Monitoring of urban particulate using an electret-based passive sampler

Site sampling trials have been carried out in the urban environment in order to assess the usefulness of a passive sampling device, originally developed for personal monitoring of airborne dust levels in industry. The sampling element is a small disc of electret material (polymer carrying a permanent electric charge) within a metal frame weighing approximately 15 g. The sampler is designed to capture particles by electrostatic attraction, in which case the capture rate depends on their electrical mobility but is independent of the rate at which air flows past the device. Passive samplers, along with miniaturized cascade impactors, have been exposed to urban particulate for periods of up to 28 days in locations with significantly different levels of airborne pollution. The cascade impactor data enabled good estimates to be made of PM10 and PM2.5 levels, and data from the passive sampler correlated with the total dust sampled by the impactor and with both the size fractions, that with the PM10 being better. Too few data have yet been obtained for its accuracy to be established, but it is unlikely that it will approach that of pumped samplers. It has been shown to be potentially useful for multiple, simultaneous site sampling and for monitoring personal environmental exposure situations in which dispensing with a power source is particularly useful. Being small, the sampler is easy to hide or camouflage, and because it is cheap, its loss or damage is not a serious matter.     

Toxic evaluation of organic extracts from airborne particulate matter in Puerto Rico

In recent years, several hypotheses have emerged to explain the toxicologic activity of particulate matter. Organic compounds, ultrafine particles, biologic components, and transition metals are some of the constituents that reportedly exert some type of adverse effect on human health. A considerable fraction of the urban particulate matter consists of carbon compounds, which originate mostly from anthropogenic sources. The toxicity of organic fractions from particulate matter have been mainly evaluated by considering their mutagenic activity. This research expands on the toxicologic profile of organic compounds adsorbed to particulate matter, specifically in Puerto Rico, by using the cytotoxic neutral red bioassay (NRB). The NRB uses normal human epidermal keratinocytes or other types of cells to measure the effect on cell viability when exposed to organic compounds associated to the particles in the air. We validated the NRB for particulate matter by using a standard reference material (SRM 1649). We used the NRB to determine toxicologic differences of extracts between an urban industrialized site with anthropogenic activity versus a coastal region with less human activity. The cytotoxicity associated with organic compounds in particulate matter collected at the urban industrialized site was detected in both the particulate matter (3/4) 10 microm in aerodynamic diameter (PM(10)) and particulate matter (3/4) 100 microm in aerodynamic diameter (PM(100)). Greater toxic effects were observed in PM(10) extracts than in PM(100) extracts, but PM(10) toxic effects were not significantly different from those in PM(100). The extracts from the industrialized site were more cytotoxic than the extracts from coastal reference site, although in the summer, extracts from both sites were significantly cytotoxic to normal human epidermal keratinocytes. In addition, the nonpolar extracts of both PM(10) and PM(100) exerted the greatest cytotoxicity, followed by the polar, and, finally, the moderately polar extract. This study demonstrates that extracts from the Guaynabo industrialized site were more toxic than similar extracts obtained from a reference coastal site in Fajardo, Puerto Rico.     

Prospective evaluation of respiratory health benefits from reduced exposure to airborne particulate matter

We aimed to investigate if short-term exposure to reduced particulate matter (PM) air pollution would affect respiratory function in healthy adults. We followed a cohort of 42 healthy participants from a community afflicted with severe PM air pollution to a substantially less polluted area for nine days. We measured daily airborne PM [with an aerodynamic diameter of less than 2.5 μm (PM_2.5) and 10 μm (PM₁₀)] and PM_2.5 carbon component concentrations. Five repeated respiratory function measurements and fractional exhaled nitric oxide test were made for each participant. Associations between respiratory health and PM exposure were assessed using linear mixed models. Each 10 μg/m³ decrease in same-day PM_2.5 was associated with small but consistent increase in the forced expiratory volume in 1 s (FEV₁) (9.00 mL) and forced vital capacity (14.35 mL). Our observations indicate that respiratory health benefits can be achieved even after a short-term reduction of exposure to PM. Our results provide strong evidence for more rigorous air pollution controls for the health benefit of populations.     

