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PubMed2007

Effects of the Irish smoking ban on respiratory health of bar workers and air quality in Dublin pubs.

BACKGROUND: Environmental tobacco smoke (ETS) causes disease in nonsmokers. Workplace bans on smoking are interventions to reduce exposure to ETS to try to prevent harmful health effects. On March 29, 2004, the Irish government introduced the first national comprehensive legislation banning smoking in all workplaces, including bars and restaurants. This study examines the impact of this legislation on air quality in pubs and on respiratory health effects in bar workers in Dublin. METHODS: Exposure study. Concentrations of particulate matter 2.5 microm or smaller (PM(2.5)) and particulate matter 10 microm or smaller (PM(10)) in 42 pubs were measured and compared before and after the ban. Benzene concentrations were also measured in 26 of the pubs. Health effects study. Eighty-one barmen volunteered to have full pulmonary function studies, exhaled breath carbon monoxide, and salivary cotinine levels performed before the ban and repeated 1 year after the ban. They also completed questionnaires on exposure to ETS and respiratory symptoms on both occasions. FINDINGS: Exposure study. There was an 83% reduction in PM(2.5) and an 80.2% reduction in benzene concentration in the bars. Health effects study. There was a 79% reduction in exhaled breath carbon monoxide and an 81% reduction in salivary cotinine. There were statistically significant improvements in measured pulmonary function tests and significant reductions in self-reported symptoms and exposure levels in nonsmoking barmen volunteers after the ban. CONCLUSIONS: A total workplace smoking ban results in a significant reduction in air pollution in pubs and an improvement in respiratory health in barmen.

Adult↗

PubMed1986

Microbial resistance to disinfectants: mechanisms and significance.

Drinking water disinfection provides the final barrier to transmission of a wide variety of potentially waterborne infectious agents including pathogenic bacteria, viruses, and protozoa. These agents differ greatly in their innate resistance to inactivation by disinfectants, ranging from extremely sensitive bacteria to highly resistant protozoan cysts. The close similarity between microorganism inactivation rates and the kinetics of chemical reactions has long been recognized. Ideally, under carefully controlled conditions, microorganism inactivation rates simulate first-order chemical reaction rates, making it possible to predict the effectiveness of disinfection under specific conditions. In practice, changes in relative resistance and deviations from first-order kinetics are caused by a number of factors, including microbial growth conditions, aggregation, and association with particulate materials. The net effect of all these factors is a reduction in the effectiveness and predictability of disinfection processes. To ensure effective pathogen control, disinfectant concentrations and contact times greater than experimentally determined values may be required. Of the factors causing enhanced disinfection resistance, protection by association with particulate matter is the most significant. Therefore, removal of particulate matter is an important step in increasing the effectiveness of disinfection processes.

Cell Division↗

PubMed2006

Seasonal variations of PM10 and TSP in residential and industrial sites in an urban area of Kolkata, India.

The objective of the study is to investigate seasonal and spatial variations of PM10 (particulate matter with aerodynamic diameter less than or equal to 10 microm) and TSP (total suspended particulate matter) of an Indian Metropolis with high pollution and population density from November 2003 to November 2004. Ambient concentration measurements of PM10 and TSP were carried out at two monitoring sites of an urban region of Kolkata. Monitoring sites have been selected based on the dominant activities of the area. Meteorological parameters such as wind speed, wind direction, rainfall, temperature and relative humidity were also collected simultaneously during the sampling period from Indian Meteorological Department, Kolkata. The 24 h average concentrations of PM10 and TSP were found in the range 68.2-280.6 microg/m3 and 139.3-580.3 microg/m3 for residential (Kasba) area, while 62.4-401.2 microg/m3 and 125.7-732.1 microg/m3 for industrial (Cossipore) area, respectively. Winter concentrations of particulate pollutants were higher than other seasons, irrespective of the monitoring sites. It indicates a longer residence time of particulates in the atmosphere during winter due to low winds and low mixing height. Spread of air pollution sources and non-uniform mixing conditions in an urban area often result in spatial variation of pollutant concentrations. The higher particulate pollution at industrial area may be attributed due to resuspension of road dust, soil dust, automobile traffic and nearby industrial emissions. Particle size analysis result shows that PM10 is about 52% of TSP at residential area and 54% at industrial area.

