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PubMed2001

Low-molecular weight dicarboxylic acids and glyoxylic acid: seasonal and air mass characteristics.

Low-molecular weight dicarboxylic acids are important constituents ofthe organic fraction of atmospheric particulate matter in remote and polluted regions. The knowledge on their sources is sparse, however, and organic aerosols in general need to be better characterized. Observations of C2-C5 alpha,omega-dicarboxylic acids (DCAs oxalic, malonic, succinic, and glutaric acid) and C2 oxomonocarboxylic acid (glyoxylic acid) from rural and urban sites in different seasons in Germany are reported using filter sampling and ion chromatography. The C2-C5 DCAs accounted for (by average) 0.07-0.51 microg m(-3) at the various sites corresponding to 3.4-23 mg g(-1) of total suspended particulate matter and glyoxylic acid for < 0.18-0.28 mg g(-1). Both, the transport of air masses over the continent and the summer season favored the occurrence of the acids. Secondary photochemical formation dominated the sources. It was found that for central Europe the anthropogenic emissions are more important than the biogenic emissions for all the acids determined and most important for oxalic acid. The biogenic precursors play a signifcant role for malonic acid. The influence of the marine sources was detectable for malonic and glutaric acid.

Air Pollutants↗

PubMed1989

Biomonitoring after controlled exposure to environmental tobacco smoke (ETS).

A rough estimation of the amounts of tobacco smoke components taken up by active and passive smoking suggests that, in the case of passive smoking, gas phase constituents in ETS are of greater relevance than particle-bound substances. Since this aspect is of importance for the risk evaluation of passive smoking, it was decided that it should be investigated further in a series of exposure studies with human volunteers. The ETS exposure conditions were characterized by measuring tobacco smoke components such as carbon monoxide (CO), nitrogen oxides (NOx), nicotine, formaldehyde, tobacco-specific nitrosamines (N-nitrosonornicotine (NNN), 4-methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), benzo(a)pyrene (BaP) and particulate matter in the air of the exposure room. The biomonitoring covered carboxyhemoglobin (COHb), thioethers and mutagenic activity in urine. These parameters were compared to those observed after controlled active smoking. It was found that urinary thioether excretion increased in non-smokers after extremely high ETS exposure. This effect could be attributed to gas phase ETS components. Urinary mutagenicity was not measurably increased in non-smokers under these conditions. This indicates that in passive smoking, as opposed to smoking, the gas phase might be more important in terms of possible effects than the particulate matter. It would, therefore, be misleading to make extrapolations based on the burden of smoking to establish the burden of passive smoking.

Adult↗

PubMed2000

Characteristics of heavy metals on particles with different sizes from municipal solid waste incineration.

Information on the concentration and size distribution of particles in the flue gas streams is essential for selecting and designing particle removal systems. Two municipal solid waste incinerators (MWIs) were selected for conducting flue gas sampling to determine the particulate distribution and heavy metals concentration on particles with different sizes by US EPA Method 5 sampling train and a cascade impactor. In addition, the characteristics of heavy metals contained on particles were investigated via isokinetic sampling of flue gas stream of air pollution control devices (APCDs). The experimental results indicated that average particulate matter (PM) concentrations at APCDs inlet were 2288.2+/-825.9 and 3069.2+/-810. 0mg/Nm(3), while the concentrations of PM at stack were 1.51+/-0.20 and 14.81+/-4.52mg/Nm(3) in MWI-A and MWI-B, respectively. The differential mass size distribution of PM and differential elemental size distribution of Zn, Pb, and Cu in front of APCDs were of bimodal forms. Results indicate that Zn>Pb>Cu in order of mass concentration in each stage. The fine particles represent approximately 70% and the coarse particles account for the rest 30% of total particulate matters collected on eight stages for both incinerators. Zn, Pb and Cu on fine particles account for approximately 80% and those on the coarse particles are less than 20% of the total heavy metals collected on eight stages of the cascade impactor for both incinerators.

