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PubMedDate not supplied

Oxidant mechanisms in response to ambient air particles.

The toxic effects of air pollution are widely documented. In recent years, however, there has been an increasing interest in the study of the health effects of particulate matter (PM), a previously unexplored constituent of urban air pollution. Exposure to increased levels of PM of respirable size is strongly and consistently associated with increased cardiopulmonary morbidity and mortality. Conversely, improved air quality appears to correlate with decreased mortality. Particulate matter is a mixture of inorganic and organic components that vary in size, origin, and composition. The mechanisms of PM health effects are still poorly understood. However, studies in cellular and animal models suggest a variety of possible mechanisms including direct effects of particle components on the intracellular sources of reactive oxygen species (ROS), indirect effects due to pro-inflammatory mediators released from PM-stimulated macrophages, and neural stimulation after particle deposition in the lungs. The involvement of ROS in each one of these possible pathways is discussed.

Air↗

PubMedDate not supplied

The 1997 haze disaster in Indonesia: its air quality and health effects.

In this study, the authors assessed air quality and health effects of the 1997 haze disaster in Indonesia. The authors measured carbon monoxide, carbon dioxide, sulfur dioxide, nitrogen dioxide, ozone, particulate matter with diameters less than or equal to 10 microm, inorganic ions, and polycyclic aromatic hydrocarbons. The authors also interviewed 543 people and conducted lung-function tests and determined spirometric values for these individuals. Concentrations of carbon monoxide and particulate matter with diameters less than or equal to 10 microm reached "very unhealthy" and "hazardous" levels, as defined by the Pollution Standards Index. Concentrations of the polycyclic aromatic hydrocarbons were 6-14 times higher than levels in the unaffected area. More than 90% of the respondents had respiratory symptoms, and elderly individuals suffered a serious deterioration of overall health. In multivariate analysis, the authors determined that gender, history of asthma, and frequency of wearing a mask were associated with severity of respiratory problems. The results of our study demonstrate the need for special care of the elderly and for care of those with a history of asthma. In addition, the use of a proper mask may afford protection.

Adult↗

PubMed1999

Relation between indoor and outdoor exposure to fine particles near a busy arterial road.

Various studies on indoor and outdoor particulate matter in the urban environment in the vicinity of busy arterial roads in the centre of the subtropical city of Brisbane have indicated that the revised United States Environmental Protection Agency National Ambient Air Quality Standards (US EPA NAAQS) for Particulate matter PM2.5 could be exceeded not only outdoors but also indoors. The aim of this work was to investigate outdoor exposure to submicrometer particles and their relationship with indoor exposure in a hypothetical office building located in the vicinity of a busy arterial road. The outdoor exposure values and trends were measured in terms of particle number in the submicrometer size range and were then recalculated to represent mass concentration trends. The results of this study indicate that exposure to PM0.7 particles in ambient air close to a busy road often exceeds the levels of the annual and 24-hour US EPA NAAQS PM2.5 standards. It is likely that exposure to PM2.5 is even higher, and may significantly exceed these standards.

Air Pollution, Indoor↗

PubMed2001

[Airborne dust particles in indoor environment and allergy].

BACKGROUND: The overall aim of this study was to investigate how airborne house dust particles may contribute to an allergic immune response, and thereby also to asthma and allergic diseases. MATERIAL AND METHODS: Using transmission electron microscopy, we quantified and characterized airborne house dust particles, with regard to elemental and size distribution. Furthermore, an immunogold labelling technique was used to study whether some common allergens were present on the surface of airborne house dust particles. Finally, a mouse model was used to study the adjuvant activity of airborne house dust on the IgE antibody response. RESULTS: A vast majority of the airborne particles samples from homes in Oslo were found to be less than 2.5 microns in diameter, thus they are liable to penetrate deep into the respiratory tree. This PM2.5 fraction contained, in addition to sulphur aerosols and silicates, many soot particles, most of them being less than 1 micron in diameter. These soot particles were found to carry allergens on their surface. We also found that diesel exhaust particles, which is probably a main soot component of airborne house dust, absorbed several wellknown allergens in vitro. Furthermore, the airborne house dust particles were found to elicit a local lymph node response, and to have an adjuvant activity on the production of IgE antibodies to ovalbumin as a model allergen. INTERPRETATION: These results show that indoor suspended particulate matter contains a lot of potential allergen carriers, i.e. soot particles (carbon aggregates), most of them being less that 1 micron in diameter and thereby able to transport allergens deep into the airways. In addition, our results indicate that suspended particulate matter may have an adjuvant effect on the production of IgE to common environmental allergens, and also may provoke a local inflammatory response.

