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PubMed1995

1-Nitropyrene as a marker for the mutagenicity of diesel exhaust-derived particulate matter in workplace atmospheres.

The use of 1-nitropyrene (1-NP) as a marker for the occupational exposure to diesel exhaust (DE) mutagens was investigated in workplace atmospheres contaminated with DE from a variety of emission sources, such as power supplies, forklifts, trucks, caterpillar vehicles, trains, ships' engines, and vehicles in city traffic. Total suspended particulate matter was collected by area sampling. The 1-NP content of acetone extracts of these samples as determined by gas chromatography-high resolution mass spectrometry varied from 0.080 to 17 micrograms/g acetone extractable matter, corresponding to air concentrations of 0.012 to 1.2 ng/m3. A sample collected in a rural area contained 0.0017 ng/m3 1-NP. The mutagenicity of the extracts was tested in the Salmonella typhimurium strains TA98 and TA1538, using the microsuspension assay with and without metabolic activation by an exogeneous metabolizing system (rat liver S9-fraction). In addition, the S. typhimurium strains YG1021 and YG1024 were used because of their high sensitivity towards the mutagenicity of nitro polycyclic aromatic hydrocarbons. When plotting the mutagenic potency of the air sample extracts as determined in the absence of liver S9 versus the particle-associated 1-NP level, a relatively high correlation (r = 0.80-0.91) was observed in all of the S. typhimurium strains. High correlations (r = 0.80-0.93) were also observed when plotting the results of mutagenicity testing after activation by S9 versus the outcome of chemical analysis. These results show that the 1-NP content of workplace air samples is associated with their mutagenic potency, suggesting that 1-NP may be used as a marker for occupational exposure to DE-derived particle-associated mutagens.

Air Pollutants, Occupational↗

PubMed2005

Assessing truck driver exposure at the World Trade Center disaster site: personal and area monitoring for particulate matter and volatile organic compounds during October 2001 and April 2002.

The destruction of the World Trade Center (WTC) in New York City on September 11, 2001, created a 16-acre debris field composed of pulverized and burning material significantly impacting air quality. Site cleanup began almost immediately. Cleanup workers were potentially exposed to airborne contaminants, including particulate matter, volatile organic compounds, and asbestos, at elevated concentrations. This article presents the results of the exposure assessment of one important group of WTC workers, truck drivers, as well as area monitoring that was conducted directly on site during October 2001 and April 2002. In cooperation with a local labor union, 54 drivers (October) and 15 drivers (April) were recruited on site to wear two monitors during their 12-hour work shifts. In addition, drivers were administered a questionnaire asking for information ranging from "first day at the site" to respirator use. Area monitoring was conducted at four perimeter locations during October and three perimeter locations during April. During both months, monitoring was also conducted at one location in the middle of the rubble. Contaminants monitored for included total dust (TD), PM10, PM2.5, and volatile organic compounds. Particle samples were analyzed for mass, as well as elemental and organic carbon content. During October, the median personal exposure to TD was 346 microg/m3. The maximum area concentration, 1742 microg/m3, was found in middle of the debris. The maximum TD concentration found at the perimeter was 392 microg/m3 implying a strong concentration gradient from the middle of debris outward. PM2.5/PM10 ratios ranged from 23% to 100% suggesting significant fire activity during some of the sampled shifts. During April, the median personal exposure to TD was 144 microg/m3, and the highest area concentration, 195 microg/m3, was found at the perimeter. During both months, volatile organic compounds concentrations were low.

Air Pollutants↗

PubMed2005

Associations between health effects and particulate matter and black carbon in subjects with respiratory disease.

