Accurate Ozone concentration datasets are essential for comprehensively understanding air quality, climate change, and the health and societal impacts related to Ozone exposure. Currently, there is limited research comparing near-surface Ozone concentration products. In this study, we employed continuous evaluation metrics (R-2, RMSE, RB) and classified statistical indicators (POD, FAR, CSI) to comprehensively compare and assess three near-surface Ozone concentration products (CHAP O-3, LGAP O-3, TAP O-3) in China from 2015 to 2020. Our findings indicate that CHAP outperforms other products in estimating near-surface Ozone concentration and monitoring Ozone pollution in China. In terms of temporal scale, the three Ozone products exhibited a strong correlation in specific regions across multiple time scales (R-2 > 0.6). The RMSE values of the products were lower in CHAP, followed by TAP, and higher in LGAP. Notably, LGAP significantly underestimated Ozone concentrations over time. Regarding spatial scale, CHAP and TAP align closely with ground observations, whereas LGAP shows significant underestimation in latitude and longitude, with the discrepancy increasing gradually along the longitude. All three products exhibited strong correlations with measured data at various sites (R-2 > 0.6). The RMSE and | RB| distributions of CHAP and TAP were similar and superior to LGAP. CHAP and TAP perform better than LGAP under specific land cover types, especially in urban and vegetation-covered areas, while their performance is relatively poorer in farmland- covered areas. Concerning pollution events, CHAP and TAP exhibit strong detection capabilities for Ozone pollution events in the Beijing-Tianjin-Hebei (BTH) region and other majority areas, with POD values exceeding 0.6, and FAR values below 0.1, showcasing excellent CSI performance. In contrast, LGAP has weaker detection capabilities, with POD values primarily in the 0-0.2 range and lower CSI values. This comprehensive evaluation sheds light on the strengths and weaknesses of different near-surface Ozone concentration products and their implications for assessing Ozone pollution in China.

The oxidative potential (OP) of particulate matter (PM) is crucial for understanding its ability to generate reactive oxygen species. However, the major chemical drivers influencing OP still need to be better understood. This study investigated the seasonal variations of OP and identified key drivers and source mechanisms in the industrial city of Zibo, located in North China Plain. We used the XGBoost model and Positive Matrix Factorization (PMF) to identify key drivers and source mechanisms. In 2022, PM2.5 samples were collected from an urban site in Zibo, and major chemical components were analyzed. OP was quantified using the dithiothreitol (DTT) method. The results revealed that the annual average DTTv in Zibo City for 2022 was 1.1 nmol/min/m3, with the highest DTTv levels observed in autumn, followed by spring, summer, and winter. Using the XGBoost model, we identified that metal elements such as Pb, Ba, and Cu, along with water-soluble ions NO3- and SO42-, significantly contributed to DTTv. Source apportionment analysis via PMF identified five major sources of PM2.5. Throughout the study period, secondary particles were the predominant contributors to PM2.5 (49 %), while coal combustion had the lowest contribution (7 %). To further elucidate the sources of OP in PM2.5, we integrated the measured OP with source contributions derived from PMF. The findings indicated that secondary particles and industrial sources contributed the most to DTTv, accounting for 40 % and 21 %, respectively. The OP sources exhibited seasonal variations: secondary particles were the primary contributors in winter, while dust sources dominated in spring. In summer, vehicle emissions increased substantially, and industrial emissions became the major source in autumn. This study highlighted the critical drivers and source mechanisms of OP in industrial cities and would be beneficial for future air quality control and risk reduction.

