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.     

Indoor/outdoor relationships of airborne ionic substances: Comparison of electronic equipment room and factory environments

In previous work, the indoor and outdoor airborne concentrations and indoor surface accumulation rates of ionic substances contained in fine (<2.5) and coarse (2.5–15 μm) particles were determined for low-occupancy electronic equipment rooms. This work has now been extended to an electronic equipment manufacturing environment.Comparison of indoor and outdoor concentrations at the manufacturing facility for both fine and coarse particles show substantially different behavior from that seen for the electronic equipment rooms.As was found previously, the dominant species in fine particles are ammonium and sulfate, which closely track each other. Their indoor and outdoor concentrations also track, but the indoor/outdoor ratios are larger by a factor of 4–5 than those found for the electronic equipment rooms. Sodium shows tracking behavior similar to ammonium and sulfate and its indoor/outdoor ratio is also large. Other ions in fine particles show elevated indoor/outdoor ratios for some sampling intervals and tracking is not evident, thought it may be masked by the large fractional error associated with species with low concentrations. There is no dominant species in the coarse fraction. Sodium and chloride track each other strongly indoors and outdoors and the indoor and outdoor concentrations of each track closely. Potassium, as well as chloride, exhibit indoor/outdoor ratios that are sometimes much larger than 1.Modelling of indoor/outdoor relationships using a mass-balance model has shown that indoor concentrations can be accurately predicted from outdoor concentrations for species with no indoor sources. The model also shows that the source generation rates for fine and coarse particles indoors range from 0 to 6.6 and 2.3 to 5.8 mg min⁻¹, respectively, for a room with a volume of 6336m³.     

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.     

北京某小学室内外VOC浓度及有毒害物种识别

采用美国EPA推荐的TO14/15方法定量分析了北京市某小学室内外夏季观测的空气样品,得到82种挥发性有机物（VOCs）的浓度水平及组成特征,对其中可能危害儿童健康的有毒有害物质进行了识别.结果表明,室内总VOCs浓度高于室外,烷烃是含量最丰富物种,平均占室内外空气中定量VOCs总浓度的32.8%.室内外VOCs组成相似,异戊烷、苯、甲苯、丙醛、丙烯和二氯甲烷为浓度优势物种,受到室外源的影响较大,室内的对二氯苯、环己烷及间二氯苯较为特征,前2种物质室内/室外浓度比例平均值分别为65.8和10.5,间二氯苯室内平均浓度为2.02×10^-9（体积分数）,而室外浓度低于检测限,这3种物质可能来自室内源. 1, 3-丁二烯、氯乙烯、苯和氯甲烷4种物质在学校室内、室外及儿童家中都超过1×10^-6的癌症风险值,平均风险值分别为1.3×10^-5、 6.4×10^-6、 5.1×10^-6和3.3×10^-6,小学室外、室内及儿童家中的累积癌症风险超过1×10^-6的癌症风险值24～39倍.丙烯醛未确认具有致癌性,但具有毒有害性,在室内外及儿童家中超过基准浓度13～72倍.     

苏州工业园区室内外颗粒物中多溴联苯醚污染特征及人体暴露水平

利用大流量主动采样技术在苏州市工业园区工厂车间、办公室、住宅区和风景区,采集PM₁₀样品,GC-MS测定PM₁₀中8种PBDEs的含量.室内PM₁₀中PBDEs总浓度范围为9.22~64.15 pg·m^-3（均值为20.93 pg·m^-3）,室外样品中PBDEs总浓度范围为1.06~8.44 pg·m^-3（均值为5.11 pg·m^-3）,室内含量显著高于室外含量.PM₁₀中∑₈PBDEs平均浓度从高到低顺序依次为工业车间、办公室、住宅区和室外大气,与其他地区室内外颗粒物含量相比,苏州室内外大气颗粒物中PBDEs都处于较低水平.室内外大气中BDE-209是最主要化合物（平均占总PBDEs的63%）,其次为BDE-99和BDE-47.车间员工、办公室员工和儿童的PBDEs日呼吸摄入剂量分别为3.75、2.78和2.60 pg·（kg·d）^-1,这表明苏州居民呼吸暴露PBDEs的潜在健康危害并不明显.     

