利用浙江省气象局13个酸雨观测站观测的降水pH值和降水电导率数据,分析了2010-2021年浙江地区的酸雨污染变化趋势.结果显示,浙江省酸雨污染逐年减轻,降水pH值总体上在逐渐上升,酸雨发生频率在逐年下降,至2021年全省平均降水pH值达到近10 a的最高值5.29,酸雨发生频率降至40％.酸雨污染的季节变化特征表现为夏季较轻、冬季较重.对比浙江二氧化硫(SO2)、二氧化氮(NO2)排放量的年际变化趋势以及2020年疫情管控期间浙江的酸雨污染特征表明,污染物排放量的减少是缓解酸雨污染的重要因素.

二氧化碳(CO2)是引起全球变暖的最主要的温室气体(GHGs),直接观测大气CO2浓度对于研究人类活动和自然活动对大气温室气体的贡献至关重要,而在多个高度上观测大气CO2浓度则有助于明晰CO2浓度的时空变化规律,确定其影响机制.本文利用临安区域大气本底站2018-12-2020-11不同高度(距地面21m、53m)处的CO2在线观测数据,结合日变化及地面风的影响,对观测数据进行筛分,采用HYSPLIT后向轨迹模型和潜在源贡献因子法,初步探讨气象因素以及大气远距离传输对长江三角洲地区大气CO2浓度的影响.结果表明,临安站高低层大气CO2日变化呈夜间高于白天的特点;低层CO2浓度大于高层,冬季高低层浓度差小于其他三季;日较差呈夏季＞春季＞秋季＞冬季的特点;大气CO2本底季节变化由于受到风向和气团传输的影响呈现出冬季＞春季＞秋季＞夏季的特点;潜在源贡献分析得到浙江省东部的污染源是导致临安站CO2浓度高的重要来源.此外,新冠疫情期间的CO2浓度与往年同期相比有所下降,低层为5.86×10-6(摩尔比,下同),高层为5.67x10-6,新冠疫情使得长三角地区的电力、运输业以及水泥生产部门排放的CO2减少.减少浙江省北部和东部人为排放CO2是降低长三角地区CO2浓度的关健.

基于北京上甸子与浙江临安区域大气本底站2011-2019年氢氯氟碳化物(HCFCs)采样观测数据,开展了京津冀与长三角地区 6 种 HCFCs(HCFC-22、HCFC-141b、HCFC-142b、HCFC-124、HCFC-132b 和 HCFC-133a)本底特征研究.研究结果表明:临安站HCFCs浓度水平和浓度变率比上甸子站明显更高,尤其是HCFC-133a,其浓度及浓度变率均比上甸子站高1个量级,表明长三角地区HCFCs排放量可能较京津冀地区更大.2个站点HCFCs本底浓度基本一致,差异范围为-6.1％～7.1％.上甸子站本底数据占比为26.4％～69.0％,而临安站本底数据占比不足23％.在《关于消耗臭氧层物质的蒙特利尔议定书》的约束下,2个站点多数HCFCs年均浓度呈下降趋势或变化较小.2个站点HCFC-132b浓度相对较低,但2019年相比2018年有明显升高.结合风向进行分析,发现上甸子站HCFC-22、HCFC-141b、HCFC-142b和HCFC-132b高浓度水平主要由西南扇区(北京城区方向)的WSW、SSW及SW方向贡献,而HCFC-124和HCFC-133a在各风向上的浓度和载荷差异较小.临安站HCFC-124高浓度水平主要由SSE和NNE方向贡献,分别对应金华和湖州方向;其他5种HCFCs的高浓度水平主要由东北扇区的ENE方向贡献,对应杭州城区方向.