The unique geographical features of Hainan Island result in spatial and temporal differences in atmospheric Aerosol Optical Depth (AOD) that not only exhibit oceanic characteristics but are also significantly influenced by land sources. As for the above characteristics of the study area, MOD04_3K AOD data from 2015 to 2021 were selected, and linear trend analysis was utilized to explore and analyze the overall spatial distribution pattern and trend of the atmospheric environment in Hainan Island. The AQI data of PM2.5, PM10, O3, NO2, SO2, and CO, provided by ground air quality monitoring stations, were used to probe the spatial and temporal distribution characteristics of the near-surface atmospheric environment. A correlation analysis method and the Apriori algorithm were used to study the correlation between AOD and AQIs. The key findings are as follows: (1) The overall atmospheric environment in Hainan Island showed a decreasing trend from 2015 to 2021; (2) The period of relatively high AOD in Hainan Island occurred during the peak tourist season from November to April of the following year; (3) The AQI values of PM2.5, PM10, NO2, and SO2 demonstrated a decreasing trend, while the AQI value of O3 showed the opposite trend in some local areas; (4) The correlation values between AOD and PM2.5, PM10, and NO2 were higher than those between AOD and SO2, O3, and there was no significant correlation between AOD and CO; (5) The mining results of association rule displayed that the association between AOD and AQI index was closest in Wuzhishan area, followed by Sanya area, and the association between AOD and AQI index was lowest in Wuzhishan area. The results provide credible scientific data and theoretical support for atmospheric pollution monitoring and joint prevention and control in the region.

Culture is both national and universal. The excellent traditional Chinese culture has nourished the Chinese nation and provided Chinese wisdom for constructing "a community with a shared future for mankind." This article analyzes the significance of inheriting and innovating China's outstanding traditional culture. Culture serves as the "root" and "soul" of the Chinese nation and should be rejuvenated in the new era. The article also explores the current challenges in cultural communication and the need to find new ideas to help traditional culture break free from its current constraints. It is essential to develop traditional culture by selecting the best elements and discarding outdated aspects. Applying ideas such as polyphonic communication, technology empowerment, equality, and mutual understanding to the communication system can further enhance the reach of excellent traditional Chinese culture. China's discourse power and global standing can be elevated by using Chinese narratives effectively. This will contribute to a stronger voice for China and its rich cultural heritage on the world stage.

The heavy metals in atmospheric fine particles are of great concern to human health. To understand the pollution characteristics and health risks of heavy metals in particulate matter with an aerodynamic equivalent diameter ≤2.5 μm (PM2.5) during winter in the suburb of Cangzhou, PM2.5 samples were collected with an intelligent medium-flow atmospheric particulate matter sampler from January to February 2019. The Fe, Cu, Mn, Pb and Zn contents in PM2.5 were determined via inductively coupled plasma optical emission spectrometry (ICP-OES). The sources and health risks of heavy metals in PM2.5 were analysed via the enrichment factor (EF) method and the United States Environmental Protection Agency (US EPA) health risk assessment model. The results showed that the average PM2.5 concentration in the suburb of Cangzhou reached 71.6 μg/m3, ranging from 23.7 to 169.5 μg/m3. The exceeding standard rate was 29.4% during the sampling period. The PM2.5 concentration during the nighttime was higher than that during the daytime. The heavy metal concentrations in PM2.5 decreased in the order of Fe > Mn > Zn > Cu > Pb, and the Fe, Mn, Pb and Zn concentrations decreased in the order of clean days the daytime. EF analysis revealed that Zn, Pb and Cu were significantly enriched, and Pb was highly enriched on heavy pollution days with increasing pollution degree. The enrichment level of heavy metals during the nighttime was higher than that during the daytime. Health risk assessment demonstrated that Mn posed non-carcinogenic risks to both adults and children, following the sequence of clean days . The study revealed that the pollution levels of heavy metals in PM2.5 in the suburb of Cangzhou were low, and Pb and Mn in PM2.5 posed certain health risks to the population.

