大学校园室内BTEX浓度水平变化规律及健康风险

采用Tenax-TA吸附/热脱附-气相色谱法(TD-GC)对大学校园室内外空气中5种苯系物(BTEX,苯、甲苯、乙苯、间/对-二甲苯和邻二甲苯)的平均浓度进行了检测。检测结果显示,5种苯系物的平均浓度均低于国家标准值。被测空气的苯系物中甲苯所占比例最大,为27.9%～32.0%。室内BTEX浓度稍高于室外,多数采样点的室内浓度与室外浓度比值(CI/CO)大于1.0。通风可有效降低空气中苯系物浓度。大学校园室内空气中的苯对学生的致癌风险为3.67×10-7～1.09×10-6。     

Pollution characteristics of 15 gas- and particle-phase phthalates in indoor and outdoor air in Hangzhou

Phthalate esters (PAEs), typical pollutants widely used as plasticizers, are ubiquitous in various indoor and outdoor environments. PAEs exist in both gas and particle phases, posing risks to human health. In the present study, we chose four typical kinds of indoor and outdoor environments with the longest average human residence times to assess the human exposure in Hangzhou, including newly decorated residences, ordinary residences, offices and outdoor air. In order to analyze the pollution levels and characteristics of 15 gas- and particle-phase PAEs in indoor and outdoor environments, air and particulate samples were collected simultaneously. The total PAEs concentrations in the four types of environments were 25,396, 25,466.8, 15,388.8 and 3616.2?ng/m³, respectively. DEHP and DEP were the most abundant, and DMPP was at the lowest level. Distinct variations in the distributions of indoor/outdoor, gas/particle-phase and different molecular weights of PAEs were observed, showing that indoor environments were the main sources of PAEs pollution. While most PAEs tended to exsit in indoor sites and gas-phase, the high-molecular-weight chemicals tended to exist in the particle-phase and were mainly found in PM_2.5. PAEs were more likely adsorbed by small particles, especially for the indoor environments. There existed a good correlation between the particle matter concentrations and the PAEs levels. In addition, neither temperature nor humidity had obvious effects on the distributions of the PAEs concentrations.     

公路收费亭内外空气污染特征及其影响因素

2003-06～2003-07对重庆市辖4个收费站中的收费亭内外一氧化碳(CO)、二氧化氮(NO₂)、总烃(THC)和可吸入颗粒物(PM₁₀)进行了采样监测,同时还观测了气温、大气压、风速和车流量等影响因素,通过二元相关和偏相关分析方法探讨了收费亭内外各空气污染指标与影响因素之间的关系.结果表明,收费亭外CO和PM₁₀小时平均浓度值比亭内高,亭内NO₂和THC的小时平均浓度值比亭外高.重庆站亭内外NO₂和茶园站亭内外CO的小时平均浓度值超过环境空气二级标准,其它各收费亭内外NO₂和CO的小时平均浓度均值未超过相关标准限值,其最高值均超过相关标准;各收费亭内外THC小时平均浓度均值分别达7.728 mg/m³和7.216　mg/m³,均超过标准限值10倍以上;收费亭内外PM₁₀变化幅度较大,亭外均值0.217　mg/m³,高于环境空气质量二级标准,亭内最高值达0.631　mg/m³,是室内空气标准日均值标准限值的4.2倍.在4个收费站的收费亭内外空气污染程度比较分析中,以重庆收费站为最严重,有3个指标的均值比其他收费站高.在污染指标与影响因素相关分析中,收费亭内外污染物之间的存在着一定的相关关系,CO、PM₁₀和NO₂呈极显著相关,亭内外THC呈显著性相关,车流量与NO₂、THC、PM₁₀均呈极显著（p<0.01）或显著相关(0.01<p<0.05),而与CO的污染程度相关性不显著;天气条件不同程度地影响各污染指标的浓度,分别以大气压和气温影响为主,风速影响不大.     