Air Pollutants↗

PubMed1984

Doppler ultrasonic detection of particulate release during hemodialysis with cellulose hollow-fiber and sorbent suspension reciprocating dialyzers.

Doppler ultrasound is a noninvasive technique for monitoring moving objects such as flowing blood while ignoring stationary objects such as shunt tubing. A Doppler system was investigated to determine its sensitivity in detecting particulate release in blood during hemodialysis. Seven hemodialysis procedures with dogs and six trials with humans were done using a sorbent suspension reciprocating dialyzer ( SSRD ). Two additional trials were done with humans using a cellulose acetate hollow-fiber dialyzer (HFD). A large increase (approximately twofold) was found in the reflected Doppler signal in outflowing blood from the SSRD and HFD in both dogs and humans. Numerous additional studies to characterize the nature of the particulate matter showed platelet aggregates in the dogs and fibrinogen-fibrin degradation products in the humans to be present in the outflowing blood. In vitro studies suggested microscopic air bubbles (less than 25 micron in diameter) may have contributed to the particulate matter detected during hemodialysis by this sensitive monitoring system.

Animals↗

PubMed2004

[Atmospheric pollution and cardiovascular damage].

The damaging effect of atmospheric pollution with particulate matter and toxic gases on the respiratory system and its effect in the incidence and severity of respiratory diseases, is well known. A similar effect on the cardiovascular system is currently under investigation. Epidemiological studies have demonstrated that the inhalation of particulate matter can increase cardiovascular disease incidence and mortality, specially ischemic heart disease. The damage would be mediated by alterations in the autonomic nervous system, inflammation, infections and free radicals. In human studies, environmental pollution is associated with alterations in cardiac frequency variability and blood pressure and with changes in ventricular repolarization. Experimentally, an enhancement of ischemia, due to coronary obstruction, has been demonstrated. The study of the toxic effects of environmental pollution over the cardiovascular system, is an open field, specially in Chile, were the big cities have serious contamination problems.

Aged↗

PubMed2000

Inhalation study on exposure to bitumen fumes. Part 2: Analytical results at two exposure levels.

During the hot application of bitumen-containing materials, e.g. in road paving or roofing, fumes are emitted that contain traces of polycyclic aromatic compounds (PACs). Although worker's exposure to these fumes is low, it might lead to health problems. For studying DNA adduct formation as a consequence of inhalation of bitumen fumes we developed and validated an inhalation system (a dynamic fume generator plus a nose only inhalation chamber). This paper presents and discusses the analytical results from the different laboratories involved in this study on the fumes sampled in the inhalation chamber during three series of experiments where the animals were exposed to fumes at the 5 mg/m3 and 50 mg/m3 level, coming from bitumen heated at 200 degrees C and, as a positive control, fumes from coal tar, heated to 110 degrees C at the 5 mg/m3 level. The following parameters were controlled: temperatures at different key places in the generator; humidity of the chamber; the bitumen or coal tar flow rate; and Total Particulate Matter (TPM). Analyses were performed for Benzene Soluble Matter (BSM), the EPA polycyclic aromatic hydrocarbon (PAH) mixture and for a number of heteroatom-containing PACs. The data show that the coal tar fumes produced at 110 degrees C were very volatile and that most of the differences in particulate matter found between the laboratories can be attributed to evaporative losses. The bitumen fumes boil 25-50 degrees C higher and contain higher boiling compounds. A comparison is made between the PAC exposure profiles for bitumen experiments aimed at 5 and 50 mg/m3. Although the same molecules are found in both fumes their proportion is dramatically different. This effect is largest with the 2- and 3-ring PACs, the ratio of the concentrations found in the 50 mg/m3 TPM concentration to that in the 5 mg/m3 experiment gradually declines from 5500 for acenaphthene to 500 for pyrene, for the 5-ring PACs this ratio is 20-30. As function of their vapour pressure, the ratios of the concentrations of the hetero PACs follow the same trend as that of the 16 EPA PAHs and are of the same order of magnitude. In conclusion, for the compounds investigated, the equipment delivers a fume atmosphere in a reproducible manner. The 50 mg/m3 bitumen fumes are not representatives of field fumes. The reason for these quantitative differences is unclear and further work would be needed to clarify this. Nevertheless it was felt that these fumes at 50 mg/m3 might be a useful tool for qualitative detection of DNA adducts in an animal exposure study.

