Identification of the sources of polycyclic aromatic hydrocarbons based on molecular and isotopic characterization from the Yangtze estuarine and nearby coastal areas

推迟的微粒事(SPM ) 的样品，表面沉积和道路灰尘从 Yangtze 被收集河口和附近沿海的区域，沿海的河，和中央上海。样品为 16 多不的芳香的烃的存在被分析(哼) 在由 GCMS 的 USEPA 控制优先级的表。个人的混合物特定的稳定的碳同位素哼被 GC-C-IRMS 也分析。来源在 Yangtze 河口和附近沿海的区域在 SPM 和表面沉积哼然后用多重来源鉴定技术被识别综合分子的质量与器官的混合物特定的稳定的同位素索引。结果表明 3 戒指和 4 戒指哼混合物在 SPM 和表面沉积是主导的，它类似于从 Wusong 污水分泌物插头， Shidongkou 污水处理植物， Huangpu 河，沿海的河和中央上海在样品发现的 PAH 混合物。主要部件分析(PCA ) 与显示的分子的集体索引综合那汽油，柴油机，煤和木头燃烧和导出石油的残余是主要来源在 Yangtze 河口哼。使用哼混合物特定的稳定的同位素也启用了 PAHs 输入小径的鉴定。哼源于木头和煤燃烧，导出石油的残余在沿海的河边是进 Yangtze 河口和附近沿海的区域的输入，污水分泌物插头在洪水季节期间在旱季和城市的暴风雨期间浇流量。哼源于首先从城市的交通的线和商业区域在道路灰尘积累然后在洪水季节期间在旱季和暴风雨水流量经由向西北占优势的风进入了沿海的区域的车辆排出物。

Particulate Amines in the Background Atmosphere of the Yangtze River Delta,China:Concentration,Size Distribution,and Sources

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.

Effect of cOVID-19 lockdown on the characterization and mixing state of carbonaceous particles in the urban atmosphere of Liaocheng, the North China Plain

To investigate the effect of covID-19 control measures on aerosol chemistry,the chemical compositions,mixing states,and formation mechanisms of carbonaceous particles in the urban atmosphere of Liao-cheng in the North China Plain(NCP)were compared before and during the pandemic using a single particle aerosol mass spectrometry(SPAMS).The results showed that the concentrations of five air pollutants including PM2.5,PM1o,SO2,NO2,and cO decreased by 41.2%-71.5%during the pandemic compared to those before the pandemic,whereas O3 increased by 1.3 times during the pandemic because of the depressed titration of O3 and more favorable meteorological conditions.The count and percentage contribution of carbonaceous particles in the total detected particles were lower during the pandemic than those before the pandemic.The carbonaceous particles were dominated by elemental and organic carbon(ECOC,35.9%),followed by elemental carbon-aged(EC-aged,19.6%)and organic carbon-fresh(OC-fresh,13.5%)before the pandemic,while EC-aged(25.3%),ECOC(17.9%),and secondary ions-rich(SEC,17.8%)became the predominant species during the pandemic.The carbonaceous particle sizes during the pandemic showed a broader distribution than that before the pandemic,due to the condensation and coagulation of carbonaceous particles in the aging processes.The relative aerosol acidity(Rra)was smaller before the pandemic than that during the pandemic,indicating the more acidic particle aerosol during the pandemic closely related to the secondary species and relative humidity(RH).More than 95.0%and 86.0%of carbonaceous particles in the whole period were internally mixed with nitrate and sulfate,implying that most of the carbonaceous particles were associated with secondary oxidation during their formation processes.The diurnal variations of oxalate particles and correlation analyses suggested that oxalate particles before the pandemic were derived from aqueous oxidation driven by RH and liquid water content(LwC),while oxalate particles during the pandemic were originated from O3-dominatedphotochemical oxidation.

