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1.
Toxics ; 12(9)2024 Aug 23.
Article in English | MEDLINE | ID: mdl-39330550

ABSTRACT

This study leveraged 2019 online data of particulate matter (PM2.5) and volatile organic compounds (VOCs) in Tianjin to analyze atmospheric pollution characteristics. PM2.5 was found to be primarily composed of water-soluble ions, with nitrates as the dominant component, while VOCs were predominantly alkanes, followed by alkenes and aromatic hydrocarbons, with notable concentrations of propane, ethane, ethylene, toluene, and benzene. The receptor model identified six major sources of PM2.5 and seven major sources of VOCs. The secondary source is the main contribution source, while motor vehicles and coal burning are important primary contribution sources in PM2.5. And, industrial processes and natural gas volatilization were considered major contributors for VOCs. A health risk assessment indicated negligible non-carcinogenic risks but potential carcinogenic risks from trace metals As and Cr, and benzene within VOCs, underscoring the necessity for focused public health measures. A risk attribution analysis attributed As and Cr in PM to coal combustion and vehicular emissions. Benzene in VOCs primarily originates from fuel evaporation, and industrial and vehicular emissions. These findings underscore the potential for reducing health risks from PM and VOCs through enhanced regulation of emissions in coal, industry, and transportation. Such strategies are vital for advancing air quality management and safeguarding public health.

2.
Environ Sci Technol ; 58(39): 17355-17363, 2024 Oct 01.
Article in English | MEDLINE | ID: mdl-39301696

ABSTRACT

Solubility largely determines the impacts of aerosol Fe on marine ecosystems and human health. Currently, modeling studies have large uncertainties in aerosol Fe solubility due to inadequate understanding of the sources of dissolved Fe. This work investigated seasonal variations of Fe solubility in coarse and fine aerosols in Qingdao, a coastal city in the Northwest Pacific, and utilized a receptor model for source apportionment of total and dissolved aerosol Fe. Desert dust was found to be the main source of total Fe, contributing 65 and 81% annually to total Fe in coarse and fine particles, respectively; in contrast, dissolved aerosol Fe originated primarily from combustion, industrial, and secondary sources. The annual average contributions to dissolved Fe in coarse and fine particles were 68 and 47% for the secondary source and 32 and 33% for the combustion source, respectively. Aerosol Fe solubility was found to be highest in summer and lowest in spring, showing seasonal patterns similar to those of aerosol acidity. Increase in Fe solubility in atmospheric particles, when compared to desert dust, was mainly caused by secondary processing and combustion emission, and the effect of secondary processes was dictated by aerosol acidity and liquid water content.


Subject(s)
Aerosols , Dust , Iron , Solubility , Iron/chemistry , Seasons , Air Pollutants/analysis , Particle Size , Particulate Matter , Environmental Monitoring
3.
Sci Total Environ ; 953: 176002, 2024 Nov 25.
Article in English | MEDLINE | ID: mdl-39233082

ABSTRACT

Particulate nitrate is an important component of particulate matter and poses a significant threat to the ecosystem and human health. The gas-phase formation pathway of nitrate is extremely important, which mainly comprises the NO2 oxidation process triggered by OH radicals and the nitrate partitioning process. The response of nitrate to source emission reduction during different pollution periods remains unclear. Here, we applied the chemical kinetic and thermodynamics model to explore the importance oxidation process and partitioning process during different pollution periods based on high-time resolution observation data. The result indicated that with the aggravation of pollution, the partitioning process gradually ceases to be a limiting step in the formation of nitrates. The results of the influencing factor analysis indicate that NO2 concentration and aerosol pH values play a more significant role in the formation of nitrates. Specifically, during the clean period, nitrate formation is sensitive to both NO2 concentration and pH values, but during the pollution period, it becomes sensitive only to NO2 concentration. By combining source apportionment, we explored the response of nitrate formation to source emission reduction, and the results showed that the control of vehicle exhaust emissions and coal combustion sources is more effective in mitigating nitrate pollution. Additionally, this study also emphasized the importance of early prevention and control of pollution sources. This research provides scientific evidence for the precise management and control of nitrates.