The assessment of personal exposure to nitrogen dioxide in epidemiological studies

Personal and indoor exposure to nitrogen dioxide (NO₂ were studied in a population of housewives and children. Personal exposure, indoor concentrations and peak exposures were measured using Palmes' diffusion tubes during three measurement periods of 1 week within 1 year. Very high peak concentrations were found in the kitchens (up to 2000 μg m⁻³).Three different estimates of personal exposure were constructed using indoor concentrations and time budget data. All three were found to be closely associated with measured personal exposure.The variability over time of personal and indoor concentrations, and of the three exposure estimates was investigated in a one-way analysis of variance. The within-location or within-subject variances of indoor concentrations and estimated personal exposures were found to be smaller, relative to the between-location or between-subject variances, than the within-subject variance of measured personal concentrations. The close association between measured indoor concentrations (or exposure estimates based on indoor concentrations) and measured personal exposure suggests that measuring indoor concentrations of nitrogen dioxide in the home is sufficient to estimate personal exposure accurately.Short term peak concentrations were found to be only weakly associated with indoor NO₂ sources and weekly average indoor NO₂ concentrations. Repeated exposure to short term peak concentrations has been suggested that diffusion type measurements of personal and indoor exposure to NO₂, which are widely used suggests that diffusion type measurements of personal and indoor exposure to NO₂, which are widely used in epidemiologic studies, may not adequately reflect the most biologically relevant exposure.     

室内外PM10中多环芳烃相关关系及来源分析

为研究室内外PM10中多环芳烃相关性和来源特征,于2009年非采暖季、采暖季在天津市某小区36位住户室内和室外进行PM10膜采样,并分析其中12种PAHs浓度.结果表明,非采暖季较采暖季更为良好的室内外通风性,导致非采暖季室内外PM10中PAHs浓度没有显著差异(P>0.05),而采暖季室内PM10中PAHs浓度显著小于室外浓度;非采暖季室内外PM10中各PAHs占总PAHs的质量百分比基本一致,而采暖季其室内外质量百分比有明显不同;采暖季和非采暖季室内外PM10中PAHs的I/O平均值均低于1,但采暖季I/O值小于非采暖季. 对参与者的时间活动模式分析表明,在采暖季和非采暖季,室内吸烟、清洁活动以及烹饪对室内PM10中PAHs浓度变化均没有显著影响(P>0.05). 室内外PAHs浓度线性回归分析表明,室内PM10中5~7环PAHs主要受到室外源的影响,2~4环PAHs主要受到室内源的影响,非采暖季和采暖季室内外PM10中总PAHs的有效穿透因子分别为0.73和0.51. 通过特征比值法对PM10中PAHs来源进行解析得出,燃煤源、柴油机动车是其主要来源.     

中国严寒地区细颗粒物细菌群落特征研究

通过对中国严寒地区典型城市大庆市供暖季3类建筑（办公室、教室、住宅）室内外共计110个测点长期监测,分析大庆市供暖季室内外细颗粒物关联性,并基于16S rDNA基因测序技术和BLAST源解析技术研究大庆市供暖季3类建筑室内外细颗粒物上细菌的组分及来源.研究结果表明：大庆市供暖季室内外PM_2.5平均质量浓度分别为（32±22）和（45±34）μg/m³.其中办公室的平均渗透系数处于较低的状态（0.2886）,教室的渗透系数处于较高的状态（0.5702）,农村住宅（0.6513）比城市住宅的渗透系数略大（0.6057）.不同类型建筑室内细颗粒物中的细菌组分存在一定差异,室外细颗粒物中的细菌组分根据采样地点也存在不同,但整体上厚壁菌门（Firmicuts）、变形菌门（Proteobacteria）、拟杆菌门（Bacteroidetes）和生氧光细菌（Oxyphotobacteria）是大庆市供暖季细颗粒物中的优势菌群.3类建筑室内外细颗粒物细菌来源主要为土壤、水体、人体、腐败有机物和粪便,但不同建筑类型及采样区域的细菌来源比例具有一定差异性.室内较室外人体来源所占比重大,而室外较室内土壤来源比重大.     

广州市室内尘土中多溴联苯醚的分布特点及来源

随机采集了广州市46个家庭和12个办公室内尘土样品,同时采集了17个室外尘土样品、2个电视机和2个电脑尘土样品并分析了室内尘土中多溴联苯醚(PBDEs)的含量、单体分布及来源.结果表明,家庭尘土中∑10PBDEs(BDE28,47,66,85,99,100,153,154,183,209之和)的含量为 564.3~9654ng/g,中值和均值分别为 2686,3407ng/g;办公室尘土中∑10PBDEs 的含量为 1737~4408ng/g,中值和均值分别为3133,3179ng/g.室内尘土中PBDEs的最主要单体为BDE209,分别占家庭尘土和办公室尘土∑10PBDEs的97.4%和99.0%.BDE47、99和183在室内尘土中含量也较高.大多数室内尘土中∑10PBDEs的含量高于室外,说明室内可能有重要的PBDEs释放源.室内尘土中PBDEs的主要工业品来源为十溴联苯醚,五溴联苯醚次之,八溴联苯醚较少.     