Invasive Spartina alterniflora accelerates the increase in microbial nitrogen fixation over nitrogen removal in coastal wetlands of China

Salt marsh plants play a vital role in mediating nitrogen(N)biogeochemical cycle in estuarine and coastal ecosystems.However,the effects of invasive Spartina alterniflora on N fixation and removal,as well as how these two processes balance to determine the N budget,remain unclear.Here,simultaneous quantifications of N fixation and removal via^(15)N tracing experiment with native Phragmites australis,invasive S.alterniflora,and bare flats as well as corresponding functional gene abundance by qPCR were carried out to explore the response of N dynamics to S.alterniflora invasion.Our results showed that N fixation and removal rates ranged from 0.77±0.08 to 16.12±1.13 nmol/(g·h)and from 1.42±0.14 to 16.35±1.10 nmol/(g·h),respectively,and invasive S.alterniflora generally facilitated the two processes rates.Based on the difference between N removal and fixation rates,net N_(2)fluxes were estimated in the range of-0.39±0.14 to 8.24±2.23 nmol/(g·h).Estimated net N_(2)fluxes in S.alterniflora stands were lower than those in bare flats and P.australis stands,indicating that the increase in N removal caused by S.alterniflora invasion may be more than offset by N fixation process.Random forest analysis revealed that functional microorganisms were the most important factor associated with the corresponding N transformation process.Overall,our results highlight the importance of N fixation in evaluating N budget of estuarine and coastal wetlands,providing valuable insights into the ecological effect of S.alterniflora invasion.

Oxidative Potential of Metal-Containing Nanoparticles in Coal Fly Ash Generated from Coal-Fired Power Plants in China

The overwhelming magnitude of coal-fired power plants has caused an inevitable release of metal-containing nanoparticles(MNPs)into the atmosphere,which may be inhaled into the respiratory system and cause oxidative stress.In this study,MNPs and oxidative potential(OP)were analyzed in<1μm fractions of 56 coal fly ashes collected from Chinese CFPPs.The particle number concentrations(PNCs)of Fe-and Ti-containing NPs,as the dominant MNPs in CFAs,were in the range of 1.5×10^(9)to 9.4×10^(10)and 6.4×10^(8)to 4.1×10^(10)particles/mg,with average particle sizes of 87 and 89 nm,respectively.Average OP values of<1μm fractions were 1.4−2.2 nmol AA min^(−1)μg^(−1)for three simulated lung fluids,which were 2−3 orders of magnitude higher than those of urban atmospheric PM_(2.5).According to structural equation model analysis,metal concentrations in<1μm fractions,PNCs of Fe-/Ti-containing NPs,and their corresponding dissolved Fe/Ti(including NPs with minute sizes)can regulate OP of<1μm fractions in CFAs.Elevated PNCs of MNPs in CFAs can be produced by CFPPs burning low-rank coals and with a low combustion efficiency boiler(e.g.,circulating fluidized-bed boiler).Once entering lung fluids,they likely release more dissolved metals or tiny corresponding NPs,thus generating greater OP.This study provides the first comprehensive investigation of OP generated by MNPs in CFAs.

Separating the impacts of climate variability,land-use change and large reservoir operations on streamflow in the Yangtze River basin,China,using a hydrological modeling approach

Separating the individual effects of climate variability and human activities on streamflow is more important than just knowing their combined effects.In this paper,using a scenario-based hydrological simulation approach,the streamflow changes caused by climate variability and two different types of human activities(i.e.land-use change and large reservoirs operations)as well as the contribution rates of these three factors over 272 sub-basins in the Yangtze river basin were quantified and compared among 5 different periods(i.e.1988–1992(P1),1993–1997(P2),1998–2002(P3),2003–2007(P4)and 2008–2012(P5)).Results demonstrate that,at the annual scale,climate variability played a leading role in the change in outflow of most sub-basins.With regard to the seasonal variations in discharge at Datong station,climate factors played a predominant role during P1-P2 and P2-P3.Since the Three Gorges Reservoir began operating in 2003,the discharge was enhanced by reservoirs in January-May and reduced by reservoirs in JulyDecember.Reservoir and climate factors codetermined seasonal streamflow change during P3-P4 and P4-P5.Land-use change made the smallest contribution to seasonal discharge fluctuations.This study can support decision-making in regional water resources planning and management.