We measured fractional exhaled nitric oxide (FE(NO)), spirometry, blood pressure, oxygen saturation of the blood (SaO2), and pulse rate in 16 older subjects with asthma or chronic obstructive pulmonary disease (COPD) in Seattle, Washington. Data were collected daily for 12 days. We simultaneously collected PM10 and PM2.5 (particulate matter < or = 10 microm or < or = 2.5 microm, respectively) filter samples at a central outdoor site, as well as outside and inside the subjects' homes. Personal PM10 filter samples were also collected. All filters were analyzed for mass and light absorbance. We analyzed within-subject associations between health outcomes and air pollution metrics using a linear mixed-effects model with random intercept, controlling for age, ambient relative humidity, and ambient temperature. For the 7 subjects with asthma, a 10 microg/m3 increase in 24-hr average outdoor PM10 and PM2.5 was associated with a 5.9 [95% confidence interval (CI), 2.9-8.9] and 4.2 ppb (95% CI, 1.3-7.1) increase in FE(NO), respectively. A 1 microg/m3 increase in outdoor, indoor, and personal black carbon (BC) was associated with increases in FE(NO) of 2.3 ppb (95% CI, 1.1-3.6), 4.0 ppb (95% CI, 2.0-5.9), and 1.2 ppb (95% CI, 0.2-2.2), respectively. No significant association was found between PM or BC measures and changes in spirometry, blood pressure, pulse rate, or SaO2 in these subjects. Results from this study indicate that FE(NO) may be a more sensitive marker of PM exposure than traditional health outcomes and that particle-associated BC is useful for examining associations between primary combustion constituents of PM and health outcomes.

Age Factors↗

PubMed1988

A model for the release of adsorbed molecules from the surfaces of airborne particulate matter based on liquid-phase desorption from amorphous carbon blacks.

The release of molecules adsorbed on the surfaces of amorphous carbon blacks has been studied using liquid-solid chromatography. Adsorbate molecules, adsorbents, and mobile phases were selected on the basis of their relevance as models for the release of toxic agents adsorbed on inhalable environmental particulate matter that originates from the incomplete combustion of organic materials. The presence of surface active groups on the carbon blacks has been shown to adsorb and retain adsorbate molecules selectively, and this selectivity can be reduced by competition for these active groups by the displacing solvent. Release is also governed by the surface coverage of the particles and increases as coverage approaches the monolayer.

Adsorption↗

PubMed1991

Exposure assessment approaches to evaluate respiratory health effects of particulate matter and nitrogen dioxide.

Several approaches can be taken to estimate or classify total personal exposures to air pollutants. While personal exposure monitoring (PEM) provides the most direct measurements, it is usually not practical for extended time periods or large populations. This paper describes the use of indirect approaches to estimate total personal exposure for NO2 and particulate matter (PM), summarizes the distributions of these estimates, and compares the effectiveness of these estimates with microenvironmental concentrations for evaluating effects on respiratory function and symptoms. Pollutant concentrations were measured at several indoor and outdoor locations for over 400 households participating in an epidemiological study in Tucson, Arizona. Central site monitoring data were significantly correlated with samples collected directly outside homes, but the former usually had higher pollutant concentrations. Integrated indices of daily total personal exposure were calculated using micro-environmental (ME) measurements or estimates and time-budget diary information. Peak expiratory flow rates (PEFR) were measured for up to four times a day during two-week study periods. In thirty children (ages 6-15 years) with current diagnosed asthma, a significant reduction in PEFR was associated with NO2 levels measured outside of their homes. Additional decrements of morning PEFR were found in those children sleeping in bedrooms with higher measured NO2 levels. Morning and noon PEFR decrements were also linked to higher morning NO2 levels that were measured at central monitoring stations. Effects of PM were also found, but were limited to morning PEFR. No effects were found in non-asthmatic children. The relationship of PEFR to the calculated indices of daily average total exposure were weaker than to the microenvironment concentrations. This suggests that diary and ME monitoring data need to yield better time resolution in order to incorporate short-term average exposures to higher concentrations into the exposure indices and into the analysis of within day health responses.

Adolescent↗

PubMed1991

Indoor sources of mutagenic aerosol particulate matter: smoking, cooking and incense burning.

