Volatile Organic Compounds Emissions Research Articles

Research on ozone pollution control strategies for urban agglomerations based on ozone formation sensitivity and emission source contributions

Despite recent enhancements in China's anthropogenic emission controls, ozone (O3) concentrations have continuously increased owing to its nature as a secondary pollutant and the complexities of its production and consumption processes. This study quantified the contributions of urban and sectoral cross-emission sources to O3 levels and identified the anthropogenic emission sources requiring targeted control. Moreover, O3 sensitivity tests were conducted to determine optimal reduction ratios for nitrogen oxides (NOx) and volatile organic compounds (VOCs) emissions. The results were used to recommend effective measures for controlling O3 pollution in the Central Plains urban agglomeration (CPUA). The top 35 cities and sectoral cross-emission sources accounted for 80% of the O3 concentrations in the region, indicating the need for prioritized management of these sources. To achieve reductions in O3 concentrations across all cities, it was found that a 10% reduction in total NOx emissions would require a minimum of 18% reduction in VOCs emissions. Our results indicated that the appropriate coordination of reductions in VOCs and NOx emissions reduced the maximum daily 8-h average O3 (MDA8) concentrations in CPUA by 0.14%–4.78%. Enhancing control measures for prioritized emission sources reduced MDA8 concentrations by 0.78%–7.09%. Furthermore, adjusting the production and emission hours of the industrial sector resulted in a decrease in MDA8 concentrations by 1.10%–12.62%. Overall, our findings indicate that appropriately coordinated reduction of precursor emissions can reduce O3 levels. Further efforts to mitigate O3 pollution should include optimizing the timing of emissions from the industrial sector and other major sources of VOCs emissions.

Process‐Based Modeling of Ecosystem‐Level Monoterpene From a Japanese Larch (Larix kaempferi) Forest

AbstractGlobally, the emission of biogenic volatile organic compounds (BVOC) by plants represents the dominant source of volatile organic compounds emitted to the atmosphere. Monoterpenes, as the major BVOC group, can contribute to forming secondary organic aerosols and influence cloud properties. In this study, we developed a process‐based monoterpene module in the Vegetation Integrative SImulator for Trace gases (VISIT) model by considering the production, storage, and emission of monoterpene as three main processes. We further evaluated the modeled monoterpene emissions against the ecosystem‐level observation data at a half‐hour scale at a Japanese larch (Larix kaempferi) forest site on Mt. Fuji, Japan. The VISIT model performed with relatively higher accuracy with a Willmott's index of agreement at 0.61, a mean bias error (MBE) at 0.29, and a root mean squared error (RMSE) at 0.43, comparable to that of Model of Emissions of Gases and Aerosols from Nature model with a Willmott's index of agreement at 0.63, a MBE at 0.40, and a RMSE at 0.54. In a long‐term simulation under high CO2 emission scenarios, the ratio between monoterpene emission and gross primary production exhibited a stronger correlation with CO2 concentration than temperature. Our study provides a process‐based modeling approach for more accurately simulating monoterpene emissions from Japanese larch.

Active lattice oxygen trigger for propane total oxidation: [MnO6] tunnel-restrained Cu2+ chain in α-MnO2

The elimination of propane is particularly important in volatile organic compounds (VOCs) emissions control. We designed a special Cu-type α-MnO2 with tunnel-restrained Cu2+ chain for propane total oxidation. It can effectively elevate the reaction rate and reduce the apparent activation energy. Cu2+ mainly stabilizes as tunnel [CuO4] configurations, changing the charge distribution and ligand field inside the tunnel, compared to the original ionic [KO8] and [KO12] in α-MnO2. The covalency between Cu−O as well as exacerbated Jahn-Teller distortion of [MnO6] occur. The resulting charge transfer of Cu−O−Mn units via bridging O atoms further affects the outside-tunnel properties, specifically, facilitating oxygen vacancy formation and lattice oxygen activation. Moreover, abundant oxygen vacancies can promote the dehydrogenation of propane to generate alcohol at low temperatures. The above intermediates undergo successively oxidation with activated lattice oxygen to produce C3~C1 carboxylates as temperature elevates.