4.
J Diabetes Investig ; 2024 Sep 14.
Article in English | MEDLINE | ID: mdl-39275947

ABSTRACT

AIMS/INTRODUCTION: To investigated the association between serum asprosin and metabolic characteristics in type 2 diabetes mellitus patients with different durations. MATERIALS AND METHODS: A total of 436 patients with type 2 diabetes mellitus were enrolled in this study from the community health service center in southeastern Shanxi Province. All the patients were divided into two groups according to their diabetes duration: diabetes duration ≤5 years group (n = 132) and diabetes duration ≥10 years group (n = 304). Fasting blood samples were gathered and serum asprosin was tested. Pearson/Spearman correlation analysis was carried out. RESULTS: Asprosin was comparable between the two groups. Asprosin was positively correlated with systolic blood pressure (SBP), triglycerides, creatinine, serum uric acid and low-density lipoprotein cholesterol in the diabetes duration ≤5 years group (P < 0.05). In the diabetes duration ≥10 years group, asprosin was independently correlated with SBP, diastolic blood pressure, body mass index, total cholesterol, triglycerides, low-density lipoprotein cholesterol, creatinine, serum uric acid, fasting plasma glucose and glycosylated hemoglobin (P < 0.05). Asprosin was associated with alanine aminotransferase and estimated glomerular filtration rate (P < 0.05). Multiple linear regression analysis found that SBP and diastolic blood pressure is an independent factor related to serum asprosin in the group with diabetes duration ≤5 years (P < 0.05). Fasting plasma glucose, SBP, total cholesterol and serum uric acid is an independent factor related to serum asprosin in the group with diabetes duration ≥10 years (P < 0.05). CONCLUSIONS: Serum asprosin was significantly increased in the group with diabetes duration ≥10 years, and glycosylated hemoglobin, blood pressure and estimated glomerular filtration rate were independent risk factors in long-duration type 2 diabetes mellitus.

5.
J Hazard Mater ; 478: 135558, 2024 Oct 05.
Article in English | MEDLINE | ID: mdl-39159579

ABSTRACT

As the two important ambient air pollutants, particulate matter (PM2.5) and ozone (O3) can both originate from gas nitrogen oxides. In this study, applied by theoretical analysis and machine learning method, we examined the effects of atmospheric reactive nitrogen on PM2.5-O3 pollution, in which nitric oxide (NO), nitrogen dioxide (NO2), gaseous nitric acid (HNO3) and particle nitrate (pNO3-) conversion process has the co-directional and contra-directional effects on PM2.5-O3 pollution. Of which, HNO3 and SO2 are the co-directional driving factors resulting in PM2.5 and O3 growing or decreasing simultaneously; while NO, NO2, and temperature represent the contra-directional factors, which can promote the growth of one pollutant and reduce another one. Our findings suggest that designing the suitable co-controlling strategies for PM2.5-O3 sustainable reduction should target at driving factors by considering the contra-directional and co-directional effects under suitable sensitivity regions. For co-directional driving factors, the design of suitable mitigation strategies will jointly achieve effective reduction in PM2.5 and O3; while for contra-directional driving factors, it should be more patient, otherwise, it is possible to reduce one item but increase another one at the same time.

