Power plants, major emitters of air pollutants and greenhouse gases, must achieve pollution and carbon reduction synergy for low-carbon development and competitiveness. This study focuses on the enterprise-level challenges of thermal power plants by evaluating the pollution and carbon emission reduction path of a state-owned thermal power plant in northern China. The research applies the LEAP (Long-range Energy Alternatives Planning) model for the emission analysis of pollutants and carbon dioxide from the power plants, and SWOT (Strengths, Weaknesses, Opportunities, and Threats) analysis to evaluate the internal strengths and weaknesses as well as external opportunities and threats of power enterprises. The results indicate that 2.31 million t of CO2 were emitted during the thermal power production process in 2022. The company produced 3.89 billion kWh of clean energy, reducing CO2 emissions by 14,700 t from photovoltaic energy and 2.59 million t from hydropower. By 2030, clean energy is expected to exceed 80.00 % of installed capacity, reaching 20.00 million kW. This study predicts the emissions of pollutants and CO2 from power plants based on different development scenarios. Under comprehensive Scenario, CO2 emissions nearing zero by 2060, while SO2 and NOx emissions decrease by 97.29 % and 94.69 %. Cost-effectiveness ratio (CER) analysis shows initial increases to 1.80 by 2035 due to investments in clean energy and Carbon Capture, Utilization, and Storage (CCUS) technology, then declines to 0.37 by 2060 with technological maturity and economies of scale. The study proposes a strategic low-carbon development plan emphasizing renewable energy expansion, technological innovation, and policy support to achieve sustainable power generation and improve market competitiveness.

Given the global prevalence of schizophrenia (SCZ), it is urgent to elucidate and quantify its burden and clarify its environmental and social influencing factors. This study aimed to quantify the global disease burden of SCZ. It also investigated the causes of regional disparities and the impact of environmental and social factors. This study conducted an extensive analysis of the global, regional and national incidence, prevalence, and disability-adjusted life years (DALYs) of SCZ. In 2021, there were 1.22 million incident cases, 23.18 million prevalent cases and 14.82 million DALYs. From 1990 to 2021, the global incidence, prevalence, and DALYs of SCZ exhibited consistent upward trends, whereas the age-standardized rates remained stable. The prevalence of SCZ was found to be higher in males and exhibited age-related fluctuations. The highest incidence risk was observed in the 20–24 age group, while the highest DALYs risk was in the 35–39 age group. The highest disease burden of DALYs was observed in East Asia. The study delivered an analysis of the distribution of disease burden at the socio-demographic index level and investigated the impact of environmental factors on regional disparities. Projection analyses indicated a continued escalation in the incidence, prevalence, and DALYs attributable to SCZ by 2040. The disease burden of SCZ has increased since 1990. To mitigate the future impact of SCZ, these findings call for a multi-pronged approach: targeted service planning informed by disease burden, environmental emission reduction, and a renewed clinical focus on early intervention and functional recovery.

Vegetation plays a dual role in the Earth's climate system: it removes atmospheric CO2 through photosynthesis while emitting biogenic volatile organic compounds (BVOCs), which can weaken the net carbon sink and contribute to air pollution. To assess the long-term interplay between carbon uptake and BVOC emissions, and to clarify how vegetation characteristics and climate regulate this relationship, we developed a Biogenic Carbon Efficiency Index (BCEI). The BCEI integrates BVOC emissions with gross primary productivity (GPP) to quantify their spatial ratio, thereby capturing the concurrent "source" and "sink" attributes of vegetation. We characterize the spatiotemporal heterogeneity of the BCEI across China and identify its dominant environmental drivers. The BCEI decreases from southeast to northwest, and during 2001-2020 exhibited a declining trend over 78% of the country, with increases mainly in Southwest China and on the Shandong and Liaodong Peninsulas. Driver analyses indicate that variables linked to hydrothermal conditions, including temperature, precipitation, evapotranspiration, and soil moisture, primarily control BCEI variability. Across most regions, the BCEI is negatively correlated with soil moisture and precipitation, positively correlated with evapotranspiration, and shows regionally varying associations with temperature. These findings deepen understanding of vegetation's dual role as a source and sink and its driving mechanisms, providing a theoretical basis for optimizing regional vegetation management strategies.