Understanding the role of flux chamber configuration in the measurement of VOC emissions from porous media

The accurate quantification of volatile organic compound (VOC) emission rates from porous media to the air is a challenging problem, as measurements are affected by the chemical and physical characteristics of the porous media, and the operating parameters of the sampling device itself. The main objective of this study is to investigate how flux chamber (the most commonly used sampling device) configurations influence emission rate measurement from three selected porous media. Various parameters were studied, including sweep air flow rate, presence of a mixing fan, headspace volume and thickness of media. Controlled experiments focused on the behaviour of two VOCs commonly found in area sources: acetic acid and 1-butanol. Sweep gas flow rate emerged as the most influential factor, inducing turbulence and dilution over porous media surfaces and impacting emission rate measurements more significantly than headspace volume and fan installation. Variations in porous media properties also affected mass transfer, with emissions from coco coir showing higher mass transfer as its porosity and particle size facilitated gas transportation. While behaviour of acetic acid emission through the media supported the diffusion theory, emission of 1-butanol was affected by a combination of factors, highlighting the role of both diffusive and advective transport mechanisms. Understanding how flux chamber setups and porous media properties influence emission rates is crucial for accurately interpreting data. This knowledge also guides the design of studies, especially when investigating complex sources like biosolids and organic-amended soil.

Implications of 1.5 K climate warming on warm-season ozone exposure and atmospheric oxidation capacity in China

Surface ozone (O3) poses significant threats to public health, agricultural crops, and plants in natural ecosystems. Global warming is likely to increase future O3 mainly by altering atmospheric photochemical reactions and enhancing biogenic volatile organic compound (BVOC) emissions. To assess the impacts of the future 1.5 K climate target on O3 concentrations and ecological O3 exposure in China, numerical simulations were conducted using the CMAQ (Community Multiscale Air Quality) model during April–October 2018. Ecological O3 exposure was estimated using six indices (i.e., M7, M24, N100, SUM60, W126, and AOT40f). The results show that the temperature rise increases the MDA8 O3 (maximum daily eight-hour average O3) concentrations by ∼3 ppb and the number of O3 exceedance days by 10–20 days in the North China Plain (NCP), Yangtze River Delta (YRD), and Sichuan Basin (SCB) regions. All O3 exposure indices show substantial increases. M24 and M7 in eastern and southern China will rise by 1–3 ppb and 2–4 ppb, respectively. N100 increases by more than 120 h in the surrounding regions of Beijing. SUM60 increases by greater than 9 ppm h−1, W126 increases by greater than 15 ppm h−1 in Shaanxi and SCB, and AOT40f increases by 6 ppm h−1 in NCP and SCB. The temperature increase also promotes atmospheric oxidation capacity (AOC) levels, with the higher AOC contributed by OH radicals in southern China but by NO3 radicals in northern China. The change in the reaction rate caused by the temperature increase has a greater influence on O3 exposure and AOC than the change in BVOC emissions.摘要地表臭氧(O₃)对公众健康, 农作物以及自然生态系统构成重大威胁. 全球变暖会增强大气光化学反应以及增加生物源挥发性有机化合物(BVOC)排放, 从而导致 O₃浓度增加. 为了评估未来 1.5 K 气候目标对中国 O₃浓度以及生态 O₃暴露的影响, 在 2018 年 4 月至 10 月期间使用 CMAQ模型进行了数值模拟. 使用六个指标(即 M7, M24, N100, SUM60, W126 和 AOT40f)估算生态 O₃暴露. 结果表明, 在华北平原,长江三角洲和四川盆地地区, 温度升高使每日最大8 小时平均 O₃浓度增加约 3 ppb, O₃超标天数增加 10–20 天.所有 O₃暴露指标均显著增加. 中国东部和南部的 M24 和 M7 将分别增加 1–3 ppb 和 2–4 ppb. 北京周边地区的 N100 增加超过 120 小时. 陕西和四川盆地的 SUM60 增加超过 9 ppm h⁻¹, W126 增加超过 15 ppm h⁻¹, 华北平原和四川盆地的 AOT40f 增加 6 ppm h⁻¹.温度升高还提升了大气氧化能力(AOC)水平, 在中国南部较高的 AOC 由羟基自由基贡献, 而在中国北部则由硝基自由基贡献. 由温度升高引起的反应速率变化对 O₃暴露和 AOC 的影响比 BVOC 排放增加带来的贡献更大.