Spatial and temporal patterns in summertime sulfate aerosol acidity and neutralization within a metropolitan area

A study of sulfate aerosol acidity in Metropolitan Toronto was conducted during the summer of 1986. Fine-fraction aerosol (<2.5-μm) were collected using Teflon membrane filters and analyzed for major ionic species (H⁺, NH⁺₄, NO⁻₃, SO²⁻₄). Samples were collected for 6 weeks at three study sites: one in the Center City and the others 13 km (WNW) and 20 km (NE) away. There were very strong correlations among the three sites with respect to measured aerosol species (r² > 0.9 for 24-h data). However, spatial variations in the magnitude of aerosol acidity were observed during sulfate episodes. For example, the peak concentrations for all sites occurred on 25–26 July 1986. While the 24-h data for sulfate were quite uniform at the three sites (34, 34 and 35 μg m⁻³), H⁺ concentrations were 9.4, 8.3 and 6.0 μg m⁻³ (as H₂SO₄) for the NE, WNW and Center City sites, respectively. For most of the summertime episodes, the downtown area also had lower aerosol acidity compared to the two sites in suburban areas.     

Modeling of SO2, Pb and Cd atmospheric deposition over a one-year period

Atmospheric deposition of SO₂, and fine particles of Pb and Cd are calculated over a one-year period in a 66 km² airshed with a segment-puff model. Emission variations, hourly mixing heights and meteorological values are considered to compute monthly averages of concentrations and deposition. Dry deposition is calculated by means of deposition velocities which are season- and land use-dependent. Wet deposition is determined using a washout coefficient. To assess the simulation performance, calculated SO₂ results from the combination between the deposition velocity, the windspeed and direction and the location and type of sources. As annual averages, results for dry plus wet deposition are computed to be 0.84 mg m⁻²d⁻¹ for sulfur, 4.15 μgm⁻²d⁻¹ for lead and 0.0013 μgm⁻²d⁻¹ for cadmium. A variation factor is derived from a sensitivity analysis. This factor amounts to 2.3−2.8 for the concentrations and 2.6−3.1 for the deposition, depending on the pollutant.     

A characterization of the principal PM-10 species in Claremont (summer) and Long Beach (fall) during SCAQS

As part of the Southern California Air Quality Study (SCAQS), General Motors Research Laboratories made comprehensive air quality measurements during the summer of 1987 in Claremont, CA, and during the fall of 1987 in Long Beach, CA. These locations are typically in the areas of highest pollution for the respective seasons. Claremont's air quality during the summer was characterized by high concentrations of photochemically produced pollutants including ozone (O₃), nitric acid (HNO₃), particulate nitrate (NO₃⁻) and particulate organic carbon (OC). The highest concentrations of these species were experienced during the daytime sampling period (0600–1800 h) and were associated with transport from the western part of the basin. Long Beach's air quality during the fall was characterized by frequent periods of air stagnation that resulted in high concentrations of primary pollutants including PM-10, OC and elemental carbon (EC) as well as particulate NO₃⁻. Night-time levels of most constituents exceeded daytime levels due to poorer night-time dispersion conditions. At Claremont, OC and NO₃⁻ compounds account for 52% of the PM-10 while at Long Beach they account for 67% of the PM-10. On the average, there appears to be sufficient particulate ammonium (NH₄⁺) to completely neutralize the nitrate and acidic sulfates. Significant artifact OC was detected and corrected for at both sites. At Claremont the artifact accounted for 21% of the uncorrected OC mass and 13% at Long Beach. Because of NO₃⁻ and NH₄⁺ losses on Teflon filters, the measured PM-10 and fine particulate mass (FPM) had to be corrected. This correction amounted to increasing the average measured FPM and PM-10 by 17 and 12%, respectively, at Claremont, and 8 and 6%, respectively, at Long Beach.     

Unusually high indoor radon concentrations

Measurements of indoor radon concentrations in the village Umhausen (2600 inhabitants, Ötztal valley, Tyrol, Austria) revealed unusually high indoor radon concentrations up to 274,000 Bq m⁻³. The medians measured on the basements were 3750 Bq m⁻³ in winter and 361 Bq m⁻³ in summer, those on the ground floors were 1180 Bq m⁻³ and 210 Bq m⁻³, respectively. Seventy-one per cent of the houses showed basement radon concentrations above the Austrian action level of 400 Bq m⁻³ in winter, 33% in summer. There are indications that the high radon concentrations are due to a giant rock slide about 8700 years ago. The unusually high radon concentrations in Umhausen coincide with a statistically significant increase in lung cancer mortality. For the period 1970–1991 the age and sex standardized mortality rate is 3.85 (95% confidence interval: 2.9 to 5.1). The control population is the total population of Tyrol (630,000 inhabitants).     