Membrane separation technology for carbon dioxide (CO2) is recognized for its high efficiency, environmental sustainability, and cost-effectiveness. that incorporating amino acid ionic liquids (AAILs) into polyether-blockamide (Pebax 1657) can modulate polymer chain interactions, optimize free volume distribution, and thereby enhance CO2 separation performance through synergistic solubility-diffusivity effects. Molecular dynamics and Monte Carlo simulations were employed to elucidate the role of AAILs in enhancing the separation performance of AAIL/Pebax mixed matrix membranes (MMMs) and to clarify the gas mass transfer mechanisms within the membranes at the microscopic level. Gas permeation experiments revealed that the incorporation of AAILs significantly enhanced CO2 permeability as well as CO2/N2 and CO2/CH4 selectivities. Specifically, when the AAIL mass fraction was 1.0 wt%, the CO2 separation performance of the AAIL/Pebax MMMs reached its optimum, exhibiting a CO2 permeability of 104.5 Barrer, which is 70.20 % higher than that of pristine Pebax, and CO2/N2 and CO2/CH4 selectivities of 79.17 (an increase of 97.27 %) and 34.72 (an increase of 93.38 %), respectively. Furthermore, the experimental results showed excellent agreement with the molecular simulation data, confirming the reliability of the theoretical predictions. This study creatively integrates molecular simulation with experimental analysis to elucidate the microscopic mechanisms of CO2 adsorption and separation in AAIL/Pebax MMMs, providing valuable insights and a practical foundation for the rational design and application of high-performance CO2 separation membranes.

Biogenic volatile organic compounds (BVOCs) emitted by plants contribute to secondary air pollution through photochemical reactions in sunlight. Due to the influence of multiple factors, accurately characterizing and quantifying the emission of BVOCs from plant sources is challenging, which poses significant obstacles to the effective management and control of BVOCs. Therefore, this paper summarizes the emission mechanisms of BVOCs from plants, explores the primary factors influencing variations in the emission rates of these compounds, and evaluates the advantages and limitations of contemporary “measurement-modeling” methods for characterizing BVOC emissions. It is concluded that current measurement techniques still need to be further developed to meet the criteria of simplicity, affordability, and high precision simultaneously, and in terms of modeling and prediction studies, there is a lack of in-depth research on the atmospheric chemistry of BVOCs and the synergistic effects of multiple factors. Finally, it is suggested to leverage interdisciplinary strengths to develop advanced measurement technologies and high-resolution models for monitoring volatile compounds. Additionally, strategically selecting low-BVOC tree species in pollution-vulnerable urban areas—contingent on rigorous ecological assessments—combined with stringent controls on anthropogenic precursors (e.g., anthropogenic volatile organic compounds (AVOCs)) could serve as a complementary measure to mitigate secondary pollution.