卤代烃类温室气体是全球增温潜势较高的温室气体,大气寿命长,多种物种被列入《蒙特利尔议定书》或《京都议定书》限制排放的物种中.长江三角洲地区经济发展较快,氟化工产业较为发达,是全国卤代烃类温室气体排放量较大的地区之一.采用卤代烃类温室气体采样器,在衢州国家基本气象站进行采样分析,获得了卤代烃类温室气体浓度数据,并与临安区域大气本底站进行对比,最后分析了其与气象要素的相关性.结果表明:(1)衢州第一代消耗臭氧层物质(ODS)的浓度相比临安站浓度偏低,第二代ODS、氢氟碳化物HFCs的浓度比临安站偏高,说明衢州及周边地区的第一代ODS排放控制得较好,但受第二代ODS,尤其是HFCs的影响仍然较大.(2)气象要素中的温度、相对湿度与卤代烃类温室气体的相关系数相对较高.相关系数最高的是二氟一氯甲烷HCFC-22,与温度、相对湿度的相关系数分别为0.87、-0.74,均通过了 0.05的显著性检验.

采用位于长三角地区的临安区域大气本底站罐采样获得的全氟温室气体(PFCs、SF6、NF3、SO2F2)浓度,分析2011～2020年该地区大气中全氟温室气体的浓度分布特征和变化趋势.结果显示,临安站绝大部分全氟温室气体的浓度均呈现逐年升高的变化趋势,至2020年长三角地区全氟温室气体本底浓度分别达到(86.30±0.52)×10-12(CF4)、(5.03±0.00)×10-12(C2F6)、(0.70±0.01)×10-12(C3F8)、(1.82±0.00)×10-12(c-C4F8)、(10.44±0.01)×10-12(SF6)、(2.36±0.04)×10-12(NF3)、(2.61±0.05)×10-12(SO2F2).长三角地区大部分全氟温室气体的本底浓度与全球本底值接近.通过对临安站全氟温室气体污染浓度的潜在源贡献作用(PSCF)和浓度权重轨迹(CWT)分析显示,临安站全氟化碳PFCs(CF4、C4F10、C2F6、C3F8、c-C4F8)的潜在源区主要包括山东、江苏?安徽?上海?浙江中北部和江西东北部地区,NF3?SF6?SO2F2的潜在源区则集中在江苏中南部?上海?浙北地区.

Hydrochlorofluorocarbons (HCFCs) are used as temporary substitutes for chlorofluorocarbons and other ozone depleting substances because they have reduced ozone depletion and global warming potentials. The consumption and production of HCFCs are regulated via the Montreal Protocol and its amendments till 2013, with a complete phase-out being scheduled by 2030 for Article 5 parties (developing countries). To better understand the characteristics and emissions of HCFCs in the Yangtze River Delta (YRD), which is the largest metropolitan area in China, weekly flask samples were collected at the Lin'an regional background station located in the YRD from 2011 to 2018 and measured for four HCFCs (HCFC-22, HCFC-141b, HCFC-142b, and HCFC-124). The HCFC-132b and HCFC-133a measurements began in 2018. The ambient mixing ratios of the HCFCs exhibited higher concentrations and larger variabilities than those at the Shangrila regional background station at similar latitudes in southwest China. The HCFC emissions in the YRD were estimated based on the tracer ratio method using CO and HFC-134a as tracers, and were comparable within the uncertainties. Our results are generally consistent with previous estimates obtained using top-down approaches. HCFC-22 and HCFC-141b contributed 52% +/- 23% and 41% +/- 24% of the total ODP-weighted (CFC-11-equivalent) HCFC emissions from the YRD, respectively, whereas HCFC-22 contributed the most (83% +/- 36%) to the total CO2-equivalent HCFC emissions from the YRD. The cumulative ODP-weighted and CO2-equivalent emissions of HCFCs from the YRD accounted for 25% +/- 15% and 20% +/- 11% of the national corresponding totals, respectively, for 2011-2017. The HCFC-141b emissions from the YRD contributed approximately half of the total Chinese emissions. HCFC-133a emissions in the YRD accounted for approximately one-fifth of the global total in 2018. Thus, the YRD is an important contributor of HCFC emissions on national and global scales.

