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Seasonal and spatial relationship of chemistry and toxicity in atmospheric particulate matter using aquatic bioassays.

In light of current interest in better understanding the environmental impact of atmospheric particulate matter (PM), a new strategy has been employed to screen the relative toxicities of ambient and source aerosols. Short-term and acute aquatic bioassays using Ceriodaphnia dubia and a green alga (Selenastrum capricornutum) as test organisms have been in use for many years in the regulation of wastewater effluents. These tests have been employed in the present study to compare the toxicity of water extracts of atmospheric particulate matter and dichloromethane (DCM) extracts that have been transferred to dimethyl sulfoxide and diluted in water. Atmospheric PM was collected at four sites located near the south shore of Lake Michigan and one site in Michigan's Upper Peninsula at discrete events during three seasons. Parallel chemical analyses of the two extracts directly assessed the relation between the chemical composition and the toxicity of the extract. Inductively coupled plasma analysis of the metals in the water extract and gas chromatography-mass spectroscopy of the organics in the DCM extract showed a relationship between high toxicity and high water-soluble copper concentration and high secondary organic aerosol tracers in the extracted aerosol. Although previous fractionation studies have not looked at water-soluble copper, significant toxicity has been measured in the semipolar and polar organic fractions of ambient aerosols and diesel exhaust particles, which are the fractions in which secondary organic aerosol components would be expected. For the water extracts, the summer samples were consistently more toxic than the autumn or spring samples. There was not a seasonal pattern for the toxicity of the DCM extracts; however, spatial differences were apparent. The toxicity end points of select samples from one site qualitatively correlate with the high polycyclic aromatic hydrocarbon concentrations. Additionally, high toxicity in the July DCM extracts from another site may be tied to the presence of the insecticide carbaril. The seasonal and spatial variations captured in the toxicity results in this study tend to qualitatively correlate with trace organic components and metals and not bulk particulate matter composition.

Air Pollutants↗

Roadside concentration of gaseous and particulate matter pollutants and risk assessment in Dar-es-Salaam, Tanzania.

This study used manual air sampling method to assess the contribution of road traffic to air pollution level in Dar-es-Salaam City, Tanzania. Samples were collected from 11 different sites. Parameters measured were: sulphur dioxide using pararosaniline method, nitrogen dioxide using saltzman method, particulate matter and particulate lead using filtration method and atomic absorption spectrometric method, respectively. Results showed that hourly average sulphur dioxide concentration range from 127 to 1385 microg/m3. The measured values of sulphur dioxide were above the recommended WHO guidelines with an hourly objective value of 350 microg/m3 at 87% of the sampling sites. The hourly average nitrogen dioxide concentration ranged from 18 to 53 microg/m3. The maximum hourly nitrogen dioxide concentration at 53 microg/m3 was below the WHO guideline value of 200 microg/m3. The hourly average suspended particulate matter (SPM) ranged from 98 to 1161 microg/m3, exceeding the recommended value of 230 microg/m3 by WHO at 87% of the sampling sites. The hourly average lead concentration was found to range from 0.60 to 25.6 microg/m3, exceeding again the WHO guideline value of 1.5 microg/m3 at 83% of the sampling sites. Results predicted by Gaussian model when compared with the measured values were found to have a correlation coefficient of 0.8, signifying a good correlation. The risk assessment was undertaken considering the people who spend a significant portion of their time near the roads, such as the Uhuru primary school pupils and the adult population who reside by the roadside. The unit risk realised was 18.2 x 10(-6) for adult population and 2.2 x 10(-6) for pupils, both scenarios showing risk higher than the United Sates of America Environmental Protection Agency (USEPA) acceptable limit of 1 x 10(-6). Considering the magnitude of the problem at hand, this study recommends an introduction of mandatory emission tests of SPM, lead and sulphur dioxide (SO2). The study further recommends the introduction of continuous and/or regular air quality monitoring and the use non-leaded petrol in Tanzania.

Air Pollutants↗

Chemical and mutagenic patterns of airborne particulate matter collected in 17 Italian towns.

The mutagenicity of airborne particulate matter collected in 17 towns of Italy in 1990 was assessed using the Ames test. The mutagenicity of crude extract correlated with amount of lead, suggesting the direct contribution of gasoline car exhausts. Moreover, the mutagenicity correlated with particulate matter amounts. An inverse correlation with temperature was observed. The crude extracts were fractionated in acid, basic, and neutral fractions. The latter was further separated into polycyclic aromatic hydrocarbon (PAH), polar, and nonpolar fractions. Acid and polar fractions showed the higher mutagenicity. Average recovery of mutagenicity was about 60%.

