Environmental science: atmospheres最新文献

{"title":"Formation of phthalic anhydride from nighttime oxidation of various heterocyclic volatile organic compounds: implications for wildfire smoke","authors":"Kunpeng Chen, Raphael Mayorga, Linhui Tian, Roya Bahreini, Haofei Zhang and Ying-Hsuan Lin","doi":"10.1039/D5EA00065C","DOIUrl":"https://doi.org/10.1039/D5EA00065C","url":null,"abstract":"<p >Wildfires impact global climate and public health by releasing gases and aerosols. Phthalic anhydride, a toxic chemical detected in wildfire smoke, has been primarily linked to the daytime oxidation of naphthalene and methylnaphthalenes. The recent report of phthalic anhydride in the nighttime oxidation of furan and furfural suggests that other heterocyclic volatile organic compounds (VOCs) may also act as potential precursors of phthalic anhydride through previously unrecognized pathways. This study presents the production of phthalic anhydride derived from the nighttime chemistry of 2-methylfuran, thiophenes, and methylpyrroles, with its mass fraction comprising ∼0.1–0.4% of the secondary organic aerosols (SOAs) derived from these heterocyclic VOCs. Phthalic anhydride is proposed to be produced <em>via</em> the cycloaddition of heterocyclic backbones. We estimate that the nighttime oxidation of heterocyclic VOCs may contribute variably to phthalic anhydride production across different fuel types, with a ∼30% contribution during wiregrass combustion. Overall, our findings highlight the need to further investigate the production of phthalic anhydride from these previously unrecognized precursors and pathways in wildfire smoke to better understand their atmospheric implications.</p>","PeriodicalId":72942,"journal":{"name":"Environmental science: atmospheres","volume":" 9","pages":" 962-972"},"PeriodicalIF":3.5,"publicationDate":"2025-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/ea/d5ea00065c?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145028056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A diagonal volatility basis set to assess the condensation of organic vapors onto particles†","authors":"Brandon Lopez, Nirvan Bhattacharyya, Jenna DeVivo, Mingyi Wang, Lucia Caudillo-Plath, Mihnea Surdu, Federico Bianchi, Zoé Brasseur, Angela Buchholz, Dexian Chen, Jonathan Duplissy, Xu-Cheng He, Victoria Hofbauer, Naser Mahfouz, Vladimir Makhmutov, Ruby Marten, Bernhard Mentler, Maxim Philippov, Meredith Schervish, Dongyu S. Wang, Stefan K. Weber, André Welti, Imad El Haddad, Katrianne Lehtipalo, Markku Kulmala, Douglas Worsnop, Jasper Kirkby, Roy L. Mauldin, Dominik Stolzenburg, Siegfried Schobesberger, Richard Flagan and Neil M. Donahue","doi":"10.1039/D5EA00062A","DOIUrl":"10.1039/D5EA00062A","url":null,"abstract":"<p >We present a “diagonal” Volatility Basis Set (dVBS) comparing gas-phase concentrations of oxygenated organic molecules (OOM) to their condensed-phase mass fractions. This permits closure of vapor concentrations with particle composition constrained by particle growth rates, allowing the contributions of quasi non-volatile condensation, equilibrium partitioning, and reactive uptake to be separated. The dVBS accommodates both equilibrium and dynamical (growth) conditions. Growth implies an association between gas and particle concentrations governed by a “condensation line” that is set by the particle growth rate, which fixes the total (excess) concentration of condensible vapors. The condensation line defines an infeasible region of high particle mass fraction and low gas concentration; under steady-state growth conditions, compounds cannot appear in this infeasible region without being formed by condensed-phase chemistry. We test the dVBS with observations from the CLOUD experiment at CERN using data from a FIGAERO I<small>⁻</small> Chemical Ionization Mass Spectrometer measuring vapors directly and particle composition <em>via</em> temperature programmed desorption from a filter. A dVBS analysis finds that data from an α-pinene + O<small>₃</small> run at 243 K are consistent with volatility driven condensation forming the large majority of particle mass, with no compounds clearly within the infeasible region.</p>","PeriodicalId":72942,"journal":{"name":"Environmental science: atmospheres","volume":" 9","pages":" 1035-1061"},"PeriodicalIF":3.5,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12314873/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144777058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"UK air quality showed clear improvement from 2015 to 2024 but breaching of targets remains very common†","authors":"James Weber and Helen F. Dacre","doi":"10.1039/D5EA00055F","DOIUrl":"https://doi.org/10.1039/D5EA00055F","url":null,"abstract":"<p >The impact of poor air quality (AQ) on public health has long been recognised and considerable efforts have been made to improve it across the UK. The UK has a far reaching AQ monitoring network and this study summarises the evolution of UK AQ over the period 2015–2024, focusing on the pollutants NO<small>₂</small>, O<small>₃</small> and PM<small>_2<em>.