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PubMed2002

Source apportionment of PM2.5 in the Southeastern United States using solvent-extractable organic compounds as tracers.

A chemical mass balance (CMB) receptor model using particle-phase organic compounds as tracers is applied to apportion the primary source contributions to fine particulate matter and fine particulate organic carbon concentrations in the southeastern United States to determine the seasonal variability of these concentrations. Source contributions to particles with aerodynamic diameter < or =2.5 microm (PM2.5) collected from four urban and four rural/suburban sites in AL, FL, GA, and MS during April, July, and October 1999 and January 2000 are calculated and presented. Organic compounds in monthly composite samples at each site are identified and quantified by gas chromatography/mass spectrometry and are used as molecular markers in the CMB model. The major contributors to identified PM2.5 organic carbon concentrations at these sites in the southeastern United States include wood combustion (25-66%), diesel exhaust (14-30%), meat cooking (5-12%), and gasoline-powered motor vehicle exhaust (0-10%), as well as smaller but statistically significant contributions from natural gas combustion, paved road dust, and vegetative detritus. The primary sources determined in the present study when added to secondary aerosol formation account for on average 89% of PM2.5 mass concentrations, with the major contributors to PM2.5 mass as secondary sulfate (30+/-6%), wood combustion (15+/-12%), diesel exhaust (16+/-7%), secondary ammonium (8+/-2%), secondary nitrate (4+/-3%), meat cooking (3+/-2%), gasoline-powered motor vehicle exhaust (2+/-2%), and road dust (2+/-2%). Distinct seasonality is observed in source contributions, including higher contributions from wood combustion during the colder months of October and January. In addition, higher percentages of unexplained fine organic carbon concentrations are observed in July, which are likely due to an increase in secondary organic aerosol formation during the summer season.

Aerosols↗

PubMed1997

The role of particulate size and chemistry in the association between summertime ambient air pollution and hospitalization for cardiorespiratory diseases.

In order to address the role that the ambient air pollution mix, comprised of gaseous pollutants and various physical and chemical measures of particulate matter, plays in exacerbating cardiorespiratory disease, daily measures of fine and coarse particulate mass, aerosol chemistry (sulfates and acidity), and gaseous pollution (ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide) were collected in Toronto, Ontario, Canada, in the summers of 1992, 1993, and 1994. These time series were then compared with concurrent data on the number of daily admissions to hospitals for either cardiac diseases (ischemic heart disease, heart failure, and dysthymias) or respiratory diseases (tracheobronchitis, chronic obstructive long disease, asthma, and pneumonia). After adjusting the admission time series for long-term temporal trends, seasonal variations, the effects of short-term epidemics, day of the week effects, and ambient temperature and dew point temperature, positive associations were observed for all ambient air pollutants for both respiratory and cardiac diseases. Ozone was least sensitive to adjustment for the gaseous and particulate pollution measures. However, the association between the health outcomes and carbon monoxide, fine and coarse mass, sulfate levels and aerosol acidity could be explained by adjustment for exposure to gaseous pollutants. Increases in ozone, nitrogen dioxide, and sulfur dioxide equivalent to their interquartile ranges corresponded to an 11% and 13% increase in daily hospitalizations for respiratory and cardiac diseases, respectively. The inclusion of any one of the particulate air pollutants in multiple regression models did not increase these percentages. Particle mass and chemistry could not be identified as an independent risk factor for the exacerbation of cardiorespiratory diseases in this study beyond that attributable to climate and gaseous air pollution. We recommend that effects of particulate matter on health be assessed in conjunction with temporally covarying gaseous air pollutants.

Air Pollutants↗

PubMedDate not supplied

Mutagenicity studies on complex environmental mixtures: selection of solvent system for extraction.

The mutagenic activities in the Salmonella/microsome assay of dichloromethane (DCM) and acetone extracts of complex environmental mixtures were compared. The particulate samples used in the IPCS collaborative study were Soxhlet-extracted twice with DCM followed by a third extraction with acetone. Compared with the mutagenic activity of the first extract, the third (acetone) extract of the urban particulate matter showed a relatively high mutagenic activity. In contrast to this the third extract of the diesel particulate matter contributed very little additional mutagenic activity. Furthermore, 10 filter samples of air particulates from a suburban airport area were collected for comparison of the extraction efficiency of DCM and acetone. Each sample was divided into two samples of identical size followed by extraction with acetone and DCM, respectively. No clear difference in the mutagenic activity of these extracts was observed in strains TA98 and TA98NR. It is concluded that for ambient air particulates (but not emission samples) acetone may extract some mutagenic compounds which are not extracted by DCM. The amount of these additional extractable compounds seems to depend on the composition of the sample. As DCM extracts are better suited for further fractionation and chemical analysis DCM is considered to be the best choice for a general solvent system for extraction of complex environmental mixtures.

Acetone↗

PubMed1995

Scanning electron microscopy of immunogold labeled cat allergens (Fel d 1) on the surface of airborne house dust particles.