Molecular characterization of oxidized organic nitrogen in the polluted urban atmosphere of Beijing

Oxidized organic nitrogen (OON) serves as a crucial link between volatile organic compounds (VOCs), nitrogen oxides, ozone, and secondary organic aerosol (SOA). However, the comprehension of the molecular composition, formation mechanism, and implications of OON remains limited, particularly in urban environments influenced heavily by anthropogenic emissions. This study presents the field measurements of OON conducted at an urban site in Beijing using chemical ionization mass spectrometry with nitrate as the reagent ion. The molecular characteristics, dominant species, and oxidation states of OON were investigated. Positive matrix factorization analysis disentangled the diverse OON into factors characterized by unique fingerprint features and formation pathways. A modified workflow was used to classify the majority of OON as terpene (3.0 %), isoprene (15.2 %), aliphatic (38.1 %, containing dinitrate), and aromatic (36.0 %, containing aromatic ring retaining) OON. This highlights the significant impact of anthropogenic sources and underscores the need for stringent controls on anthropogenic VOC emissions to mitigate OON formation. Volatility estimates further indicate that aromatic and aliphatic OON, with relatively low volatility, are expected to be the primary contributors to SOA formation by condensation or gas-particle partitioning in urban Beijing. In addition, hazy weather conditions may facilitate multi-generation reactions, leading to the production of large amounts of semi-volatile dinitrate OON and promoting its conversion to SOA.

Soil benzene emissions and inhalation health risks affected by various land covers

Accurate quantification of soil volatile organic compounds (VOCs) flux is crucial for assessing inhalation environmental health risks and developing region-specific remediation strategies. However, land cover significantly influences VOCs emissions from soil. This study investigated benzene, a representative VOCs, using a laboratory flux chamber and numerical simulations to evaluate its release patterns under different surface covers, including bare soil (no cover), clay brick, cement, and grass. In the experiment, gaseous benzene was collected using an adsorption tube filled with Tenax-TA adsorbent. The collected samples were subsequently analyzed using thermal desorption coupled with gas chromatography-mass spectrometry. By integrating these findings with environmental health risk assessment methodologies, we developed a tailored approach for assessing inhalation health risks at benzene-contaminated sites with varying land covers. Additionally, we conducted application studies of this method across various scenarios. The results indicate that soil benzene emissions could be reduced by using low-permeability coverings such as clay brick and cement, as well as by planting vegetation. The average fluxes of benzene through covering materials were of the order of 1.22 × 10−2, 4.37 × 10−3, 2.47 × 10−3, and 9.88 × 10−4 mg m−2·s−1 for bare soil, clay brick, grass, and cement, respectively. The application of clay brick and cement coverings on the soil surface results in more pollutants remaining in the soil in liquid and adsorbed states, making them less likely to volatilize. The inhalation carcinogenic risk (CR) values for soil benzene at an abandoned oil refinery site in Northwestern China under bare soil, brick, and cement cover are 1.3 × 10−6, 1.22 × 10−6, and 9.73 × 10−7, respectively. Low-permeability covers such as clay brick and cement reduces the inhalation CR of gaseous benzene from the surface soil, and delays the growth trend of cumulative inhalation CR.