Exposure to airborne particulate matter in Kathmandu Valley, Nepal

Kathmandu Valley, Nepal, has severe air pollution, although few studies examine air pollution and health in this region. To the best of our knowledge, no previous studies in Nepal used time-activity diaries or conducted personal monitoring of individuals' exposures. We investigated personal exposure of particulate matter (PM) with aerodynamic diameter ≤2.5 μm (PM(2.5)) by location, occupation, and proximity to roadways. PM(2.5) monitoring, time-activity diary, respiratory health questionnaire, and spirometer testing were performed from 28 June 2009 to 7 August 2009 for 36 subjects, including traffic police (TP), indoor officer workers next to main road (IOWs_NMR) and away from main road (IOWs_AMR), in urban area (UA), urban residential area, and semi-UA (SUA). TP had the highest exposure of all the occupations (average 51.2?μg/m(3), hourly maximum >500?μg/m(3)). TP levels were higher at the UA than other locations. IOW_NMR levels (averaged 46.9 μg/m(3)) were higher than those of IOW_AMR (26.2?μg/m(3)). Exposure was generally higher during morning rush hours (0800-1100 hours) than evening rush hours (1500-1800 hours) for all occupations and areas (78% of days for TP and 84% for urban IOW). PM(2.5) personal exposures for each occupation at each location exceeded the World Health Organization ambient PM(2.5) guideline (25?μg/m(3)). Findings suggest potential substantial health impacts of air pollution on this region, especially for TP.     

Field evaluation of a personal, bioaerosol cyclone sampler

A personal cyclone sampler (cyclone) was operated continuously alongside a 25-mm filter sampler (filter), a slit impactor (Burkard slide), and a high-volume cyclone sampler (Burkard cyclone) at an outdoor location with abundant naturally occurring fungi (N = 30; sampling time: 12.5 +/- 2.3 hr). Air concentrations (spore m(-3)) of 28 fungal groups were determined for all samplers by microscopy. Cyclone performance was judged using various indices to determine if it agreed with the other samplers in determination of the frequencies with which the fungal groups were observed, as well as their proportions of the total air concentration. Fungal diversity estimates were similar for all samplers and in the range of what has been reported nationally, i.e., observation of 9-11 equal groups per sample, but spore concentration dominated by 2-3 groups. Plots of paired cyclone:comparison sampler ratios against average concentrations identified biases. For example, ratios were correlated with concentration and there was greater uncertainty at lower concentrations. Mean ratios for cyclone:filter comparisons were not significantly different from one for ascospores, Aspergillus-Penicillium spp., basidiospores, Cladosporium spp., or total spore m(-3). However, agreement was less consistent with the Burkard slide (0.74, 1.12, 0.91, 1.09, and 0.92, respectively) and the Burkard cyclone (2.31, 1.62, 1.43, 1.91, and 1.33, respectively). Concentrations of cell equivalent m(-3) also were determined for the filter and two cyclone samples by polymerase chain reaction. Cell equivalents for Aspergillus fumigatus and Penicillium brevicompactum were compared with Aspergillus-Penicillium spp. spores, and Cladosporium cladosporioides and Cladosporium herbarum cell equivalents were compared with Cladosporium spp. spores. Cell equivalent:spore ratios below one for A. fumigatus and P. brevicompactum indicated that these species comprised smaller factions of total spores or were collected less efficiently than the larger C. cladosporioides and C. herbarum spores. The personal cyclone was shown to be suitable for collection of ambient airborne fungal spores and for analysis by microscopy and polymerase chain reaction.     