Animals↗

PubMed2005

Determination of dibenzopyrenes in standard reference materials (SRM) 1649a, 1650, and 2975 using ultrasonically assisted extraction and LC-GC-MS.

A method has been developed for analysis of the highly potent polycyclic aromatic hydrocarbon (PAH) carcinogens dibenzo(a,l)pyrene, dibenzo(a,h)pyrene, and dibenzo(a,i)pyrene (molecular weight 302) present in small amounts in diesel and air particulate material. The method can also be used for analysis of the PAH benzo(a)pyrene, coronene, and perylene, for which reference and certified values are available for the standard reference materials used for validation of the method--SRM 1649a (urban dust) and SRM 2975 (diesel particulate matter). The only NIST values that have been published for these dibenzopyrene isomers in the analyzed SRM are reference values for dibenzo(a,i)pyrene and dibenzo(a,h)pyrene in SRM 1649a. The concentrations determined in the SRM were in good agreement with reported NIST-certified and reference values and other concentrations reported in the literature. Standard reference material 1650 (diesel particulate matter) was also analyzed. The method could not, however, be validated using this material because certification of SRM 1650 had expired. The method is based on ultrasonically assisted extraction of the particulate material, then silica SPE pre-separation and isolation, and, separation and detection by hyphenated LC-GC-MS. The method is relatively rapid and requires only approximately 1-5 mg SRM particulate material to identify and quantify the analytes. Low extraction recoveries for the analytes, in particular the dibenzopyrenes, when extracting diesel SRM 2975 and 1650 resulted, however, in the dibenzopyrenes being present in amounts near their limits of quantifications in these samples. The method's limit of quantification (LOQ), based on analyses of SRM 1649a, is in the range 10-77 pg. By use of this method more than 25 potential PAH isomers with a molecular weight of 302 could be separated.

Journal Article↗

PubMed1987

The effects of laser smoke on the lungs of rats.

The sequelae of long-term inhalation of carbon dioxide laser smoke on 10 white rats were studied in a three-phase experiment. The fine particulate matter resulting from tissue vaporization was deposited in the animals' alveoli, which produced congestive interstitial pneumonia, bronchiolitis, and emphysema. The pathologic findings induced by laser plume are not dissimilar to those resulting from the long-term inhalation of other types of particulate matter. Use of an efficient smoke evacuator should offer substantial protection against these normal effects.

Animals↗

PubMed2004

All I need is the air that I breath: outdoor air quality and asthma.