Agricultural soils near industrial parks in the Yellow River bend region face severe heavy metal pollution, posing a significant to human health. This study integrated field sampling with laboratory analysis and applied geostatistical analysis, positive matrix factorization (PMF) modeling, and health risk assessment models to systematically investigate the pollution levels, spatial distribution, sources, and ecological health risks of heavy metals in the area. The main findings are as follows: (1) The average concentrations of the eight heavy metals (Hg, Cr, Cu, Pb, Zn, As, Cd, and Ni) in the study area were 0.04, 48.3, 54.3, 45.7, 70.0, 22.9, 0.4, and 35.7 mg·kg−1, respectively. The concentrations exceeded local background values by factors ranging from 1.32 to 11.2. Exceedances of soil screening and control values were particularly pronounced for Cd and As. Based on the geoaccumulation index, over 75% of the sampling sites for Cr, Pb, Zn, and Cd were classified as moderately to heavily polluted. Potential ecological risk assessment highlighted Cd as the significant ecological risk factor, indicating considerable heavy metal pollution in the region. (2) Kriging interpolation demonstrated elevated concentrations in the western (mid-upper) and eastern (mid-lower) subregions. Pearson correlation analysis suggested common sources for Cu-Pb-As-Cd and Cr-Zn-Ni. (3) PMF source apportionment identified four primary sources: traffic emissions (38.19%), natural and agricultural mixed sources (34.55%), metal smelting (17.61%), and atmospheric deposition (10.10%). (4) Health risk assessment indicated that the non-carcinogenic risk for both adults and children was within acceptable limits (adults: 0.065; children: 0.12). Carcinogenic risks were also acceptable (adults: 5.67 × 10−5; children: 6.70 × 10−5). In conclusion, priority should be given to the control of traffic emissions and agriculturally derived sources in the management of soil heavy metal contamination in this region, while the considerable contribution of smelting activities warrants heightened attention. This study provides a scientific basis for the prevention, control, and targeted remediation of regional soil heavy metal pollution.

Potamogeton crispus (P. crispus), with strong nitrogen uptake capacity, plays an important ecological role during winter and early spring when most aquatic plants are inactive. Its presence can also influence microbial denitrification in sediments by regulating oxygen levels and organic carbon availability. In this study, an indoor hydroponic simulation system was used to systematically evaluate the effects of P. crispus under different nitrogen-loading conditions on nitrogen removal from water, changes in sediment carbon and nitrogen fractions, microbial community structure, and greenhouse gas fluxes. The results showed that P. crispus effectively removed TN, NH4+-N, NO3−-N, and NO2−-N, maintaining strong denitrification capacity even under high-nitrogen loading. Under all nitrogen conditions, TN removal exceeded 80%, while NH4+-N and NO3−-N removal efficiencies surpassed 90%, with effective suppression of NO2−-N accumulation. Rhizosphere-mediated regulation by P. crispus enhanced the transformation and stabilization of DOC and NO3−-N in sediments, while also mitigating nitrogen-induced disturbances to carbon–nitrogen balance. The plant also exhibited strong CO2 uptake capacity, low CH4 emissions with a slight increase under higher nitrogen loading, and N2O fluxes that were significantly affected by nitrogen levels—showing negative values under low nitrogen and sharp increases under high-nitrogen conditions. Correlation analyses indicated that CO2 and N2O emissions were mainly regulated by microbial taxa involved in carbon and nitrogen transformation, while CH4 emissions were primarily driven by methanogenic archaea and showed weaker correlations with environmental factors. These findings highlight the importance of water restoration during low-temperature seasons and provide a theoretical basis for integrated wetland management strategies aimed at coordinated pollution reduction and carbon mitigation.

Biogenic volatile organic compounds (BVOCs) are crucial players in atmospheric chemistry, significantly impacting the formation of tropospheric ozone (O3). While China has made substantial strides in reducing anthropogenic VOC (AVOCs) emissions, O3 levels persist, highlighting the complex interplay between biogenic and anthropogenic sources. A critical knowledge gap exists in understanding how BVOC emissions influence ozone formation regimes (OFRs) and how this knowledge can inform effective air quality policies. This study employs the Model of Emissions of Gases and Aerosols from Nature (MEGAN) version 3.2 and the Community Multiscale Air Quality Modeling System (CMAQ) version 5.3.3 models, combined with process analysis (PA) and the Integrated Source Apportionment Method (ISAM), to evaluate the impact of BVOC emissions on OFRs in China. The models simulate BVOC emissions and their effects on OFRs across various regions during July 2019. The findings highlight that BVOCs play a pivotal role in shifting OFRs, with significant implications for ozone mitigation strategies in China. The study suggests that effective ozone control measures must consider the dual impact of BVOCs and AVOCs, with tailored strategies for different regions and times of day. The study also proposes potential challenges in mitigating BVOC emissions and outlines future research directions for interdisciplinary collaboration to address the complexities of ozone pollution management. This research advances the understanding of BVOCs' roles in ozone formation dynamics and provides a foundation for developing more effective air quality management policies in China, especially as global greening and climate change continue to influence BVOC emissions.