Air Pollutants↗

PubMed2005

Health effects of subchronic exposure to diesel-water emulsion emission.

The U.S. Environmental Protection Agency (EPA) National Ambient Air Quality Standards for ozone and particulate matter are requiring urban nonattainment areas to implement pollution-reduction strategies for anthropogenic source emissions. A type of fuel shown to decrease combustion emissions components versus traditional diesel fuels is the diesel-water emulsion. The Lubrizol Corporation in conjunction with Lovelace Respiratory Research Institute and several subcontracting laboratories recently conducted a rodent health assessment of inhaled combustion emissions of PuriNO(x) diesel fuel emulsion. Combustion emissions from either of two 2001 model Cummins 5.9-L ISB engines were diluted with charcoal-filtered air to exposure concentrations of 100, 200, and 400 microg total particulate matter/m(3). The engines were operated on a continuously repeating, heavy-duty certification cycle (U.S. Code of Federal Regulations, Title 40, Chapter I) using Rotella-T 15W-40 engine oil. Nitrogen oxide and particulate matter were reduced when engines were operated on PuriNO(x) versus California Air Resources Board diesel fuel under these conditions. Male and female F344 rats were housed in Hazleton H2000 exposure chambers and exposed to exhaust atmospheres 6 h/day, 5 days/wk for the first 11 wk and 7 days/wk threafter. Exposures ranged from 58 to 70 days, depending on the treatment group. Indicators of general toxicity (body weight, organ weight, clinical pathology, and histopathology), neurotoxicity (glial fibrillary acidic protein assay), genotoxicity (Ames assay, micronucleus, sister chromatid exchange), and reproduction and development were measured. Overall, effects observed were mild. Emulsion combustion emissions were not associated with neurotoxicity, reproductive/developmental toxicity, or in vivo genotoxicity. Small decreases in serum cholesterol and small increases in platelet values in some groups of exposed animals were observed. Particulate matter accumulation within alveolar macrophages was evident in all exposure groups. These findings are consistent with normal physiological responses to particle inhalation. Other statistically significant effects were present in some measured parameters of other exposed groups but were not clearly attributed to emissions exposure. Positive mutagenic responses in several strains of Salmonella typhimurium were observed subsequent to treatment with emulsion emissions subfractions. Based on the cholesterol and platelet results, it can be concluded that the 100 microg/m(3) exposure level was the no-observed-effect level. In general, biological findings in diesel emulsion emission-exposed animals and bacteria were consistent with exposure to petroleum diesel exhaust in the F344 rat and Ames assays.

Administration, Inhalation↗

PubMed2006

Continuous monitoring of particle emissions during showering.

Particle formation from showering may be attributed to dissolved mineral aerosols remaining after evaporation of micron-sized satellite droplets produced by the showerhead or from splashing of larger shower water droplets on surfaces. Duplicate continuous particle monitors measured particle size distributions in a ventilated residential bathroom under various showering conditions, using a full-size mannequin in the shower to simulate splashing effects during showering. Particle mass concentrations were estimated from measured shower particle number densities and used to develop emission factors for inhalable particles. Emission source strengths of 2.7-41.3 microg/ m3/min were estimated under the various test conditions using residential tap water in Columbus, OH. Calculated fine particulate matter (PM2.5) concentrations in the bathroom reached several hundred micrograms per cubic meter; calculated coarse particulate matter (PM10) levels approached 1000 microg/m3. Rates of particle formation tended to be highest for coarse shower spray settings with direct impact on the mannequin. No consistent effects of water temperature, water pressure, or spray setting on overall emission rates were apparent, although water temperature and spray setting did have an effect when varied within a single shower sampling run. Salt solutions were injected into the source water during some tests to assess the effects of total dissolved solids on particle emission rates. Injection of salts was shown to increase the PM2.5 particle formation rate by approximately one third, on average, for a doubling in tap water-dissolved solids content; PM10 source strengths approximately doubled under these conditions, because very few particles >10 microm were formed.