In recent years, developing insight into the pathophysiology of asthma and advances in asthma management have been substantial. Despite these advancements, asthma remains a significant health problem in the paediatric population. In the USA, the prevalence of asthma in children under 18 years of age is estimated at 7% [US Environmental Health Protection Agency. Publication # EPA-100-r-018. Washington, DC, 2000]. Prevalence rates in various subpopulations, particularly African and Hispanic Americans, are much higher. Certain inner-city census tracts have estimated prevalence rates of 20 to 25% [ Crain EF Weiss KP, Stein REK. Pediatric 1994; 94: 356-362]. Many of these subpopulations experience alarmingly disparate and apparently increasing morbidity and mortality associated with asthma. Similar trends in prevalence and morbidity have been observed in urban populations outside the USA as well [Sears MR. Lancet 1997; 350: 1015-1020]. There is considerable controversy as to the scientific basis for these observed trends. While the identification of a single factor or even a closely related group of factors appears unlikely, there is considerable speculation about the role of environmental factors, particularly outdoor air quality. In the USA, the National Ambient Air Quality Standards (NAAQs) offer specific standards for air quality. These standards are applied to certain criteria pollutants, including ozone, particulate matter (both PM(10) and PM(2.5)), sulfur dioxide, nitrogen dioxide, lead and carbon monoxide [ Committee on Environmental Health, AAP. In: Handbook of Pediatric Environmental Health. Elk Grove Village, IL, 1999; 181-191]. The NAAQs were recently revised for both ozone and particulate matter based on data that suggested health risks existed at levels below those set forth in the previous standards. Monitoring data reveals that urban populations are more likely to be exposed to elevated levels of these pollutants [Dickey JH. Disease Monitor 2000; 46(9): 566-589]. Children are uniquely predisposed to the potential harmful effects of these pollutants. This predisposition is related to unique physiologic, anatomic and behavioural characteristics of the infant, child and adolescent. There is compelling evidence that an interplay of genetic predisposition and environmental exposure to a number of chemical and infectious agents may be operative in both the inception and persistence of the clinical asthma phenotype. The relative role of the criteria air pollutants in this interplay is the subject of considerable study. The potential value of intervention by regulatory agencies or by behavioural modification among individuals or communities should be explored. At the very least, the current data offers implications for situational strategies of asthma management based on local monitoring data.

Air Pollutants↗

PubMed2004

Heart rate variability and particulate exposure in vehicle maintenance workers: a pilot study.

The association between occupational exposure to PM(2.5) and heart rate variability was investigated in a repeated measures, longitudinal study of vehicle maintenance workers occupationally exposed to automobile emissions. Five subjects were monitored for occupational exposure to fine particulate matter (PM(2.5)) on 6 workdays using an aerosol photometer, validated with side-by-side sampling with a gravimetric method. End-of-day heart rate variability statistics were derived using short-term electrocardiogram recordings for each participant. Workplace carbon monoxide and outdoor, ambient fine particulate matter were also monitored. Regression statistics were used to investigate associations between same-day PM(2.5) levels and heart rate variability statistics using mixed-effects multiple regression of pooled data. No statistically significant associations were observed between occupational PM(2.5) and measures of heart rate variability. A statistically significant increase in total spectral power was associated with ambient PM(2.5) (p < 0.05). The data suggest a threshold below which no degradation in cardiac autonomic control of healthy workers occurs when challenged by occupational PM(2.5) exposure. This study was limited in population, exposure level, and type of particulate exposures. Additional studies are recommended on broader occupational populations.

Adult↗

PubMed1998

Evaluation of external breathing in children living in a region with industrial pollution.

BACKGROUND: The changes in respiratory functions are among the most sensitive indicators available for the evaluation of the influence of air pollution on health. OBJECTIVE: The objective of the present study was to evaluate the respiratory functions of children from three schools situated at a different distance from the major sources of air pollution--an asbestos-cement plant, a fertilizer plant and a steam-power plant which utilize brown coal as a main source of energy. METHODS: Comprehensive functional investigation of breathing (FIB) was performed on 97 children from the town of Dimitrovgrad--mean age 10.4 +/- 0.1 years and height 145 +/- 0.6 cm (mean +/- Sx) in a special university medical center laboratory. The characterization of the degree of air pollution was based on the analysis of the mean yearly concentrations of particulate matter, sulfur dioxide, nitrogen dioxide, ammonia and hydrogen sulphide in the three zones of exposure in the town on the basis of the criteria outlined in the Uniform National System for Control of Air Pollution in Bulgaria. RESULTS: The mean yearly concentrations of particulate matter up to 0.19 mg/m3, of hydrogen sulphide--up to 0.07 mg/m3, of nitrogen dioxide--up to 0.025 mg/m3, of ammonia--up to 0.16 mg/m3, of hydrogen sulphide--up to 0.13 mg/m3 and lead aerosols--up to 0.00012 mg/m3 recorded at the different stations reached statistical significance at some of them. No significant differences were found in the values of lung function parameters of the healthy children from all three zones. MEF50% (94 +/- 2%) and the Single Breath Transfer Factor (TLCO = 93 +/- 1.5%) showed a tendency towards lower values. CONCLUSIONS: In the low-grade pollution that we found in the present study no significant differences were found in the lung function parameters of the children from the three regions.