8.
Sci Total Environ ; 945: 173729, 2024 Oct 01.
Article in English | MEDLINE | ID: mdl-38839009

ABSTRACT

PM2.5 and O3 are two of the main air pollutants that have adverse impacts on climate and human health. The evolution process of PM2.5 and O3 co-pollution are of concern because of the increased frequency of PM2.5 and O3 co-pollution days. Here, we examined the chemical coupling and revealed the driving factors of the PM2.5 and O3 co-pollution evolution process from cleaning day, PM2.5 pollution day, or O3 pollution day, applied by theoretical analysis and model calculation methods. The results demonstrate that PM2.5 and O3 co-pollution day frequently occurred with high concentrations of gaseous precursors and higher sulfur oxidation ratio (SOR) and nitrogen oxidation ratio (NOR), which we attribute to the enhancement of atmospheric oxidation capacity (AOC). The AOC is positively correlated with O3 and weakly correlated with PM2.5. In addition, we found that the correlation coefficients of PM2.5-NO2 (0.62) were higher than that of PM2.5-SO2 (0.32), highlighting the priority of NOx controlling to mitigate PM2.5 pollution. Overall, our discovery can provide scientific evidence to design feasible solutions for the controlling PM2.5 and O3 co-pollution process.

9.
Nat Commun ; 15(1): 4625, 2024 May 30.
Article in English | MEDLINE | ID: mdl-38816351

ABSTRACT

Traditional atmospheric chemistry posits that sulfur dioxide (SO2) can be oxidized to sulfate (SO42-) through aqueous-phase reactions in clouds and gas-phase oxidation. Despite adequate knowledge of traditional mechanisms, several studies have highlighted the potential for SO2 oxidation within aerosol water. Given the widespread presence of tropospheric aerosols, SO42- production through aqueous-phase oxidation in aerosol water could have a pervasive global impact. Here, we quantify the potential contributions of aerosol aqueous pathways to global sulfate formation based on the GEOS-Chem simulations and subsequent theoretical calculations. Hydrogen peroxide (H2O2) oxidation significantly influences continental regions both horizontally and vertically. Over the past two decades, shifts in the formation pathways within typical cities reveal an intriguing trend: despite reductions in SO2 emissions, the increased atmospheric oxidation capacities, like rising H2O2 levels, prevent a steady decline in SO42- concentrations. Abating oxidants would facilitate the benefit of SO2 reduction and the positive feedback in sulfate mitigation.

10.
Sci Total Environ ; 918: 170620, 2024 Mar 25.
Article in English | MEDLINE | ID: mdl-38320696

ABSTRACT

Fine particles (PM2.5) pollution is still a severe issue in some cities in China, where the chemical characteristics of PM2.5 remain unclear due to limited studies there. Herein, we focused on PM2.5 pollution in small and medium-sized cities in key urban agglomerations and conducted a comprehensive study on the PM2.5 chemical characteristics, sources, and health risks. In the autumn and winter of 2019-2020, PM2.5 samples were collected simultaneously in four small and medium-sized cities in four key regions: Dingzhou (Beijing-Tianjin-Hebei region), Weinan (Fenwei Plain region), Fukang (Northern Slope of the Tianshan Mountain region), and Bozhou (Yangtze River Delta region). The results showed that secondary inorganic ions (43.1 %-67.0 %) and organic matter (OM, 8.6 %-36.4 %) were the main components of PM2.5 in all the cities. Specifically, Fukang with the most severe PM2.5 pollution had the highest proportion of SO42- (31.2 %), while the dominant components in other cities were NO3- and OM. The Multilinear Engine 2 (ME2) analysis identified five sources of PM2.5 in these cities. Coal combustion contributed most to PM2.5 in Fukang, but secondary sources in other cities. Combined with chemical characteristics and ME2 analysis, it was preliminarily determined that the primary emission of coal combustion had an important contribution to high SO42- in Fukang. Potential source contribution function (PSCF) analysis results showed that regional transport played an important role in PM2.5 in Dingzhou, Weinan and Bozhou, while PM2.5 in Fukang was mainly affected by short-range transport from surrounding areas. Finally, the health risk assessment indicated Mn was the dominant contributor to the total non-carcinogenic risks and Cr had higher carcinogenic risks in all cities. The findings provide a scientific basis for formulating more effective abatement strategies for PM2.5 pollution.