Environmental chamber analysis of objective volatile organic compounds emissions and subjective olfactory perception from main automotive interior components

This study examined the emissions of volatile organic compounds (VOCs) and their associated odors from five key automotive interior components: door panels, weatherstrips, seats, headliners, and carpets. Objective VOC emissions and subjective odor evaluations were conducted in an environmental chamber with controlled temperature, humidity, and ventilation rates. VOC analysis revealed that alkanes and aromatic compounds were the predominant emissions, together accounting for 43 %–61 % of the total number of emission types. Other notable emissions included aldehydes and ketones. The overlap in the emitted compounds was substantial, with 13 % of the compounds being universally emitted, 42 % emitted by two or more components, and 45 % unique to individual components. Subjective odor evaluations identified distinct odor fingerprints for each component, with weatherstrips having the highest odor intensity and headliners having the lowest. Perceived pleasantness (PP) ratings were generally negative, indicating the unappealing nature of the odors. Odor activity value (OAV) analysis showed a weak linear relationship with odor intensity, particularly because of the negative correlation in weatherstrips, suggesting significant masking or enhancement effects among odor molecules. Aldehydes and acids were the major contributors to OAV, whereas alkanes, which are often overlooked, were also significant because of their high emission levels.

Source apportionment of Volatile Organic Compounds (VOCs) in the South Coast Air Basin (SoCAB) During RECAP-CA

Ozone (O3) concentrations in the South Coast Air Basin (SoCAB) surrounding Los Angeles remain at unhealthy levels despite multiple decades of control programs designed to reduce emissions of precursor Volatile Organic Compounds (VOCs). Here we report on comprehensive VOC measurements made at Redlands, which has the highest measured O3 concentrations in SoCAB, as part of the Re-Evaluating the Chemistry of Air Pollutants in California (RECAP-CA) field campaign (July–October 2021). Positive matrix factorization (PMF) analysis was applied to identify nine VOC factors. A photochemical chamber model initialized by field measurements was configured with a tagging technique to quantify the VOC factor contributions to O3 formation in Redlands. Biogenic VOCs (BVOCs) made the largest contribution (26.6%) to O3 formation, followed by traffic VOCs (21.2%), volatile chemical products (VCPs) (19%), and plant decomposition (14.9%). High O3 episodes were not driven by increased VOC emissions from any single source, but rather were associated with stagnation events that concentrated VOCs from all sources and high temperature days that enhanced O3 formation efficiency. This implies that VOC controls optimized to reduce O3 concentrations would look similar in both the NOx-limited and VOC-limited regimes that can occur at Redlands. These results suggest that control strategies that reduce VOC and NOx emissions from the on-road vehicle fleet, such as increasing electrification, may yield O3 reductions on days in both the NOx-limited and VOC-limited chemical regimes at Redlands.

Experimental investigation on suppression effect of molecular sieve powders on asphalt fume

The tremendous emission of asphalt during pavement construction has been posing significant health hazards and environmental pollution. Molecular sieves such as homogeneous porous powders possess the potential to suppress asphalt fume. However, the effective reduction of asphalt emissions via porous materials is limited owing to the lack of understanding of their absorption mechanism. This study investigated a series of molecular sieve powders (3A, 5A, 10X, 13X, NaY, MCM-41-Al and MCM-41-Si) for fume suppression, including their micromorphology, pore characteristics, pollutants emission concentrations, organic volatile compositions, and rheological properties by comparing pristine asphalt and the molecular sieves modified asphalt. The results indicated that molecular sieves could effectively suppress 69.5–83.2% of volatile organic compounds (VOC) emissions and absorb nearly all the NO, H2S, and SO2. Adsorption mechanism of asphalt fume by molecular sieves was mainly depends on polarity of molecules size and relationship. Pollutants with higher polarity could be well absorbed. Pore size of molecular sieves needed to be slightly larger than the width of targeted pollutant molecules to absorb them and suppress the emissions. This study attributed molecular characteristics of the main pollutants, the adsorption mechanism of porous materials and effective asphalt fume reduction with molecular sieves, which supports future research on practical technologies for asphalt fume suppression.