Air Pollutants↗

Recent exposure to particulate matter and C-reactive protein concentration in the multi-ethnic study of atherosclerosis.

Ambient levels of particulate matter have been linked to cardiovascular disease. The mechanisms mediating these associations are poorly understood. One candidate mechanism is inflammation. Using data from the Multi-Ethnic Study of Atherosclerosis (2000-2002), the authors investigated the relation between exposure to particulate matter of less than or equal to 2.5 microm in diameter (PM2.5) and C-reactive protein concentration in 5,634 persons aged 45-84 years who were free of cardiovascular disease. Data from US Environmental Protection Agency monitors were used to estimate PM2.5 exposures for the prior day, prior 2 days, prior week, prior 30 days, and prior 60 days. Only the 30-day and 60-day mean exposures showed a weak positive association with C-reactive protein, and confidence intervals were wide: relative increases in C-reactive protein per 10 microg/m3 of PM2.5 adjusted for person-level covariates were 3% (95% confidence interval (CI): -2, 10) for a 30-day mean and 4% (95% CI: -3, 11.0) for a 60-day mean. The means of 7-day, 30-day, and 60-day exposures were weakly, positively, and nonsignificantly associated with the odds of C-reactive protein of greater than or equal to 3 mg/liter: adjusted odds ratios were 1.05 (95% CI: 0.96, 1.15), 1.12 (95% CI: 0.98, 1.29), and 1.12 (95% CI: 0.96, 1.32), respectively. Slightly stronger associations were observed in persons without other risk factors for elevated C-reactive protein, but this heterogeneity was not statistically significant. The authors' results are not compatible with strong effects of particulate matter exposures on population levels of C-reactive protein.

Aged↗

[Genotoxicity of urban air particulate matter].

This paper reviews the genetic toxicology of urban air particulate. Dusts present in the urban environment are composed of a special type of soot, currently mainly emitted by motor vehicles. This soot contains variable quantities of adsorbed highly active genotoxic compounds (polycyclic aromatic hydrocarbons and their nitro derivatives, i.e., nitroarenes). Nitroarenes are among the compounds with the highest genotoxic activity according to the Ames test (genetic point mutation on bacteria), and are particularly abundant in ultrafine particulate matter (< 1.1 microns) emitted by diesel engines, mainly trucks. Diesel emissions have been considered as probable carcinogenic agents for man by the International Agency for Research on Cancer (IARC). Highly mutagenic activity is present in the air of all the cities in the world, and there is increasing concern about possible carcinogenic effects on the general population as a result of exposure to urban particulate matter. Early epidemiological studies on city-dwellers exposed to heavy pollution indicate an excess of lung tumours. Lastly, there is a possible carcinogenic risk for occupationally exposed workers, such as traffic police and those working for city road cleaning services, etc., who are constantly obliged by their jobs to be exposed to polluted city air at work.

Air Pollutants↗

Trace gases and particulate matter emissions from wildfires and agricultural burning in Northeastern Mexico during the 2000 fire season.

An inventory of air pollutants emitted from forest and agricultural fires in Northeastern Mexico for the period of January to August of 2000 is presented. The emissions estimates were calculated using an emissions factor methodology. The inventory accounts for the emission of carbon monoxide (CO), methane, nonmethane hydrocarbons, ammonia, nitrogen oxides, and particulate matter (PM). Particulate matter emissions include estimates for fine PM and coarse PM. A total of 2479 wildfires were identified in the domain for the period of interest, which represented approximately 810,000 acres burned and 621,130 short tons emitted (81% being CO). The main source of information used to locate and estimate the extent of the fires came from satellite imagery. A geographic information system was used to determine the type of vegetation burned by each fire. More than 54% of the total area burned during the period of study was land on the State of Tamaulipas. However, >58% of the estimated emissions came from the State of Coahuila. This was because of the mix of vegetation types burned in each state. With respect to the temporal distribution, 76.9% of the fires occurred during the months of April and May consuming almost 78% of the total area burned during the period of study. Analysis of wind forward trajectories of air masses passing through the burned areas and 850-mb wind reanalyses indicate possible transboundary transport of the emissions from Mexico to the United States during the occurrence of the major wildfires identified.

Agriculture↗

Spatial and seasonal variation of major and trace elements in settling particulate matter in an estuarine-like archipelago area in the Northern Baltic proper.