Zibo, a highly industrialized cluster city in the central area of the North China Plain (NCP), has suffered from serious ozone pollution in recent years. In this study, a comprehensive field campaign was conducted during July 2019 at three representative and diversified areas in Zibo, including two suburban sites (Tianzhen (TZ) and Xindian (XD)) and one urban site (Beijiao (BJ)). The O3 variation patterns were overall similar among the three sites, while its precursors (i.e. volatile organic compounds (VOCs) and nitrogen oxides (NOx)) showed distinct site-to-site differences. A 0-D box model incorporating the latest Master Chemical Mechanism (MCMv3.3.1) was applied using observations as constraints, and NOx-limited, VOC-limited and transitional regimes were generally identified for TZ, BJ and XD respectively, particularly during high-O3 episodes. We believe that such large variability of O3-precursor relationship found in Zibo may exist widely in many other cities, which challenges the current O3 pollution control. It was further concluded that both high in-situ O3 production rate (daytime peak 21-27 ppbv h-1) and O3 transported from residual layer are responsible for the high ground-level O3. Detailed mechanism modelling with many scenarios suggested that a synergic reduction plan for NOx and VOC would be the most feasible and effective option to achieve O3-attainment levels. It is suggested that the minimum reduction in NOx should be by more than 40% (TZ), 60% (BJ) and 20% (XD), while anthropogenic VOC should simultaneously be cut more than 60% (TZ), 40% (BJ) and 60% (XD). Our fundamental chemical mechanism modelling provided an improved understanding of O3-precursor relationship, and the derived policy-relevant guidance can assist the local government like Zibo to deal with O3 challenge. These results could also provide insights for regional O3 control across the North China Plain.

To develop effective mitigation policies, a comprehensive understanding of the evolution of the chemical composition, formation mechanisms, and the contribution of sources at different pollution levels is required. PM2.5 samples were collected for 1 year from August 2016 to August 2017 at an urban site in Zibo, then chemical compositions were analyzed. Secondary inorganic aerosols (SNA), anthropogenic minerals (MIN), and organic matter (OM) were the most abundant components of PM2.5, but only the mass fraction of SNA increased as the pollution evolved, implying that PM2.5 pollution was caused by the formation of secondary aerosols, especially nitrate. A more intense secondary transformation was found in the heating season (from November 15, 2016, to March 14, 2017), and a faster secondary conversion of nitrate than sulfate was discovered as the pollution level increased. The formation of sulfate was dominated by heterogeneous reactions. High relative humidity (RH) in polluted periods accelerated the formation of sulfate, and high temperature in the non-heating season also promoted the formation of sulfate. Zibo city was under ammonium-rich conditions during polluted periods in both seasons; therefore, nitrate was mainly formed through homogeneous reactions. The liquid water content increased significantly as the pollution levels increased when the RH was above 80%, indicating that the hygroscopic growth of aerosol aggravated the PM2.5 pollution. Source apportionment showed that PM2.5 was mainly from secondary aerosol formation, road dust, coal combustion, and vehicle emissions, contributing 36.6%, 16.5%, 14.7%, and 13.1% of PM2.5 mass, respectively. The contribution of secondary aerosol formation increased remarkably with the deterioration of air quality, especially in the heating season.

As one of the biggest cities in North China, Jinan has been suffering heavy air pollution in recent decades. To better characterize the ambient particulate matter in Jinan during heavy pollution periods, we collected daily PM2.5 (particulate matter with aerodynamic diameters equal to or less than 2.5 μm) filter samples from 15 October 2017 to 31 January 2018 and analyzed their chemical compositions (including inorganic water-soluble ions (WSIs), carbonaceous species, and inorganic elements). The daily average concentration of PM2.5 was 83.5 μg/m3 during the sampling period. A meteorological analysis revealed that both low wind speed and high relative humidity facilitated the occurrence of high PM2.5 pollution episodes. A chemical analysis indicated that high concentrations of water-soluble ions, carbonaceous species, and elements were observed during heavy pollution days. The major constituents of PM2.5 in Jinan were secondary aerosol particles and organic matter based on the results of mass closure. Chemical Mass Balance (CMB) was used to track possible sources and identified that nitrate, sulfate, vehicle exhaust and coal fly ash were the main contributors to PM2.5 during heavy pollution days in Jinan, accounting for 25.4%, 18.6%, 18.2%, and 13.3%, respectively.