The emission of aerosol particles and their mutagenic activity as well as the emission of some gaseous pollutants has been studied experimentally in order to compare the emission from some indoor pyrolysis processes. Cigarette (tobacco and herbal) smoking, incense and mosquito-coil burning and frying of experimental lean minced pork emitted particulate matter. Their extracts were mutagenic in the Ames Salmonella test with TA98 and activation as well as, with a higher response, in a microsuspension test with the same strain and activation condition. The response of the particles from the smoking and burning processes varied from 3000 to 50,000 revertants per gram of smoked or burnt material in the conventional Salmonella test and from 50,000 to 350,000 revertants per gram in the microsuspension assay. The frying of lean minced pork gave an airborne emission of about 53 and 560 revertants per gram of fried pork, respectively, in the 2 assays. The frying of some common food items following cookbook recipes also emitted mutagenic aerosol particles but the emitted activity was less than that in the pork experiment. Carbon monoxide, isoprene and benzene were present in the emissions from the smoking and burning processes but were not detectable in the frying fumes. The results suggest that incense and mosquito-coil burning can cause indoor air pollution akin to that from cigarette smoking. Indoor air pollution from cooking requires further study.

Aerosols↗

PubMed2005

Herbicide sorption to fine particulate matter suspended downwind of agricultural operations: field and laboratory investigations.

Tillage-induced erosion of herbicides bound to airborne soil particles has not been quantified as a mechanism for offsite herbicide transport. This study quantifies the release of two preemergent herbicides, metolachlor and pendimethalin, to the atmosphere as gas- and particle-phase species during soil incorporation operations. Fine particulate matter (PM2.5) and gas-phase samples were collected at three sampling heights during herbicide disking into the soil in Davis, CA, in May 2000 and May 2001 using filter/PUF sampling. Quartz fiber filters (QFFs) were used in May 2000, and Teflon membrane filters (TMFs) were used in May 2001. The field data were combined with laboratory filter/PUF partitioning experiments to account for adsorption to the filter surfaces and quantify the mass of PM2.5-bound herbicides in the field samples. Laboratory results indicate a significant adsorption of metolachlor, but not pendimethalin, to the quartz filter surfaces. Metolachlor partitioning to PM2.5 collected on TMF filters resulted in corrected PM2.5 field partition coefficient values, Kp,corr = Cp/Cg, of approximately 10(-3.5) m3/microg, indicating its preference for the gas phase. Pendimethalin exhibited more semivolatile behavior,with Kp,corr values that ranged from 10(-3) to 10(-1) m3/ microg and increased with sampling height and distance downwind of the operation. An increase in pendimethalin enrichment at a height of 5 m suggests winnowing of finer, more sorptive soil components with corresponding higher transport potential. Pendimethalin was enriched in the PM2.5 samples by up to a factor of 250 compared to the field soil, indicating thatfurther research on the processes controlling the generation of PM-bound herbicides during agricultural operations is warranted to enable prediction of off-site mass fluxes by this mechanism.

Acetamides↗

PubMed2003

Particulate matter emissions during transient locomotive operation: preliminary study.

Certification testing of locomotive diesel engines is conducted by testing the locomotive in a series of steady-state conditions, or notches. The aim of this work was to determine whether notch changes, which are made on the order of twice per minute during normal locomotive operation, significantly affect emission rates. Particulate matter (PM) measurements recorded by others over 5, 15, and 30 min immediately at notch change were analyzed. By assuming that PM emissions during steady-state conditions were constant, it was possible to determine the amount of PM emitted because of notch change. Certification line-haul and switching duty cycles were modified to include a representative number of notch changes. The results of these calculations suggest that in test cycles in which a representative number of notch changes were included, approximately 40% of PM emissions occurred because of notch changes.

Air Pollutants↗

PubMed2003

Development of a microscale emission factor model for particulate matter for predicting real-time motor vehicle emissions.

The U.S. Environmental Protection Agency's National Exposure Research Laboratory is pursuing a project to improve the methodology for modeling human exposure to motor vehicle emissions. The overall project goal is to develop improved methods for modeling the source through the air pathway to human exposure in significant exposure microenvironments. Current particulate matter (PM) emission models, particle emission factor model (used in the United States, except California) and motor vehicle emission factor model (used in California only), are suitable only for county-scale modeling and emission inventories. There is a need to develop a site-specific real-time emission factor model for PM emissions to support human exposure studies near roadways. A microscale emission factor model for predicting site-specific real-time motor vehicle PM (MicroFacPM) emissions for total suspended PM, PM less than 10 microm aerodynamic diameter, and PM less than 2.5 microm aerodynamic diameter has been developed. The algorithm used to calculate emission factors in MicroFacPM is disaggregated, and emission factors are calculated from a real-time fleet, rather than from a fleet-wide average estimated by a vehicle-miles-traveled weighting of the emission factors for different vehicle classes. MicroFacPM requires input information necessary to characterize the site-specific real-time fleet being modeled. Other variables required include average vehicle speed, time and day of the year, ambient temperature, and relative humidity.