Subject(s)
Air Pollutants , Air Pollution , Air Pollutants/analysis , Cities , Air Pollution/analysis , Particulate Matter/analysis , Environmental Monitoring/methods , China , Seasons , Coal/analysis
11.
J Diabetes Investig ; 15(5): 608-613, 2024 May.
Article in English | MEDLINE | ID: mdl-38363189

ABSTRACT

AIMS/INTRODUCTION: Serum asprosin is expected to become a screening indicator in early-stage diabetic heart disease. The relationship between serum asprosin and left ventricular diastolic dysfunction (LVDD) was studied in elderly patients with type 2 diabetes mellitus in the community. MATERIALS AND METHODS: A total of 252 elderly patients with type 2 diabetes mellitus were recruited from Zhuoma Community Care Station and Chengbei West Street Community Care Service Center in Changzhi City of Shanxi Province from November 2019 to July 2021. Patients were divided into the LVDD group (n = 195) and the non-LVDD group (n = 57). The t-test, Mann-Whitney U test, and χ2 test were used to compare indicators between the LVDD group and the non-LVDD group. Pearson or Spearman correlation analysis was adopted to evaluate the correlation between serum asprosin and other clinical data. Multivariate logistic regression analysis was applied to analyze the influencing factors on LVDD. RESULTS: Compared with patients without LVDD, patients with LVDD had a higher level of low-density lipoprotein cholesterol (LDL-C), fasting blood glucose (FPG), and asprosin, but a lower level of early diastolic movement speed (A) to diastolic movement velocity (E) (E/A). Asprosin was positively associated with waist circumference (WC), body mass index (BMI), creatinine, triglycerides (P < 0.05), and negatively associated with E/A and high density lipoprotein cholesterol HDL-C (P < 0.05). The risk of LVDD increased with elevated asprosin levels after adjustment for age, systolic blood pressure (SBP), BMI, FPG, and LDL-C. Compared with patients in the lowest tertile of serum asprosin (<275.25 pg/mL), a serum level of asprosin between 275.25-355.08 pg/mL [OR (95% CI) is 2.368 (1.169-4.796), P < 0.05] and asprosin >355.08 pg/mL [OR (95% CI) is 2.549 (1.275-5.095), P < 0.05] patients have a higher risk of left ventricular diastolic dysfunction. CONCLUSIONS: Serum asprosin was positively associated with left ventricular diastolic dysfunction, and the risk of LVDD increased significantly with increased serum levels of asprosin.


Subject(s)
Adipokines , Diabetes Mellitus, Type 2 , Fibrillin-1 , Ventricular Dysfunction, Left , Aged , Female , Humans , Male , Biomarkers/blood , Blood Glucose/analysis , Diabetes Mellitus, Type 2/blood , Diabetes Mellitus, Type 2/complications , Diabetes Mellitus, Type 2/physiopathology , Diastole , Fibrillin-1/blood , Ventricular Dysfunction, Left/blood , Ventricular Dysfunction, Left/physiopathology , Ventricular Dysfunction, Left/etiology
12.
Adv Mater ; 36(18): e2309507, 2024 May.
Article in English | MEDLINE | ID: mdl-38273713

ABSTRACT

Maintaining a match between input solar energy and required energy by water supply management is key to achieving efficient interfacial solar-driven evaporation (ISDE). In practice, the solar radiation flux is constantly changing throughout the day, so keeping a dynamic water-energy-balance of ISDE is a big challenge. Herein, a photothermal water diode (WD) evaporator concept is proposed by an integrated hydrophilic/hydrophobic Janus absorber to overcome the issue. Due to the unique unidirectional water transport properties induced by asymmetric wettability, a self-adaptive balance between photothermal energy input and water uptake is established, thus realizing the energy matching and utilization maximization. The experimental and simulation results exhibit that with the increase of sunlight intensity, the water supply speed is significantly accelerated due to the dynamic management and self-regulation on water replenishment. Therefore, an excellent evaporation rate of up to 2.14 kg m-2 h-1 with a high efficiency of 93.7% under 1 sun illumination is achieved. This water diode engineering with Janus wettability provides a novel strategy and extends the path for designing solar evaporation systems with diverse water supply properties, which shows great potential in different environmental conditions.