Characterization and Sources of VOCs during PM2.5 Pollution Periods in a Typical City of the Yangtze River Delta

To investigate the characteristics and sources of volatile organic compounds (VOCs) as well as their impacts on secondary organic aerosols (SOAs) formation during high-incidence periods of PM2.5 pollution, a field measurement was conducted in December 2019 in Hefei, a typical city of the Yangtze River Delta (YRD). During the whole process, the mixing ratios of VOCs were averaged as 21.1 ± 15.9 ppb, with alkanes, alkenes, alkyne, and aromatics accounting for 59.9%, 15.3%, 15.0%, and 9.8% of the total VOCs, respectively. It is worth noting that the contributions of alkenes and alkyne increased significantly during PM2.5 pollution periods. Based on source apportionment via the positive matrix factorization (PMF) model, vehicle emissions, liquefied petroleum gas/natural gas (LPG/NG), and biomass/coal burning were the main sources of VOCs during the research in Hefei. During pollution periods, however, the contribution of biomass/coal burning to VOCs increased significantly, reaching as much as 47.6%. The calculated SOA formation potential (SOAFP) of VOCs was 0.38 ± 1.04 µg m−3 (range: 0.04–7.30 µg m−3), and aromatics were the dominant contributors, with a percentage of 96.8%. The source contributions showed that industrial emissions (49.1%) and vehicle emissions (28.3%) contributed the most to SOAFP during non-pollution periods, whereas the contribution of biomass/coal burning to SOA formation increased significantly (32.8%) during PM2.5 pollution periods. These findings suggest that reducing VOCs emissions from biomass/coal burning, vehicle, and industrial sources is a crucial approach for the effective control of SOA formation in Hefei, which provides a scientific basis for controlling PM2.5 pollution and improving air quality in the YRD region.

Human health impacts and indoor chemical reactions of VOCs from cleaning products and occupants

Occupants and indoor activities are sources of volatile organic compounds (VOCs). We propose a framework to simulate the pollutant pathway using the INCA-Indoor© model and VOC emission rates to derive dynamic concentrations, and the USEtox model to evaluate health impacts in DALYs (Disability-Adjusted Life Years). The applicability of the framework is tested on a case study, and the effect of indoor chemical reactions on health impacts is assessed. In this case study, health impacts were of 0.3 μDALY/day without and 0.4 μDALY/day (13 s/day) with indoor air chemistry (+28 %) out of which 12 % were linked to occupant breath and skin emissions. Cleaning activities led to the highest impacts without chemical reactions (terpinolene, responsible for 0.14 μDALY/day), but indoor air chemistry led to high impacts linked to formaldehyde formation (0.18 μDALY/day). These reactions led to the formation of more formaldehyde, hence leading to 20% more impacts, in summer than in winter. Occupants’ contribution to CO2 concentrations exceeded recommended limits under the given occupancy and ventilation scenario. Secondary organic aerosol (SOA) formation affected indoor particulate matter mass concentrations by up to a factor 1.2 and their number concentrations by up to a factor 25,000 in the presence of VOC emissions. Results of this study indicate that chemical reactions and SOA formation are important factors to consider in indoor air quality impact assessment. A larger number of activities and scenarios can be tested to improve the robustness of the conclusions, since, under different scenarios (for e.g. activities with lower emission rates) and with more complete toxicity data, these conclusions are likely to change.

Photothermal synergistic catalytic oxidation mechanism of toluene by Ce-doped SrTiO3 via one-pot hydrothermal synthesis

Industrial volatile organic compounds (VOCs) emissions pose significant environmental and human health risks, with photothermal catalysis degradation emerging as a promising VOCs treatment technology. The light response range and catalysis degradation efficiency of photocatalysts, however, need to be improved. This study prepared Ce-doped SrTiO3 perovskite catalysts via a one-pot hydrothermal method. The synergistic photic/thermal degradation mechanism of toluene was uncovered via XPS, Uv–Vis, EPR, and in-situ DRIFTS analysis. It was found that the toluene removal rate and CO2 yield reached their maximums at 200 °C, reaching 95 % and 90 %, respectively, at a Ce doping ratio of 50 %. During the catalytic process, the prerequisite to trigger toluene oxidation, and light promote the generation of reactive oxygen species (·OH and ·O2–), which facilitates the formation of intermediates and thus accelerates the deep oxidation of toluene. The doped Ce increases surface oxygen vacancies while lowering the energy band gap of the catalyst, facilitating the separation of holes and photogenerated electrons. Furthermore, in situ DRIFTS studies demonstrated that toluene undergoes a ring-opening process, producing intermediates such as benzaldehyde and benzoic acid. This study will assist in promoting the use of photothermal synergistic catalytic degradation technology to remove VOCs from industrial sources.