Air Pollutants↗

PubMed2001

Tissue injury following inhalation of fine particulate matter and hydrogen peroxide is associated with altered production of inflammatory mediators and antioxidants by alveolar macrophages.

Hydrogen peroxide (H(2)O(2)) is present in the atmosphere at concentrations known to induce cell and tissue damage. However, inhaled H(2)O(2) vapor should not reach the lower lung due to its high water solubility. It has been suggested that hygroscopic components of particulate matter (PM) may transport H(2)O(2) into the lower lung and induce tissue injury and this was investigated. Ammonium sulfate [(NH(4))(2)SO(4)] was selected as a model for fine atmospheric PM. Treatment of female Sprague-Dawley rats with (NH(4))(2)SO(4) (429 or 215 microg/m(3); 0.3-0.4 microm mass median diameter) or H(2)O(2) (10, 20, or 100 ppb) alone or in combination for 2 h had no major effect on bronchoalveolar lavage fluid cell number or viability or on protein content or lactate dehydrogenase levels, either immediately or 24 h after exposure, relative to air-exposed rats. However, electron microscopy revealed increased numbers of neutrophils in pulmonary capillaries adhered to the vascular endothelium in rats treated with the combination of (NH(4))(2)SO(4) + H(2)O(2). Exposure of rats to (NH(4))(2)SO(4) + H(2)O(2) also resulted in tumor necrosis factor-alpha (TNF-alpha) production by alveolar macrophages. This was observed immediately and 24 h after exposure. Immediately after inhalation of (NH(4))(2)SO(4) + H(2)O(2), a transient increase in production of superoxide anion by alveolar macrophages was observed. In contrast, nitric oxide production by cells from rats exposed to (NH(4))(2)SO(4) + H(2)O(2) or H(2)O(2) alone was decreased, and this persisted for 24 h. Decreases in nitric oxide may be due to superoxide anion-driven formation of peroxynitrite. In this regard, nitrotyrosine, an in vivo marker of peroxynitrite, was detected in lung tissue after exposure of rats to (NH(4))(2)SO(4) + H(2)O(2) or H(2)O(2). We also found that expression of the antioxidant enzyme heme oxygenase-1 by stimulated alveolar macrophages was increased following exposure of rats to (NH(4))(2)SO(4) + H(2)O(2). Taken together, these studies demonstrate that the biological effects of inhaled fine PM are augmented by H(2)O(2). Moreover, tissue injury induced by fine PM may be related to altered production of cytotoxic mediators by alveolar macrophages.

Administration, Inhalation↗

PubMed2003

Seasonal variability of endotoxin in ambient fine particulate matter.

Endotoxin is a toxic, pro-inflammatory compound that has been detected in indoor air and dust in homes and occupational settings, and also in outdoor air. Data on the outdoor sampling of endotoxin are limited. Currently, little is known about the seasonal variation and influence of temperature on outdoor endotoxin levels. In the present study, we report endotoxin levels in fine fraction particulate matter with a 50% aerodynamic cutoff diameter of 2.5 microm (PM2.5) and describe the seasonal variation of endotoxin in Munich, Germany. In 1999-2000, PM2.5 was collected at forty outdoor monitoring sites across Munich. Approximately four samples were collected at each site for a total of 158 samples. Endotoxin concentrations in the PM2.5 samples were determined using the kinetic chromogenic Limulus Amebocyte Lysate (LAL) assay. The geometric mean endotoxin concentration was 1.07 EU mg PM2.5(-1) (95% C.I.: 0.915-1.251) or 0.015 EU m(-3) of sampled air (95% C.I.: 0.013-0.018). Munich endotoxin levels were significantly related to ambient temperature (p < 0.0001) and percent relative humidity (p < 0.0001). Sampling periods with higher average temperatures yielded higher levels of endotoxin in PM2.5 (r = 0.641), whereas decreases in percent relative humidity were associated with increased endotoxin levels in PM2.5 (r = -0.388). Endotoxin levels were significantly higher during the warmer seasons of spring [means ratio (MR): 2.5-2.7] and summer (MR: 2.1-3.0) than during winter. Although temperature and relative humidity do not explain all of the variability in endotoxin levels, their effects were significant in our data set. Temperature effects and seasonal variation of endotoxin should be considered in future studies of outdoor endotoxin.

