太湖流域近地表主要温室气体本底浓度特征

根据2003年1月-2005年6月太湖流域近地表大气中主要温室气体CO2、CH4和N2O本底浓度的监测资料,研究了该流域近地表大气主要温室气体浓度的变化特征.结果表明,在观测时段内,该流域近地表大气CO2浓度呈上升趋势;CH4浓度呈逐年递减趋势;N2O浓度呈先减后增趋势.3种气体主要与人类活动、工农业生产和交通运输业发展有关,CO2浓度的季节变化明显,冬春季高,夏秋季低,最高值在12月,最低值在8月;CH4浓度由春至夏升高,由夏至秋至冬递减,最高值在7月,最低值在2月;N2O浓度没有明显的季节变化,它们主要受源汇强度变化影响.CO2浓度的日变化基本呈双峰态,是源汇强度变化和边界层稳定程度相互作用的原因,CH4浓度无明显日变化规律,N2O浓度日变化中的最高值总体呈现是夏、秋、春至冬逐渐延迟的状态.     

长春市大气污染物变化规律及原因分析

本文通过对长春市城区6个监测子站2007年1月至12月监测资料的统计,分析了长春市大气污染物季节变化规律,及各功能区间的空气质量差异。结合2001年以来的大气监测数据分析了长春市空气质量的总体变化趋势。结果表明,长春市空气质量季节变化明显,采暖期的大气污染物浓度明显增高,首要污染物是PM10。历年的数据显示PM10变化不明显,但SO2和NO2具有略有升高趋势。     

焦作市大气污染物特征和相关性分析

为研究焦作市大气污染特征及其相关性,对2015—2017年焦作市4个国控空气监测点位的监测数据进行统计分析。结果表明:2015—2017年城区环境空气污染SO_2、NO_2、CO、PM_(10)、PM_(2.5)浓度均呈逐年下降趋势;大气污染浓度季节变化特征明显,PM_(10)、PM_(2.5)、SO_2、NO_2、CO的浓度均为冬季最高、夏季最低,空气质量指数也在冬季达到最高值; O_3浓度则为夏季最高、冬季最低。2017年焦作市沙尘天气共计36 d,严重影响了环境空气中颗粒物的浓度。由PM_(2.5)与PM_(10)的比值说明大气颗粒物污染以PM_(2.5)为主。通过SPSS软件分析,SO_2、NO_2、CO、PM_(10)、PM_(2.5)浓度间呈两两正相关,O_3浓度与NO_2、CO呈负相关。     

用后向空气轨迹方法对胶州湾主要大气污染物分布的分析

采用青岛崂山点位2005-2009年的大气监测数据,利用HYSPLIT4.8模式和象限分析方法,计算出污染物的方位贡献情况,判断出胶州湾大气污染物的传输路径主要为北、西北和西部路径,S02、N02和PM10在北部和西北部象限的5年平均贡献率分别为25.32％和28.21％、21.16％和21.53％以及20.25％和22.83％,这与胶州湾东方和东南方为海洋、北方和西北方为工业城市有关.通过个例分析得出的传输路径与象限分析的结果一致.另一方面,胶州湾地区的主要污染物在过去5年中的年均值浓度变化显示,SD2浓度呈下降趋势,NO2浓度呈上升趋势,PM10浓度变化趋势不明显.为调查青岛市和周边5个省污染物排放水平对胶州湾污染物分布的影响,分析了2005-2009年的相关环境统计数据,SO,的排放量下降,燃料煤消耗量、氮氧化物排放量以及机动车数量逐年升高可能是导致胶州湾地区污染物浓度变化的原因.     

华东森林及高山背景区域CO2和CH4浓度变化特征

对国家大气背景监测福建武夷山站2014—2018年的主要温室气体监测数据进行分析,探讨华东森林及高山背景区域大气中CO_2和CH_4浓度的变化特征。结果表明:华东森林及高山区域CO_2背景浓度为414.1×10~(-6)(摩尔分数,下同),5年间呈逐年上升趋势; CH_4背景浓度为1 977×10~(-9),2014—2016年呈逐年上升趋势,2016—2018年保持稳定;两者均具有较明显的季节和月变化特征,CO_2还具有较明显的日变化特征,但季节变化幅度、月平均浓度振幅和日变化幅度均较小,具有区域背景特征。     

京津冀与长三角地区氢氯氟碳化物本底特征

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。     

夏季上海城区大气中二氧化碳浓度特征及相关因素分析

利用连续自动监测仪器,获得CO2源区上海城区2010年夏季高时间分辨率的CO2连续监测数据.监测期间CO2平均浓度为414±16ppm,高于同期全球本底观测站约6%,与中国其他城市化地区的浓度水平基本相当或略低.CO2浓度日变化呈显著早晚双峰特征;周变化呈显著的波浪形,高值集中出现在工作日.除O3外,与其他污染物呈显著...     