天津市老年人PM2.5暴露研究

为了解老年人PM2.5暴露特征并为流行病学研究提供数据支持,本研究选取天津市某社区101名老年人(平均年龄为67岁),在2011年夏季(6月13日~7月2日)和冬季(11月30日~12月12日)分别对其PM2.5暴露水平进行了监测,并对其时间活动模式进行了记录.结果显示,老年人平均85%以上的时间是在居室内度过的.夏季和冬季老年人PM2.5个体暴露浓度分别为 (124.2±75.2)μg/m3和(170.8±126.6)μg/m3.使用时间加权模型对老年人个体暴露浓度进行预测,夏季和冬季个体暴露实测浓度与预测浓度差值分别为0.6~220.9 μg/m3和0.6~416.8 μg/m3.吸烟活动会导致老年人个体暴露浓度升高.相关性分析表明PM2.5个体暴露浓度与环境浓度的相关性强于其与室内浓度的相关性,这为使用环境浓度替代或预测个体暴露浓度提供了支持.     

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。     

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.     

Results from the 1987 total exposure assessment methodology (team) study in Southern California

Volatile organic compound (VOC) levels in breath, personal air and fixed-site (indoor and outdoor) air were measured and compared for a sample of 50 individuals in the Los Angeles area of California. Comparisons were also made between seasons (winter and summer), between breath samples taken at three different times during the 24-h monitoring period, and between exposure levels of smokers and non-smokers. Personal air levels were higher than indoor air levels and indoor levels were much higher than outdoor levels. Air concentrations in the kitchen and living area were quite similar. Air and breath levels were higher in the winter than in the summer. Little difference was found between levels for the three breath sampling periods. Mean personal air levels of VOCs related to smoking were higher in individuals exposed to tobacco smoke vs those who were not exposed. The personal air levels of smokers and passive smokers (those non-smokers exposed to tobacco smoke) were not significantly different; while similar air levels were found in the kitchen and primary living area of homes with smokers.     

Spatial and temporal patterns in nitrogen dioxide concentrations in a hot desert region

This paper reports seasonal and spatial variations in the ambient air concentration of nitrogen dioxide throughout the State of Bahrain, from February to December 1992. Monitoring sites were chosen to include urban areas with high traffic density, suburban areas with low traffic density, commercial and industrial areas. Correlations between meteorological parameters and mean NO₂ concentrations were analysed, and NO₂ levels were only significantly correlated with temperature (r = 0.63). Only February, a winter month, showed a significantly lower concentration of NO₂ with an overall mean value of 23 μgm⁻³, whereas in August, a summer month, it was 33 μgm⁻³. The results revealed that in a hot region like Bahrain, NO₂ concentrations do not show significant monthly variations. Also summer-averaged NO₂ values exceeded corresponding spring and winter values. In cold regions opposite patterns were observed. Moreover, the results revealed significant spatial variations in NO₂ concentrations. In suburban areas with low traffic density, the overall mean NO₂ level was 15, with a range of 12–17 μg m⁻³, while in urban areas with high traffic density, the overall mean value was 52 with a range of 44–60 μg m⁻³. The mean NO₂ value in industrial sites with low traffic density was 21 with a range of 14–27 μg m⁻³, whereas in the same areas near major roads, it was 32 with a range of 31–32 μg m⁻³. These results indicate that automobiles exhaust are the dominant source of NO₂ in Bahrain. The highest NO₂ levels were found in roads with high traffic density, which are narrow, with several traffic lights and roundabouts, suggesting the effect of road geometry on NO₂ levels.     

PM10 source apportionment in California's San Joaquin valley

A PM10 (particulate matter with aerodynamic diameter equal to or less than 10 μm) aerosol study was carried out at six sites in California's San Joaquin Valley (SJV) from 14 June 1988 to 9 June 1989, as part of the 1988–1989 Valley Air Quality Study (VAQS). Concentrations of PM10 and PM2.5 (particles with aerodynamic diameters equal to or less than 2.5 μm) mass, organic and elemental carbon, nitrate, sulfate, ammonium and elements were determined in 24-h aerosol samples collected at three urban (Stockton, Fresno, Bakersfield) and three non-urban (Crows Landing, Fellows, Kern Wildlife Refuge) locations during this period. The sources which contributed to ambient concentrations of PM10 were determined by applying the Chemical Mass Balance (CMB) receptor model using the source profiles determined specifically for that study area.The VAQS data indicates the federal 24-h PM10 standard of 150 μg m⁻³ was exceeded at four out of the six sites and for reasons which differ by season and by spatial region of influence. The annual average source contributions to the PM10 at Bakersfield, the site with the highest annual average, were 54% from primary geological material, 15% from secondary ammonium nitrate, 10% from primary motor vehicle exhaust, 8% from primary construction; the remaining 4% was unexplained. The results of the source apportionment at all sites show that geological contributions (fugitive dust from tilling, roadways and construction) are largest in summer and fall months, while secondary ammonium nitrate contributions (deriving from direct emissions of ammonia and oxides of nitrogen from agricultural activities and engine exhaust) are largest during winter months.