Aerosols↗

PubMed2001

Diesel exhaust enhances airway responsiveness in asthmatic subjects.

Particulate matter (PM) pollution has been associated with negative health effects, including exacerbations of asthma following exposure to PM peaks. The aim of the present study was to investigate the effects of short-term exposure to diesel exhaust (DE) in asthmatics, by specifically addressing the effects on airway hyperresponsiveness, lung function and airway inflammation. Fourteen nonsmoking, atopic asthmatics with stable disease, on continuous treatment with inhaled corticosteroids, were included. All were hyperresponsive to methacholine. Each subject was exposed to DE (particles with a 50% cut-off aerodynamic diameter of 10 microm (PM10) 300 microg x m(-3)) and air during 1 h on two separate occasions. Lung function was measured before and immediately after the exposures. Sputum induction was performed 6 h, and methacholine inhalation test 24 h, after each exposure. Exposure to DE was associated with a significant increase in the degree of hyperresponsiveness, as compared to after air, of 0.97 doubling concentrations at 24 h after exposure (p < 0.001). DE also induced a significant increase in airway resistance (p=0.004) and in sputum levels of interleukin (IL)-6 (p=0.048). No changes were detected in sputum levels of methyl-histamine, eosinophil cationic protein, myeloperoxidase and IL-8. This study indicated that short-term exposure to diesel exhaust, equal to high ambient levels of particulate matter, is associated with adverse effects in asthmatic airways, even in the presence of inhaled corticosteroid therapy. The increase in airway responsiveness may provide an important link to epidemiological findings of exacerbations of asthma following exposure to particulate matter.

Adult↗

PubMed2004

Concept and validation of a novel approach for producing large batches of reference material of ambient aerosols on filters.

A novel method for preparing reference material of aerosol particulate matter (PM) on filters was developed by using the concept of very high volume, multiport sampling, and this was subsequently applied to produce more than 300 well-characterised units. The dedicated sampler built for this purpose features a 0.94-m-diameter, vacuum-tight main chamber with a total of 349 monitor ports, each holding a 37-mm-diameter, cellulose acetate-nitrate ester (CA) membrane filter with a nominal pore size of 0.8 microm. At a pressure difference of about 130 hPa across the filter cassettes, the total initial air flow rate was 350 m3 h-1 (1.0 m3 h-1 per filter). Investigations into the variability of filter parameters showed that the flow resistance of CA filters is mostly determined by and proportional to their blank mass, with a mean uncertainty of about 5%. Total suspended particulate matter (TSP) was sampled for a total of 50 h using 349 selected filters with a relatively narrow spread in blank mass. The mean TSP mass per filter thus produced was 3.35 mg. Corrected for small differences in blank mass of the filters, the normalised aerosol masses per filter of 96% of the samples exhibited normal distributions with standard deviations of only 2.1 and 3.4%, depending on details of the normalisation procedure. Within the limits of the technique, a variation of aerosol mass with radial distance from the centre of the sampler is not clearly evident. The results provide evidence that the multiport approach allows large batches of particulate matter on filters to be produced in a reliable manner.

Aerosols↗

PubMed2002

Sampling and analysis of carbon in diesel exhaust particulates--an international comparison.