Reconfiguring closed-loop desorption for industrial solvent recycling by retaining post-condensation volatile organic compounds

Massive emissions of volatile organic compounds (VOCs) from industrial solvent evaporation have exacerbated atmospheric pollution. As high-value pollutants, VOCs can be concentrated and condensed into liquid solvents for reuse instead of destructive elimination, minimizing environmental threats and treatment costs. However, classical thermal swing adsorption (TSA) using nitrogen as the purge gas are inclined to be in closed form to economize on nitrogen, which results in desorption residues at the outlet of the adsorber and leads to environmental risks. In this study, one-step closed-loop desorption (OCD) and two-step closed-loop desorption (TCD) were proposed for industrial solvent recovery by reconfiguring TSA and condensation to improve desorption efficiency and recovery performance. A detailed mathematical model was developed and validated experimentally to describe dynamic behaviors of closed-loop desorption. The results showed that the standby adsorber connected to the thermal desorption process effectively retained the post-condensation VOCs and reduced the desorption residual for the re-absorption efficiency. By using the orthogonal experimental design, desorption temperature, condensation temperature, and feed concentration were proved to be more significant on recovery capacity than packing height and purge velocity. A broader feasible recovery domain was achieved by the TCD cycle, with an increase of 48.15 % compared to the OCD cycle at low feed concentrations. The OCD cycle was more energy-efficient, except in scenarios of low adsorption loading and low-grade energy sources. The findings provide new insights and promising approaches for achieving synergies between industrial exhaust treatment and organic solvent recovery.

Fabrication of Highly Dispersed Ru Catalysts on CeO2 for Efficient C3H6 Oxidation.

Emissions of volatile organic compounds (VOCs) threaten both the environment and human health. To realize the elimination of VOCs, Ru/CeO2 catalysts have been intensively investigated and applied. Although it has been widely acknowledged that the catalytic performance of platinum group metal catalysts was highly determined by their dispersion and coordination environment, the most reactive structures on Ru/CeO2 catalysts for VOCs oxidation are still ambiguous. In this work, starting from Ce-BTC (BTC = 1,3,5-benzenetricarboxylic acid) materials, atomically dispersed Ru catalysts and agglomerated Ru catalysts were successfully created via one-step hydrothermal method (Ru-CeO2-BTC) and conventional incipient wetness impregnation method (Ru/CeO2-BTC), respectively. In a typical model reaction of C3H6 oxidation, atomically dispersed Ruδ+ species with the formation of abundant Ru-O-Ce linkages on Ru-CeO2-BTC were found to perform much better than agglomerated RuOx species on Ru/CeO2-BTC. Further characterizations and mechanism study disclosed that Ru-CeO2-BTC catalyst with atomically dispersed Ru ions and more superior low temperature redox performance compared to Ru/CeO2-BTC could better facilitate the adsorption/activation of C3H6 and the decomposition/desorption of intermediates, thus exhibiting superior C3H6 oxidation activity. This work elucidated the reactive sites on Ru/CeO2 catalysts in the C3H6 oxidation reaction and provided insightful guidance for designing efficient Ru/CeO2 catalysts to eliminate VOCs.

Exploring exhaled breath volatile organic compounds in occupational asthma: a pilot cross-sectional study