</em>5</small> and exploring their drivers. Concentrations of NO<small>₂</small> and PM<small>_2<em>.</em>5</small> exhibit robust negative trends across the whole country while concentrations of O<small>₃</small> increase. Comparing 2015–2016 to 2023–2024, the median number of days per year for which DEFRA AQ sites breached the WHO 2021 target decreased from 136 to 40 (−70%) for NO<small>₂</small> and from 60 to 22 (−63%) for PM<small>_2<em>.</em>5</small>. This trend was mirrored in other AQ monitoring networks and highlights that, while progress is being made, acceptable levels of AQ are yet to be reached. Over the same period, median O<small>₃</small> exceedances increased from 7 to 14 days per year. Nationwide analysis of diurnal variation in the pollutants and the use of airmass back trajectory clustering and statistical modelling for three locations – Reading, Sheffield and Glasgow – suggests that local traffic plays a dominant role in NO<small>₂</small> pollution, PM<small>_2<em>.</em>5</small> is influenced more by long range transport and O<small>₃</small> increases are being driven in part by decreases in NO<small>₂</small>. From an AQ policy perspective, this suggests continued focus on traffic emissions will reduce NO<small>₂</small>, (inter)national rather than local efforts are most critical for PM<small>_2<em>.</em>5</small> improvements, and reductions to VOC emissions must accompany NO<small>₂</small> if further O<small>₃</small> increases are to be avoided.</p>","PeriodicalId":72942,"journal":{"name":"Environmental science: atmospheres","volume":" 9","pages":" 987-997"},"PeriodicalIF":3.5,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/ea/d5ea00055f?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145028058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ice nucleating activity of coastal seawater from the entrance to the Baltic Sea†","authors":"Eva R. Kjærgaard, Amanda S. Sejersen, Max F. Skov, Markus D. Petters and Merete Bilde","doi":"10.1039/D5EA00031A","DOIUrl":"https://doi.org/10.1039/D5EA00031A","url":null,"abstract":"<p >Atmospheric ice nucleating particles (INPs) can affect cloud radiative properties and lifetimes and thus Earth's climate. Such particles may be emitted into the atmosphere from seawater <em>via</em> wave breaking processes. Here, we perform an exploratory investigation on the ice nucleating properties of seawater sampled on four days over a year (February, April, June, and November) from a coastal site near Aarhus in Denmark. We use a cold stage instrument (droplet size: 1 μL) to probe immersion mode freezing events. We find that bulk seawater contains INPs with <em>T</em><small>₅₀</small> values around −20 °C independent of the month of sampling and INP concentrations ranging from 6 × 10<small>³</small> to 5 × 10<small>⁶</small> INP L<small>⁻¹</small> in a temperature range of −12 to −34 °C across all four samples. All samples displayed sensitivity to filtration (0.02 μm), as indicated by a decrease in INP concentration (lowering of freezing temperature). The filtered April and June samples froze at higher temperatures than the filtered November and February samples, which could indicate a variation in the population of INPs (&gt;0.02 μm) over the year. Sea surface microlayer samples did not show enrichment of INPs compared to bulk seawater. Our results are discussed in the context of INP activity of seawater from other locations. While further studies are needed to understand the nature and potential seasonality of seawater INPs, we confirm the presence of INPs in coastal Baltic seawater that may contribute to atmospheric INP concentrations.</p>","PeriodicalId":72942,"journal":{"name":"Environmental science: atmospheres","volume":" 9","pages":" 1014-1022"},"PeriodicalIF":3.5,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/ea/d5ea00031a?