Air Pollutants↗

PubMed1998

Pulmonary host defenses.

The lung is constantly exposed to invading particulate matter and potential pathogens. To cope with this pressure, the lung has evolved a sophisticated, multitiered defense mechanism designed to clear offending agents while inducing a minimum amount of concomitant inflammation. Mechanical defense mechanisms first attempt to remove material physically from the tracheobronchial tree. Particulate matter and pathogens that circumvent this first line of defense are ingested by resident and recruited phagocytes in the lower respiratory tract and alveoli. If phagocytic defenses are impaired or overwhelmed, specific immune mechanisms become operational and lead to the generation of delayed-type hypersensitivity (granulomatous), cytotoxic, and humoral (antibody) responses. Congenital or acquired impairment of pulmonary host defenses can occur at any of these steps. Impairment of a particular component of pulmonary host defense is usually associated with a characteristic spectrum of infectious and noninfectious pulmonary complications. Thus, understanding all the components of pulmonary host defense and how to evaluate them will greatly aid the physician who cares for immunocompromised patients with lung disease.

Antibody Formation↗

PubMed2001

The role of particulate pollutants in pulmonary inflammation and asthma: evidence for the involvement of organic chemicals and oxidative stress.

We review the literature indicating that the adverse health effects of ambient particulate matter involve the generation of oxidative stress and inflammation, as well as immunomodulating effects by particle-associated chemicals. We discuss evidence that diesel exhaust particle organic extracts induce reactive oxygen species in macrophages and bronchial epithelial cells, two key cell types targeted by particulate matter in the lung. Reactive oxygen species activate the promoters of cytokines and chemokines involved in allergic inflammation through activator protein-1 and nuclear factor- kappaB signaling pathways, which may explain exacerbation of allergic inflammation. Organic diesel exhaust particle chemicals also induce apoptosis and necrosis in bronchial epithelial cells via a mitochondrial pathway. This may be responsible for epithelial shedding and bronchial hyperreactivity in asthma.

Asthma↗

PubMed1994

Abnormal pattern of lung functions in rubber factory workers.

The influence of suspended particulate matter, benzo(e) pyrene, benzo(e) pyrene and benzo(a) anthracene concentration on pulmonary lung functions ie, residual volume, total lung capacity, residual volume/total lung capacity, forced residual capacity were studied in 667 rubber factory workers during 1990-91. The respirable fraction of the particulate size (< 0.5 micron) showed high mean concentration of suspended particulate matter, benzo(a) pyrene, benzo(e) pyrene and benzo(a) anthracene in the compounding section (group III), when compared with vulcanising (group II) and packing loading (group I) units. While comparing the lung functions amongst these groups, the higher results of residual volume, residual volume/total lung capacity ratio, forced respiratory capacity and lower values of total lung capacity were observed in group III workers as compared with other two groups. And also these results seem to be correlated with the high pollutant concentrations to which group III workers were exposed, and reflect a clear combination of obstructive and restrictive pattern of lung functions in them.

Air Pollutants, Occupational↗

PubMed2006

Investigation of the ultraviolet photolysis method for the determination of organic nitrogen in aerosol samples.