OBJECTIVES: The European Co-ordination on Diesel Soot Exposure (ECDSE) working group organised a laboratory inter-comparison which integrated both the sampling and the analytical determination. The aim was to gain more information on the performance of the methods for the determination of diesel particulate matter at workplaces and on their comparability, and to also confirm that the requirements of the European standard EN 482 are fulfilled for this analytical procedure. METHODS: Sampling was carried out in a diesel aerosol test chamber where participants used their own sampling devices. Overall, ten sampling exercises at two different concentration levels were performed and both personal air sampling systems and stationary samplers were used. The analytical determination was performed according to the laboratory's own standard procedure. RESULTS: There was good agreement between the laboratories for the determination of organic carbon (OC), elemental carbon (EC) and total carbon (TC). Almost all the results when expressed as a coefficient of variation were in the range +/-30% of the overall means. The results also showed that the coefficient of variation for OC was approximately twice the coefficient of variation for EC. This is not too critical, because existing occupational exposure levels (OELs) are based on the measurement of EC. CONCLUSIONS: The inter-comparison showed that existing analytical procedures for the determination of diesel particulate matter at workplaces fulfil the requirements of European standard EN 482. Both personal air samplers and stationary samplers give comparable results. The parameters for the analytical determination are not critical within the range of parameter values presented in this article. Additionally, it may be concluded that the diesel aerosol test chamber used in this exercise is well suited for producing an atmosphere containing a constant and reproducible level of diesel particulate matter.

Atmosphere Exposure Chambers↗

PubMed1997

The metropolitan acid aerosol characterization study: results from the summer 1994 Washington, D.C. field study.

An ambient particle monitoring study was conducted in Washington, D.C. during the summer of 1994 as part of the Metropolitan Acid Aerosol Characterization Study (MAACS). Acid aerosol and inhalable (particulate matter with aerodynamic diameters < 10 micron; PM10) and fine (particulate matter with aerodynamic diameters < 2.5 micron; PM2.5) particle samples were collected for 24-hr periods (9 A.M.-9 A.M. EDT) on alternate days at six monitoring sites located throughout the greater Washington, D.C. area. Monitoring sites were located in both urban and rural areas and were generally situated along a southwest to northeast line due to the prevailing winds. Information on site characteristics, including population density and distance from the city center, was also obtained, as were data on meteorological parameters. Results from this study show strong correlations among the particulate measures, PM10, PM2.5, SO4(2-), and H+. These strong correlations resulted from the fact that PM2.5 comprised 77% of PM10, with SO4(2-)-related species accounting for 49% of total PM2.5. PM10, PM2.5, SO4(2-), and H+ concentrations were found to be uniform across the metropolitan Washington area. Spatial variation was found, however, for coarse particles (PM2.5-10) and NH3 concentrations. In our previous Philadelphia study, population density was an important determinant of spatial variation in coarse particles and NH3 concentrations, however, in Washington, D.C., population density was not associated with observed spatial patterns in coarse particle concentrations, but was an important determinant of NH3 concentrations. When data from one site (Reservoir) was excluded from the analysis, population density explained larger percentage of the variability in NH3 levels and became an important determinant of the H+/SO4(2-) ratio as well. Ambient H+ models developed from Philadelphia data were found to predict H+ concentrations in Washington, D.C. reasonably well, representing an improvement over measurements made at a single stationary ambient monitoring site.

Aerosols↗

PubMed1999

Characterization of chemical species in PM2.5 and PM10 aerosols in suburban and rural sites of central Taiwan.

Aerosol samples for PM2.5 (particulate matter with aerodynamic diameters less than 2.5 microns), PM2.5-10 (particulate matter with aerodynamic diameters between 2.5 and 10 microns) and TSP were collected from June to September 1998 at THU (suburban) and HKIT (rural) sites in central Taiwan. The ratios of PM2.5/PM10 averaged 0.70 for the daytime and 0.63 for the nighttime at THU, respectively. At HKIT, the PM2.5/PM10 ratios averaged 0.56 for the daytime and 0.72 in the nighttime, respectively. These results indicated that the PM2.5 concentrations contribute the majority of the PM10 concentration and PM10 concentrations contribute the majority of the TSP at both sites. The averaged PM2.5 concentrations at THU are higher than those measured at HKIT during the daytime period. However, the average PM2.5-10 concentrations in THU are lower than those measured at HKIT during nighttime. The samples collected were also analyzed by atomic absorption spectrophotometry for the elemental analysis of Ca, Fe, Pb, Zn, Cu, Mn and Cr. Meanwhile ion chromatography was used to analyze for the water-soluble ions: sulphate, nitrate and chloride in the Universal samples. The concentrations of heavy metals in PM10 during daytime were all higher than nighttime at THU. However, the averaged concentrations of metal elements in PM10 during day and night period were distributed irregularly at HKIT. The results indicated that for metal elements collected at HKIT have different emission sources. The concentrations of metal elements during daytime in PM10 at THU were generally higher than HKIT. The phenomena owing to the averaged PM2.5 particle concentrations at THU (suburban) were higher than those measured at HKIT (rural) and PM2.5 occupied the major portions of PM10 for both sites during the day period. For anion species, there are no significant differences between day and night period in PM10 concentrations at both suburban and rural sites.