Air Pollutants↗

PubMed2001

Differences among black smoke, PM(10), and PM(1.0) levels at Urban Measurement Sites.

n Amsterdam, the Netherlands, we measured airborne particulate matter (PM) during winter 1998-1999, taking daily average measurements at an urban background site, at a busy street, and at a motorway. Comparison of black smoke, PM(10), and PM(1.0) levels showed that daily averages were highly correlated over time. Median daily concentrations were elevated at sites affected by traffic. The highest increase relative to the background in median daily concentration was noted for black smoke at the motorway (300%), whereas for PM(10) and PM(1.0) the increase was only 37% and 30%. These results indicate that mass measurements of ambient particulate matter underestimate the exposure to particles generated by traffic.

Air Pollutants↗

PubMed2004

Aerosol ion characteristics during the Big Bend Regional Aerosol and Visibility Observational study.

The ionic compositions of particulate matter with aerodynamic diameter < or = 2.5 microm (PM2.5) and size-resolved aerosol particles were measured in Big Bend National Park, Texas, during the 1999 Big Bend Regional Aerosol and Visibility Observational study. The ionic composition of PM2.5 aerosol was dominated by sulfate (SO4(2-)) and ammonium (NH4+). Daily average SO4(2-) and NH4+ concentrations were strongly correlated (R2 = 0.94). The molar ratio of NH4+ to SO4(2-) averaged 1.54, consistent with concurrent measurements of aerosol acidity. The aerosol was observed to be comprised of a submicron fine mode consisting primarily of ammoniated SO4(2-) and a coarse particle mode containing nitrate (NO3-). The NO3- appears to be primarily associated with sea salt particles where chloride has been replaced by NO3-, although formation of calcium nitrate (Ca(NO3)2) is important, too, on several days. Size-resolved aerosol composition results reveal that a size cut in particulate matter with aerodynamic diameter < or = 1 microm would have provided a much better separation of fine and coarse aerosol modes than the standard PM2.5 size cut utilized for the study. Although considerable nitric acid exists in the gas phase at Big Bend, the aerosol is sufficiently acidic and temperatures sufficiently high that even significant future reductions in PM2.5 SO4(2-) are unlikely to be offset by formation of particulate ammonium nitrate in summer or fall.

Aerosols↗

PubMed1992

Psychopharmacological effects of smoking a cigarette with typical "tar" and carbon monoxide yields but minimal nicotine.

Five male smokers were tested, after 48-h abstention from tobacco-product use, smoking a leading "lights" category cigarette (Control-FTC nicotine yield 0.6 mg) and another cigarette yielding similar amounts of "tar" and carbon monoxide (CO), but only 0.06 mg nicotine (Test). Heart rate (HR) and the electroencephalogram (EEG) were monitored before, during and after the smoking of each cigarette. Other measures obtained included the subjects' puffing and breathing behaviors during smoking, plasma nicotine concentrations, blood carboxyhemoglobin concentrations and expired-air CO. The results indicated no significant differences in the way the subjects puffed and inhaled the two cigarettes and they were therefore assumed to have inhaled similar amounts of particulate matter and gas-phase components. Plasma nicotine concentrations were significantly higher following smoking of the Control cigarette. HR (percent relative change) increased following smoking of either cigarette; however, HR increase was significantly greater following smoking of the Control cigarette. Smoking the Test cigarette had no effect on the EEG. Smoking the Control cigarette produced a significant increase in beta 2 magnitude and a significant decrease in delta magnitude. This indicates that the effects of smoking on the EEG are a function of nicotine absorbed from cigarette smoke upon inhalation and not a function of inhaled particulate matter, CO, or other gas-phase components.

Analysis of Variance↗

PubMed2004

Analysis of inorganic mercury species associated with airborne particulate matter/aerosols: method development.

This paper describes a method for speciation of Hg associated with airborne particulate matter. This method uses a mini-sampler for sample collection and analysis, thermal desorption for separating Hg species, and inductively coupled plasma mass spectrometry (ICP-MS) for identification and quantification of Hg. Coal fly ash spiked with different Hg compounds (e.g. Hg0, HgCl2, HgO, and HgS) was used for qualitative calibration. A standard reference material with a certified value for Hg concentration was used to evaluate the method. When the temperature of the furnace was programmed at a linear rate of increase of 50 degrees min(-1), different Hg compounds could clearly be separated. Three airborne particulate matter samples were collected in parallel in Toronto, ON, Canada and analyzed using this method. Reproducible results were obtained and Hg0, HgCl2, HgO, and HgS species from these samples were detected.

