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| 1 | Chemical characteristics of haze particles in Xi'an during Chinese Spring Festival: Impact of fireworks burning显示文摘Fireworks burning releases massive fine particles and gaseous pollutants, significantly deteriorating air quality during Chinese Lunar New Year(LNY) period. To investigate the impact of the fireworks burning on the atmospheric aerosol chemistry, 1-hr time resolution of PM_(2.5) samples in Xi'an during the winter of 2016 including the LNY were collected and detected for inorganic ions, acidity and liquid water content(LWC) of the fine aerosols. PM_(2.5) during the LNY was 167 ± 87 μg/m^3, two times higher than the China National Ambient Air Quality Standard(75 μg/m^3). K^+(28 wt.% of the total ion mass) was the most abundant ion in the LNY period, followed by SO_4^(2-)(25 wt.%) and Cl-(18 wt.%). In contrast, NO_3^-(34 wt.%) was the most abundant species in the haze periods(hourly PM32-2.5> 75 μg/m), followed by SO_4(29.2 wt.%) and NH_4^+(16.3 wt.%), while SO_4^(2-)(35 wt.%) was the most abundant species in the clean periods(hourly PM_(2.5)< 75 μg/m^3), followed by NO_3^-(23.1 wt.%) and NH_4^+(11 wt.%). Being different from the acidic nature in the non-LNY periods, aerosol in the LNY period presented an alkaline nature with a pH value of 7.8 ± 1.3. LWC during the LNY period showed a robust linear correlation with K_2SO_4 and KCl, suggesting that aerosol hygroscopicity was dominated by inorganic salts derived from fireworks burning. Analysis of correlations between the ratios of NO--3/SO_4^(2-) and NH_4^+/SO_4^(2-) indicated that heterogeneous reaction of HNO_3 with NH_3 was an important formation pathway of particulate nitrate and ammonium during the LNY period. | Can Wu Gehui Wang Jiayuan Wang Jianjun Li Yanqin Ren Lu Zhang Cong Cao Jin Li Shuagshuang Ge Yuning Xie Xinpei Wang Guoyan Xue | 2018 | Journal of Environmental Sciences2018，30，9： | 10 |
| 2 | Seasonal variation and size distribution of biogenic secondary organic aerosols at urban and continental background sites of China显示文摘Size-resolved biogenic secondary organic aerosols(BSOA) derived from isoprene and monoterpene photooxidation in Qinghai Lake, Tibetan Plateau(a continental background site) and five cities of China were measured using gas chromatography/mass spectrometry(GC/MS). Concentrations of the determined BSOA are higher in the cities than in the background and are also higher in summer than in winter. Moreover, strong positive correlations(R2= 0.44–0.90) between BSOA and sulfate were found at the six sites,suggesting that anthropogenic pollution(i.e., sulfate) could enhance SOA formation,because sulfate provides a surface favorable for acid-catalyzed formation of BSOA. Size distribution measurements showed that most of the determined SOA tracers are enriched in the fine mode(< 3.3 μm) except for cis-pinic and cis-pinonic acids, both presented a comparable mass in the fine and coarse(> 3.3 μm) modes, respectively. Mass ratio of oxidation products derived from isoprene to those from monoterpene in the five urban regions during summer are much less than those in Qinghai Lake region. In addition, in the five urban regions relative abundances of monoterpene oxidation products to SOA are much higher than those of isoprene. Such phenomena suggest that BSOA derived from monoterpenes are more abundant than those from isoprene in Chinese urban areas. | Yanqin Ren Gehui Wang Jianjun Li Can Wu Cong Cao Jiayuan Wang Lu Zhang Fan Meng Hong Li | 2018 | Journal of Environmental Sciences2018，30，9： | 4 |
| 3 | Ammonia in urban atmosphere can be substantially reduced by vehicle emission control:A case study in Shanghai, China显示文摘To investigate the impact of emission controls on ammonia(NH_(3)) pollution in urban atmosphere, observation on NH_(3)(1 hr interval) was performed in Shanghai before, during and after the 2019 China International Import Expo (CIIE) event, along with measurements on inorganic ions, organic tracers and stable nitrogen isotope compositions of ammonium in PM_(2.5). NH_(3)during the CIIE period was 6.5±1.0μg/m^(3), which is 41% and 32% lower than that before and after the event, respectively. Such a decrease was largely ascribed to the emission controls in nonagricultural sources, of which contribution for measured NH_(3)in control phase abated by ~20% compared to that during uncontrol period. Molecular compositions of PAHs and hopanes further suggested a dominant role of the reduced vehicle emissions in the urban NH_(3)abatement during the CIIE period. Our results revealed that vehicle exhaust emission control is an effective way to mitigate NH_(3)pollution and improve air quality in Chinese urban areas. | Can Wu Shaojun Lv Fanglin Wang Xiaodi Liu Jin Li Lang Liu Si Zhang Wei Du Shijie Liu Fan Zhang Jianjun Li Jingjing Meng Gehui Wang | 2023 | Journal of Environmental Sciences2023，，4： | 1 |