Urban areas face environmental pollution and greenhouse emissions challenges, demand collaborative efforts to mitigation. Urban forests play a crucial role in absorbing CO2 emissions and contributing to carbon sequestration potential, but they also release biogenic volatile organic compounds (BVOCs), which contribute to the formation of tropospheric ozone and secondary organic aerosols (SOA). This study aimed to understand the role of urban forests in carbon stock and BVOCs emission by establishing optimal biomass models for six typical tree species (Robinia pseudoacacia, Quercus, Populus, Pinus tabulaeformis, Betula platyphylla, and Larix gmelinii) in Beijing. Biomass models were developed using field surveys and remote sensing data, with R2 values ranging from 0.364 to 0.921. Applying these models to forest resource inventory data, carbon stock and BVOCs emission models were constructed. In 2021, the total carbon stock for these pure forest tree species was estimated at 5.638 million tons, with a carbon density of 58.86 t/ha. The carbon density ranking for pure forest tree species was: Robinia pseudoacacia > Populus tomentosa > Betula platyphylla > Quercus Linn> Pinus tabulaeformis > Larix gmelinii. Total BVOCs emission in 2021 from the studied species were calculated at 25,789.72 t, with an average emission of 0.27 t/ha. Populus tomentosa had the highest BVOCs emission per unit area, followed by Robinia pseudoacacia, and Larix gmelinii had the smallest. Betula platyphylla and Robinia pseudoacacia were identified as species with high carbon stock and low BVOCs emissions in Beijing, offering insights for future urban forest planning and eco-friendly urban environment development strategies.

Biogenic volatile organic compounds (BVOCs) significantly contribute to atmospheric chemistry at both regional and global scales. The composition and intensity of BVOC emissions vary significantly among different plant species. Previous studies have focused on BVOC emissions from tree species, but the results of research on BVOC emissions from wetland plants are still limited. Therefore, in this study, BVOCs emitted by three aquatic plants (Phragmites australis, Typha angustifolia, and Iris pseudacorus) were sampled and analyzed using a dynamic headspace technique combined with GC-MS at daily scales. The diurnal observation data showed that the total BVOC emission rates of the three plants peaked with the increase in environmental factors (temperature, PAR, and water temperature). P. australis was the only of the three plants that emitted isoprene with a high rate of 48.34 μg·g−1Dw·h−1. Moreover, the peak emission rates of total BVOC (78.45 μg·g−1Dw·h−1) in P. australis were higher than most tree species. The emissions rates of volatile organic compounds, including monoterpenes, oxygenated volatile organic compounds, alkanes, and other volatile organic compounds, were statistically correlated across all species. The emission rates of isoprene from P. australis had significant associations with intercellular CO2 concentration (Ci) (0.58, p < 0.05) and transpiration rate (Tr) (−0.63, p < 0.01). The emission rates of monoterpenes from P. australis were found to have a significantly positive correlation with the net photosynthetic rate (Pn) (0.58, p < 0.05) while T. angustifolia (−0.59, p < 0.05) and I. pseudacorus (−0.47, p < 0.05) showed the opposite trend. Such findings hold significance for the refinement of localized emission inventories and the development of comprehensive emission process models in future research, as BVOC emissions from wetland plants were reported here for the first time.