Air Pollutants↗

PubMed2002

Effects of fractions of traffic particulate matter on TH2-cytokines, IgE levels, and bronchial hyperresponsiveness in mice.

In recent decades an increased prevalence of allergic conditions has been observed in developed countries. Although lifestyles, exposure to infection, and diet are all likely important factors, many studies have also shown a strong link between industrialization and allergy. The aim of this study was to investigate which extract fractions from traffic particulate matter (TPM, collected in a tunnel in Prague) have the greatest impact on different inflammatory and immunological parameters, such as cytokine production, levels of immunoglobulin E (IgE) antibodies, and bronchial hyperresponsiveness (BHR) in mice, when the extracts are used together with birch pollen for immunization. BP2 mice were immunized with birch pollen and different fractions of TPM (fractions 1-8). They were provoked intranasally with a mixture of pollen and TPM or pollen alone before they were challenged with methacholine. The BHR was evaluated in a whole-body plethysmograph. Th2 cytokines and fibronectin concentrations were measured, and differential cell counts were performed in the bronchioalveolar lavage (BAL) fluid. Sera were collected for determination of antibody titers. The highest titers of IgE and the highest BHR were found in the positive control mice (immunized and provoked with a mixture of pollen and TPM), followed by mice immunized with pollen and fraction 2 (which contains organic acids). Fraction 2 also induced the highest number of eosinophils and increased levels of interleukin 5 (IL-5) in the BAL fluid. The highest levels of IL-5, in BAL fluid and sera, were obtained in mice immunized with fraction 6 (moderately polar compounds), a somewhat surprising result since those mice did not produce any IgE, did not have any eosinophils in their BAL, or showed almost no BHR. Our data demonstrate that fractions 2 (organic acids) and 7 (highly polar compounds) seem to contain potential adjuvants stimulating the IL-5 production, the IgE synthesis, the eosinophil recruitment, and the bronchial hyperreactivity. Further characterization at the molecular level is now necessary to be able to identify the exact nature of those potential adjuvants. This will be of help in the future to improve the quality of the urban air aerosol.

Air Pollutants, Occupational↗

PubMed2002

Carbonaceous characteristics of atmospheric particulate matter in Hong Kong.

To determine the characteristic of carbonaceous species in atmospheric particles in Hong Kong, PM10 and PM2.5 samples were collected using high volume (hi-vol.) air samplers from November 2000 to February 2001. The organic carbon (OC) and elemental carbon (EC) were analyzed by the selective thermal manganese dioxide oxidation (TMO) method. The ratios of PM2.5/PM10 mass ratios were 0.61, 0.78 and 0.53 for particulate matter collected at PolyU station (PolyU, near a major traffic corridor), Kwun Tong station (KT, mixed residential/commercial/industrial) and the Hok Tsui background station (HT), respectively. These results indicate that the PM2.5 concentrations constitute the majority of the PM10) concentrations, especially in urban and industrial areas of Hong Kong. The average concentrations at the three sites ranged from 73.11 to 83.52 microg/m3 for PM10 and from 42.37 to 57.38 microg/m3 for PM2.5. The highest daily mass concentrations of PM10 and PM2.5 were 125.89 microg/m3 and 116.89 microg/m3 at KT, respectively. The correlation between PM10 and PM2.5 was high at KT and HT (r > 0.9, P < 0.01). This means that the sources of PM10 and PM2.5 may be the same at both sites. The highest mean concentration of OC (12.02 microg/m3) and EC (6.86 microg/m3) in PM10 was found at the PolyU among the three sites. For PM2.5, the highest mean concentration of OC (10.16 microg/m3) was at KT while the highest mean concentration of EC (7.95 microg/m3) was at PolyU. However, the background concentrations at HT were higher than another background area, Kosan, Korea. Transportation of pollutants from the Asian continent may be responsible for the elevations of EC+ OC at the remote site. More than 74% of the EC and more than 79% of the OC were found in the PM2.5 fraction at the three sampling locations. At PolyU station, PM2.5 consisted of 18.18% OC and 11.16% EC while 17.70% OC and 8.81% EC were found in KT station. Thus OC and EC are major constituents of aerosols in Hong Kong. OC/EC ratios for PM10 and PM2.5 were less than 2 at PolyU and KT stations while the ratio exceeded 3 at HT background station. This indicates that OC measured in the urban area may be emitted directly as a primary aerosol.