Journal Article↗

PubMed1992

Fractionation of atmospheric acid and base components within storm events by precipitation scavenging processes.

Concentrations of ions in storm rainwater in Texas have been monitored for each 0.254 mm increment of precipitation. The changes in concentrations have been analyzed to investigate the role of differential rates of scavenging of particulate matter of differing particle size, and especially the major acid and base components. The empirical trend at the onset of rainfall is a chemical fractionation of acids and bases with correspondingly wide pH variations. These results are confirmed by model calculations, which show a significant preferential scavenging of calcium relative to sulfate in the first 10 mm of rainfall, resulting in fractionation of bases and acids from their atmospheric concentrations. Previous studies, using Target Transformation Factor Analysis of ion concentrations in storm precipitation and regional ambient aerosol data, statistically determined the average source for acidic secondary species and alkaline particulate matter. Two types of crustal sources were identified as western and eastern soil dust. In this study, an alternate physical explanation for these two soil dust factors is offered. As a storm progresses, the elements in the local soil dust are fractionated as a result of their differential rates of precipitation scavenging, enriching species predominantly in the fine particle size and depleting elements predominantly in the coarse particle size. This fractionation process results in a single source having different elemental ratios at the beginning and at the end of a rain event. For Austin, Dallas, and Tyler, Texas, the soil dust previously identified as being from eastern sources could, instead, be a fractionated form of the western soil source.

Journal Article↗

PubMed2004

Trends in secondary organic aerosol at a remote site in Michigan's upper peninsula.

The trends in secondary organic aerosol at a remote location are studied using atmospheric fine particulate matter samples collected at Seney National Wildlife Refuge (NWR) in northern Michigan. Detailed analysis of particle-phase organic compounds revealed very low concentrations of primary anthropogenic emissions and relatively high levels of organic di-, tri-, and tetracarboxylic acids thought to be indicators of secondary organic aerosols. Seasonal changes in these organic compounds were tracked by analyzing composites of monthly average samples. The concentration of aromatic and aliphatic dicarboxylic acids peak in July and taper off in the fall, which coincides with fine particle organic carbon concentration. In contrast, a chemical mass balance model used to quantify primary sources of particulate matter shows higher contributions from primary emissions in the winter. Complementing the monthly average concentrations, event-based composites of high volume samples were used to track the different species of secondary organic aerosol at the Seney NWR location. The distribution of aliphatic diacids and the aromatic di- and triacids varied with different atmospheric conditions, which suggests different precursor gases for these secondary organic aerosol components. The aliphatic diacid concentrations track with ambient concentrations of particle-phase pinonic acid. In addition, back-trajectories for the eight event-based composites are compared to the organic acid distributions and are linked to the distribution of organic acids present in the composites.

Aerosols↗

PubMedDate not supplied

[Air pollution and the lung: epidemiological approach].

Epidemiological evidence has concurred with clinical and experimental evidence to correlate current levels of ambient air pollution, both indoors and outdoors, with respiratory effects. In this respect, the use of specific epidemiological methods has been crucial. Common outdoor pollutants are particulate matter, nitrogen dioxide, carbon monoxide, volatile organic compounds and ozone. Short-term effects of outdoor air pollution include changes in lung function, respiratory symptoms and mortality due to respiratory causes. Increase in the use of health care resources has also been associated with short-term effects of air pollution. Long-term effects of cumulated exposure to urban air pollution include lung growth impairment, chronic obstructive pulmonary disease (COPD), lung cancer, and probably the development of asthma and allergies. Lung cancer and COPD have been related to a shorter life expectancy. Common indoor pollutants are environmental tobacco smoke, particulate matter, nitrogen dioxide, carbon monoxide, volatile organic compounds and biological allergens. Concentrations of these pollutants can be many times higher indoors than outdoors. Indoor air pollution may increase the risk of irritation phenomena, allergic sensitisation, acute and chronic respiratory disorders and lung function impairment. Recent conservative estimates have shown that 1.5-2 million deaths per year worldwide could be attributed to indoor air pollution. Further epidemiological research is necessary to better evaluate the respiratory health effects of air pollution and to implement protective programmes for public health.