Occupational asthma (OA) is divided into allergic asthma (AA) and irritant-induced asthma (IIA). IIA can be divided further into three different phenotypic subtypes. Volatile organic compounds (VOCs) in exhaled breath can reflect metabolic changes in the body, and a wide range of them have been associated with various diseases in the last two decades. This is the first known study to explore breath VOCs in subjects with OA, aimed to identify potential biomarkers to distinguish OA from healthy controls, as well as between different OA subgroups. In a cross-sectional investigation, exhaled breath from 40 patients with OA and 45 respiratory healthy healthcare workers were collected with ReCIVA® Breath Sampler. Samples were analyzed through an untargeted approach using thermal desorption-gas chromatography mass spectrometry (TD-GC-MS), and VOCs were identified according to tier classification. The data underwent analysis using both non-parametric and parametric statistical methods. 536 VOCs were identified. Significance (p<0.05) was observed in several emitted VOCs. Among these, compounds such as 1-hexadecanol, 2,3-butanediol, xylene, phenol, acetone, 3-methylhexane, methylcyclohexane, and isoprene have biological implications or are associated with exposures linked to OA. These VOCs may reflect metabolic changes in the body and the microbiome, as well as external exposures due to occupation.&#xD;In particular, 1-hexadecanol, 2,3-butanediol, xylene and phenol are associated with reduced nicotinamide adenine dinucleotide (NADH) and production of reactive oxygen species (ROS), mechanisms that can be linked to asthmatic diseases and therefore suggests its potential as biomarkers. This study demonstrates that VOCs detected in exhaled breath could serve as indicators of occupational exposure and enhance diagnostic accuracy for asthma.&#xD.

A comprehensive evaluation of the atmospheric impacts and health risks of cooking fumes from different cuisines

Pollutants emitted by catering enterprises pose a significant threat to the environment and public health. In this study, based on a systematic analysis of volatile organic compound (VOC) emission characteristics of different cuisines, the contribution of cooking emissions from catering enterprises to the PM2.5 and O3 concentrations in the atmosphere was evaluated using generation potential calculations and WRF-CAMx simulations. The health exposure risks of VOCs in kitchen breathing areas and those of PM2.5 and O3 contributed by the catering enterprises were evaluated. The generation potential calculation results showed that the catering enterprises exhibit 2.21–5.00 gO3/gVOCs of ozone formation potential (OFP) and 0.07–0.21 gSOA/gVOCs of secondary organic aerosol production potential (SOAP). The WRF-CAMx simulation results indicated that cooking emissions from catering enterprises contribute 0.36–1.91 μg/m3 and 0.05–0.21 μg/m3 to PM2.5 and maximum daily 8-h average (MDA8) concentrations of O3. The health exposure risks of PM2.5 and O3 were higher in catering enterprises in southern cities than in northern cities and were higher in urban areas than in suburban areas. The average hazardous VOCs (HVOCs) concentrations ranged from 53 ± 16 to 357 ± 31 μg/m3 in kitchen breathing areas. Acrolein was the primary contributor to the hazard index (HI) of all VOC species, accounting for 50.9%–99.5%. The total incremental lifetime carcinogenic risk (ILCR) of all cuisines exceeded the acceptable thresholds of 1.00 × 10−6. These findings provide insights that can aid in the formation and implementation of pollutant mitigation strategies in the catering industry.

Impact of meteorological conditions on the biogenic volatile organic compound (BVOC) emission rate from eastern Mediterranean vegetation under drought

Abstract. A comprehensive characterization of drought's impact on biogenic volatile organic compound (BVOC) emissions is essential for understanding atmospheric chemistry under global climate change, with implications for both air quality and climate model simulation. Currently, the effects of drought on BVOC emissions are not well characterized. Our study aims to test (i) whether instantaneous changes in meteorological conditions can serve as a better proxy for drought-related changes in BVOC emissions compared to the absolute values of the meteorological parameters, as indicated by previous BVOC mixing-ratio measurements and (ii) the impact of a plant under drought stress receiving a small amount of precipitation on BVOC emission rate, and on the manner in which the emission rate is influenced by meteorological parameters. To address these objectives, we conducted our study during the warm and dry summer conditions of the eastern Mediterranean region, focusing on the impact of drought on BVOC emissions from natural vegetation. Specifically, we conducted branch-enclosure sampling measurements in Ramat Hanadiv Nature Park, under natural drought and after irrigation (equivalent to 5.5–7 mm precipitation) for six selected branches of Phillyrea latifolia, the highest BVOC emitter in this park, in September–October 2020. The samplings were followed by gas chromatography–mass spectrometry analysis for BVOC identification and flux quantification. The results corroborate the finding that instantaneous changes in meteorological parameters, particularly relative humidity (RH), offer the most accurate proxy for BVOC emission rates under drought compared to the absolute values of either temperature (T) or RH. However, after irrigation, the correlation of the detected BVOC emission rate with the instantaneous changes in RH became significantly more moderate or even reversed. Our findings highlight that under drought, the instantaneous changes in RH and to a lesser extent in T are the best proxy for the emission rate of monoterpenes (MTs) and sesquiterpenes (SQTs), whereas under moderate drought conditions, T or RH serves as the best proxy for MT and SQT emission rate, respectively. In addition, the detected emission rates of MTs and SQTs increased by 150 % and 545 %, respectively, after a small amount of irrigation.