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145028054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Across land, sea, and mountains: sulphate aerosol sources and transport dynamics over the northern Apennines†","authors":"Manuel Bettineschi, Bruno Vitali, Arineh Cholakian, Dino Zardi, Federico Bianchi, Victoria Sinclair, Johannes Mikkola, Paolo Cristofanelli, Angela Marinoni, Martina Mazzini, Liine Heikkinen, Minna Aurela, Marco Paglione, Bertrand Bessagnet, Paolo Tuccella and Giancarlo Ciarelli","doi":"10.1039/D5EA00035A","DOIUrl":"10.1039/D5EA00035A","url":null,"abstract":"<p >In this study, we combine aerosol observations with high-resolution Eulerian (WRF-CHIMERE) and Lagrangian (FLEXPART) modelling to investigate the source regions, emission sources, transport pathways, and chemical transformation of sulphate aerosols at the high-altitude Monte Cimone station during July 2017. Our analysis shows that marine air masses are linked to higher levels of sulphate at Monte Cimone. In particular, the sea plays a dominant role in enhancing the oxidation of sulphur dioxide (SO<small>₂</small>) into sulphate due to prolonged exposure to elevated hydroxyl radical (OH) concentrations over the sea. At the same time, sensitivity simulations reveal that industrial emissions contribute significantly to sulphate levels at Monte Cimone, even when air masses have spent a long time travelling over the sea. Furthermore, examination of vertical atmospheric dynamics indicates that free tropospheric air masses favour higher concentrations of sulphuric acid likely due to lower condensation sink (CS) conditions in the free troposphere (FT). In contrast, boundary layer conditions were found to enhance the transport of dimethyl sulphide (DMS) oxidation products, meaning that, over the Mediterranean Sea, DMS and its oxidation products do not reach the FT efficiently. Our results highlight the complex interaction between marine and terrestrial sources, atmospheric chemistry, and transport mechanisms in shaping sulphate aerosol levels at high-altitude sites. They also provide valuable insights into sulphate sources and transport processes over large geographical areas.</p>","PeriodicalId":72942,"journal":{"name":"Environmental science: atmospheres","volume":" 9","pages":" 1023-1034"},"PeriodicalIF":3.5,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12261285/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144661161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A perspective on the reactions of organic peroxy radicals with HO2","authors":"Niklas Illmann","doi":"10.1039/D5EA00023H","DOIUrl":"https://doi.org/10.1039/D5EA00023H","url":null,"abstract":"<p >The chemistry of organic peroxy radicals (RO<small>₂</small>) is crucial for ozone and secondary organic aerosol formation in the troposphere. The level of nitrogen monoxide (NO) exerts a major control on further reactions of peroxy radicals. The research on these reactions in the absence of NO has been receiving increasing attention recently. The current studies under these conditions, typically associated with pristine environments, are focused on understanding the formation of highly oxygenated organic molecules (HOMs) <em>via</em> autoxidation and generation of accretion products, which supposedly result from peroxy radical permutation reactions (RO<small>₂</small> + RO<small>₂</small>). Apart from the potential OH production from some oxygenated peroxy radicals, there is less research activity on the reactions of peroxy radicals with HO<small>₂</small>. This article reviews the existing literature data available on RO<small>₂</small> + HO<small>₂</small> reactions and highlights the gaps where future research is required. To date, limited information has been provided on the reactions of HO<small>₂</small> with functionalized RO<small>₂</small>, particularly for β-hydroxyalkyl peroxy radicals, carbonyl-substituted peroxy radicals other than acyl peroxy, and peroxy radicals containing at least two functionalities. In addition, the temperature dependence of product branching ratios is not well established. Future studies targeting the influence of RO<small>₂</small> + HO<small>₂</small> on the tropospheric HO<small>_<em>x</em></small> (<img>OH + HO<small>₂</small>) budget should ideally enlarge the dataset of OH yields from various peroxy radical structures. This also highlights the need to broaden the investigations on the formed hydroperoxides, whose gas-phase chemistry is not well known.</p>","PeriodicalId":72942,"journal":{"name":"Environmental science: atmospheres","volume":" 7","pages":" 737-755"},"PeriodicalIF":2.8,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/ea/d5ea00023h?