北京大气CH4、CO2、TOC日变化规律及垂直分布的自动连续观测

提出了一种能自动连续监测CH4、CO2、TOC日变化及垂直分布的系统,利用该系统监测了2002年冬季CH4、CO2、TOC垂直分布的日变化的变化趋势.结果发现,距地面高度增加,受湍流扩散的影响,CH4、CO2、TOC浓度降低.冬季CH4浓度的日变化呈现明显的单峰周期变化,CO2日变化呈双峰形分布,TOC日变化没有明显的特征,其日变化受机动车尾气排放的影响很大.根据2002年冬季CO2浓度与2000年以前的对比结果发现,北京市冬季燃煤排放的污染物已处于一个相对稳定期,而随着北京市机动车保有量迅速增加,尾气排放成为影响某些大气微量气体日变化的主要因素.     

北京市大气气态汞变化特征

采用Tekran 2537X大气汞分析仪在线测量北京市城区大气中气态元素汞(GEM,简称大气汞) 浓度,研究大气汞浓度随不同气象条件的变化特征。通过分析2016年10月—2017年9月大气汞监测数据发现,该监测点全年大气汞浓度为0.48～16.25 ng/m³,均值为(3.41±1.79)ng/m³。春季、夏季、秋季和冬季大气汞浓度均值依次为2.93 、2.95、4.27、3.37 ng/m³,其中,秋季大气汞浓度明显高于其他季节 。秋季大气汞浓度显著偏高可能由不利的大气扩散条件导致。大气汞夜间浓度显著高于白天浓度。同时,将大气汞与SO₂、CO及PM_2.5进行相关性分析,发现大气汞浓度变化趋势与SO₂、CO和PM_2.5呈显著正相关。结合风向和风速进行污染来源分析,得到该点位大气汞在西南和东北方向上受人为排放源影响较大。污染源类型分析表明,冬季大气汞与CO同源性强,主要来自本地供暖用煤。     

无锡市区大气污染物状况及变化趋势分析

使用2012—2015年无锡市区的6种大气污染物监测数据,对无锡市区各污染物的年度变化、空间分布、影响因素进行了分析。结果表明:(1)2012—2015年无锡市区SO_2、O_3质量浓度呈下降趋势,且趋势显著;NO_2质量浓度呈下降趋势,但不明显;CO、PM_(10)、PM_(2.5)的质量浓度年际变化比较平稳。(2)无锡市区SO_2、NO_2、PM_(10)、PM_(2.5)、CO的空气质量分指数(IAQI)均为冬季最高、夏季最低;O_3的IAQI则为夏季最高、冬季最低。(3)SO_2、NO_2、PM_(10)、PM_(2.5)、CO浓度间呈两两正相关,且相关性极显著;O_3浓度与NO_2、CO呈显著负相关,与SO_2、PM_(10)、PM_(2.5)浓度之间没有明显的关联。(4)分析了无锡市区各项大气污染物浓度的空间分布特征。(5)SO_2、NO_2、PM_(10)浓度周内变化具有"周末效应"的特征,而O_3、CO和PM_(2.5)浓度周内变化出现"反周末效应"。     

Carbon monoxide concentrations in Santiago City at street levels and their vertical gradient

Carbon monoxide concentrations were measured at ground level (1 m) near heavy traffic streets in downtown Santiago de Chile in periods of low (November and December), intermediate (April) and high (May) ambient concentrations. Also, measurements were carried out at several heights (from 1 to 127 m) in Santiago’s main street during winter time. Measurements carried out at ground level show maximum values during the morning rush hour, with values considerably higher than those reported by the urban air quality network, particularly in summer time. However, the measured values are below air quality standards. Vertical CO profiles were measured in a tower located in the center of downtown. Below 40 m (average altitude of neighboring buildings), the profiles do not show a consistent vertical gradient, with CO concentrations increasing or decreasing with height, regardless of atmospheric stability. In this low altitude range, the observed vertical profiles are poorly predicted by a street canyon model, and the measured concentrations can not be described by a simple exponential decay. At higher altitudes (40 and 127 m) a negative gradient in CO concentrations is observed, both for stable and unstable atmospheric conditions. The values of CO measured at 127 m are relatively well described by an Eulerian dispersion model running with current CO emission inventories for Santiago, although this model tends to predict stepper CO gradients than the observed ones.     