The dynamics of atmospheric CO2 has received considerable attention in the literature, yet significant uncertainties remain within the estimates of contribution from the terrestrial flux and the influence of atmospheric mixing. In this study we apply the WRF-Chem model configured with the Vegetation Photosynthesis and Respiration Model (VPRM) option for biomass fluxes in China to characterize the dynamics of CO2 in the atmosphere. The online coupled WRF-Chem model is able to simulate biosphere processes (photosynthetic uptake and ecosystem respiration) and meteorology in one coordinate system. We apply WRF-Chem for a multi-year simulation (2016–2018) with integrated data from a satellite product, flask samplings, and tower measurements to diagnose the spatio-temporal variations of CO2 fluxes and concentrations in China. We find that the spatial distribution of CO2 was dominated by anthropogenic emissions, while its seasonality (with maxima in April 15 ppmv higher than minima in August) was dominated by the terrestrial flux and background CO2. Observations and simulations revealed a consistent increasing trend in column-averaged CO2 (XCO2) of 2.46 ppmv (0.6 % yr−1) resulting from anthropogenic emission growth and biosphere uptake. WRF-Chem successfully reproduced ground-based measurements of surface CO2 concentration with a mean bias of −0.79 ppmv and satellite-derived XCO2 with a mean bias of 0.76 ppmv. The model-simulated seasonality was also consistent with observations, with correlation coefficients of 0.90 and 0.89 for ground-based measurements and satellite data, respectively. Tower observations from a background site at Lin'an (30.30∘ N, 119.75∘ E) revealed a strong correlation (−0.98) between vertical CO2 and temperature gradients, suggesting a significant influence of boundary layer thermal structure on the accumulation and depletion of atmospheric CO2.

In the original version of this article, the unit of the YRD total HFC emissions “Gg CO2 -e yr−1” in the abstract should be Tg CO2 -e yr−1. On Page 581, in the fifth line from the left bottom, the unit of the total CO2-equivalent emissions of HFCs “Gg yr−1” should be Tg yr−1.

In the original version of this article, the unit of the YRD total HFC emissions "Gg CO2-e yr(-1)" in the abstract should be Tg CO2-e yr(-1). On Page 581, in the fifth line from the left bottom, the unit of the total CO2-equivalent emissions of HFCs "Gg yr(-1)" should be Tg yr(-1).

Abstract. Dynamics of CO2 has received considerable attention in the literature, yet significant uncertainties remain within the estimates of contribution from terrestrial flux and the influence of atmospheric mixing. In this study we apply the Weather Research and Forecasting model coupled with Vegetation Photosynthesis and Respiration Model (WRF-VPRM) in China to characterize CO2 dynamics with tower data collected at a background site Lin’an (30.30° N, 119.75° E). The online coupled weather-biosphere WRF-VPRM simulations are able to simulate biosphere processes (photosynthetic uptake and ecosystem respiration) and meteorology in one coordinate system. Simulations are conducted for three years (2016–2018) with fine grid resolution (20 km) to detail the spatiotemporal variations of CO2 fluxes and concentrations. This is the first attempt to apply the weather-biosphere model for a multi-year simulation with integrated data from a satellite product, flask samplings, and tower measurements to diagnose the dynamics of CO2 in China. We find that the spatial distribution of CO2 is determined by anthropogenic emissions, while its seasonality (with maximum concentrations in April 15 ppmv higher than minimums in August) is dominated by terrestrial flux and background CO2. Observations and simulations reveal a consistent increasing trend in column-averaged CO2 (XCO2) of 0.6 %/yr resulting from anthropogenic emission growth and biosphere uptake. WRF-VPRM successfully reproduces ground-based measurements of surface CO2 concentration with mean bias of −0.79 ppmv (−0.20 %) and satellite derived XCO2 with mean bias of 0.76 ppmv (0.19 %). The model-simulated seasonality is also consistent with observations, with correlation coefficients of 0.90 and 0.89 for ground-based measurements and Orbiting Carbon Observatory-2 (OCO-2) satellite data, respectively. However, evaluation against Lin\u0027an tower data reveals uncertainty within the model for simulating the intensity and diurnal variation of terrestrial flux, which contributes to overestimation by ~5.35 ppmv (1.26 %). Lin\u0027an tower observations also reveal a strong correlation (−0.85) between vertical CO2 and temperature gradients, suggesting a significant influence of boundary layer thermal structure on the accumulation and depletion of atmospheric CO2.