Air pollution is an increasing threat to human health in China. In this study, daily PM10 and PM2.5 samples were collected simultaneously at the Jinan Environmental Monitoring Station (EMS)in Jinan, China from 15 November 2016 to 15 March 2017. The aim of this work was to improve the understanding of the characteristics and sources of air particles and determine different levels of PM2.5 pollution and its constituent elements, water-soluble ions and carbonaceous species. Nitrate (NO3−), organic materials (OM) and sulfate (SO42−) were identified as the three main components of PM2.5 pollution. With increasing pollution level, the contributions of SO42−, NO3− and NH4+ increased at greater rates, unlike that of OM. The proportion of SO42− exceeded that of NO3− and became predominant in severe PM2.5 pollution (SP; 250 μg m−3 ≤ PM2.5 ≤ 500 μg m−3). This work demonstrates that SO42− has a dominant role in SP level and, consequently, requires greater research attention. It is demonstrated that relative humidity (RH) enhances the rate of sulfate formation more than that of nitrate. Therefore, under the current Chinese emergency response measures, it is necessary to further reduce emissions of SO2 and NO2. Four clusters of backward trajectories identified dominant pollution vectors originating from highly industrialized areas that exacerbate the poor air quality in Jinan. It is, therefore, necessary to undertake regional control measures to reduce pollutant emissions.

An aerosol electrometer with enhanced detection limit was developed for measuring the collected particles electrical current ranging from −50 pA to 50 pA with no range switching necessary. The detection limit was enhanced by suppressing the electric current measurement noise and improving the detection efficiency. A theoretical model for the aerosol electrometer has been established to investigate the noise effect factors and verified experimentally. The model showed that the noise was a function of ambient temperature, and it was affected by the characteristics of feedback resistor and operational amplifier simultaneously. The Faraday cup structure of the aerosol electrometer was optimized by adopting a newly designed cup-shaped metal filter which increased the surface area of the cup; thus the particle interception efficiency was improved. The aerosol electrometer performance-linearity, noise and the particle detection efficiency, were evaluated experimentally. When compared with TSI-3068B, a 99.4% ( R 2 ) statistical correlation was achieved. The results also showed that the root mean square noise and the peak-to-peak noise were 0.31 fA and 1.55 fA, respectively. The particle detection efficiency was greater than 99.3% when measuring particle diameter larger than 7.0 nm.

为研究济南市冬季大气重污染过程的颗粒物化学组分特征,于2017年11月15日-12月30日在市监测站及跑马岭清洁对照点同步采集PM10和PM2.5,并对其质量浓度、水溶性离子及碳组分进行分析,结果表明重污染过程中PM2.5/PM10质量浓度比均超过0.6.NO3-(硝酸盐)、SO42-(硫酸盐)、NH4+(铵盐)、OC(有机碳)浓度及百分占比与颗粒物浓度同步增加,其中NO3-、SO42-、NH4+、OC的浓度增加倍数远大于PM2.5的浓度增加,重污染日市监测站NO3-、SO42-、NH4+、OC质量浓度分别是非污染日的5.1倍、8.8倍、8.3倍、7.0倍,跑马岭重污染日NO3-、SO42-、NH4+、OC质量浓度分别是非污染日的3.0倍、3.9倍、3.7倍、4.6倍;且SO42-和NH4+质量百分占比涨幅比NO3-的大,说明重污染天气下SO42-和NH4+对PM2.5浓度增加的贡献更大.通过经验公式计算得出市监测站和跑马岭SOC质量浓度分别占OC的82.4％和92.3％,说明重污染期间SOC是OC主要组成部分.二次无机离子和二次有机碳是导致重污染的主因,表明在冬季重污染过程中,大气化学反应非常重要,这可能与空气静稳和湿度较大的气象条件、前体物的大量积累、液相非均相化学过程的加强紧密相关.重污染天气下需要重视NO2对SO2液相催化氧化作用,严格控制NO2的排放.