This study describes the spatial and the seasonal variation of flux and concentration of 11 metals (Al, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Zn), organic matter and C and N in settling particulate matter collected with sediment traps during seven interconnective, continuous periods totalling 15 months. Ten sediment traps were placed out along the metropolis-affected fresh water outflow of Lake Mälaren, out through a non-tidal estuarine-like region with a low salt content, through the Stockholm archipelago to the Baltic. The metal concentrations of the particles were analysed with AAS using the flame technique and the amounts of C and N were determined with elemental analysis (CHN). The flux of particulate matter and of all metals decreased rapidly outwards in a gradient from the innermost stations. The distribution and composition of the particles were dominated by variations in the runoff from Lake Mälaren and by the seasonal dependence on primary production. However, they were also influenced locally by the supply of nutrients via water treatment plant effluents and probably by the special sedimentation conditions in the mixing zones and by resuspension. The concentrations of Cu, Hg, Pb and Cd in the interior of the area under investigation were the most elevated of the elements and decreased markedly further out in the archipelago, indicating local anthropogenic input. Zn, Cr and Fe also showed signs of supply from the urbanized environment. The flux of most of the metals studied displayed both spatial and seasonal correlation with the weight (TPM) of the material, whereas seasonal variation of Cd was correlated to its volume (TPV) and concentration of organic matter (POM, PC and PN).

Journal Article↗

Comparison of the sensitivity of three lung derived cell lines to metals from combustion derived particulate matter.

While the effects of inhalation of combustion-derived particulate matter have received extensive study, there remains no reliable means to rapidly quantify inhalation toxicity outside of a laboratory setting. Cell-based biosensors provide a potential solution, but few comparisons have been made of the sensitivity of various cell lines to the wide range of inhalation health hazards that are likely to be encountered. This work compares the response of three immortalized lung cell lines (A549 human epithelia, RLE-6TN rat type II epithelia, and NR8383 rat alveolar macrophages) to metals commonly present in combustion-derived particulate matter. Quantifications of the cell response involved measurement of inhibition of cell culture metabolism (mitochondrial succinate dehydrogenase activity) and cell death (release of lactate dehydrogenase). While these three cell types generally ranked metals in ED50 values similarly (V<Zn<Cu<Ni<Fe), with one exception, the concentrations of metals leading to a 50% reduction in cell population health differed significantly. Macrophages were most sensitive to metals by nearly an order of magnitude in metal concentration, followed by RLE-6TN rat epithelia, then A549 human cells. This comparison of the sensitivity of three cell types provides a basis for selection of cell types for use in cell-based biosensors.

Air Pollutants↗

[Direct collection with graphite probe filters and determination of trace cadmium in atmospheric particulate matter by graphite probe furnace atomic absorption spectrometry].

After atmospheric particulate matter was directly collected with graphite probe filters, the trace cadmium in APM was determined by graphite probe furnace atomic absorption spectrometry. The results showed that the absorbance (peak-area mode)and the concentration of cadmium had a excellent linearity in the range of 0-50 microg/L. The characteristic mass and detection limit (3 sigma) were 2.48 and 1.86 pg, respectively. Its relative standard deviation was 2.06% (n = 11). The results of analysis of the National Bureau of standards of America, Standard Reference Material (SRM) No. 1648, Urban Particulate Matter, gave a recovery of 90.15-99.29% with RSD of 4.09%. The method proved to be accurate, sensitive, rapid and simple.

English Abstract↗

Toxicity of ambient atmospheric particulate matter from the Lake Michigan (USA) airshed to aquatic organisms.

Short-term chronic and acute aquatic bioassays are valuable tools in screening a variety of environmental samples. However, only a limited number of studies have used these methods for testing the toxicity of atmospheric particulate matter samples. Previous studies have shown that compounds known to have adverse biological effects, such as polycyclic aromatic hydrocarbons, are deposited in significant quantities into Lake Michigan (USA); however, these compounds comprise a small portion of the total particulate matter deposition. In the present study, a method is described for using Ceriodaphnia dubia, Selenastrum capricornutum (green algae), and MitoScan bioassays to compare the toxicities of reconstituted hard freshwater and methylene chloride extracts of atmospheric particulate matter collected at three locations around the southern shore of Lake Michigan in August 2000. The locations include an urban/industrial site in Milwaukee (WI, USA), an urban-impacted/industrial site in Porter (IN, USA), and a rural site in Bridgman (MI, USA). The bulk chemistry, including organic and elemental carbon, sulfate, nitrate, ammonium, and chloride, shows regional similarities over the sampling event, but the toxicities vary spatially by site, by extraction solvent, and by bioassay. Thus, the bioassays are sufficiently sensitive to show differences in toxicity among the atmospheric particulate matter extracts and have significantly different responses to the samples to enable an initial comparison of toxicity from the different sites.

Air Pollutants↗

Associations between ambient, personal, and indoor exposure to fine particulate matter constituents in Dutch and Finnish panels of cardiovascular patients.