Aerosols↗

PubMed2005

The Steubenville comprehensive air monitoring program (SCAMP): associations among fine particulate matter, co-pollutants, and meteorological conditions.

We determined 24-hr average ambient concentrations of PM2.5 and its ionic and carbonaceous components in Steubenville, OH, between May 2000 and May 2002. We also determined daily average gaseous co-pollutant concentrations, meteorological conditions, and pollen and mold spore counts. Data were analyzed graphically and by linear regression and time series models. Multiple-day episodes of elevated fine particulate matter (PM2.5) concentrations often occurred during periods of locally high temperature (especially during summer), high pressure, or low wind speed (especially during winter) and generally ended with the passage of a frontal system. After removing autocorrelation, we observed statistically significant positive associations between concentrations of PM2.5 and concentrations of CO, NOx, and SO2. Associations with NOx and CO exhibited significant seasonal dependencies, with the strongest correlations during fall and winter. NOx, CO, SO2, O3, temperature, relative humidity, and wind speed were all significant predictors of PM2.5 concentration in a time-series model with external regressors, which successfully accounted for 79% of the variance in log-transformed daily PM2.5 concentrations. Coefficient estimates for NOx and temperature varied significantly by season. The results provide insight that may be useful in the development of future PM2.5 reduction strategies for Steubenville. Additionally, they demonstrate the need for PM epidemiology studies in Steubenville (and elsewhere) to carefully consider the potential confounding effects of gaseous co-pollutants, such as CO and NOx, and their seasonally dependent associations with PM2.5.

Air Pollutants↗

PubMed1996

Occurrence of polychlorinated terphenyls (PCTs) in indoor particulate matter.

In the course of a routine investigation concerned with polychlorinated biphenyl (PCB) contamination of dust collected in classrooms of a junior high school, a group of electron capture detector (ECD)-sensitive compounds with high boiling points were found in addition to PCBs. Using gas chromatographic-mass spectrometric techniques, these compounds were identified as polychlorinated terphenyls (PCTs). Additional measurements indicated that the PCTs were present only in particulate matter collected from the tops of fluorescent light frames but not in air samples obtained concomitantly in the classrooms. Attempts to identify the PCT emission source were unsuccessful. A survey of the literature revealed that PCTs are ubiquitously distributed environmental contaminants, although no data on their indoor occurrence have been reported to date. In view of the toxic effects of PCTs, which seem to be as important as those of PCBs, further attention should be given to the possible presence of PCTs in indoor environments.

Air Pollutants↗

PubMed2003

Enhanced pesticide sorption by soils containing particulate matter from crop residue burns.