Do the pollution related to high-traffic roads in urbanised areas pose a significant threat to the local population?

Many large neighbourhoods are located near heavy-traffic roads; therefore, it is necessary to control the levels of air pollution near road exposure. The primary air pollutants emitted by motor vehicles are CO, NO₂ and PM. Various investigations identify key health outcomes to be consistently associated with NO₂ and CO. The objective of this study was the measurement-based assessment for determining whether by high-traffic roads, such as motorways and express ways, and the concentrations of CO and NO₂ are within normal limits and do not pose threat to the local population. Average daily values (arithmetic values calculated for 1-h values within 24 h or less, depending on result availability) were measured for concentrations of NO₂ and CO by automatic stations belonging to the Voivodship Environmental Protection Inspectorate in Katowice, in areas with similar dominant source of pollutant emission. The measurements were made in three sites: near the motorway and expressway, where the average daily traffic intensity is 100983 and 35414 of vehicles relatively. No evidence was found of exceeding average daily values equal to the maximum allowable NO₂ concentration due to the protection of human health in the measurement area of the stations. No daily average values exceeding the admissible CO concentration (8-h moving average) were noted in the examined period. The results clearly show lack of hazards for general population health in terms of increased concentrations of CO and NO₂ compounds that are closely related to high intensity car traffic found on selected motorways and speedways located near the city centres.     

乌鲁木齐市2种主要温室气体浓度水平

利用2010年乌鲁木齐市近地面大气主要温室气体的自动监测数据,分析了CO2和CH4浓度的分布特征和时间变化规律.结果表明,乌鲁木齐市CO2小时浓度在(349.1～605.0)×10-6之间;采暖期浓度高,平均浓度为438.1 ×10-6,非采暖期浓度低,平均浓度为375.0×10-6.CH4浓度日变化明显,昼间低、夜间...     

Seasonal evaluation of outdoor/indoor air quality in primary schools in Lisbon

The aim of this study was to evaluate the indoor (I) and outdoor (O) levels of NO?, speciated volatile organic compounds (VOCs) and carbonyls at fourteen primary schools in Lisbon (Portugal) during spring, autumn and winter. Three of these schools were also selected to be monitored for comfort parameters, such as temperature and relative humidity, carbon dioxide (CO?), carbon monoxide (CO), total VOCs, and both bacterial and fungal colony-forming units per cubic metre. The concentration of CO? and bioaerosols greatly exceeded the acceptable maximum values of 1800 mg m?3 and 500 CFU m?3, respectively, in all seasons. Most of the assessed VOCs and carbonyls occurred at I/O ratios above unity in all seasons, thus showing the importance of indoor sources and building conditions in indoor air quality. However, it has been observed that higher indoor VOC concentrations occurred more often in the colder months, while carbonyl concentrations were higher in the warm months. In general, the I/O NO? ratios ranged between 0.35 and 1, never exceeding the unity. Some actions are suggested to improve the indoor air quality in Lisbon primary schools.     

Seasonal variation, sources, and gas/particle concentrations of PCBs and OCPs at high altitude suburban site in Western Black Sea Region of Turkey

Daily gas and particle phase samples were collected during winter and summer seasons in Bolu, which is located in the high altitude Western Black Sea Region of Turkey. Samples were analyzed to determine the concentrations of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). Concentrations of endosulfan sulfate and methoxychlor were found to be highest in the summer and winter periods, respectively. The measured average concentration of endrin was considerably higher (10-50 fold) than the values reported in the literature for similar sites. The agricultural areas located to the south, south-east and south-west of the sampling point were identified as source regions. PCBs were found predominantly in the gas phase in both seasons and 3-chlorinated biphenyls were found to be abundant in the winter period, due to pollutants transported from the city centre and a waste incineration plant by southerly and easterly winds. The concentrations of PCB-180 and PCB-194 were found to be higher than values reported in the literature. The correlation between atmospheric concentrations and temperature was obtained by using Clausius-Clapeyron (CC) plots. The CC plots for most of the OCPs showed shallow negative slopes with low r(2) values, which might be due to the presence of local sources, i.e., agricultural areas around the sampling site and the dominance of evaporation. The CC plots showed steep positive slopes for most of the PCB compounds. Most of the PCB compounds were carried from the ongoing local sources.     