Chamber evaluation of a personal, bioaerosol cyclone sampler

A personal cyclone sampler (cyclone) was operated in a 0.9-m3 chamber, side by side with a 25-mm filter sampler (filter) and either a slit impactor (Air-O-Cell) or a single-stage, multiple-hole, agar impactor (N6). Aerosols of two fungal spores were collected for 5 min to 5 hr-Aspergillus versicolor: 10, 20, 40, 80, 160, and 320 min; concentration: 10(2)-10(5) spore m(-3); Scopulariopsis brevicaulis: 5, 10, 15, 20, 25, and 30-min; concentration: 10(3)-10(5) spore m(-3) (six replicates for each sampling time). For each fungus, air concentrations were determined by a 15-channel optical particle counter (particle m(-3); N = 36), microscopy (spore m(-3); cyclone and filter, N = 36; Air-O-Cell, N = 18), culture (colony forming unit m(-3); cyclone and filter, N = 36; N6, N = 18), and polymerase chain reaction (cell equivalent m(-3); cyclone and filter, N = 36). Samplers were significantly correlated with each other as were the three analyses (correlation coefficients = 0.79-1.00 and 0.87-0.98, respectively). Ratios were calculated for simultaneous measurements with the cyclone and comparison samplers and for paired colony:spore, colony:cell equivalent, and cell equivalent:spore measurements for the cyclone and filter samples. The cyclone equaled or underestimated the other samplers for both fungi and all analyses (mean ratio: 0.75-1.04). A. versicolor colony and cell equivalent measurements exceeded spore measurements although microscopy should detect all spores not just culturable ones, perhaps due to difficulty observing the smaller spores or detection of DNA in cell fragments in addition to intact spores. Plots of the ratios of paired measurements against their averages identified biases between samplers and analyses. For example, ratios were correlated with spore concentration, and there was greater uncertainty at lower concentrations. These chamber tests have shown that the cyclone is suitable for collection of airborne fungal spores over a wide concentration range and time period and for analysis by microscopy, culture, and polymerase chain reaction.     

Exposure to airborne particulate matter in the ambient, indoor, and occupational environments

Exposure to airborne particulate matter results in various adverse health effects. Unlike other pollutants, such as ozone, sulfur dioxide, carbon monoxide, and oxides of nitrogen, for which there is significant exposure, particulate matter exposure is much more complex because it is not a single chemical species or even a limited number of chemical species. Particulate matter includes various chemical species in particles having a wide range of diameters and shapes that have widely varying toxicities. People are exposed to particles in the ambient environment, in indoor spaces, and in the occupational environment. This article reviews the information available on the concentrations of particulate matter and its composition in these general environmental categories.     

北京市气传柏树花粉浓度监测分析

目的 了解北京市气传柏树花粉的浓度,并对花粉浓度进行分级.方法 2007年3月1日-4月30日,应用Burkard采样器,对北京市气传花粉浓度进行监测,并对单一柏树花粉过敏的过敏性鼻炎和/或哮喘患者进行随访,对其病情及柏树花粉浓度进行统计学分析.结果 2007年北京市柏树花粉季节始于3月14日,止于4月12日;柏树花粉是3月下旬(3.20～3.31)空气中最主要气传花粉,浓度最高达294 g/(m<'3>·d),平均浓度为81 g/(m<'3>·d);柏树花粉浓度与柏树花粉过敏患者症状严重程度存在明显相关,Spearman相关系数为0.804,P<0.001;柏树花粉浓度可分为4级:0级≤6 g/m<'3>;Ⅰ级Ⅰ>7 g/m<'3>;Ⅱ级≥16 g/m<'3>;Ⅲ级≥67 g/m<'3>;结论首次应用Burkard采样装置对北京市柏树花粉进行浓度监测,北京市柏树花粉共持续4周,3月下旬是柏树花粉致敏高危时段.     

Evaluation of airborne operating room bacteria with a Biap slit sampler.

A Biap slit sampler and a Casella Mk 2 slit sampler were studied in an orthopaedic operating theatre. Both showed similar bacterial counts in the range of 74-640 c.f.u. (colony forming units)/m3. During operations, as average count of 220 c.f.u./m3 (range 52-482) was obtained. A close relationship was demonstrated between the number of airborne bacteria and the frequency of traffic through doors.     

Laboratory evaluation of the CIP 10 personal dust sampler

The "capteur individuel de poussiere" CIP 10 personal dust sampler--developed by the Centre d'Etudes et Recherches de Charbonnages de France (CERCHAR) research organization--is a small, quiet, lightweight unit which samples at a flow rate of 10 L/min. It is a three-stage sampler, using two stages to remove nonrespirable dust particles and one stage to collect the respirable fraction. Airflow through the sampler is induced by the third stage, which is a rotating collector cup that contains a fine grade sponge. Laboratory tests were conducted in a dust chamber using aerosols of Arizona road dust, coal dust and silica dust. Aerosol concentrations measured with the CIP 10 were compared to those measured with the coal mine dust personal sampler unit used in the United States. The results of this study showed that aerosol concentrations measured with the CIP 10 were linearly related to those obtained with the coal mine dust personal sampler. The relationship, however, was dependent on preselector configuration and aerosol characteristics. The collection medium allows some small particles (less than 3 microns) to pass through the sampler without being collected. As much as 13% (by weight) of the aerosol that penetrated through the preseparating stages was exhausted from the sampler.     