As the predominant pollutant in North China during the summer months, ozone (O3) exhibits strong oxidizing capabilities. Long-term exposure of crops to ozone will cause a decrease in various physiological indicators, affect crop yields, and pose a serious threat to food security. The North China Plain, the primary region for summer maize production in China, is afflicted by ozone pollution. In order to explore the effects of increasing O3 concentration on the physiological characteristics and photosynthetic characteristics of summer maize, this study took summer-sown maize as the research object and carried out the ozone exposure experiment with open-top chamber (OTCs). The response of maize to O3 exposure was studied by measuring the damage, physiological indexes and photosynthetic indexes in the silking stage (late July to late August) and filling stage (late August to mid-September). The results indicated the following: (1) Prolonged exposure to high O3 concentrations exacerbated leaf chlorosis and damage. (2) The increase in O3 concentration caused lipid peroxidation. The content of malondialdehyde was significantly increased by 32.6%~122.56%. At the same time, chlorophyll was destroyed and decreased by 2.17% to 4.86%. Under ozone exposure, ascorbic acid content was significantly increased by 7.58%~35.69%. The antioxidant indexes of maize were more sensitive during the filling stage. (3) Under O3 exposure, photosynthetic rate, stomatal conductance and intercellular carbon dioxide concentration decreased significantly, indicating that the influence of O3 on maize was mainly due to stomatal limitation. Water use efficiency and transpiration rate decreased significantly. The water use efficiency decreased by 12.84%~35.62%, which led to the weakening of the carbon fixation ability of maize and affected the normal growth and development of maize.

In order to solve ecological remediation issues for abandoned mines with steep slopes, a kind of hydrogels with high cohesion and water-retaining were designed by inorganic mineral skeleton combining with polymeric organic network cavities. This eco-friendly hydrogel (MFA/HA-g-p(AA-co-AM)) was prepared with acrylic acid (AA)-acrylamide (AM) as network, which was grafted with humic acids (HA) as network binding point reinforcement skeleton and polar functional group donors, KOH-modified fly ash (MFA) as internal supporter. The maximum water absorption capacities were 1960 g/g for distilled water, which followed the pseudo-secondorder model. This super water absorption was attributed to the first stage of 62 % fast absorption due to the high specific surface area, pore volume and low osmotic pressure, moreover, the multiple hydrophilic functional groups and network structure swell contributed to 36 % of the second stage slow adsorption. In addition, the pore filling of water in mesoporous channels contributed the additional 2 % water retention on the third stage. The high saline-alkali resistance correlated with the electrostatic attraction with MFA and multiple interactions with oxygen-containing functional groups in organic components. MFA and HA also enhanced the shear strength and fertility retention properties. After 5 cycles of natural dehydration and reabsorption process, these excellent characteristics of reusability and water absorption capacity kept above 97 %. The application of 0.6 wt% MFA/ HA-g-p(AA-co-AM) at 15 degrees slope could improve the growth of ryegrass by approximately 45 %. This study provides an efficient and economic superabsorbent material for ecological restoration of abandoned mines with steep slopes.