污染源位置对气体污染物影响的数值模拟

在自然通风、置换通风和单侧送侧回式通风3种方式下,通过改变污染源位置,运用CFD软件模拟研究了办公室内苯污染物的浓度分布规律,比较得出最佳通风方式下的最合理污染源位置。结果表明,3种通风方式下污染源放置的最合理位置是点3;苯污染源处于位置3时,3种通风方式中自然通风各平面苯污染物平均浓度普遍相对最高,而单侧送侧回方式的相对最低,置换通风居于二者之间。最终确定单侧送侧回通风方式下污染源处于位置3时为最佳物理模型,在该模型下办公室内通风效果最好,能够有效地排出室内气体污染物。因此,不同污染源位置对办公室内空气品质的影响不同。     

Characteristics of airborne particles inside southern California museums

The concentrations and chemical composition of suspended particulate matter were measured in both the fine and total size modes inside and outside five southern California museums over summer and winter periods. The seasonally averaged indoor/outdoor ratios for particulate matter mass concentrations ranged from 0.16 to 0.96 for fine particles and from 0.06 to 0.53 for coarse particles, with the lower values observed for buildings with sophisticated ventilation systems which include filters for particulate matter removal. Museums with deliberate particle filtration systems showed indoor fine particle concentrations generally averaging less than 10 μg m⁻³. One museum with no environmental control system showed indoor fine particle concentrations averaging nearly 60 μg m⁻³ in winter and coarse particle concentrations in the 30–40 μg m⁻³ range. Analyses of indoor vs outdoor concentrations of major chemical species indicated that indoor sources of organic matter may exist at all sites, but that none of the other measured species appear to have major indoor sources at the museums studied. Significant fractions of the dark-colored fine elemental (black) carbon and soil dust particles present in outdoor air are able to penetrate to the indoor atmosphere of the museums studied, and may constitute a soiling hazard to works of art displayed in museums.     

Characterization and source analysis of indoor/outdoor culturable airborne bacteria in a municipal wastewater treatment plant

The potential health risks of airborne bacteria emission from a wastewater treatment process have been concerned. However, few studies have investigated the differences in community structure between indoor and outdoor bacteria. In this work, the characterization of airborne bacteria was studied in a municipal wastewater treatment plant in Beijing, China. Two indoor (i.e., fine screen room and sludge dewatering house) and two outdoor (i.e., aeration tank and control site) sampling sites were selected. An Andersen six-stage impactor was used for collecting culturable airborne bacteria in the air, and Illumina MiSeq sequencing was conducted to track the emission source of the culturable airborne bacteria. The results indicate that, compared with the outdoor aeration tank site, the concentrations of culturable airborne bacteria in the indoor fine screen room with poor ventilation were more than ten times higher and the particle size was about twice as large. The community structures of indoor and outdoor culturable airborne bacteria were obviously different. Enterobacteriaceae and opportunistic pathogens were detected in indoor culturable airborne bacteria, with wastewater and sludge dewatering machine identified as the primary sources. Conversely, Enterobacteriaceae and opportunistic pathogens were not detected in outdoor culturable airborne bacteria. Outdoor high wind speed might have resulted in rapid dilution and mixing of culturable airborne bacteria generated from the aeration tank with the ambient air. The results of the present research suggest that covering pollution sources, increasing ventilation rates, and using protective measures for personnel should be implemented to decrease the exposure risk to indoor culturable airborne bacteria.     

Indoor-outdoor air pollution relations: particulate matter less than 10 μm in aerodynamic diameter (PM10) in homes of asthmatics

Concentrations of particulate matter are typically measured at fixed-site sampling locations selected to provide representative measurements of pollutant levelsin a given geographic area. These fixed-site monitors, however, may not adequately measure exposure of humans to particles; and among the major air pollutants, particles less than 10 μm in aerodynamic diameter (PM10) have received relatively little attention in indoor-outdoor and personal exposure studies. These particles reach the deepest airways and are also known to contain a number of compounds including sulfates, nitrates and carcinogens. In order to investigate the relationship between indoor and outdoor PM10 mass concentrations, a pilot investigation was conducted in 10 homes, 9 with resident asthmatics, in southern California. Sampling was conducted using PM10 and cyclone samplers inside and outside of each home with particle collection of Teflon filters. Mass was determined gravimetrically and mass concentrations were determined by pre- and post-sampling flow checks using a calibrated rotameter. PM10 and cyclone masses were reproducibly measured, as determined with paired field samples and laboratory pretesting. PM10 and cyclone masses were well correlated (R²=0.89, n=27) with slightly more mass found on the PM10 samplers, as expected. In the homes of non-smokers and asthmatics surveyed in this study, indoor concentrations were consistently lower than outdoor concentrations (ratio of PM10 indoor/outdoor medians=0.70; ratio of cyclone indoor/outdoor medians=0.79). Indoor cyclone concentrations were moderately correlated with outdoor concentrations (R²=0.56), indicating that much of the variation of indoor concentrationswas driven by variation in ambient concentration. The indoor concentrations of PM10 were less well correlated to outdoor PM10 (R²=0.34), presumably due to larger size particles or different chemical characteristics of PM10 compared to cyclone-collected particles. When data from the non-asthmatic's homes were removed, the correlations between indoor and outdoor concentrations were increased. The homes of these non-smokers and asthmatics afforded some protection from higher outdoor concentrations of particles less than 10 μm in aerodynamic diameter.     