Flonicamid, a novel selective systemic pesticide, can effectively control a broad range of insect pests. However, the dissipation behaviors and the terminal residues of flonicamid and its metabolites in some crops and soils remain unclear. Herein, an easy, sensitive and reliable method using a modified QuEChERS extraction coupled with LC-MS/MS for the simultaneous analysis of flonicamid and its metabolites in cabbage and soil was developed. Based on this method, the dissipation behaviors of flonicamid and its metabolites as well as their persistence in cabbage and soil during harvest were investigated. Flonicamid degraded rapidly, and the half-lives of flonicamid only and total residues (the sum of flonicamid and its metabolites) were 1.49-4.59 and 1.97-4.99 days in cabbage, and 2.12-7.97 and 2.04-7.62 days in soil, respectively. When 50% flonicamid WG was sprayed once or twice at the recommended dose and 1.5-fold the recommended dose, the highest residues of total flonicamid in cabbage and soil from different pre-harvest intervals (3, 7 and 14 days) were 0.070 and 0.054 mg kg(-1), respectively. The risk quotient (RQ) of flonicamid based on the consumption data from China was below 16.84%, indicating that the use of flonicamid is non-hazardous to humans. These results could not only guide the safe and responsible use of flonicamid in agriculture but also help the Chinese government establish the maximum residue level (MRL) for flonicamid in cabbage.

Author(s): Wang, Jian | Advisor(s): King, Jennifer Y | Abstract: Wetland carbon sequestration is offset by carbon dioxide (CO2) and methane (CH4) emissions for which the magnitudes remain coarsely constrained. To better understand the spatial and temporal variations of gaseous carbon fluxes from marsh soils in a Mediterranean climate, I collected air and soil samples over the course of 10 months at Carpinteria Salt Marsh Reserve (CSMR) located in the County of Santa Barbara, California. The CSMR consists of four zones characterized by differences in elevation, tidal regime, soil properties, and vegetation. Twelve static chambers were deployed among two lower marsh zones, a mudflat, and a marsh-upland transition zone for fortnightly flux measurements from September 2015 to May 2016. In August 2015 and June 2016, soil cores up to 50 cm deep were extracted near the chambers, segmented by depth, and analyzed for soil moisture, bulk density, particle size distribution, electrical conductivity, pH, organic/inorganic carbon, and total nitrogen content. Averaged over the 9-month study period, the marsh-upland transition zone had the highest CO2 fluxes at 5.3 ± 0.7 g CO2 m-2 d-1, followed closely by the lower marsh zones (3.8 ± 0.6 g CO2 m-2 d-1 and 2.8 ± 0.7 g CO2 m-2 d-1), which were one order of magnitude higher than the CO2 fluxes from the mudflat (0.4 ± 0.1 g CO2 m-2 d-1). The CO2 fluxes varied significantly on a seasonal scale but were not consistently correlated with environmental variables measured. The CH4 fluxes had no clear seasonal patterns, but overall CH4 flux rates from the lower marsh zones (2.2 ± 1.5 mg CH4 m-2 d-1 and 1.9 ± 0.2 mg CH4 m-2 d-1) surpassed those from the mudflat (0.2 ± 0.06 mg CH4 m-2 d-1) by an order of magnitude, and the marsh-upland transition zone was a net methane sink (-0.07 ± 0.1 mg CH4 m-2 d-1). The CH4 fluxes correlated well with most soil properties by zone. Our results show that soil gaseous carbon fluxes from a coastal salt marsh vary by salt marsh zone.

Current science and policy requirements have focused attention on the need to expand and improve particulate matter (PM) sampling methods. To explore how sampling filter type affects artifacts in PM composition measurements, size-resolved particulate SO42−, NO3− and NH4+ (SNA) were measured on quartz fiber filters (QFF), glass fiber filters (GFF) and cellulose membranes (CM) concurrently in an urban area of Beijing on both clean and hazy days. The results showed that SNA concentrations in most of the size fractions exhibited the following patterns on different filters: CM > QFF > GFF for NH4+; GFF > QFF > CM for SO42−; and GFF > CM > QFF for NO3−. The different patterns in coarse particles were mainly affected by filter acidity, and that in fine particles were mainly affected by hygroscopicity of the filters (especially in size fraction of 0.65–2.1 μm). Filter acidity and hygroscopicity also shifted the peaks of the annual mean size distributions of SNA on QFF from 0.43–0.65 μm on clean days to 0.65–1.1 μm on hazy days. However, this size shift was not as distinct for samples measured with CM and GFF. In addition, relative humidity (RH) and pollution levels are important factors that can enhance particulate size mode shifts of SNA on clean and hazy days. Consequently, the annual mean size distributions of SNA had maxima at 0.65–1.1 μm for QFF samples and 0.43–0.65 μm for GFF and CM samples. Compared with NH4+ and SO42−, NO3− is more sensitive to RH and pollution levels, accordingly, the annual mean size distribution of NO3− exhibited peak at 0.65–1.1 μm for CM samples instead of 0.43–0.65 μm. These methodological uncertainties should be considered when quantifying the concentrations and size distributions of SNA under different RH and haze conditions.