Clinical Effects of the COVID-19 Pandemic Among the Uninfected Pregnant Women—6 PLADs,China,2019−2020

Summary What is already known about this topic?The coronavirus disease 2019(COVID-19)pandemic potentially affected prenatal care quality and maternal and fetal outcomes globally.What is added by this report?During COVID-19 pandemic period,the rates of caesarean sections(CS)and preterm birth for uninfected pregnant women increased slightly in areas that were relatively severely impacted by the pandemic in China.

Chemical characteristics of haze particles in Xi＇an during Chinese Spring Festival： Impact of fireworks burning

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.

Seasonal variation and size distribution of biogenic secondary organic aerosols at urban and continental background sites of China

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.

Trends in particulate matter and its chemical compositions in China from 2013–2017

Accurate determination of the atmospheric particulate matter mass concentration and chemical composition is helpful in exploring the causes and sources of atmospheric enthalpy pollution and in evaluating the rationality of environmental air quality control strategies.Based on the sampling and chemical composition data of PM2.5 in different key regions of China in the CARE-China observation network,this research analyzes the environmental air quality data released by the China National Environmental Monitoring Centre during the studied period to determine the changes in the particulate matter mass concentration in key regions and the evolution of the corresponding chemical compositions during the implementation of the Action Plan for Prevention and Control of Air Pollution from 2013-2017.The results show the following.(1)The particulate matter mass concentration in China showed a significant downward trend;however,the PM2.5 annual mass concentration in 64%of cities exceeds the New Chinese Ambient Air Quality Standard(CAAQS)GradeⅡ(GB3095-2012).The region to the east of the Taihang Mountains,the Fenhe and Weihe River Plain and the Urumqi-Changji regions in Xinjiang,all have PM2.5 concentration loading that is still high,and heavy haze pollution occurred frequently in the autumn and winter.(2)During the heavy pollution in the autumn and winter,the concentrations of sulfate and organic components decreased significantly.The mean SO42-concentration in PM2.5 decreased by 76%,12%,81%and 38%in Beijing-Tianjin-Hebei(BTH),the Pearl River Delta(PRD),the Sichuan-Chongqing region(SC)and the Fenhe and Weihe River Plain,respectively.The mean organic matter(OM)concentration decreased by 70%,44%,48%and 31%,respectively,and the mean concentration of NH4+decreased by 68%,1.6%,38%and 25%,respectively.The mean elemental carbon(EC)concentration decreased by 84%and 20%in BTH and SC,respectively,and it increased by 61%and 11%in the PRD and Fenhe and Weihe River Plain,respectively.The mean concentration of mineral and unresolved chemical components(MI)dropped by 70%,24%and 13%in BTH,the PRD and the Fenhe and Weihe River Plain,respectively.The change in the PM2.5 chemical composition is consistent with the decrease of the PM2.5mass concentration.(3)In 2015,the mean OM concentration contributions to fine particles and coarse particles were 13-46%and 46-57%,respectively,and the mean MI concentration contributions to fine particles and coarse and particles were 31-60%and 39-73%,respectively;these values are lower than the 2013 values from the key regions,which is the most important factor behind the decrease of the particulate matter mass concentration.From 2013 to 2015,among the chemical components of different particle size fractions,the peak value of the coarse particle size fraction decreased significantly,and the fine particle size fractions of SO42-,NO3-,and NH4+decreased with the decrease of the particulate matter mass concentration in different particle size fractions.The fine-particle size peaks of SO42-,NO3-and NH4+shifted from 0.65-1.1μm to the finer size range of0.43-0.65μm during the same time frame.