Air Pollutants↗

PubMed2006

Experimental and numerical smoke carcinogen deposition in a multi-generation human replica tracheobronchial model.

A better understanding of submicron particle deposition in the respiratory tract is needed to study the health effects caused by carcinogenic particles. Recent studies indicate that random diffusion is not sufficient to describe the motion of these particles in complex geometries, rendering conventional models inaccurate. A solid replica of excised human lung segments was used to create digital and hollow models of the tracheobronchial region to investigate deposition of mainstream (MS) and sidestream (SS) cigarette smoke particles. Particle sizes for the carcinogen Benzo(a)pyrene (BaP) in SS smoke, and total particulate matter (UVPM) in SS and MS smoke were measured and used to compare the simulation to experimental data. Excellent agreement was found between predicted and measured results. Random diffusion was not found to be significant for submicron particles indicating that particles were instead transported to the airway wall by convective diffusion. BaP in SS smoke was an average 0.3 mum compared to 0.36 mum for UVPM in SS smoke. The trends in both experimental and numerical results indicated that the BaP in SS smoke deposits at a slightly higher efficiency than the UVPM, indicating that carcinogen-specific deposition, rather than total particulate matter should be considered when investigating health effects.

Benzopyrenes↗

PubMed2004

Ambient endotoxin concentrations in PM10 from Southern California.

Concentrations of endotoxin in urban air pollution have not previously been extensively characterized. We measured 24-hr levels of PM10 (particulate matter < 10 microm in aerodynamic diameter) and the associated endotoxin component once every 6 weeks for 1 year in 13 communities in Southern California. All the samples collected had detectable PM10 and endotoxin levels. The geometric mean PM10 was 34.6 microg/m3 [geometric SD (GSD), 2.1; range, 3.0-135]. By volume, the endotoxin geometric mean was 0.44 endotoxin units (EU)/m3 (GSD, 3.1; range, 0.03-5.44). Per unit material collected, the geometric mean of endotoxin collected was 13.6 EU/mg (GSD, 3.2; range, 0.7-96.8). No correlation was found between endotoxin concentrations and other ambient pollutants concurrently measured [ozone, nitrogen dioxide, total acids, or PM2.5 (particulate matter < 2.5 micro m in aerodynamic diameter]. PM10 and endotoxin concentrations were significantly correlated, most strongly in summer. Samples collected in more rural and agricultural areas had lower PM10 and mid-range endotoxin levels. The high desert and mountain communities had lower PM10 levels but endotoxin levels comparable with or higher than the rural agricultural sites. By volume, endotoxin levels were highest at sites downwind of Los Angeles, California, which were also the locations of highest PM10. Endotoxin concentrations measured in this study were all < 5.5 EU/m3, which is lower than recognized thresholds for acute adverse health effects for occupational exposures but in the same range as indoor household concentrations. This study provides the first extensive characterization of endotoxin concentration across a large metropolitan area in relation to PM10 and other pollutant monitoring, and supports the need for studies of the role of endotoxin in childhood asthma in urban settings.

Air Pollutants↗

PubMed2003

Impact of unleaded gasoline introduction on the concentration of lead in the air of Dhaka, Bangladesh.

Airborne particulate matter (APM) samples collected at a semiresidential area in Dhaka, Bangladesh, during the periods of 1994 and 1997-2000 have been studied to assess the impact of the use of unleaded gasoline in Bangladesh. According to scanning electron microscopy/ energy-dispersive X-ray microanalyzer studies, lead (Pb) was found as Pb sulfates and Pb halides in motor-vehicle exhaust particles, whose diameters were some hundreds of nanometers. No significant changes in the annual averages of APM mass and black carbon concentrations have been observed over the period. The yearly average Pb concentration reached a maximum value of 370 ng/m3 in the particulate matter with an aerodynamic diameter < 2.5 microm fraction in 1998. In 2000, the concentration decreased to approximately one-third (106 ng/m3) of the high earlier values after the introduction of unleaded gasoline in 1999. A significant lowering of the blood Pb level of the population over next few years is expected as a result of this great decrease in Pb concentration.