Aerosols↗

PubMed1991

Stable isotope studies of nicotine kinetics and bioavailability.

The stable isotope-labeled compound 3',3'-dideuteronicotine was used to investigate the disposition kinetics of nicotine in smokers, the systemic absorption of nicotine from cigarette smoke, and the bioavailability of nicotine ingested as oral capsules. Blood levels of labeled nicotine could be measured for 9 hours after a 30-minute intravenous infusion. Analysis of disposition kinetics in 10 healthy men revealed a multiexponential decline after the end of an infusion, with an elimination half-life averaging 203 minutes. This half-life was longer than that previously reported, indicating the presence of a shallow elimination phase. Plasma clearance averaged 14.6 ml/min/kg. The average intake of nicotine per cigarette was 2.29 mg. A cigarette smoke-monitoring system that directly measured particulate matter in smoke was evaluated in these subjects. Total particulate matter, number of puffs on the cigarette, total puff volume, and time of puffing correlated with the intake of nicotine from smoking. The oral bioavailability of nicotine averaged 44%. This bioavailability is higher than expected based on the systemic clearance of nicotine and suggests that there may be significant extrahepatic metabolism of nicotine.

Administration, Inhalation↗

PubMed1990

Woodstove smoke and CO emissions: comparison of reference methods with the VIP sampler.

A new field sampler has been developed for measuring the particulate matter (PM) and carbon monoxide emissions of woodburning stoves. Particulate matter is determined by carbon balance and the workup of a sample train which is similar to a room-temperature EPA Method 5G train. A steel tank, initially evacuated, serves as the motive force for sampling and also accumulates a gas sample for post-test analysis of time-averaged stack CO and CO2 concentrations. Workup procedures can be completed within 72 hours of sampler retrieval. The system has been compared to reference methods in two laboratory test series involving six different woodburning appliances and two independent laboratories. The correlation of field sampler emission rates and reference method rates is strong.

Air Pollutants↗

PubMed2002

The association between personal measurements of environmental exposure to particulates and heart rate variability.

BACKGROUND: Epidemiologic evidence indicates that airborne particulates are associated with mortality risk, predominately from heart disease. This may occur through changes in the cardiac autonomic nervous system, witnessed by changes in heart rate variability. METHODS: This short-term longitudinal study used continuous personal particulate matter measurements to examine the effects of exposure to particulate matter less than 2.5 microm in diameter (PM2.5) on heart rate and rate variability in 20 relatively young, healthy male workers. Continuous exposure and cardiac monitoring were performed on each subject on a nonwork day. The 5-minute standard deviation of the normal-to-normal interval was used as the main measure of heart rate variability. RESULTS: Mixed-effects regression models estimate an average 1.4% (95% confidence limits = -2.1, -0.6) decrease in the 5-minute standard deviation of the normal-to-normal interval for each 100 microg/m3 increase in the 3-hour PM2.5 moving average, and small increases in heart rate, after adjustment for potential confounding factors. Predicted effects of exposure were greatest using the 3-hour averaging interval for PM2.5 and decreased in magnitude using shorter and longer intervals. CONCLUSIONS: These results reveal an association between cardiac autonomic function and environmental PM2.5 exposure. These observed associations may result from decreased vagal or increased sympathetic tone.

Adult↗

PubMed2006

Simultaneous monitoring method of polycyclic aromatic hydrocarbons and persistent organic pollutants in the atmosphere using activated carbon fiber filter paper.