Amino acid ionic liquids (AAILs) have good absorption performance for carbon dioxide (CO2). However, there is no unified understanding of the absorption mechanism. In this study, synthesis and characterization of four ionic liquids (ILs) based on amino acid (aminate) anions, namely 1-butyl-3-methylimidazolium L-alaninate ([BMIm]Ala), 1-butyl-3-methylimidazolium arginate ([BMIm]Arg), 1-butyl-3-methylimidazolium glycinate ([BMIm]Gly) and 1-butyl-3-methylimidazolium lysinate ([BMIm]Lys), were accomplished, where the cation adopted was [BMIm]+. Further, their CO2 absorption capacities were examined. The CO2 molar uptake rankings for the investigated aminate-ILs are [BMIm]Arg > [BMIm]Lys > [BMIm]Gly > [BMIm]Ala, with [BMIm]Arg displaying stronger CO2 absorption (0.85 mol CO2/mol IL under 10.0 bar). In contrast to non-functionalized ILs and amine functionalized cation ILs, the CO2 solubility of as-synthesized aminate-ILs is higher. More importantly, the Quantum Theory of Atoms-in-Molecules (QTAIM) at the M06-2X/6-311++G(d, p) level was exploited to theoretically explore the CO2 absorption mechanism and kinetics of the aminate-ILs. It was found that the alkyl chain length along with the quantity of amine (–NH2) groups in aminate anions affected their absorption of CO2. Facilitated absorption of CO2 was noted when the amine group quantity of ILs structures rose. The chemisorption nature was determined according to the enthalpy changes in the process of CO2 capture. As suggested by the kinetic findings, [BMIm]Gly exhibited higher absorption rate of CO2 compared to [BMIm]Ala, since the steric hindrance in the latter is higher because of an extra methyl group in the aminate chain. Additionally, topological exploration revealed that the C–N bond critical point had a covalent nature, indicating that CO2 capture was a chemisorption event. In conclusion, based on the kinetic energy findings combined with the interaction and topological analyses, [BMIm]Arg was identified as the optimal candidate for CO2 absorption from the thermodynamic and kinetic perspectives, which was consistent with the CO2 absorption experiment. Finally, four other aminate-ILs were synthesized using 1-ethyl-3-methylimidazolium ([EMIm]+) as a cation, namely 1-ethyl-3-methylimidazolium asparagine ([EMIm]Asn), 1-ethyl-3-methylimidazolium glutamine ([EMIm]Gln), 1-ethyl-3-methylimidazolium threonine ([EMIm]Thr) and 1-ethyl-3-methylimidazolium glutamic ([EMIm]Glu). The universality of the above conclusions was verified through theoretical calculations and CO2 absorption experiments.

Air pollution poses a significant threat to public health, while biogenic volatile organic compounds (BVOCs) play a crucial role in both aspects. However, the unclear relationship between BVOCs and air pollutants in the under-canopy space limits the accuracy of air pollution control and the exploitation of forest healthcare functions. To clarify the variation of BVOCs in forest therapy bases, and their impacts on ozone (O3) and fine particulate matter (PM2.5) at nose height, total VOCs (TVOCs) in the forest were collected during typical sunny days, while air pollutants and meteorological factors were observed simultaneously. The results showed that the branch-level emissions of P. tabuliformis were dominated by healthcare-effective monoterpenoids, with only α-pinene having relative air concentrations of over 5 % in forest air samples. The correlation between concentrations of under-canopy TVOCs and emission rates of BVOCs from P. tabuliformis was weak (p > 0.09) in all seasons. However, the correlation between concentrations of TVOCs and the concentrations of O3 and PM2.5 showed clear seasonal differences. In spring, TVOCs only showed a significant negative correlation with PM2.5 in the forest (p < 0.01). In summer and autumn, TVOCs were significantly negatively correlated with both O3 (p < 0.001) and PM2.5 (p < 0.01). Specifically, the negative linear relationships were more pronounced for O3 and oxygenated VOCs in autumn (R2 = 0.40, p < 0.001) than for other relationships. The relationship between air pollutant concentrations inside and outside the forest also showed significant seasonal differences, generally characterized by a weaker correlation between them during seasons of strong emissions. Therefore, BVOCs in coniferous forests are health functions as they can provide healthcare effects and mitigate the concentration of air pollutants in the forest, and the establishment of forest therapy bases in rural areas with low NOx can be a sensible approach to promote good health, well-being, and sustainable development.