Lack of proper techniques to isolate black carbon (BC) from soils has hindered the understanding of their roles in the sorption and environmental fate of organic contaminants in soils and sediments. The burning of crop residues may be the primary source of BC in agricultural soils. In this study, wheat (Triticum aestivum L.) and rice (Oryza sativa L.) residues were burned, and the resulting particulate matter (ashes) along with a soil were used to sorb diuron from water. Calculations indicated that the burning of crop residues may result in an appreciable level of ashes in soils. The diuron sorption isotherms on ashes were curvilinear Langmuir type, suggestive of surface adsorption and similar to that with activated carbon. Ashes were 400-2500 times more effective than soil in sorbing diuron over the concentration range of 0-6 mg/L. Sorption by wheat ash-amended soils and the degree of isotherm nonlinearity increased with increasing ash content from 0% to 1% (weight), indicating the significant contribution of wheat ash to the sorption. Calculations show that wheat ash and soil independently contributed to the sorption. Above the wheat ash content of 0.05%, the sorption was largely controlled by the ash. Density-based fractionation and repeated HCI-HF washing of wheat ash yielded carbon-enriched fractions and enhanced diuron sorption by these fractions. BC appeared primarily responsible for the high adsorptivity of ashes. Ashes arising from the burning of crop residues may be an important determinant of pesticide immobilization and environmental fate in soils.

Adsorption↗

PubMed2001

Particulate matter induces cytokine expression in human bronchial epithelial cells.

The present study was designed to determine cytokines produced by primary human bronchial epithelial cells (HBECs) exposed to ambient air pollution particles (EHC-93). Cytokine messenger RNA (mRNA) was measured using a ribonuclease protection assay and cytokine protein production by enzyme-linked immunosorbent assay. Primary HBECs were freshly isolated from operated lung, cultured to confluence, and exposed to 10 to 500 microg/ml of a suspension of ambient particulate matter with a diameter of less than 10 microm (PM(10)) for 2, 8, and 24 h. The mRNA levels of leukemia inhibitory factor (LIF), granulocyte macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-1alpha, and IL-8 were increased after exposure to PM(10), and this increase was dose-dependent between 100 (P < 0.05) and 500 (P < 0.05) microg/ml of PM(10) exposure. The concentrations of LIF, GM-CSF, IL-1beta, and IL-8 protein measured in the supernatant collected at 24 h increased in a dose- dependent manner and were significantly higher than those in the control nonexposed cells. The soluble fraction of the PM(10) (100 microg/ml) did not increase these cytokine mRNA levels compared with control values and were significantly lower compared with HBECs exposed to 100 microg/ml of PM(10) (LIF, IL-8, and IL-1beta; P < 0.05), except for GM-CSF mRNA (P = not significant). We conclude that primary HBECs exposed to ambient PM(10) produce proinflammatory mediators that contribute to the local and systemic inflammatory response, and we speculate that these mediators may have a role in the pathogenesis of cardiopulmonary disease associated with particulate air pollution.

Aged↗

PubMed2004

Use of a high-throughput umu-microplate test system for rapid detection of genotoxicity produced by mutagenic carcinogens and airborne particulate matter.

In the present study, we developed a rapid umu-microplate test system that uses the nitroreductase- and O-acetyltransferase-overproducing Salmonella typhimurium strain NM3009 and the O-acetyltransferase-overproducing S. typhimurium strain NM2009 to detect genotoxic activity in small volume samples. The assay was used to test the genotoxicity of several standard mutagens and environmental samples. Exponentially growing cultures of NM3009, NM2009, and the parental strain TA1535/pSK1002 were incubated in 96-well microplates with test chemicals both in the presence and in the absence of rat liver S9. The relative beta-galactosidase activities were then determined colorimetrically using either chlorophenol red-beta-D-galactopyranoside (CPRG) or O-nitrophenyl-beta-D-galactopyranoside (ONPG) as a measure of umuC gene induction activity. The sensitivities of NM3009 without S9 mix and NM2009 with S9 mix to nitroarenes and aromatic amines were up to 24- to 75-fold higher than those of the parent strain. Induction of umuC gene expression was detected more readily with CPRG than ONPG. The umu-microplate assay also detected genotoxicity in organic extracts of particulate matter from air samples collected in Osaka City, Japan. The pattern of the responses suggested that the genotoxic activity of the particulate extract was due primarily to nitrated polycyclic aromatic hydrocarbons. Our results indicate that the umu-microplate assay may be a useful way of carrying out rapid screens for genotoxicity in small-volume environmental samples.

Air Pollutants↗