In situ measurement of CO2 concentration(volume fraction) was carried out in both urban and rural areas of Hangzhou from August 2015 to September 2016. The characteristics of CO2 concentration at the urban site were compared to those at the rural site, and the factors affecting CO2 concentration in Hangzhou were analyzed via wind direction, weekday-weekend difference in CO2 concentration, and evolution of CO2 concentration during the G20 summit. The results revealed that the diurnal variation of CO2 concentration in both the urban and rural areas presented a single peak curve most of the time, which resulted from the daily evolution of plant photosynthesis/respiration and atmospheric transport conditions. The diurnal variation of the difference in CO2 concentration observed at the urban and rural sites showed a bimodal peak curve, because anthropogenic emissions played a more important role. The diurnal amplitude of CO2 concentration in rural area was higher than that in urban area in spring and summer, but lower in autumn. The seasonal variation of CO2 concentration in both the urban and rural areas showed the same trend, with higher values appearing in winter and spring and lower values in summer. The difference in CO2 concentration observed at the urban and rural sites reached its highest level in winter, and dropped to its lowest in summer. The wind direction induction of high CO2 concentration was consistent with the location of the surrounding urban areas. A weekday-weekend difference in CO2 concentration was observed in Hangzhou, especially in urban area, as traffic emissions had an impact on the weekday-weekend difference in diurnal distribution of CO2 concentration. The average volume fraction of CO2 in urban area of Hangzhou was 9.3×10-6 higher than that in rural area, and the reduction of anthropogenic emissions during the G20 summit reduced the atmospheric CO2 concentration effectively, especially in urban area.

为了研究浙北地区PM 2.5中多环芳烃(PAHs)的季节性变化和它们的来源,于2014年11月～2015年11月收集了杭州和宁波2个城市中4个采样点的PM 2.5样品,利用气-质联用仪测定了17种PAHs浓度.结果表明,∑PAHs年平均浓度范围为24.1～51.9ng/m3,平均值为(35.5±12.3)ng/m3.2～3环PAHs在PM 2.5中的浓度较低(<1ng/m3),而4～6环PAHs占总PAHs的77.0％.∑PAHs的浓度与PM 2.5呈相似的季节性变化特征,冬季浓度最高而夏季最低.惹烯作为软木燃烧的示踪物,冬季的浓度是夏季的4倍,表明在冬季软木燃烧的排放和对PM 2.5的贡献都有所增加.除了夏季的2个城区站点,其它季节和站点∑PAHs浓度和PM 2.5呈现一定的正相关性.特征PAHs比值显示,浙北地区气溶胶相关的多环芳烃主要来自燃烧和热解排放,如生物质燃烧和煤燃烧,而交通排放和石油挥发源的影响不大.

To investigate the seasonal variations and sources of carbonaceous aerosols in the cities of Hangzhou and Ningbo, field PM2.5 sampling was conducted at four representative sites (two urban, one suburban, and one rural) in this region from December 2014 to November 2015. A thermal/optical carbon analyzer was employed to analyze both organic carbon (OC) and elemental carbon (EC) contents in PM2.5 by identifying eight different carbon fractions, including OC1, OC2, OC3, OC4+OPC, EC1-OPC, EC2, and EC3. Based on these fractions, OC and EC were defined as OC1+OC2+OC3+OC4+OPC and EC1+EC2+EC3-OPC, respectively; total carbon (TC) was calculated as the sum of OC and EC; and total carbonaceous aerosols (TCAs) were quantified via the sum of organic aerosols (OAs; converted from OC) and EC. The results showed the following. ①The annual average level of TC in this region was (14.3±4.1) μg·m-3, accounting for (26.2±6.5)% of the annual average PM2.5 concentration. The annual average OC and EC concentrations were (11.3±3.4) μg·m-3 and (3.0±0.9) μg·m-3, respectively. The highest TC level was observed in winter among the four seasons. ②The annual average TCA concentration in this region was (25.6±7.5) μg·m-3, contributing (42.2±10.0)% of PM2.5. In addition, secondary organic carbon (SOC) was also estimated by the commonly applied EC method. It was found that SOC contributed (41.1±5.5)% to OC on an annual average basis. ③The sources of carbonaceous aerosols were determined using the correlation between OC and EC, OC/EC mass ratio, and different carbon fraction characteristics. The annual average OC/EC ratio in this region was 4.7±1.7, which falls in the diagnostic ratio range for vehicular emissions, coal combustion, and biomass burning, indicating these sources are probably the major contributors of the regional carbonaceous aerosols. Moreover, a higher char-EC/soot-EC ratio was observed during winter and autumn at all sites, possibly implying the enhanced biomass burning activities during these two seasons.