A luminol-H2O2-HRP chemiluminescence system with high relative luminescent intensity (RLU) and long stabilization time was investigated. First, the comparative study on the enhancement effect of ten compounds as enhancers to the luminol-H2O2-HRP chemiluminescence system was carried out, and the results showed that 4-(imidazol-1-yl)phenol (4-IMP), 4-iodophenol (4-IOP), 4-bromophenol (4-BOP) and 4-hydroxy-4'-iodobiphenyl (HIOP) had the best performance. Based on the experiment, the four enhancers were dissolved in acetone, acetonitrile, methanol, and dimethylformamide (DMF) with various concentrations, the results indicated that 4-IMP, 4-IOP, 4-BOP and HIOP dissolved in DMF with the concentrations of 0.2%, 3.2%, 1.6% and 3.2% could get the highest RLU values. Subsequently, the influences of pH, ionic strength, HRP, 4-IMP, 4-IOP, 4-BOP, HIOP, H2O2 and luminol on the stabilization of the luminol-H2O2-HRP chemiluminescence system were studied, and we found that pH value, ionic strength, 4-IMP, 4-IOP, 4-BOP, HIOP, H2O2 and luminol have little influence on luminescent stabilization, while HRP has a great influence. In different ranges of HRP concentration, different enhancers should be selected. When the concentration is within the range of 0~6 ng/mL, 4-IMP should be selected. When the concentration of HRP ranges from 6 to 25 ng/mL, 4-IOP was the best choice. And when the concentration is within the range of 25~80 ng/mL, HIOP should be selected as the enhancer. Finally, the three well-performing chemiluminescent enhanced solutions (CESs) have been further optimized according to the three enhancers (4-IMP, 4-IOP and HIOP) in their utilized HRP concentration ranges.

A simple analytical method was developed for the simultaneous analysis of 18 perfluorinated compounds (PFCs) in edible oil. The target compounds were extracted by acetonitrile, purified by gel permeation chromatography (GPC) and dispersive solid-phase extraction (DSPE) using graphitized carbon black (GCB) and octadecyl (C18), and analyzed by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ES-MS/MS) in negative ion mode. Recovery studies were performed at three fortification levels. The average recoveries of all target PFCs ranged from 60 to 129%, with an acceptable relative standard deviation (RSD) (1-20%, n = 3). The method detection limits (MDLs) ranged from 0.004 to 0.4 μg/kg, which was significantly improved compared with the existing liquid-liquid extraction and cleanup method. The method was successfully applied for the analysis of all target PFCs in edible oil samples collected from markets in Beijing, China, and the results revealed that C6-C10 perfluorocarboxylic acid (PFCAs) and C7 perfluorosulfonic acid PFSAs were the major PFCs detected in oil samples.

A highly sensitive chemiluminescent enzyme immunoassay (CLEIA) method was developed in this study for efficient screening of triazophos residues in a large number of samples. Based on the maximum residue limits (MRLs) set by China and CAC for triazophos in different agro-products, the representative apple, orange, cabbage, zucchini, and rice samples were selected as spiked samples, and the triazophos at the concentrations of the MRL values were spiked to blank samples. Subsequently, the five samples with the spiked triazophos standard were measured by CLEIA 100 times, and the detection results indicated that the correction factors of the apple, orange, cabbage, zucchini, and rice were determined as 0.79, 0.66, 0.85, 0.76, and 0.91, respectively. In this experiment, 1500 real samples were detected by both the CLEIA and the GC-MS methods. With the GC-MS method, 1462 samples were identified as negative samples and 38 samples as positive samples. Based on the correction factors, the false positive rate of the CLEIA method was 0.13%, and false negative rate was 0. The results showed that the established CLEIA method could be used to screen a large number of real samples.