In recent years, the issue of PM2.5 and O3 pollution in China has gradually become a hot topic in air pollution control. Powerful, precise, and clear policies are important to guide the efficient control of PM2.5 and O3 pollution. However, research on PM2.5 and O3 pollution policies is very limited. Moreover, these reports have failed to identify all the specific characteristics of the PM2.5 and O3 pollution policies in China, leading to inefficient control of PM2.5 and O3 pollution. Therefore, based on the external features and internal structures of relevant policy documents, this paper conducts a detailed bibliometric analysis to elucidate the evolution of PM2.5 and O3 pollution control policies in China. The results reveal the following: (1) The PM2.5 and O3 pollution control policies in China exhibit a characteristic of “top-down cross-level response lag”, transitioning from individual pollutant control to coordinated control of PM2.5 and O3 pollution. (2) The Ministry of Environmental Protection and the Ministry of Ecology and Environment have been the two major policy issuers in China’s government, focusing on “Technology” and “Monitoring”, respectively. However, the aforementioned policies are mainly implemented by local governments, with limited interregional cooperation but an overemphasis on enterprise pollution control and emergency systems. (3) In terms of policy instruments, supply- and environment-oriented policy instruments are predominant, whereas demand-oriented policy instruments are inadequate. Therefore, it is suggested to utilize the synergistic effect of pollution reduction and carbon mitigation to achieve the goal of the “dual carbon” strategy, enhance public participation to strengthen cooperation among diverse stakeholders, strengthen cross-regional cooperation to overcome governance barriers, and reasonably optimize the use of policy instruments to form an effective combination of policy instruments.

As the power industry is the primary carbon emission industry, the research on the construction path of "zero-carbon" power plants against the background of the "dual-carbon" goal must be strengthened. Considering a state-owned power generation enterprise as an example, based on the carbon emissions of the power plant in recent years, the LEAP model was constructed by combining its energy structure and geographical and climatic conditions and the baseline, energy structure adjustment, technological progress, and comprehensive scenarios were set up. The energy consumption demand under each scenario was analyzed and the future carbon emissions under each scenario were predicted. The results showed that in 2060, the total carbon emissions from the power generation sector under the technological progress and energy structure adjustment scenarios decrease by 54.55% and 75.97% compared with those in the baseline scenario, respectively, which demonstrated the large potential for carbon emission reduction from clean energy substitution and that the flexibility transformation of thermal power units and the upgrading and replacement of ultra-supercritical generating units could reduce coal consumption and decrease carbon emissions, whereas the development of CCUS technology was significant, and the construction of CCUS projects was a necessary condition for realizing carbon neutrality of power plants while retaining a certain scale of thermal power generation. Under a comprehensive scenario, "zero carbon" emissions from power plants could be realized around 2056. The results of the study provide ideas for the construction of "zero carbon" power plants.

Variability in biogenic volatile organic compound (BVOC) emissions across species and seasons poses challenges for accurate regional emission estimates and effective ozone (O-3) control policies. To address this issue, we conducted in-situ measurements of emission factors for six dominant tree species in Beijing across four seasons. Subsequently, we developed monthly dynamic standard emission factors (SER-MDs) to model monthly BVOC emissions and their impacts on O-3 formation at citywide and district levels. Our observations revealed pronounced seasonal differences in the BVOC composition and emission rates, as well as their responsiveness to monthly average temperature. By introducing the SER-MDs, we estimated BVOC emissions from the dominant tree species in Beijing to be 38.2 Gg yr(-1), with monoterpenes and isoprene contributing 49% and 11%, respectively. This calculation reduced the overestimation associated with constant standard emission factors by 31%-38% at district level. The estimates also revealed regional differences in plant compositions rather than simple feedback from regional temperature and photosynthetically active radiation periods. Under these conditions, the maximum monthly BVOC-induced O-3 concentration occurred in August and ranged from 4 to 17 mu g m(-3) across districts, with isoprene being the dominant contributor. Quercus mongolica and Populus tomentosa played significant roles in the formation of BVOC-induced O-3 due to their strong isoprene emitting potential in July-August. These results indicate the necessity of introducing species-specific rhythms of BVOC emissions from dominant species in the development of urban BVOC emission inventories. This approach could inform the development of air pollution management policies that are consistent with the local vegetation composition and O-3 pollution characteristics. For Beijing and other similar northern cities, reducing the use of tree species emitting substantial amounts of isoprene during periods of regional peak ambient O-3 concentrations could constitute an effective nature-based solution for improving urban air quality in the future.