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144598181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A systematic review of wet and dry deposition of reactive nitrogen, sulfur, and heavy metals: ecosystem contamination and food chain disruption in Ghana","authors":"Zikrullah Safi, Michael Miyittah, Benjamin Kwasi Offei and Godwin Amenorpe","doi":"10.1039/D5EA00018A","DOIUrl":"https://doi.org/10.1039/D5EA00018A","url":null,"abstract":"<p >Environmental contamination in Ghana, driven by dust deposition, particulate matter (PM), reactive nitrogen, sulfur, and heavy metals, poses significant risk to public health and the environment. However, comprehensive assessments of the spatial distribution and seasonal variations of these pollutants remain limited. To address this gap, this study synthesizes data from 68 site-specific studies conducted between 1997 and 2024. Our findings reveal substantial regional disparities in contamination levels. During the Harmattan season, the Northern region accounted for 52% of total dust deposition, while the Central and Southern regions contributed 12% and 37%, respectively. The Central region exhibited the highest concentrations of PM, with median values of PM2.5 (489 μg m<small>⁻³</small>), PM10 (703.5 μg m<small>⁻³</small>), and TSP (710.5 μg m<small>⁻³</small>). Heavy metal contamination in agricultural products was particularly concerning, with cocoa showing elevated levels of copper (48.67 mg kg<small>⁻¹</small>), lead (70.03 mg kg<small>⁻¹</small>), and iron (41.60 mg kg<small>⁻¹</small>). Fish samples revealed high lead (5.97 mg kg<small>⁻¹</small>) and iron (156.39 mg kg<small>⁻¹</small>). Lettuce and onions demonstrated moderate contamination with lead and cadmium. In mining regions such as Obuasi, lead and arsenic concentrations exceeded WHO safety limits. Sulfur deposition was notably high in Southern Ghana, constituting 81.4% of airborne pollutants. Rainwater contamination, primarily from sulfate, contributed to acidic rainfall (pH &lt; 6.5) in the Southern and Central regions. These findings underscore the urgent need for targeted interventions, particularly in mining and urban areas. Implementing stronger pollution control measures, enhancing monitoring systems, and developing specific strategies to mitigate risks to public health and agriculture are critical steps toward addressing these environmental challenges.</p>","PeriodicalId":72942,"journal":{"name":"Environmental science: atmospheres","volume":" 7","pages":" 756-784"},"PeriodicalIF":2.8,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/ea/d5ea00018a?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144598182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Subtropical southern Africa fire emissions of nitrogen oxides and ammonia obtained with satellite observations and GEOS-Chem.","authors":"Eloise A Marais, Martin Van Damme, Lieven Clarisse, Christine Wiedinmyer, Killian Murphy, Guido R van der Werf","doi":"10.1039/d5ea00041f","DOIUrl":"10.1039/d5ea00041f","url":null,"abstract":"<p><p>Landscape fires in subtropical southern Africa (2-20°S) are a prominent regional source of nitrogen oxides (NO _<i>x</i> ) and ammonia (NH₃), affecting climate and air quality as precursors of tropospheric ozone and aerosols. Here we evaluate GEOS-Chem model skill at reproducing satellite observations of vertical column densities of NO₂ from TROPOMI and NH₃ from IASI driven with three distinct and widely used biomass burning inventories (FINNv2.5, GFEDv4s, GFASv1.2). We identify that GFASv1.2 use of fire radiative power and a NO _<i>x</i> emission factor that is almost half that used by the other two inventories is most consistent with TROPOMI and that FINNv2.5 use of active fires and landscape-specific fuel loads and biomass consumed is most consistent with IASI. We use a simple mass-balance inversion to calculate top-down NO _<i>x</i> emissions of 1.9 ± 0.6 Tg NO for June-October and NH₃ emissions of 1.2 ± 0.4 Tg for July-October. All inventories collocate NO _<i>x</i> and NH₃ emissions, whereas most of the pronounced emissions of NO _<i>x</i> and NH₃ are separate and have distinct seasonality in the top-down estimate. We infer with GEOS-Chem more efficient ozone production (13 Tg ozone per Tg NO) with the top-down informed NO _<i>x</i> emissions than the inventory emissions, as GFASv1.2 NO _<i>x</i> is almost 20% less than top-down NO _<i>x</i> and the 2.3- to 2.5-times greater FINNv2.5 and GFEDv4s NO _<i>x</i> reduces sensitivity of ozone formation to NO _<i>x</i> . Both NO _<i>x</i> and NH₃ top-down emissions are unaffected by use of plume injection heights, limited to GFASv1.2 in GEOS-Chem, and NH₃ is insensitive to acidic sulfate and nitrate aerosol emissions absent in all inventories. The top-down emissions estimates and comparison to satellite observations suggest a hybrid bottom-up approach could be adopted to discern byproducts of smouldering and flaming fires.