13.
Materials (Basel) ; 16(17)2023 Aug 30.
Article in English | MEDLINE | ID: mdl-37687637

ABSTRACT

Alloys Mg-8Gd-4Y-0.6Zn-0.5Zr (referred to as 0.6Zn) without the bulk long-period stacking ordered (LPSO) phase and Mg-8Gd-4Y-1.1Zn-0.5Zr (referred to as 1.1Zn) containing the bulk LPSO phase were prepared and a series of hot compression tests were conducted to examine and evaluate the influence of the bulk LPSO phase on the thermal deformation behavior and characteristics of the Mg-Gd-Y-Zn-Zr alloy. The bulk LPSO phase affects the dynamic recrystallization behavior, resulting in differences in flow stress between two alloys under different conditions. Specifically, in the temperature range of 380~460 °C, compression at lower strain rates is beneficial for the LPSO phase to promote dynamic recrystallization, while compression at a high strain rate inhibits the dynamic recrystallization due to the severe deformation of the bulk LPSO phase to release the stress concentration instead. The increase in temperature helps the LPSO promote dynamic recrystallization. As a result, the LPSO phase promotes dynamic recrystallization at all experimental strain rates at 500 °C. Furthermore, the thermal processing maps of the 0.6Zn and 1.1Zn alloys are established, and their optimal processing windows are located at 500 °C/0.001~0.01 s-1 and 500 °C/0.01 s-1, respectively. In addition, the instability zones for the 1.1Zn alloy are much larger than that for the 0.6Zn alloy, which corresponds to the microcracks generated at the interfaces between α-Mg and bulk LPSO phases.

14.
Front Neurol ; 14: 1195664, 2023.
Article in English | MEDLINE | ID: mdl-37602246

ABSTRACT

Neuroblastoma (NB) is a leading cause of death in children. It usually occurs in the adrenal gland and rarely in the spinal canal. Here, we report the case of a 48-year-old male patient with abnormal thickening of the cauda equina nerve as revealed by lumbosacral magnetic resonance imaging. The patient's main clinical manifestations were numbness and pain in both lower limbs. The patient underwent surgical treatment; however, intraoperatively, an unclear border was observed between the cauda equina nerve and the tumor; therefore, the tumor was not forcibly excised. The postoperative pathological results were reported as NB. The disease known as NB, which is extremely rare. We believe that a pathological biopsy is extremely vital for diagnosing NB, and aggressive post-operative radio-chemotherapy could potentially prolong the patient's survival time.

15.
Sci Total Environ ; 899: 165679, 2023 Nov 15.
Article in English | MEDLINE | ID: mdl-37481086

ABSTRACT

Air pollutants represented by fine particulate matter (PM2.5) and the greenhouse effect caused by carbon dioxide (CO2), are both urgent threats to public health. Tackling the synergistic reduction of PM2.5 and CO2 is critical to achieving improvements in clean air worldwide. A persistent issue is the identification of their common sources and integrated impacts under different environmental conditions. In this study, we investigated the characteristics of the pollution types captured by combined analysis through a comprehensive observational dataset for 2017-2020, and applied machine learning algorithms to quantify the effects of drivers on air pollutants and CO2 formation. More importantly, detailed conclusions were drawn for the joint control of PM2.5-CO2 in multiple pollution types by using ensemble traceability technique. We demonstrated that reducing coal combustion emissions was an effective measure to maximize the benefits of PM2.5-CO2 in weather with low CO2 levels and no PM2.5 pollution. Correspondingly, on days with severe PM2.5 episodes, prioritizing control of vehicle emissions can simultaneously mitigate PM2.5 and CO2. Similar conclusions were found at high CO2 levels, accompanied by a more extensive role of vehicle emissions. Furthermore, a comparison of the differences in source impacts between PM2.5-CO2 and individual species suggests that focusing only on the sources that contribute significantly to one species may result in an underestimation or overestimation of PM2.5-CO2 source impacts. One such implication, as evidenced by our findings, is that synergistic controlling common sources of pollutants should be efficient. Thereby, common source management targeting PM2.5-CO2 under multiple pollution types is a more workable solution to alleviate environmental pollution.