Pinewood VOC emissions protect from oxazolone-induced inflammation and dysbiosis in a mouse model of atopic dermatitis

Pinewood, increasingly used in construction and interior fittings, emits high amounts of volatile organic compounds (VOCs), which tend to accumulate in indoor air. Whether indoor VOCs affect the development of atopic dermatitis (AD) is a matter of debate. We aimed to evaluate the effects of pinewood VOCs on the development of AD-like inflammatory phenotype and linked microbiome alterations, both hallmarks of AD. An oxazolone-induced mouse model of AD was exposed to three different VOC concentrations emitted by pinewood plates throughout the experiment. The disease course and associated immunological and microbiological changes were evaluated. To validate and translate our results to humans, human keratinocytes were exposed to a synthetic pinewood VOCs mixture in an AD environment. Pinewood emitted mainly terpenes, which at a total concentration of 5 mg/m3 significantly improved oxazolone-induced key AD parameters, such as serum total IgE, transepidermal water loss, barrier gene alteration, inflammation, and dysbiosis. Notably, exposure to pinewood VOCs restored the loss of microbial richness and inhibit Staphylococci expansion characteristic of the oxazolone-induced mouse AD model. Most beneficial effects of pinewood VOCs were dose-dependent. In fact, lower (<3 mg/m3) or higher (>10 mg/m3) pinewood VOC levels maintained only limited beneficial effects, such as preserving the microbiome richness or impeding Staphylococci expansion, respectively. In the human in-vitro model, exposure of keratinocytes grown in an AD environment to a pinewood VOCs mixture reduced the release of inflammatory markers. In conclusion, our results indicate that airborne phytochemicals emitted from pinewood have beneficial effects on an AD-like phenotype and associated dysbiosis. These investigations highlight the effects of terpenes as environmental compounds in the prevention and/or control of atopic skin disease.

Identification of atmospheric emerging contaminants from industrial emissions: A case study of halogenated hydrocarbons emitted by the pharmaceutical industry

With the development of the pharmaceutical industry, halogenated hydrocarbons, which are the main raw materials and emissions of the pharmaceutical industry, may be defined as atmospheric emerging contaminants due to toxicity and low oxidation of the atmosphere. This study analyzed the volatile organic compounds (VOCs) emissions from four pharmaceutical companies located in the Yangtze River Delta. Samples were taken three times at each of the selected fixed and fugitive sampling sites in each company. Through testing, 141 VOCs were identified. The mean concentration and proportion of halogenated hydrocarbons from the four pharmaceutical companies were the highest of all the industries in the industrial park. They reached 18.9 ppm and 28.8 %, respectively. Fixed emissions of the companies exhibited the mean maximum concentration of dichloromethane and chlorobenzene, which are 11.4 ppm and 250.67 ppb. The mean concentration of fugitive emission of dichloromethane from the four companies in this study is lower than that of pharmaceutical companies in other studies. Newly detected halogenated hydrocarbons, such as 1,1-dichloropropanone and dichloronitromethane, present potential non-cancer and cancer risks to workers. Chlorobenzene was identified as a key potential cancer risk halogenated hydrocarbon the value of which reaches 0.00965. 2,6-dichloropyridine could be a potential emerging contaminant due to its lower MIR value and higher potential cancer risk. The study suggests that relevant pharmaceutical companies focus on the emissions of chlorobenzene and dichloromethane, which may be the atmospheric emerging contaminants for the pharmaceutical industry and focus on improve the treatment of waste gases in workshops and sewage stations.