In order to simultaneously monitor the concentrations of PAHs and POPs in the atmosphere, an activated carbon fiber filter paper (ACFP) was used as the adsorbing material in this study. The pressurized liquid extraction method (PLE method) was used to extract PAHs and POPs collected on the ACFP. Toluene was an effective solvent to extract them from ACFP using the PLE method, but some of PAHs, such as benzo(a)pyrene, benzo(g,h,i)perylene, dibenzo(a,h)anthracene and indeno(1,2,3-cd)pyrene, were hardly extracted. These PAHs were adsorbed on the particulate matter in the atmosphere. In general, these forms of particulate matter could be collected using a quartz fiber paper (QFP); these PAHs were efficiently extracted from the QFP using the PLE method with toluene. In this study, the collecting method of the PAHs was modified by using QFP overlapped in front of the ACFP. Atmospheric monitoring of PAHs and POPs in Niigata area was performed using this method, and most of the target compounds were detected. However, some of the POPs, such as aldrin, endrin, mirex, could not be detected. The POPs, such as hexachlorobenzene, alpha-hexachlorocyclohexane and chlordanes, and most of the PAHs were detected from all of the samples collected throughout the monitoring period. It was confirmed that these methods were effective to simultaneously monitor the concentrations of the PAHs and POPs in the atmosphere.

Journal Article↗

PubMed2024

Effects of particulate air pollution on BPDE-DNA adducts, telomere length, and mitochondrial DNA copy number in human exhaled breath condensate and BEAS-2B cells.

Traffic-related particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) have been linked to respiratory diseases and cancer risk in humans. Genomic damage, including benzo[a]pyrene diolepoxide (BPDE)-DNA adducts as well as alterations in telomere length (TL) and mitochondrial DNA copy number (mtDNA-CN) are associated with respiratory diseases. This study aimed to investigate the association between exposure to traffic-related particulate pollutants and genomic damage in exhaled breath condensate (EBC) in human subjects and a bronchial epithelial cell line (BEAS-2B). Among the 60 healthy recruited subjects, residents living in high-traffic-congested areas were exposed to higher concentrations of PM2.5 (1.66-fold, p < 0.01), UFPs (1.79-fold, p < 0.01), PM2.5-PAHs (1.50-fold, p < 0.01), and UFPs-PAHs (1.35-fold, p < 0.05), than those in low-traffic-congested areas. In line with increased exposure to particulate air pollution, the high-traffic-exposed group had significantly increased BPDE-DNA adducts (1.40-fold, p < 0.05), TL shortening (1.24-fold, p < 0.05), and lower mtDNA-CN (1.38-fold, p < 0.05) in EBC. The observations in the human study linking exposure to PM2.5, UFPs, PM2.5-PAHs, and UFPs-PAHs with the aforementioned biological effects were confirmed by an in vitro cell-based study, in which BEAS-2B cells were treated with diesel exhaust particulate matter (DEP) containing fine and ultrafine PM and PAHs. Increased BPDE-DNA adducts levels, shortened TL, and decreased mtDNA-CN were also found in treated BEAS-2B cells. The shortened TL and decreased mtDNA-CN were in part mediated by decreased transcript levels of hTERT, and SIRT1, which are involved in telomerase activity and mitochondrial biogenesis, respectively. These results suggest that exposure to traffic-related particulate pollutants can cause genomic instability in respiratory cells, which may increase the health risk of respiratory diseases and the development of cancer.

Humans↗

PubMed1989

Dust inhalation exposures from the handling of small volumes of powders.