16.
Sensors (Basel) ; 23(9)2023 Apr 22.
Article in English | MEDLINE | ID: mdl-37177385

ABSTRACT

Sustainable management is a challenging task for large building infrastructures due to the uncertainties associated with daily events as well as the vast yet isolated functionalities. To improve the situation, a sustainable digital twin (DT) model of operation and maintenance for building infrastructures, termed SDTOM-BI, is proposed in this paper. The proposed approach is able to identify critical factors during the in-service phase and achieve sustainable operation and maintenance for building infrastructures: (1) by expanding the traditional 'factor-energy consumption' to three parts of 'factor-event-energy consumption', which enables the model to backtrack the energy consumption-related factors based on the relevance of the impact of random events; (2) by combining with the Bayesian network (BN) and random forest (RF) in order to make the correlation between factors and results more clear and forecasts more accurate. Finally, the application is illustrated and verified by the application in a real-world gymnasium.

17.
J Hazard Mater ; 456: 131655, 2023 Aug 15.
Article in English | MEDLINE | ID: mdl-37216807

ABSTRACT

Nitrate is formed through the chemical production of gas-phase nitric acid and subsequent partitioning to the aerosol phase during the daytime. Many studies in the past separated these two aspects, even though they occur simultaneously in the atmosphere. To better understand the nitrate formation mechanism and effectively mitigate its production, it is necessary to consider the synergy between these two mechanisms. For this, we analyze hourly-speciated ambient observations data, with EK&TMA (Empirical Kinetic & Thermodynamic Modeling Approach) map to comprehensively explore the factors controlling nitrate production. Results show that precursor NO2 concentration and aerosol pH, which are related to anthropogenic activities, are the two major factors for chemical kinetics production and gas/particle thermodynamic partitioning processes respectively. Abundant NO2 and weakly acidic environments are favorable conditions for daytime particulate nitrate pollution, thus collaborative control of coal source, vehicle source, and dust source is needed to alleviate nitrate pollution.

18.
Sci Total Environ ; 879: 163198, 2023 Jun 25.
Article in English | MEDLINE | ID: mdl-37004775

ABSTRACT

The source apportionment of particulate matter plays an important role in solving the atmospheric particulate pollution. Positive matrix factorization (PMF) is a widely used source apportionment model. At present, high resolution online datasets are increasingly rich, but acquiring accurate and timely source apportionment results is still challenging. Integrating prior knowledge into modelling process is an effective solution and can yield reliable results. This study proposed an improved source apportionment method for the regularization supervised PMF model (RSPMF). This method leveraged actual source profile to guide factor profile for rapidly and automatically identifying source categories and quantifying source contributions. The results showed that the factor profile from RSPMF could be interpreted as seven factors and approach to actual source profile. Average source contributions were also an agreement between RSPMF and EPAPMF, including secondary nitrate (26 %, 27 %), secondary sulfate (23 %, 24 %), coal combustion (18 %, 18 %), vehicle exhaust (15 %, 15 %), biomass burning (10 %, 9 %), dust (5 %, 4 %), industrial emission (3 %, 3 %). The solutions of RSPMF also exhibited good generalizability during different episodes. This study reveals the superiority of supervised model, this model embeds prior knowledge into modelling process to guide model for obtaining more reliable results.