室外空气污染对室内空气质量的影响研究

利用数值模拟方法,研究了单个建筑物外存在点污染源时室外空气污染对室内空气质量的影响.首先利用点污染源时单个建筑物周围污染物扩散的风洞实验验证了计算模型和方法的正确性,再利用自然通风的风洞实验,计算了不同污染源位置和建筑物进风口时的室内外速度场和污染物浓度场.结果表明:速度场的计算结果与风洞实验结果基本吻合,无量纲通风量的计算值略小于实验值;建筑物迎风面回流区上方的气流进入室内;当点污染源位于建筑物前的距离和建筑物高度之比约等于1时,污染源在地面处的室内污染物浓度要小于源在建筑物高度一半处的;建筑物进风口的挡风板对室内污染物浓度的影响不大;根据壁面上污染物浓度的分布来改变进风口位置,是减少室内空气受室外污染影响的有效方法.      

北京某区域儿童夏季PM2.5的污染特征及分析

近年来,随着社会和经济的不断发展,人们对室内外空气质量的重视程度也不断提高。室内外空气质量尤其是细颗粒物污染与人群健康密切相关。北京市大气细颗粒物污染形势十分严峻,因此,相关研究也成为国内外研究的热点和难点问题。本文对北京市某区域年龄在9～11岁之间的38名健康儿童人群活动场所夏季PM2.5的污染特征作了研究评价。结果表明,运用室内外环境监测与问卷调查法相结合的研究方法,儿童人员夏季PM2.5室内外浓度呈现明显的时间、空间变化特征,并受到气象因素及室内外源排放的共同影响。     

田湾核电站室内氯离子来源解析

根据2005~2006年江苏田湾核电站大气吸收液(AAS)和总悬浮颗粒物(TSP)中氯离子的一年数据,分析了室内外大气各种形态氯离子的分布特点及变化规律,并对过滤器性能进行了初步评价.结果表明:该站大气氯离子浓度大小依次为:室外吸收液>室内吸收液>室外TSP>室内TSP,年均值分别为28.12,19.20,4.22,0.11μg/m3.现有过滤器可以有效过滤室外总悬浮颗粒物,但对室外气体中氯离子的过滤效率仅为32%.相关性分析表明,室内外吸收液中氯离子浓度显著相关,相关性系数为0.859.因此,室内大气氯离子主要来源室外气态或微小气溶胶.     

Measurement and modeling of airbone concentrations and indoor surface accumulation rates of ionic substances at Neenah,Wisconsin

The objective of this continuing investigation of indoor/outdoor/surface relationships has been to develop an accurate method for predicting and subsequently managing the accumulation rates and ultimately the effects of corrosive substance on electronic equipment surface in field and manufacturing environments. We previously reported indoor/outdoor ratios and deposition velocities for Cl⁻, SO₄²⁻, Na⁺, NH₄⁺, Mg²⁺ and Ca²⁺ associated with fine and coarse particles at telephone company switching equipment locations in Wichita (Kansas), Lubbock (Texas) and Newark (New Jersey). Using the results from these studies, a methodology was developed for predicting the average indoor surface accumulation rates of ionic substances from their outdoor concentrations.In this paper we report new results for a site at Neenah, Wisconsin. At this site detailed data on the operational status of the air handling euipment were also obtained through a permanent monitoring system. These data and the data on ionic species have been used in mass balance model that calculates indoor concentrations from outdoor concentrations. Coupling this mass balance model with the measured deposition velocities substantially improves the earlier methodology for predicting surface accumulation rates from outdoor concentrations and enables decision makers to evaluate the effects of various manipulations in critical air handling system operating variables. Informed decisions can now be made when striking a balance between energy and indoor use and indoor air quality or equipment reliability.     