AIMS: To assess the relation between ambient, indoor, and personal levels of PM2.5 and its elemental composition for elderly subjects with cardiovascular disease. METHODS: In the framework of a European Union funded study, panel studies were conducted in Amsterdam, the Netherlands and Helsinki, Finland. Outdoor PM2.5 concentrations were measured at a fixed site. Each subject's indoor and personal PM2.5 exposure was measured biweekly for six months, during the 24 hour period preceding intensive health measurements. The absorbance of PM2.5 filters was measured as a marker for diesel exhaust. The elemental content of more than 50% of the personal and indoor samples and all corresponding outdoor samples was measured using energy dispersive x ray fluorescence. RESULTS: For Amsterdam and Helsinki respectively, a total of 225 and 238 personal, and 220 and 233 indoor measurements, were analysed from 36 and 46 subjects. For most elements, personal and indoor concentrations were lower than and highly correlated with outdoor concentrations. The highest correlations (median r>0.9) were found for sulfur and particle absorbance, which both represent fine mode particles from outdoor origin. Low correlations were observed for elements that represent the coarser part of the PM2.5 particles (Ca, Cu, Si, Cl). CONCLUSIONS: The findings of this study provide support for using fixed site measurements as a measure of exposure to particulate matter in time series studies linking the day to day variation in particulate matter to the day to day variation in health endpoints, especially for components of particulate matter that are generally associated with fine particles and have few indoor sources. The high correlation for absorbance of PM2.5 documents that this applies to particulate matter from combustion sources, such as diesel vehicles, as well.

Aged↗

Effects of low-toxicity particulate matter on human nasal function.

Chronic nasal and paranasal sinus problems affect approximately 15% of the population in industrialized countries. Recent studies suggest that particulate matter might contribute to this condition. The effects of acute exposure to low-toxicity particulate matter on human nasal airflow, mucociliary transport, and nasal discomfort should be assessed. Thirty-two healthy volunteers were exposed to 0 (control), 500, 1000, and 5000 micrograms/m3 calcium carbonate dust for 3 hours and nasal saccharin transport time (STT), rhinomanometry, and visual analog scales (VAS) on nasal discomfort were obtained. A dose dependent decrease of STT (P = 0.02) and nasal patency (P = 0.04), and increased sensation of nasal obstruction (P = 0.002) and dryness (P = 0.03) was observed. The results indicate that acute exposure to low-toxicity particulate matter in concentrations frequently encountered in western agglomeration areas may affect nasal functions and cause nasal symptoms.

Adult↗

Relationship between radical generation by urban ambient particulate matter and pulmonary function of school children.

The mechanisms by which particulate matter (PM) produces adverse effects on the respiratory system, such as pulmonary dysfunction in children, are largely unknown. However, oxidative stress is thought to play an important role. Various chemical compounds in ambient particulate matter, including transition metals and aromatic organic compounds, may contribute to adverse effects through intrinsic generation of reactive oxygen species (ROS). It was hypothesized that ROS generation by PM, as determined through electron spin resonance (ESR) spectroscopy, may be negatively associated with pulmonary function in school children. PM(2.5), PM(10), and total suspended particulates (TSP) were sampled at the playgrounds of six elementary schools in the city of Maastricht, the Netherlands. All children (8-13 yr) from the six schools were asked to undergo spirometry. Multivariate linear regression models were constructed to evaluate associations between oxygen radical formation by PM and lung function. The radical-generating capacity per microgram PM correlated negatively to forced expiratory volume in 1 s (FEV(1)) and forced expiratory flow at 50% (FEF(50%)) of forced vital capacity (FVC). The data indicate that chemical features that contribute to intrinsic generation of ROS may be relevant for PM risk assessment.

Adolescent↗

Bioreactivity of particulate matter in Beijing air: results from plasmid DNA assay.

An in vitro plasmid assay was employed to study the bioreactivity of PM (particulate matter) in Beijing air. It was found that the TD20 (toxic dose of PM causing 20% of plasmid DNA damage) of Beijing PM can be as low as 28 microg ml(-1) and as high as >1000 microg ml(-1). Comparison of the physical properties, such as morphology and size distribution, and oxidative potential indicates that the PM(2.5) (particulate matter with an aerodynamic diameter of 2.5 microm or less) has a stronger oxidative capacity than PM(10) (particulate matter with an aerodynamic diameter of 10 microm or less), and that the higher number percentages of soot aggregates and lower number percentages of mineral and fly ashes are associated with the higher oxidative capacity. Although the mass of PM(10) during dust storms is commonly 5 times higher than that during non-dust storm episodes, the oxidative capacity of PM(10)s of dust storms is much lower than that of the non-dust storm PM(10)s. The water-soluble fractions and intact whole particle solutions of Beijing airborne particles produce similar plasmid assay results, demonstrating that the bioreactivity of Beijing airborne particles is mainly sourced from the water-soluble fraction. In the samples with stronger bioreactivity, the total analyzed water soluble Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As and Pb (ppm) concentrations are higher. The water soluble zinc shows a good negative correlation with TD20s, suggesting that the water-soluble zinc is probably the major element responsible for the plasmid DNA damage.