19.
Environ Pollut ; 325: 121344, 2023 May 15.
Article in English | MEDLINE | ID: mdl-36878277

ABSTRACT

A long-term (2013-2019) PM2.5 speciation dataset measured in Tianjin, the largest industrial city in northern China, was analyzed with dispersion normalized positive matrix factorization (DN-PMF). The trends of source apportioned PM2.5 were used to assess the effectiveness of source-specific control policies and measures in support of the two China's Clean Air Actions implemented nationwide in 2013-2017 and 2018-2020, respectively. Eight sources were resolved from the DN-PMF analysis: coal combustion (CC), biomass burning (BB), vehicular emissions, dust, steelmaking and galvanizing emissions, a mixed sulfate-rich factor and secondary nitrate. After adjustment for meteorological fluctuations, a substantial improvement in PM2.5 air quality was observed in Tianjin with decreases in PM2.5 at an annual rate of 6.6%/y. PM2.5 from CC decreased by 4.1%/y. The reductions in SO2 concentration, PM2.5 contributed by CC, and sulfate demonstrated the improved control of CC-related emissions and fuel quality. Policies aimed at eliminating winter-heating pollution have had substantial success as shown by reduced heating-related SO2, CC, and sulfate from 2013 to 2019. The two industrial source types showed sharp drops after the 2013 mandated controls went into effect to phaseout outdated iron/steel production and enforce tighter emission standards for these industries. BB reduced significantly by 2016 and remained low due to the no open field burning policy. Vehicular emissions and road/soil dust declined over the Action's first phase followed by positive upward trends, showing that further emission controls are needed. Nitrate concentrations remained constant although NOX emissions dropped significantly. The lack of a decrease in nitrate may result from increased ammonia emissions from enhanced vehicular NOX controls. The port and shipping emissions were evident implying their impacts on coastal air quality. These results affirm the effectiveness of the Clean Air Actions in reducing primary anthropogenic emissions. However, further emission reductions are needed to meet global health-based air quality standards.


Subject(s)
Air Pollutants , Air Pollution , Air Pollutants/analysis , Vehicle Emissions/analysis , Particulate Matter/analysis , Nitrates , Environmental Monitoring , Air Pollution/analysis , Dust/analysis , China , Coal/analysis , Seasons
20.
Environ Int ; 172: 107786, 2023 02.
Article in English | MEDLINE | ID: mdl-36738582

ABSTRACT

Ground-level ozone (O3) pollution has received widespread attention because its rising trend and adverse ecological impacts. However, the extremely strong photochemical reactions of its precursor volatile organic compounds (VOCs) increase the difficulty of reducing VOCs emissions to alleviate O3. Here, we carried out a one-year comprehensive observation in two representative cities, Tianjin (TJ, Northern China) and Guangzhou (GZ, Southern China). By revealing the concentration characteristics of three different types of VOCs, i.e., initial VOCs without photochemical reaction (In-VOCs), consumed VOCs (C-VOCs), and measured VOCs after the reaction (M-VOCs), we elucidated the important role of C-VOCs in the formation of O3. Although the overall trends were similar in both cities, the average concentration level of VOCs in GZ was 8.2 ppbv higher than that in TJ, and the photochemical loss of VOCs was greater by 2.2 ppbv. In addition, various drivers affecting O3 generation from C-VOCs were specifically explored, and it was found that most alkenes of TJ were key substances for rapid O3 formation compared to aromatics of GZ. Meanwhile, favorable meteorological conditions such as high temperature (T > 31 °C in TJ, and T > 33 °C in GZ), low relative humidity (56% in TJ and 45% in GZ), and stable atmospheric environment (proper pressure and gentle wind speed) also contribute to the generation of O3. More importantly, we combined chemical kinetics and receptor model to quantify the three-type VOCs source contributions and assess the potential impact of C-VOCs sources on O3 production, thus proposing environmental abatement technologies corresponding to the three types of VOCs. The differences in the comparison results of the three-type VOCs highlight the need to reduce O3 pollution from C-VOCs sources, which provides insights for future clean air policies development.


Subject(s)
Air Pollutants , Ozone , Volatile Organic Compounds , Air Pollutants/analysis , Volatile Organic Compounds/analysis , Environmental Monitoring/methods , China , Ozone/analysis
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