| 4 | Significant coal combustion contribution to water-soluble brown carbon during winter in Xingtai, China: Optical properties and sources显示文摘To understand the characteristics of atmospheric brown carbon(BrC),daily PM2.5 samples in Xingtai,a small city in North China Plain(NCP),during the four seasons of 2018-2019,were collected and analyzed for optical properties and chemical compositions.The light absorption at 365 nm(abs λ=365 nm)displayed a strong seasonal variation with the highest value in winter(29.0±14.3 M/m),which was 3.2∼5.4-fold of that in other seasons.A strong correlation of abs λ=365 nm with benzo(b)fluoranthene(BbF)was only observed in winter,indicating that coal combustion was the major source for BrC in the season due to the enhanced domestic heating.The mass absorbing efficiency of BrC also exhibited a similar seasonal pattern,and was found to correlate linearly with the aerosol pH,suggesting a positive effect of aerosol acidity on the optical properties and formation of BrC in the city.Positive matrix factorization(PMF)analysis further showed that on a yearly basis the major source for BrC was biomass burning,which accounted for 34% of the total BrC,followed by secondary formation(26.7%),coal combustion(21.3%)and fugitive dust(18%).However,the contribution from coal combustionwas remarkably enhanced in winter,accounting for∼40%of the total.Our work revealed that more efforts of“shifting coal to clean energy”are necessary in rural areas and small cities in NCP in order to further mitigate PM2.5 pollution in China. | Dapeng Li Can Wu Si Zhang Yali Lei Shaojun Lv Wei Du Shijie Liu Fan Zhang Xiaodi Liu Lang Liu Jingjing Meng Yuesi Wang Jian Gao Gehui Wang | 2023 | Journal of Environmental Sciences2023，，2： | 1 |
| 5 | Mid-infrared optical frequency comb in the 2.7-4.0μm range via difference frequency generation from a compact laser system显示文摘We report on the generation of a mid-infrared(mid-IR)frequency comb with a maximum average output power of250 mW and tunability in the 2.7-4.0μm region.The approach is based on a single-stage difference frequency generation(DFG)starting from a compact Yb-doped fiber laser system.The repetition rate of the near-infrared(NIR)comb is locked at 75 MHz.The phase noise of the repetition rate in the offset-free mid-IR comb system is measured and analyzed.Except for the intrinsic of NIR comb,environmental noise at low frequency and quantum noise at high frequency from the amplifier chain and nonlinear spectral broadening are the main noise sources of broadening the linewidth of comb teeth,which limits the precision of mid-IR dual-comb spectroscopy. | Lian Zhou Yang Liu Gehui Xie Chenglin Gu Zejiang Deng Zhiwei Zhu Cheng Ouyang Zhong Zuo Daping Luo Bin Wu Kunfeng Chen Wenxue Li | 2020 | High Power Laser Science and Engineering2020，8，4： | 1 |
| 6 | Characteristics of Chemical Speciation in PM_(1)in Six Representative Regions in China显示文摘A better knowledge of aerosol properties is of great significance for elucidating the complex mechanisms behind frequently occurring haze pollution events.In this study,we examine the temporal and spatial variations in both PM_(1)and its major chemical constituents using three-year field measurements that were collected in six representative regions in China between 2012 and 2014.Our results show that both PM_(1)and its chemical compositions varied significantly in space and time,with high PM_(1)loadings mainly observed in the winter.By comparing chemical constituents between clean and polluted episodes,we find that the elevated PM_(1)mass concentration during pollution events should be largely attributable to significant increases in organic matter(OM)and inorganic aerosols like sulfate,nitrate,and ammonium(SNA),indicative of the critical role of primary emissions and secondary aerosols in elevating PM_(1)pollution levels.The ratios of PM_(1)/PM2.5 are found to be generally high in Shanghai and Guangzhou,while relatively low ratios are seen in Xi’an and Chengdu,indicating anthropogenic emissions were more likely to accumulate in forms of finer particles.With respect to the relative importance of chemical components and meteorological factors quantified via statistical modeling practices,we find that primary emissions and secondary aerosols were the two leading factors contributing to PM_(1)variations,though meteorological factors also played important roles in regulating the dispersion of atmospheric PM. | Kaixu BAI Can WU Jianjun LI Ke LI Jianping GUO Gehui WANG | 2021 | Advances in Atmospheric Sciences2021，38，7： | 1 |