于2014年12月-2015年11月收集了浙江北部地区4个采样点的PM2.5样品,利用高效液相色谱-串联质谱仪分析获得真菌气溶胶示踪物阿糖醇和甘露醇的浓度,研究了浙北地区真菌气溶胶的季节性变化特征及其来源.观测结果显示,浙北地区阿糖醇和甘露醇的年均浓度分别为(5.6±0.7)和(5.7±1.3)ng·m-3.真菌气溶胶示踪物夏季浓度最高,可能是由于当地夏季频繁的生物质燃烧和温暖湿润的气候条件促进了真菌孢子的释放;另外,在该地区真菌孢子对气溶胶中有机碳(OC)的贡献并不显著(＜1％).主成分分析显示,真菌气溶胶示踪物(阿糖醇、甘露醇)和生物质燃烧示踪物(左旋葡聚糖、甘露聚糖、半乳聚糖、nss-K+)在整个采样过程中都包含在同一个因子中,表明浙北地区大气中真菌气溶胶持续受到生物质燃烧排放源的影响.

A fast analytical method for organic tracers from biomass burning emissions including levoglucosan, mannosan and galactosan was developed using high performance liquid chromatography (HPLC). tandem mass spectrometry (MS/MS) without derivatization process. The optimum analytical conditions were established as follows: ammonium hydroxide (0. 005%, w/V) as mobile phase with a flow rate of 0. 35 mL/min, column temperature of 45., and negative ion electrospray ionization. Under the optimal analytical conditions, the linear concentration ranges of these organic tracers were 0. 01-1 mg/L (R-2 > 0. 999) and limits of detection (LOD) were 1. 8 mu g/L for levoglucosan, 5. 8 mu g/L for mannosan and 9. 5 mu g/L for galactosan, respectively. This new method was validated and applied to the detection of real aerosol samples, and was proved to be accurate, fast and sensitive for analysis of organic tracers from biomass burning emissions.

We collected 43 valid rainwater samples at Lin’an, a rural site in eastern China, between March 2014 and February 2015. We measured the concentrations of seven low molecular weight water-soluble organic acids using ion chromatography with the elution gradient method. We detected formic, acetic, oxalic, succinic, glutaric, malonic, and methanesulfonic acid in at least 70% of all samples, reflecting the ubiquity of these acids in the precipitation of Lin’an. The total concentration of these organic acids in individual samples was between 2.63 and 114.77 μeq L−1 (mean 16.64 μeq L−1). Formic, acetic, and oxalic acid were the most abundant organic acids in the rainwater samples, with volume-weighted mean concentrations of 9.58, 3.89, and 2.01 μeq L−1, respectively; these three acids accounted for 93% of the total mean organic acid concentration. The average contribution of organic acids to precipitation total free acidity was 13.71% in Lin’an, which was lower than has been recorded in other rural and mountainous areas of southwestern China, but much higher than has been recorded in some urban and semi-urban areas. The mean ratio of formic to acetic acid in rainwater was 2.40, and the mean ratio of malonic and succinic acid in rainwater was 0.62. These ratios indicated that, in Lin’an, formic and acetic acid mainly originated from primary biogenic sources, but malonic and glutaric acid mainly originated from motor vehicle emissions. With the exception of oxalic acid, the volume-weighted mean concentrations of other organic acids and total organic acids in the growing season (summer and spring) were higher than those in non-growing season (autumn and winter), suggesting that vegetation around the Lin’an sampling site was an important source of atmospheric organic acids. As the volume-weighted mean concentration of oxalic acid was higher during the non-growing season, this may indicate that aerosolized oxalic acid was less well diluted due to less rainfall during the drier non-growing season.