HEPA空气净化器对学校室内颗粒物的净化效果研究

为了解HEPA（high efficiency particle air filter,高效空气过滤器）空气净化器在小学教室和寝室的净化效果,于2019年3—4月在北京市一所全寄宿小学开展了一项HEPA空气净化器的交叉干预研究.记录干预组、非干预组室内和室外PM_2.5、PM₁₀、PM₁的浓度,计算空气净化器的净化率;采用多元线性回归模型探索净化效果的影响因素.结果表明:①空气净化器对PM_2.5、PM₁₀、PM₁的净化率分别为41.3%〔Q_l~Q_u（下四分位数~上四分位数,下同）:0~53.1%〕、40.7%（10.5%~46.2%）和34.9%（9.6%~40.3%）,其中对PM_2.5的净化率最高;寝室的净化率高于教室的净化率.②当室外PM_2.5浓度为[115,150）μg/m3时对PM_2.5的净化率最高,为52.83%（50.26%~56.13%）,PM₁₀和PM₁亦有类似结果.③多元线性回归分析表明,室外PM_2.5浓度 < 35 μg/m3时,开门通风和室内人员活动分别使室内PM_2.5浓度下降3.73 μg/m3〔95%置信区间（95% CI）:（0.60 μg/m3,6.86 μg/m3）〕和升高3.4 μg/m3（0.22 μg/m3,6.58 μg/m3）;室外PM_2.5浓度为[35,150）μg/m3时,空气净化器使室内PM_2.5浓度下降33.36 μg/m3（16.47 μg/m3,50.25 μg/m3）;室外PM_2.5浓度≥150 μg/m3时,空气净化器和开门通风分别使室内PM_2.5浓度下降48.87 μg/m3（25.62 μg/m3,72.12 μg/m3）和升高37.65 μg/m3（5.60 μg/m3,69.69 μg/m3）.研究显示:空气净化器可同时降低室内PM_2.5、PM₁₀、PM₁的浓度;当室外PM_2.5浓度 < 35 μg/m3时,不需开启空气净化器;当室外PM_2.5浓度为[35,150）μg/m3时,空气净化器有较好的净化效果,偶尔开窗通风不影响空气净化器的净化效果;当室外PM_2.5浓度≥150 μg/m3时,开启空气净化器时应关闭门窗,以免影响其净化效果.      

建筑室内人员污染暴露量及其特征性分析

合理确定室内人员的污染暴露量是有效改善室内空气品质的重要前提。文章结合吸入率概念和人体呼吸模型给出了室内人员污染暴露量计算模型,并以二氧化碳指标和挥发性有机化合物指标为研究对象,分析了在不同通风模式、新风量大小和污染源强度下室内人员污染暴露量的特性。研究结果表明,置换通风条件下的人员污染暴露量要低于混合通风条件下的相应结果,且在置换通风条件下站姿的污染暴露量要高于坐姿的对应结果,而在混合通风条件下情况相反;同时,新风量增大可以降低人员污染暴露量,但其有效程度存在临界点,即存在最优的新风量大小;此外,人员污染暴露量会因污染源强度的提高而增大,但其随污染源强度变化的跟随性会由于通风模式的不同而存在显著差异。     

交通主干道旁室内外苯系物的分析和研究

监测结果表明室外的机动车流量对于室外的苯系物浓度起到较大的贡献作用,并且室外苯系物浓度的变化曲线和机动车流量变化结果呈现出一致性;同时,通过监测还表明室内的三苯浓度变化中,开窗情况下室内的污染物浓度的变化和室外浓度变化是一致,而在关窗情况下室内的三苯浓度变化较为的复杂,这可能是在交通主干道旁和对照点的建筑室内存在三苯污染源。     

现代建筑物室内空气质量的影响因素分析

根据现代建筑物的特点，主要从室外大气污染物；通风空调系统；建筑、装饰材料；办公室设备和家电；室内人员自身行为等５个方面，分析了影响室内空气质量的因素。并在此基础上，提出了相应的改善措施。影响现代建筑物室内空气质量的原因有很多，应根据其具体功能和所处地理位置，以及自身的建筑结构特点，采取不同的改善措施。     

室内空气中苯和甲苯浓度分布特征调查

室内挥发性有机物(VOCs)中的苯和甲苯是造成室内空气污染的主要原因之一。对某系列办公室和民用住宅进行空气采样，运用气相色谱法进行分析。结果表明，对于内部装修后超过1年的办公室、室内苯、甲苯浓度均不超过标准限值：苯浓度占TVOC的1．3％—13％，其中大部分房间为7％左右：甲苯浓度占TVOC的0％—8．5％，其中大部分房间为5％以下：室内苯浓度一般高于甲苯浓度。对于内部装修后1—2月内的民用住宅，室内苯、甲苯污染相当严重，部分住宅远远超出标准限值：苯浓度一般低于或接近甲苯浓度。因此，可以认为室内甲苯的释放速度比苯快。     