</p>","PeriodicalId":72942,"journal":{"name":"Environmental science: atmospheres","volume":" ","pages":"906-920"},"PeriodicalIF":3.5,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12180295/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144478065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Formation of the aminoperoxyl radical in the atmospheric oxidation of ammonia†","authors":"Vili-Taneli Salo, Jing Chen and Henrik G. Kjaergaard","doi":"10.1039/D5EA00042D","DOIUrl":"https://doi.org/10.1039/D5EA00042D","url":null,"abstract":"<p >Atmospheric oxidation of ammonia is initiated by its reaction with the hydroxyl radical, producing the aminyl radical (NH<small>₂</small>). Thus far, it has been believed that the subsequent fate of NH<small>₂</small> is to react bimolecularly with other atmospheric trace gases like NO, NO<small>₂</small>, or O<small>₃</small>. Its reaction with O<small>₂</small> has been considered insignificant under atmospheric conditions. However, this is based on a rate coefficient that is orders of magnitude smaller than those known for analogous reactions of O<small>₂</small> with carbon-, sulfur-, and other nitrogen-centered radicals. We demonstrate by multireference calculations and kinetic modelling that the reaction of NH<small>₂</small> and O<small>₂</small> leading to the formation of the aminoperoxyl radical (NH<small>₂</small>O<small>₂</small>) occurs with a rate coefficient similar to those of the aforementioned analogous radicals. We show that the previously estimated small rate coefficient is due to an unimolecular rate limiting step in the formation of measured products rather than the initial NH<small>₂</small> + O<small>₂</small> reaction. The lack of experimental detection of NH<small>₂</small>O<small>₂</small> in the existing literature is likely due to the experiments being conducted at either high temperature or low pressure. We show that the atmospheric presence of NH<small>₂</small>O<small>₂</small> depends greatly on atmospheric conditions. Its formation is an important, yet previously overlooked pathway in atmospheric ammonia oxidation, especially at low temperatures.</p>","PeriodicalId":72942,"journal":{"name":"Environmental science: atmospheres","volume":" 7","pages":" 848-856"},"PeriodicalIF":2.8,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/ea/d5ea00042d?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144598189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exposure and comparative risk assessment of PAHs in dust from roadside solid surfaces in three semiurban areas of Eastern Nigeria†","authors":"John Kanayochukwu Nduka, Chideraa Courage Offor, Henrietta Ijeoma Kelle and Perpetua Chioma Okafor","doi":"10.1039/D5EA00038F","DOIUrl":"https://doi.org/10.1039/D5EA00038F","url":null,"abstract":"<p >Settled road dust is a sink for polycyclic aromatic hydrocarbons (PAHs), which have hazardous effects on ecosystems. Sampled dust from the solid surfaces of Awka, Ekwulobia, and Rumuodomaya-Ogale, Eastern Nigeria, was collected between December 2019 and March 2020, sieved to obtain uniform particle size, subjected to solvent extraction, and subsequently purified using silica gel/Na<small>₂</small>SO<small>₄</small> column. The extracts were analyzed using gas chromatography coupled with a flame ionization detector (GC-FID), and the measured PAH concentrations followed the decreasing order: Rumuodomaya-Ogale &gt; Ekwulobia &gt; Awka. Dusts from the Eze-Uzu junction, Ekwulobia roundabout axis, Victoria hospital premises, Eleme junction, and Elelenwo-Akpajo bypass had total PAH concentrations (μg g<small>⁻¹</small>) that ranged from 0.480–0.613, 0.672–0.926, 0.739–1.388, 1.497–7.915, and 1.423–7.037, respectively. The concentration of benzo(<em>a</em>)pyrene equivalent (BaPE) (μg g<small>⁻¹</small>) in dust samples varied across locations as follows: Eze-Uzu junction (0.0047–0.0690), Government house (0.0047–0.0689), Ekwulobia roundabout (0.0720–0.1942), Victoria hospital premises (0.0720–0.2291), Eleme junction (0.2570–1.4930), and Elelenwo-Akpajo bypass (0.2455–1.3934). Benzo(<em>a</em>)pyrene total toxicity equivalence (BaP-TEQ) values in dust of all the sampled locations indicated no cancer risk (CR) to residents, with benzo(<em>a</em>)pyrene as the main contributor. In all cases, CRing values were higher in children than in adults. PAHs in dust indicate contamination <em>via</em> vehicular emissions, waste burning, and incomplete diesel or gasoline combustion. The point source of PAH in the study areas—open waste burning and the explosion of diesel-laden vehicles—should be regulated.</p>","PeriodicalId":72942,"journal":{"name":"Environmental science: atmospheres","volume":" 7","pages":" 831-847"},"PeriodicalIF":2.8,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/ea/d5ea00038f?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144598188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}