Temporal trend of visibility and factors affecting it in the background area of Yangtze River Delta (YRD) were studied based on in-situ observation at Lin'an regional atmospheric background station from 2008 to 2015. A new extraction method was developed in order to obtain the regional background visibility in YRD and assess the impact of human activities on it. The results revealed that the diurnal variation of visibility presented a single peak at Lin'an station, with the lowest value observed at dawn and the highest in the afternoon, respectively; besides, the diurnal variation of visibility showed a negative correlation with that of relative humidity. The seasonal variation of visibility appeared to be mainly influenced by atmospheric pollution, which presented higher value in spring and summer, and lower value in autumn and winter. In addition, from 2008 to 2015, the annual growth rate of visibility had a significant increase in spring and summer while maintained at a stable level in autumn and winter. The statistical analysis showed that high relative humidity and severe air pollution were two important factors for low visibility at Lin'an station. The new extraction method was established based on the observations of both air pollutants and meteorological conditions. The daily average regional background visibility in YRD was 9.7 ± 2.2km, which appeared to be affected significantly by anthropogenic emissions, and decreased by 4.4km compared to the regional natural visibility.

An accurate,fast and sensitive analytical method for fungi aerosol tracers including both arabitol and mannitol has been developed using high performance liquid chromatography (HPLC)-tandem mass spectrometry (MS/MS) without any derivatization process,which is able to greatly reduce sample preparation time.The optimum analytical condition has been established as below:ammonium hydroxide (ωo:0.0001％) as mobile phase with a flow rate of 0.4 mL· min-1,oven temperature of 45 ℃,and negative ion electrospray ionization.Under the abovementioned analytical condition,the linear range of the two organic tracers is 0.01-1 mg·L-1(R2＞0.99) and limits of detection (LOD) are 5.6 μg · L-1 (arabitol) and 9.4 μg · L-1 (mannitol),respectively.After validation and application to the real aerosol samples,this new method has been proved to be a reliable and cost-effective alternative technique for analysis of both arabitol and mannitol.

In order to understand the rainwater acidity variation and its causes since the 1990s in Zhejiang province,the data of rainwater pH value from 13 monitoring sites in Hangzhou and Zhejiang Province was analyzed.The results showed that the pollution of acid rain in Zhejiang went through three periods.The first period was from 1992 to 1999 when the acidity of rainwater gradually weakened;the second period was from 2000 to 2004 when the acidity of rainwater enhanced;the third period was from 2005 to 2012 when the acidity of rainwater weakened again.Reduction of sulfur dioxide emissions played a significant role in the improvement of acid rain pollution in recent years in Zhejiang,while the contribution of nitrogen oxides to acid rain pollution was increasing.Acid rain pollution pattern was converting from " Sulfuric acid" to " Mixed pollution of sulfuric acid and nitric acid",implying that the contribution of vehicle emissions to acid rain pollution is increasing in Zhejiang.The region affected by serious acid rain lies in the north,the middle and eastern coastal areas where there is developed economy while acid rain pollution was slighter in southwest Zhejiang where there is a relatively poor economy,which indicates rainwater acidity is closely related to the regional economic development,hence controlling local emissions is very useful for preventing acid rain pollution in developed economy areas.

利用大气化学模式系统CUACE/Haze-fog与WRF-Chem,分别选取3次不同程度的污染天气过程进行数值模拟,并利用浙江省142个环保监测站点观测数据,对模拟的PM2.5浓度的时空演变特征进行检验,评估两个模式对PM2.5浓度的预报效果。结果表明,CUACE/Haze-fog与WRF-Chem模式均能够较好的反映出PM2.5日均浓度空间分布特征及其逐日变化特征。WRF-Chem预报与观测的PM2.5日均浓度的空间相关系数明显高于CUACE/Haze-fog,且总体来看相对偏差与均方根误差明显低于CUACE/Haze-fog。CUACE/Haze-fog与WRF-Chem模式能够基本反映出PM2.5浓度连续3 d（72 h）的变化趋势,且24 h与48 h预报效果优于72 h预报。本次模拟中气象场模拟的偏差可能是导致PM2.5浓度模拟偏差的主要因素。此外,CUACE/Haze-fog模式对化学场初始值的低估可能是其对PM2.5浓度系统性低估的重要原因之一。