患心血管病老年人夏季PM2.5和CO的暴露特征及评价

运用室内外环境监测与问卷调查法相结合的研究方法,对北京市某社区33名患心血管疾病的老年人夏季PM2.5、CO的暴露特征作了研究评价.结果表明,老年人夏季PM2.5、CO的24h个体平均暴露浓度分别为89.6μg/m3,1.9×10-6.PM2.5室内外浓度呈现明显的时间变化特征,并受到气象因素及室内外源排放的共同影响.对老年人群室内外与固定站点CO、PM2.5质量浓度变化的相关性分析显示,室外及固定站点的PM2.5浓度受区域污染源影响较大,CO浓度受局地源影响较大;大气PM2.5可能是影响该社区老年人健康的主要污染物.     

关于渗透通风条件建筑结构对室内PM2.5浓度水平影响评价模型探讨

我国京津冀地区近年频遭大气PM_2.5污染侵扰,相关研究表明,既使关闭建筑外窗,大气中PM_2.5仍可以通过渗透通风方式进入室内污染环境.为定量评价建筑渗透通风及无室内污染源条件下建筑结构（如外窗缝隙结构、房间建筑结构等）对室内ρ（PM_2.5）的影响规律,基于北京市东城区、朝阳区6个不同建筑结构的房间室内外ρ（PM_2.5）实时监测数据,重点比较分析了建筑结构对室内外ρ（PM_2.5）关联特性的影响规律.此外,根据颗粒物穿透特性及沉降特性机理,提出了反映建筑外窗缝隙结构（如缝高、缝深）的无量纲特征参数A_P与反映房间建筑结构（如层高、开间、进深）的无量纲特征参数A_k.在前期提出的室内ρ（PM_2.5）预测模型基础上,进一步构建了二者（A_P与A_k）对室内ρ（PM_2.5）影响的评价模型,并通过实测数据验证了模型的正确性.结果表明:当室外PM_2.5污染程度与气象条件一定时,建筑结构对I/O[室内外ρ（PM_2.5）之比]影响较大,其范围在0.4~0.7之间;随着建筑外窗气密性等级的提高,对应室内ρ（PM_2.5）呈显著的下降趋势.建筑外窗缝隙结构对室内ρ（PM_2.5）影响程度远大于房间建筑结构,敏感性分析结果表明,当建筑外窗缝高每降低50%或缝深每提高50%,对应室内ρ（PM_2.5）约可下降33.6%与31.9%.研究显示,气密性等级较高的建筑外窗缝隙缝高往往较小、缝深较长,渗透通风条件下对控制室内ρ（PM_2.5）水平作用更显著。      

Effect of central ventilation and air conditioner system on the concentration and health risk from airborne polycyclic aromatic hydrocarbons

Central ventilation and air conditioner systems are widely utilized nowadays in public places for air exchange and temperature control,which significantly influences the transfer of pollutants between indoors and outdoors.To study the effect of central ventilation and air conditioner systems on the concentration and health risk from airborne pollutants,a spatial and temporal survey was carried out using polycyclic aromatic hydrocarbons (PAHs) as agent pollutants.During the period when the central ventilation system operated without air conditioning (AC-off period),concentrations of 2-4 ring PAHs in the model supermarket were dominated by outdoor levels,due to the good linearity between indoor air and outdoor air (rp>0.769,p<0.05),and the slopes (1.2-4.54) indicated that ventilating like the model supermarket increased the potential health risks from low molecular weight PAHs.During the period when the central ventilation and air conditioner systems were working simultaneously (AC-on period),although the total levels of PAHs were increased,the concentrations and percentage of the particulate PAHs indoors declined significantly.The BaP equivalency (BaPeq) concentration indicated that utilization of air conditioning reduced the health risks from PAHs in the model supermarket.     

自然通风对办公室内气溶胶的影响

办公室间歇开窗自然通风可降低空内颗粒物和微生物的浓度，用ＴＳＩ公司的气溶胶自动分析仪和ＦＡ－１型空气微生物采样器对样品测定结果表明，上午９：００室外大气颗粒物浓度高于室内，不宜开窗；１０：３０左右，室内颗粒物浓度增高，开窗自然通风效果好。