Air Pollutants↗

PubMed2003

Mosquito coil emissions and health implications.

Burning mosquito coils indoors generates smoke that can control mosquitoes effectively. This practice is currently used in numerous households in Asia, Africa, and South America. However, the smoke may contain pollutants of health concern. We conducted the present study to characterize the emissions from four common brands of mosquito coils from China and two common brands from Malaysia. We used mass balance equations to determine emission rates of fine particles (particulate matter < 2.5 microm in diameter; PM(2.5)), polycyclic aromatic hydrocarbons (PAHs), aldehydes, and ketones. Having applied these measured emission rates to predict indoor concentrations under realistic room conditions, we found that pollutant concentrations resulting from burning mosquito coils could substantially exceed health-based air quality standards or guidelines. Under the same combustion conditions, the tested Malaysian mosquito coils generated more measured pollutants than did the tested Chinese mosquito coils. We also identified a large suite of volatile organic compounds, including carcinogens and suspected carcinogens, in the coil smoke. In a set of experiments conducted in a room, we examined the size distribution of particulate matter contained in the coil smoke and found that the particles were ultrafine and fine. The findings from the present study suggest that exposure to the smoke of mosquito coils similar to the tested ones can pose significant acute and chronic health risks. For example, burning one mosquito coil would release the same amount of PM(2.5) mass as burning 75-137 cigarettes. The emission of formaldehyde from burning one coil can be as high as that released from burning 51 cigarettes.

Air Pollution, Indoor↗

PubMed2005

Relation between ambient air quality and selected birth defects, seven county study, Texas, 1997-2000.

A population-based case-control study investigated the association between maternal exposure to air pollutants, carbon monoxide, nitrogen dioxide, ozone, sulfur dioxide, and particulate matter <10 microm in aerodynamic diameter during weeks 3-8 of pregnancy and the risk of selected cardiac birth defects and oral clefts in livebirths and fetal deaths between 1997 and 2000 in seven Texas counties. Controls were frequency matched to cases on year of birth, vital status, and maternal county of residence at delivery. Stationary monitoring data were used to estimate air pollution exposure. Logistic regression models adjusted for covariates available in the vital record. When the highest quartile of exposure was compared with the lowest, the authors observed positive associations between carbon monoxide and tetralogy of Fallot (odds ratio = 2.04, 95% confidence interval: 1.26, 3.29), particulate matter <10 microm in aerodynamic diameter and isolated atrial septal defects (odds ratio = 2.27, 95% confidence interval: 1.43, 3.60), and sulfur dioxide and isolated ventricular septal defects (odds ratio = 2.16, 95% confidence interval: 1.51, 3.09). There were inverse associations between carbon monoxide and isolated atrial septal defects and between ozone and isolated ventricular septal defects. Evidence that air pollution exposure influences the risk of oral clefts was limited. Suggestive results support a previously reported finding of an association between ozone exposure and pulmonary artery and valve defects.

Air Pollutants↗

PubMed1999

DNA adduct formation from the mutagenic air pollutant 3-nitrobenzanthrone.