| 7 | Differentiated emission control strategy based on comprehensive evaluation of multi-media pollution:Case of mercury emission control显示文摘In order to comprehensively evaluate the environmental impact of multi-media mercury pollution under differentiated emission control strategies in China,a literature review and case studies were carried out.Increased human exposure to methylmercury was assessed through the dietary intake of residents in areas surrounding a typical coal-fired power plant and a zinc(Zn)smelter,located either on acid soil with paddy growth in southern China,or on alkaline soil with wheat growth in northern China.Combined with knowledge on speciated mercury in flue gas and the fate of mercury in the wastewater or solid waste of the typical emitters applying different air pollution control devices,a simplified model was developed by estimating the incremental daily intake of methylmercury from both local and global pollution.Results indicated that air pollution control for coal-fired power plants and Zn smelters can greatly reduce health risks from mercury pollution,mainly through a reduction in global methylmercury exposure,but could unfortunately induce local methylmercury exposure by transferring more mercury from flue gas to wastewater or solid waste,then contaminating surrounding soil,and thus increasing dietary intake via crops.Therefore,tightening air emission control is conducive to reducing the comprehensive health risk,while the environmental equity between local and global pollution control should be fully considered.Rice in the south tends to have higher bioconcentration factors than wheat in the north,implying the great importance of strengthening local pollution control in the south,especially for Zn smelters with higher contribution to local pollution. | Dongwei Lv Qingru Wu Daiwei Ouyang Minneng Wen Gehui Zhang Shuxiao Wang Lei Duan | 2023 | Journal of Environmental Sciences2023，，1： | 0 |
| 8 | Inactivation and subsequent reactivation of Aspergillus species by the combination of UV and monochloramine: Comparisons with UV/chlorine显示文摘Ultraviolet(UV)/monochloramine(NHCl) as an advanced oxidation process was firstly applied for Aspergillus spores inactivation. This study aims to: i) clarify the inactivation and photoreactivation characteristics of UV/NHCl process, ii) compared with UV/Clin inactivation efficiency, photoreactivation and energy consumption. The results illustrated that UV/NHCl showed better inactivation efficiency than that of UV alone and UV/Cl, and could effectively control the photoreactivation. For instance, the inactivation rates for Aspergillus flavus, Aspergillus niger and Aspergillus fumigatus in the processes of UV/NHCl(2.0 mg/L) was 0.034, 0.030 and 0.061 cm^(2)/m J), respectively, which were higher than that of UV alone(0.027, 0.026 and 0.024 cm^(2)/m J) and UV/Cl(0.023, 0.026 and 0.031 cm^(2)/m J). However, there was no synergistic effect for Aspergillus flavus and Aspergillus fumigatus. As for Aspergillus niger, the best synergistic effect can reach 1.86-log 10. This may be due to their different resistance to disinfectants, which were related to the size, an outer layer of rodlets(hydrophobins) and pigments. After UV/NHCl inactivation, the degree of cell membrane damage and intracellular reactive oxygen species were higher than that of UV alone. UV/NHCl had the advantages of high inactivation efficiency and inhibition of photoreactivation, which provides a new entry point for the disinfection of waterborne fungi. | Gehui Wu Hui Zhao Qiqi Wan Xiangqian Xu Ruihua Cao Kai Li Jingyi Wang Tinglin Huang Jinsuo Lu Gang Wen | 2022 | Journal of Environmental Sciences2022，34，7： | 0 |
| 9 | Particulate Amines in the Background Atmosphere of the Yangtze River Delta,China:Concentration,Size Distribution,and Sources显示文摘Amines are important for new particle formation and subsequent growth in the atmosphere.Consequently,the processes involved are receiving more attention in recent years.Here,we conduct a field observation in order to investigate the atmospheric particulate amines at a background site in the Yangtze River Delta(YRD)during the summer of 2018.Four amines in PM_(2.5),i.e.,methylamine(MA),dimethylamine(DMA),diethylamine(DEA),and trimethylamine(TMA),were collected,twice daily and analyzed.During the campaign,our measurements found the concentrations of MA,DMA,DEA,and TMA of 15.0±15.0,6.3±6.9,20.4±30.1,and 4.0±5.9 ng m^-(3),respectively,and the four amines correlated well with each other.The concentration of amines appear to be independent of whether they were collected during the day or night.Both MA and DMA exhibited a bimodal size distribution that had peaks at 0.67 and 1.1μm,suggesting amines preferably distribute on submicron particles.Boundary layer height(BLH),relative humidity,and pH of aerosols were found have a negative relationship with amines,while aerosol liquid water content(ALWC)was found to have a positive relationship with amines.The PMF(positive matrix factorization)source apportionment results showed that the main source of amines in Chongming Island was of anthropogenic origin such as industrial and biomass emission,followed by marine sources including sea salt and marine biogenic sources.Given that the YRD region is still suffering from complex atmospheric pollution and that the knowledge on aerosol amines is still limited,more field studies are in urgent need for a better understanding of the pollution characteristics of amines. | Wei DU Xinpei WANG Fengqin YANG Kaixu BAI Can WU Shijie LIU Fanglin WANG Shaojun LV Yubao CHEN Jinze WANG Wenliang LIU Lujun WANG Xiaoyong CHEN Gehui WANG | 2021 | Advances in Atmospheric Sciences2021，38，7： | 0 |
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