Childhood respiratory symptoms, hospital admissions, and long-term exposure to airborne particulate matter

The effects of long-term exposure to air pollution on respiratory symptoms and respiratory hospitalization (for asthma, bronchitis or pneumonia) were assessed in a cross-sectional study of children (ages 7--11 years, N=667) living in a moderately industrialized city in Central Slovakia. Individual health, residence and family history data obtained through the CESAR study were coupled, using Geographic Information System (GIS) technologies, with total suspended particulate (TSP) exposure estimates derived from dispersion modeling of almost all local stationary sources. These data were used to assess, at the intra-city level and child-specific level, the potential for TSP as a risk factor for respiratory disease in children. TSP, PM10, and PM2.5 monitored ambient concentrations are highly correlated in the study location. Modeled TSP concentrations resulting from local source emissions are dominated by a large wood processing facility, suggesting variation in exposures among children. The prevalence of respiratory non-asthmatic symptoms and hospitalizations was associated with increased TSP. No association between long-term exposure to TSP and asthma diagnosis or wheeze symptoms was found. Logistic regression modeling indicated a significant increase in hospital admissions for asthma, bronchitis or pneumonia associated with increasing air pollution (OR 2.16, CI, 1.01--4.60), doctor-diagnosed bronchitis (OR 1.53, CI, 1.02-2.30), and parent-reported chronic phlegm (OR 3.43, CI, 1.64--7.16), expressed as odds for a 15 microg/m3 increase in estimated TSP exposure, and these increases are not due to differences in socio-economic, health care or other identified factors.     

A comparison of total, respirable, and real-time airborne particulate sampling in horse barns

Measurements of total, respirable, and real-time airborne particulate were obtained in 12 horse barns in summer and winter. Respirable and total particulate concentrations were measured gravimetrically; real-time particulate was measured with an aerosol photometer. Total particulate (TP) ranged from nondetectable (ND) to 2.1 mg/m3 and from ND to 1.2 mg/m3 for winter and summer sampling, respectively. Respirable particulate (RP) ranged from ND to 0.2 mg/m3 and from ND to 0.7 mg/m3 for winter and summer measurements, respectively. The mean respirable fraction of particulate for summer and winter measurements was 0.63 and 0.34, respectively Real-time particulate (RTP) concentration was significantly correlated with TP for winter measurements and for pooled data but was not significantly correlated with RP for winter, summer, or pooled measurements. Peak, 10-sec average levels of RTP were estimated to range up to 22 mg/m3 in the samples collected. The data suggest that (a) airborne particulate concentrations and particle size distributions vary considerably among horse barns, and (b) real-time sampling, with an aerosol photometer, may be a more reliable measure of airborne TP than airborne RP in these environments.     

An evaluation of analytical methods, air sampling techniques, and airborne occupational exposure of metalworking fluids

This article summarizes an assessment of air sampling and analytical methods for both oil and water-based metalworking fluids (MWFs). Three hundred and seventy-four long-term area and personal airborne samples were collected at four plants using total (closed-face) aerosol samplers and thoracic samplers. A direct-reading device (DustTrak) was also used. The processes sampled include steel tube making, automotive component manufacturing, and small part manufacturing in a machine shop. The American Society for Testing and Materials (ASTM) Method PS42-97 of analysis was evaluated in the laboratory. This evaluation included sample recovery, determination of detection limits, and stability of samples during storage. Results of the laboratory validation showed (a) the sample recovery to be about 87%, (b) the detection limit to be 35 microg, and (c) sample stability during storage at room temperature to decline rapidly within a few days. To minimize sample loss, the samples should be stored in a freezer and analyzed within a week. The ASTM method should be the preferred method for assessing metalworking fluids (MWFs). The ratio of thoracic aerosol to total aerosol ranged from 0.6 to 0.7. A similar relationship was found between the thoracic extractable aerosol and total extractable aerosol. The DustTrak, with 10-microm sampling head, was useful in pinpointing the areas of potential exposure. MWF exposure at the four plants ranged from 0.04 to 3.84 mg/m3 with the geometric mean ranging between 0.22 to 0.59 mg/m3. Based on this data and the assumption of log normality, MWF exposures are expected to exceed the National Institute for Occupational Safety and Health recommended exposure limit of 0.5 mg/m3 as total mass and 0.4 mg/m3 as thoracic mass about 38% of the time. In addition to controlling airborne MWF exposure, full protection of workers would require the institution of programs for fluid management and dermal exposure prevention.     