The environmental contaminant 3-nitrobenzanthrone (3-nitro-7H-benz[d, e]anthracen-7-one) was recently shown to be a very strong bacterial mutagen, suggesting a new class of mutagenic compounds present in airborne particulate matter and diesel exhaust. Using the 32P-postlabeling assay, we investigated the capacity for 3-nitrobenzanthrone to form DNA adducts in vitro. Calf thymus DNA was incubated with 3-nitrobenzanthrone and either xanthine oxidase, a mammalian nitroreductase or rat liver S9 or zinc. Under these conditions 3-nitrobenzanthrone formed a total of seven adducts detectable by 32P-postlabeling. Using enrichment by butanol extraction the highest level of DNA adduct formation was found with activation by zinc (RAL: 88.4+/-32 per 108 nucleotides) followed by activation with xanthine oxidase (RAL: 75.5+/-12) and activation by rat liver S9 (RAL: 48.6+/-8). Three of the seven adduct spots were detected in all activation systems, however different amounts of individual spots were obtained in the different in vitro systems. The adduct pattern observed for the enzymatic incubations consisted of three major spots and was essentially identical. Chemical reduction of 3-nitrobenzanthrone by zinc resulted in five adduct spots whose formation was found to be concentration dependent. All adducts of 3-nitrobenzanthrone observed in this study migrated primarily along a diagonal zone, typical for DNA adducts derived from extracts of airborne particulate matter. When butanol enrichment was compared with nuclease P1 enrichment one adduct was clearly sensitive to the 3'-monophosphatase activity of nuclease P1. Our results demonstrate that 3-nitrobenzanthrone binds covalently to DNA after metabolic activation, forming multiple DNA adducts in vitro all of which are reduction products. These adducts may contribute to the known genotoxicity and carcinogenicity of extracts from airborne particulates.

Air Pollutants↗

PubMed2005

Lead and cadmium in indoor air and the urban environment.

The present study was conducted to find potential terrestrial biomonitors for heavy metals in indoor air in an urban environment. TSP, PM(10), and PM(2.5) were collected in three retirement facilities in the urban area of Vienna. In addition, particulate matter and soil, vegetation, and isopods (Porcellio scaber L.) were collected in the adjacent garden areas. Aerosols were sampled with a low-volume air sampler. The sampled materials were wet ashed and total lead and cadmium contents were determined. Water-soluble heavy metal concentrations were measured in aqueous extracts from air exposed filters, soil, and vegetation. Lead and cadmium were analyzed by graphite furnace AAS. Lead contents in the vegetation were inferred from water-soluble lead in soils. Lead in isopods generally reflected the contents in vegetation. Cadmium in plants probably derived from soil solutions as well as from atmospheric input. Isopods reflected the total cadmium contents in soils. Particulate matter was dominated by PM(2.5), both with respect to mass concentrations and to heavy metal contents. The indoor aerosol was found to be influenced by human activity, indoor sources, and outdoor particles. Relationships between indoor airborne heavy metals and the contents in vegetation (lead and cadmium: positive) and isopods (lead: negative) were identified to have the potential for biomonitoring indoor air quality.

Air Pollutants↗

PubMed1991

Effect of exposure route on potency of carcinogens.

To compare the effectiveness of different exposure routes for the induction of cancer in experimental animals, the estimated dose associated with a 25% additional risk of cancer (RRD(25)) was calculated using a group of carcinogenic agents for which both inhalation and oral ingestion cancer bioassays were available. Comparisons were made of 14 agents in rats and 9 in mice. Seven of the nine compared in mice were also compared in rats. Among rats, 8 of 14 agents were more effective via the oral route, while 7 of 9 were more effective via the oral route in mice. The variation in RRD(25) values with route, however, was less than 10-fold for all the agents tested in mice and for 11 of 14 tested in rats. An overall difference in potency with route could not be detected statistically. In rats, differences in potency greater than 10-fold were found for asbestos, vinyl chloride, and hydrazine. In the case of asbestos, the agent was in the form of relatively insoluble particulate matter. The greater potency via inhalation is likely due to longer residence time of the particles in the deep lung than in the gut, allowing for a greater degree of particle dissolution with an accompanying increase in bioavailability. Vinyl chloride was generally tested by inhalation at doses high enough to saturate activation pathways, resulting in underestimates of low-dose potency. Many of the smaller potency differences with route, as well as those for hydrazine, were considered likely to be the result of variability in the design and/or quality of studies. It was concluded that, if the design and conduct of the experiments were adequate, if agents in the form of relatively insoluble particulate matter are eliminated, and if corrections are made to account for incomplete activation, then large errors during route extrapolation are unlikely to occur.

Administration, Inhalation↗