pulsed exposure regimesand delayed toxicity are critical yet overlooked components of ecologicalrisk for 6PPD-Q, and should be considered to support more environmentallyrealistic assessment of 6PPD-Q hazards in urban watersheds.

Environmentally persistent free radicals (EPFRs) arerecognizedoxidative stressors, but existing research focuses predominantly oninhalable particles. Thermally carbonized foods represent a potentiallymajor, yet unexplored, dietary EPFR pathway. Here, we quantified EPFRsin commercial barbecued foods and conducted controlled experimentsto identify thermal, heating-source, and matrix factors governingtheir formation. Barbecued foods exhibited high EPFR levels (1.7 ×10¹⁶–6.3 × 10¹⁸ spins/g), 2–3orders of magnitude higher than previously reported values for fried/steamedfoods. Controlled experiments revealed EPFR formation as a nonlinearthermal process governed mainly by temperature and food matrix withyields increasing up to 3-fold from 80 to 200 °C. Heating-sourceeffects were matrix-dependent, as charcoal grilling produced ∼9-foldhigher EPFRs of (3.6 ± 0.4) × 10¹⁸ spins/g thanelectric heating in lipid-rich meats, but only ∼2-fold higherlevelsin vegetables, indicating matrix-driven carbonization and combustion-derivedcontributions. Oxidative potential correlated positively with EPFRsand polycyclic aromatic hydrocarbons rather than trace elements, suggestingEPFRs and coformed redox-active organic mixtures drive oxidative burden.Combined with a dietary survey, the estimated burden is 2.1 ×10²⁰ spins per barbecued meal for a 65 kg adult. Thesefindings highlight thermally carbonized matrices as under-characterizedEPFR sources with significant dietary implications.