Air Pollutants↗

Ecotoxicological assessment of ashes and particulate matter from fluidized bed combustion of coal.

Toxicity of ash and particulate matter from the gases generated in coal fluidized bed combustion (FBC) has been determined by the Microtox assay according to the standard leachate procedure. Results are compared with the polycylic aromatic hydrocarbon (PAH) content of the particulate matter, which was determined by fluorescence spectroscopy. Although PAHs are considered highly toxic compounds, the low ecotoxicity values obtained could be explained by the low solubility of the compounds in water. The Microtox assay may underestimate the toxicity of water-insoluble compounds unless they are previously extracted with an organic solvent. Nevertheless, this type of assay can be very useful for measuring the potential toxicity of residues when exposed to water sources such as rain water and the risk of the components being dissolved and transported by runoff water.

Air Pollutants, Occupational↗

Effects of particulate matter on daily mortality in 13 Japanese cities.

BACKGROUND: In recent years, numerous reports demonstrating the relationship between an increase in the concentration of fine particulate matter (PM2.5) and daily mortality have been released in the United States and Europe. There have been few studies that clearly characterize the short-term effects of particulate matter on the mortality in Japan. We conducted data analysis to investigate the short-term effects of suspended particulate matter (SPM) on mortality in Japan. METHODS: In this study, we used data sets from the 13 largest cities containing data on the daily mortality of residents aged 65 years or older, concentrations of air pollutants including SPM, temperature, and humidity. Risk ratios for mortality resulting from respiratory diseases, cardiovascular diseases, and all causes other than accidents, from 1990 through 1994, were summarized using a generalized additive model (GAM) and a meta-analysis of random effect model. RESULTS: The risk ratios for an increase of 10 microg/m3 in SPM concentrations adjusted for SO2, NO2, CO, Ox, temperature, and humidity were 1.0077 for all causes of mortality, 1.0109 for respiratory diseases, and 1.0091 for cardiovascular diseases, and the lower limits of the 95% confidence intervals for the risk ratios were greater than one for all cases. With regards to the effects of time lag, risk ratios were higher for the SPM concentrations on the day when the mortality was recorded, and the preceding day. CONCLUSIONS: These results suggest a positive relationship between SPM concentrations and daily mortality in Japan.

Aged↗

Development and validation of capillary electrophoresis for the determination of selected metal ions in airborne particulate matter after sequential extraction.

A capillary electrophoresis (CE) method has been developed and validated for the determination of the distribution of metals in particulate matter after three-stage sequential extraction. Fe(II), Zn(II), Cu(II), Mn(II), and Cd(II) ions were separated using a background electrolyte consisting of 200 mmol L(-1) ammonium acetate (pH 5.5), 0.5 mmol L(-1) 1,10-phenanthroline, 10 mmol L(-1) hydroxylamine hydrochloride, and 20% acetone. The method was validated with respect to specificity, linearity, detection limits, precision, and accuracy. Detection limits are at sub-microg L(-1) levels (tens of microg g(-1) of particulate matter) using pressure injection. The analytical procedure was checked by analyzing a standard reference material, NIST SRM 1648 Urban Particulate Matter.

Air Pollutants↗

Indoor and outdoor measurements of vertical concentration profiles of airborne particulate matter.

Vertical concentration profiles of various particle size ranges of airborne particulate matter were measured from ground level up to 3 m, in outdoor and indoor environments. Indoor measurements were carried out in an electronics workshop, while two outdoor environments were chosen: a street canyon cutting across a town and an open field situated in a semi-rural environment. The novel measurement technique employed in this experimental work, which can also be used to determine vertical concentration gradients of pollutants other than airborne particles in different environments, is given particular attention. Analyses of the collected data for the environments considered are presented and some conclusions and plausible explanations of the profiles are discussed. The workshop and street canyon environments exhibited larger concentrations and vertical concentration gradients as compared to the sports field. This indicates that people breathing at different heights are subjected to different concentrations of airborne particulate matter, which has implications for sitting air pollution monitors intended for protection of public health and estimation of human exposure.

Air Pollution↗