Biogenic volatile organic compounds are emitted by plants and influence human and environmental health. They contribute to the formation of pollutants such as ozone and secondary organic aerosols, thereby influencing air quality and climate. Here we review biogenic volatile organic compounds with focus on biosynthesis, release to the atmosphere, distribution at various scales, tropospheric chemical processes, and secondary organic aerosols. Biogenic volatile organic compounds are emitted primarily through enzymatic pathways in response to environmental factors, varying across plant species and ecosystems. These emissions exhibit heterogeneity at multiple scales, influenced by meteorological conditions and plant structure.

Chemical plant shutdown (CPS) operations will employ a flare system to combust waste, unwanted, and off-spec gases dumped from process units to protect the plant safety and the local community. However, the incomplete combustion of flare source under CPS operations including plant planned shutdown (PPS) and plant emergency shutdown (PES) will cause considerable air pollution events. Hitherto, quantitative studies on both primary (CO and NO2) and secondary (ozone) pollutant impacts induced by CPS flaring are still lacking. In this paper, the dynamic effect of flare emissions from two types of CPS (PPS and PES) on ambient air-quality impacts will be systematically and quantitatively studied. The study integrates the dynamic process simulation via Aspen Plus Dynamics with the regional air-quality modelling via Comprehensive Air-quality Model with extensions (CAMx). Case studies indicated that the primary pollutants from flare emissions will be significantly diluted due to the atmospheric transportation, and the maximum concentrations of CO and NO2 can respectively reach 119.0 and 11.0 ppb under PPS, and 47.5 and 4.5 ppb under PES. Meanwhile, the increasing height of the flaring stack will decrease CO and NO2 concentrations but increase the ozone concentration under CPS. Furthermore, CPS in daytime periods will greatly promote ozone generations due to the enhanced photochemical reactions under solar radiation. The maximum 1 -hr and 8 -hr ozone increment can be 16.6 and 7.1 ppb under PPS while 10.7 and 3.3 ppb under PES, respectively. Besides, the decreasing of flare destruction and removal efficiency will increase ozone and CO under PES.

Rate coefficients for the reactions of OH radicals with C-3-C-11 alkanes were determined using the multivariate relative-rate technique. A total of 25 relative-rate coefficients at room temperature and 24 Arrhenius expressions in the temperature range of 273-323 K were obtained. Notably, a new room temperature relative-rate coefficient for 3-methylheptane that had not been previously reported was determined, and the obtained kOH value (in units of 10(-12) cm(3) molec.(-1) s(-1)) was 7.71 +/- 0.35. Interestingly, whilst results for n-alkanes agreed well with available structure-activity relationship (SAR) calculations of Kwok and Atkinson (1995), Neeb (2000), Wilson et al. (2006), Jenkin et al. (2018), and McGillen et al. (2020), the three cycloalkanes (cyclopentane, methylcyclopentane, cyclohexane) and one branched alkane (2,2,4-trimethylpentane) were found to be less reactive than predicted by the SAR approach. Conversely, the SAR estimates for 2,3-dimethylbutane were approximately 25 % lower than the experimental values, with the exception of those estimated by the Wilson group, highlighting that there may be additional factors that govern the reactivity of highly branched alkanes that are not captured by current SAR techniques. Arrhenius expressions (in units of cm(3) molec.(-1) s(-1)) for the reactions of various branched alkanes with OH radicals were determined for the first time: 2-methylheptane, 1.37 +/- 0.48x10(-11)exp[-209 +/- 100/T, and 3-methylheptane, 3.54 +/- 0.45x10(-11)exp]-374 +/- 49/T. The reactivity relation of saturated alkanes with OH radicals and chlorine atoms was obtained: log(10)(k(Cl+alkanes)=0.569xlog(10)k((OH+alkanes)))-3.111 (R-2 = 0.86). In addition, the rate coefficients for the 24 previously studied OH + alkanes reactions were consistent with existing literature values, demonstrating the reliability and efficiency of this method for the simultaneous investigation of gas-phase reaction kinetics.