Worker exposure to airborne particulates was stimulated in a laboratory under controlled conditions. Small volumes, 3.8 L (1 gal.), of finely divided powders were transferred at 1-min intervals to 23-L (6-gal.) containers over 30-min time intervals. A high-volume filter array in the exit vent of the specially designed exposure laboratory was used both to control the ventilation rate and to determine the emission factor of the pouring operation. The room ventilation rate, method of transfer, and drop height were varied, and the resulting particulate concentrations were monitored by personal and area samplers. The four powders studied were talc, sodium chloride, Portland cement, and Direct Yellow 4 dye. Based on this study, a model was developed to predict potential worker exposure from the pouring of small volumes of powders. The model is based on the following major conclusions. First, the space- and time-averaged concentration of suspended particulate matter at breathing height agrees well with the mean concentration of suspended particulate matter in the room air effluent. Second, material-specific suspended particulate emission factors vary approximately in direct proportion to the drop height. Third, emission factors for scooping/dumping operations agree well with factors for pouring operations for a given drop height. Fourth, emission factors compare well with dustiness indexes that were determined using a bench-scale dustiness test chamber described in a companion paper. Parameters of the exposure model include dustiness index, drop height of the pouring operation, total quantity of material poured, averaging time, and the fraction of respirable material. For the validation of the model, additional data would be necessary.

Air Pollutants, Occupational↗

PubMed2006

Particulate air pollution from bushfires: human exposure and possible health effects.

Toxicological studies have implicated trace metals adsorbed onto airborne particles as possible contributors to respiratory and/or cardiovascular inflammation. In particular, the water-soluble metal content is considered to be a harmful component of airborne particulate matter. In this work, the trace metal characteristics of airborne particulate matter, PM2.5, collected in Singapore from February to March 2005 were investigated with specific reference to their bioavailability. PM2.5 mass concentrations varied between 20.9 mug/m3 and 46.3 microg/m3 with an average mass of 32.8 microg/m3. During the sampling period, there were several bushfires in Singapore that contributed to sporadic increases in the particulate air pollution, accompanied by an acrid smell and asthma-related allergies. The aerosol samples were subjected to analysis of trace elements for determining their total concentrations as well as their water soluble fractions. Our results showed an increase in concentration of several water-soluble trace metals during bushfires compared to their urban background levels in Singapore. In order to measure the human exposure to particulate air pollution, the daily respiratory uptake (DRU) of several trace metals was calculated and compared between haze and nonhaze periods. The DRU values were significantly higher for several metals, including Zn, Cu, and Fe, during bushfires. Electron paramagnetic resonance (EPR) measurements showed that the particulate samples collected during bush fires generate more toxic hydroxyl radicals (OH.) than those in the background air, due to the presence of more soluble iron ions.

Air Pollutants↗

PubMed1981

Carcinogenicity of airborne fine particulate benzo(a)pyrene: an appraisal of the evidence and the need for control.

Benzo(a)pyrene(BaP) originating from fossil fuel and other organic combustion processes is largely adsorbed on fine particulate and hence is a widespread atmospheric pollutant. Available emissions and air quality data are based on the total weight of particulate matter without reference to size and give little information on trends and concentrations of fine particulate BaP. Greater reliance on coal, synfuels and diesel fuel for energy production and transportation will significantly increase ambient levels of BaP. Because of the particulate size, BaP is substantially deposited in the lower lung and readily eluted into surrounding tissue. After elution in the lung, BaP is metabolically activated to its electrophilic, carcinogenic from by a complex enzyme system whose activity is increased by prior exposure to air pollutants, cigarette smoke and certain drugs. The resultant diol epoxide metabolite has been shown to bind covalently with the DNA of the lung. In experimental animals, BaP is a potent initiating carcinogen whose action is enhanced by sulfur dioxide, promoting agents and carrier fine particles. The effect of small, divided doses of BaP has been shown to be greater than that of a single high dose; no threshold has been established. Epidemiological studies show that mixtures containing BaP (such as urban air, industrial emissions and cigarette smoke) are carcinogenic and may interact synergistically. Occupational studies indicate that the action of BaP-containing mixtures is enhanced in the presence of SO2. However, quantitative risk assessment for BaP is precluded by problems in extrapolating to the general population from small-scale animal studies; uncertainties in findings of epidemiology; and imprecise exposure data. Existing stationary and mobile controls preferentially remove coarse particulate matter and are inefficient collectors of the particulate BaP. In the current absence of health and environmental standards for BaP, there is little incentive to control BaP emissions. BaP meets the criteria for regulation under the Clean Air Act; however, no such BaP standards have yet been proposed.

Air Pollutants↗