The research objective was to adapt the ultraviolet (UV)-photolysis method to determine dissolved organic nitrogen (DON) in aqueous extracts of aerosol samples. DON was assumed to be the difference in total concentration of inorganic nitrogen forms before and after sample irradiation. Using a 2(2) factorial design the authors found that the optimal conversion of urea, amino acids (alanine, aspartic acid, glycine, and serine), and methylamine for a reactor temperature of 44 degrees C occurred at pH 2.0 with a 24-hr irradiance period at concentrations <33 microM of organic nitrogen. Different decomposition mechanisms were evident: the photolysis of amino acids and methylamine released mainly ammonium (NH4+), but urea released a near equimolar ratio of NH4+ and nitrate (NO3-). The method was applied to measure DON in the extracts of aerosol samples from Tampa, FL, over a 32-day sampling period. Average dissolved inorganic (DIN) and DON concentrations in the particulate matter fraction PM10 were 78.1 +/- 29.2 nmol-Nm(-3) and 8.3 +/- 4.9 nmol-Nm(-3), respectively. The ratio between DON and total dissolved nitrogen ([TDN] = DIN + DON) was 10.1 +/- 5.7%, and the majority of the DON (79.1 +/- 18.2%) was found in the fine particulate matter (PM2.5) fraction. The average concentrations of DIN and DON in the PM2.5 fraction were 54.4 +/- 25.6 nmol-Nm(-3) and 6.5 +/- 4.4 nmol-Nm(-3), respectively.

Aerosols↗

PubMed2005

Polycyclic aromatic hydrocarbons associated with particles in ambient air from urban and industrial areas.

This study takes into consideration an analysis of the chemical polycyclic aromatic hydrocarbon (PAH) profile and its distribution in inhalable and respirable particulate matter in urban and industrial areas in La Plata, Argentina, and Leipzig, Germany. Representative samples from three locations in La Plata (industrial, traffic influenced and control area) and two locations in Leipzig (traffic influenced and control area) were obtained in summer and winter. The sampling of particulate matter was carried out with high volume collectors using cascade impactors to separate six size fractions. PAHs were extracted with hexane through a solid-liquid equilibrium extraction and analysed by HPLC/UV/fluorescence detection. The results showed a PAH seasonal behaviour in both regions, with lower contents in summer and higher ones in winter. Highest concentrations of total PAHs were found in the industrial area in La Plata. The size distribution of particles demonstrates the greater relevance of smaller particles. More than 50% of PAHs were associated with particles of less than 0.49 microm. Moreover, this particle size fraction was associated with traffic, whereas other sources of combustion were related also to particles between 0.49 and 0.95 microm. Considering the ratio of benzo(ghi)perylene (BgP)/benzo(a)pyrene (BaP) as an indicator for traffic influence, it was observed that La Plata City was more affected than Leipzig by the same proportion in summer and in winter. The BgP/InP (indeno(123-cd)pyrene) ratio was lower in winter than in summer in both places and indicates the presence of domestic combustion sources. It is important to point out the significance of using fingerprint compound ratios to identify possible sources of pollution with PAHs bound to particles.

Air Pollutants↗

PubMedDate not supplied

Exposure assessment: input into risk assessment.

The validity of a risk assessment can be no better than that of the exposure assessment upon which it is based. The general paucity of relevant exposure data, combined with the limited appreciation by most risk assessors of the critical dimensions and metrics of exposure, often leads to an overreliance on exposure models of questionable validity. The problems of identifying and interpreting relevant metrics of exposure for epidemiologic studies and risk assessments are illustrated through the presentation of three case studies. The first examines the effects of ozone on respiratory mechanical function and demonstrates that the appropriate averaging time is greater than or equal to 6 hr, rather than 1 hr, as is implied by the current ambient air quality standard. The second case study examines the effects of sulfur oxides and particulate matter in ambient air on morbidity and mortality. It indicates that the effects are most closely associated with the acidity of the aerosol, providing a basis for an index of exposure more relevant than those currently used, i.e., sulfur dioxide and nonspecific gravimetric mass concentration of particulate matter. The third case study examines the effects of lead on blood pressure. It shows that blood lead in concentrations below 35 micrograms/dL correlates with blood pressure in both humans and animals independently of other known causal factors for blood pressure elevation. It also examines the variable relations between levels of lead in blood and in environmental media to illustrate the potential problems which can arise from the use of biological markers, such as lead in blood, as indices of exposure.

Adolescent↗