A wireless, remote query magnetoelastic CO2 sensor

This paper presents a wireless, passive, remote query CO2 sensor comprising a ribbon-like magnetoelastic thick-film coated with a mass-changing CO2 responsive polymer synthesized from acrylamide and isooctylacrylate. In response to a magnetic field impulse, the magnetostrictive magnetoelastic sensor vibrates at a characteristic resonant frequency that is inversely dependent upon the mass of the attached CO2 responsive polymer. The mechanical vibrations of the magnetostrictive sensor launch magnetic flux, which can be detected remotely using a pickup coil. By monitoring the resonant frequency of the passive sensor, the atmospheric CO2 concentration can be determined without the need for physical connections to the sensor or specific alignment requirements. The effect of humidity and the CO2 responsive copolymer composition on the measurement sensitivity are reported. Greatest sensitivity is achieved with a polymer comprising a 1:1 mole ratio of acrylamide to isooctyl acrylate. A 0.7% change in atmospheric CO2 concentration can be detected for a 20 microns thick polymer coated sensor.     

睢宁地区大气PM_(2.5)及气态污染物季节性变化特征

根据2014年全年实时在线观测数据,分析了徐州睢宁地区大气细颗粒物(PM_(2.5))和气态污染物(包括SO_2、CO、NO_x、O_3)质量浓度的季节性变化特征。结合后向轨迹模型,分析不同气团对该地区大气污染浓度的影响。PM_(2.5)与O_3值在夏季最低,呈显著相关,表明夏季PM_(2.5)主要受控于本地大气光化学活性。在冬季,除O_3外,PM_(2.5)、SO_2、CO、NO_x值最高,且大气颗粒物主要以细粒子为主。O_3在春季最高,并与远程传输的气团且经过我国东部污染源密集地区相对应。高浓度的PM_(2.5)主要与冬季缓慢移动的气团相对应,这可能将PM_(2.5)及其气态前体物传输至该地区进而加重大气污染程度。     

Artificial neural network based carbon monoxide persistence models for episodic urban air quality management

This paper describes the development of artificial neural network (ANN) based carbon monoxide (CO) persistence (ANNCOP) models to forecast 8-h average CO concentration using 1-h maximum predicted CO data for the critical (winter) period (November–March). The models have been developed for three 8-h groupings of 10 p.m. to 6 a.m., 6 a.m. to 2 p.m. and 2–10 p.m., at two air quality control regions (AQCRs) in Delhi city, representing an urban intersection and an arterial road consisting heterogeneous traffic flows. The result indicates that time grouping of 2–10 pm is dominantly affected by inversion conditions and peak traffic flow. The ANNCOP model corresponding to this grouping predicts the 8-h average CO concentrations within the accuracy range of 68–71%. The CO persistence values derived from ANNCOP model are comparable with the persistence values as suggested by the Environmental Protection Agency (EPA), USA. This work demonstrates that ANN based model is capable of describing winter period CO persistence phenomena.     

Determination of O3, NO2, SO2, CO and PM10 measured in Belgrade urban area

O(3), NO(2), SO(2), CO and PM(10) concentrations, simultaneously determined for the first time in Belgrade urban area in the autumnal period of 2005, are presented. The obtained results display similar behaviour of SO(2), NO(2), CO, PM(10) opposite from that of O(3). The weekend effect was also investigated showing diminution of average daily concentrations of SO(2), NO(2), PM(10) and CO for 72, 40, 37 and 42% respectively, and increase of the average daily concentration of O(3) for 56%. Influence of meteorological conditions on observed concentration levels was studied, too. The observed influence of wind speed on the O(3) nightly concentration levels was analyzed pointing to the phenomena of O(3) transport during episodic measurements. To make an identification of possible pollution sources and analyse the influence of meteorological parameters on pollution levels, air back trajectories for high level concentrations episodes were calculated and analysed. A multivariate receptor modelling (Principal Component Analysis, Cluster Analysis) has been applied to a set of data in order to determine the contribution of different sources. It was found that the main principal components, extracted from the air pollution data, were related to gasoline combustion, oil combustion and ozone transport.