Sampling efficiency of a modified closed-face cassette sampler for airborne toluene diisocyanate determination

Objectives: A modified closed-face cassette was developed for sampling and derivatizing airborne toluene diisocyanate (TDI). Methods: The cassette was assembled as a regular two-piece cassette sampler except that the whole inner surface of the sampler was loaded with coated filters to ensure that all of the aspirated TDI react with 1-(2-pyridyl) piperazine (1-2pp). Results: A test atmosphere study showed that the sampling efficiencies were 89.4% and 94.3% for 2,4-TDI and 2,6-TDI. One-third of the 2,4-TDI and 2,6-TDI mass was constantly collected on the top and middle-rim filters. A polyurethane (PU)-manufacturing plant study revealed an average of 35% and 33% of both isomer masses collected on the top and middle-rim filters. The 2,4-TDI collection of the closed-face cassette sampling was 21% higher than that of open-face sampling. Furthermore, consistent isomeric compositions of airborne 2,4-/2,6- TDI obtained from both types of samplers validated the use of the modified cassette sampler. Conclusions: The closed-face cassette sampler is capable of a higher collection of airborne TDI and the technique involved is as simple and feasible as that of the open-face sampler. Received: 15 October 1999 / Accepted: 10 June 2000     

An evaluation of airborne nickel, zinc, and lead exposure at hot dip galvanizing plants.

Industrial hygiene surveys were conducted at three hot dip galvanizing plants to determine occupational exposure to nickel, zinc, and lead. All three plants employed the "dry process" and used 2% nickel, by weight, in their zinc baths. A total of 32 personal and area air samples were taken. The air samples were analyzed for nickel, zinc, and lead. Some samples were also analyzed for various species of nickel (i.e., metallic, soluble, and oxidic). The airborne concentrations observed for nickel and its three species, zinc, and lead at the three plants were all well below the current and proposed threshold limit values recommended by the American Conference of Governmental Industrial Hygienists (ACGIH).     

New filter compositions for the analysis of airborne particulate and trace metals

Characteristics are presented of various new filter materials of polyvinyl chloride--polyacrylonitrile, polyimide, polyaromatic, and of quartz fibers. These filters have been specifically developed for air sampling applications. Included in the presentation are comparative performance characteristics such as: infrared and ultraviolet spectra, inorganic and trace metals analyses, chemical compatibilities and reactivities with various liquids and gases, moisture pick-up, mass per unit area, mechanical properties (tensile strength and elongations), air flows/pressure drops, and particle retention efficiencies. Examples are presented of the increased acceptance of membrane filters in air analyses due to their simplifying tedious conventional procedures and their improvement of sensitivity, precision, and accuracies. Included are the ability of specific synthetic filters to impart optical transparency for analyses of asbestos and other fibers by transmission techniques using oil immersion or dispersion staining, the direct determination of silica on an acrylonitrile membrane by infrared, the direct determination of atmospheric particulate types and the concentrations of each. Other examples given are trace metal analyses by X-ray fluorescence, and gravimetric procedures and scanning electron microscopy techniques for analyses of suspended particulate matter.     

大气细颗粒物暴露对人体免疫指标的影响

目的研究大气细颗粒物污染对人体免疫学指标的影响。方法使用个体采样器监测上海市区外勤交通警察和小区居民大气细颗粒物暴露水平,检测免疫学指标:白细胞计数(WBC)、中性粒细胞计数(NE)、中性粒细胞比率(NE%)、淋巴细胞计数(Ly)、淋巴细胞比率(Ly%)、CD4+、CD8+、CD4+/CD8+及免疫球蛋白IgA、IgM、IgG和IgE,比较交警和居民细颗粒物暴露及免疫学指标的差异。结果交警组大气细颗粒物暴露水平[(115.4±46.2)μg/m3]显著高于普通居民[(74.9±40.1)μg/m3](P0.01),两组Ly%、CD4+、CD8+、IgM、IgG、IgE、Clara细胞蛋白(CC16)及C反应蛋白(CRP)水平差异有显著性(P0.05或P0.01)。结论长期暴露于高浓度大气细颗粒物可导致血液中某些免疫指标发生改变,影响免疫系统健康。