This study investigated the ability of an immunogold labeling technique to demonstrate the presence of Fel d 1 (domestic cat) allergens on the surface of particles in samples of airborne house dust. Suspended particulate matter was sampled from ten Norwegian households, five with and five without a domestic cat. The specimens were immunogold labeled and examined in the backscatter electron imaging mode of the scanning electron microscope and in the transmission electron microscope. X-ray microanalysis was also applied to execute element analysis of the suspended particular matter. The gold probe was mainly detected on carbon particles in the suspended particulate matter, both on small (< 1 microns) and larger carbon aggregates (1-10 microns). The present method may be useful in studying the localisation of different allergens on airborne house dust particles of various sizes and composition.

Allergens↗

PubMed2004

Comparative study of PM2.5 - and PM10 - induced oxidative stress in rat lung epithelial cells.

Accurate estimation of the exposure-response relationship between ambient urban particulate matters (PM) and public health is important for regulatory perspective of ambient urban particulate matters (PM). Ambient PM contains various transition metals and organic compounds. PM10 (aerodynamic diameter less than 10 micro m) is known to induce diverse diseases such as chronic cough, bronchitis, chest illness, etc. However, recent evaluation of PM2.5 (aerodynamic diameter less than 2.5 micro m) against health outcomes has suggested that the fine particles may be more closely associated with adverse respiratory health effects than particles of larger size. This study was performed to evaluate PM2.5-induced oxidative stress in rat lung epithelial cell in order to provide basic data for the risk assessment of PM2.5. PM2.5 showed higher cytotoxicity than PM10. Also, PM 2.5 induced more malondialdehyde (MDA) formation than PM10. In Hoechst 33258 dye staining and DNA fragmentation assay, apopotic changes were clearly detected in PM2.5 treated cells in compared to PM10. Expression of catalase mRNA was increased by PM2.5 rather than PM10. PM2.5 induced higher Mth1 mRNA than PM10. In pBR322 DNA treated with PM2.5, production of single strand breakage of DNA was higher than that of PM10. In Western blot analysis, PM2.5 induced more Nrf-2 protein, associated with diverse transcriptional and anti-oxidative stress enzymes, compared to PM10. Our data suggest that PM2.5 rather than PM10 may be responsible for PM-induced toxicity. Additional efforts are needed to establish the environmental standard of PM2.5.

Air Pollutants↗

PubMedDate not supplied

Industrial hygiene sampling and applications to ambient silica monitoring.

Interest in ambient exposures to silica has prompted an evaluation of the applicability of the industrial hygiene sampling and analysis experience. Exposure to excessive levels of silica in the workplace has long been recognized as a risk factor for the development of a variety of disabling and sometimes fatal lung diseases. Initial efforts to control occupational exposure to dust were based on reducing exposures as measured by particle-counting techniques. Because silicosis, the disease resulting from exposure to silica, occurs in the lower airways, which can be reached only by small "respirable dust" particles, size selective sampling procedures were introduced for dust monitoring. The analysis of silica in collected dust samples also has undergone development. Initial methods used involved acid digestion of soluble silicates, with subsequent chemical analysis of the insoluble "free silica" fraction. Current methodology relies on the use of X-ray diffraction and infrared technologies to quantify these materials. However, these methods are sensitive to the particle size distribution of the samples. Standard reference materials (SRMs) have been developed for use with respirable size dust samples. Ambient particulate matter is now measured using the U.S. Environmental Protection Agency sampling methods for particulate matter < or = 10 microns, which approximate the collection efficiency for thoracic fraction samplers. Because the existing calibration SRMs were produced for the measurement of occupational crystalline silica, the need to develop appropriate standards and methods for ambient silica measurements should be evaluated.

Air Pollutants, Occupational↗

PubMed1978

Particle-mediated membrane uptake of chemical carcinogens studied by fluorescence spectroscopy.

The fluorescence emissions of chrysene, N-ethylcarbazole, and 1,6-diphenylhexatriene undergo large spectral shifts or changes in quantum yield, or both, upon their uptake from particulates by phospholipid vesicles. This membrane uptake of carcinogen and carcinogen-like molecules by model membranes does not result in any disruption of the lipid bilayers. The fluorescence emission of chrysene, when bound to silica, was found to be sensitive to the surface density of chrysene on the silica. These observations demonstrate the feasibility of using fluorescence spectroscopy to measure the rates of exchange of carcinogens from particulate matter to cell membranes and to characterize the surface distribution of chemical carcinogens on particulate matter. Comparison of the uptake rate of chrysene from the unperturbed crystal state, sonicated crystals, and the silica-adsorbed state demonstrated that the last condition results in the most rapid transport of chrysene into model membranes. This information should prove valuable in understanding the cocarcinogenic effects of particulates and polynuclear aromatic hydrocarbons.

Carcinogens↗

PubMed2006

Personal and ambient air pollution is associated with increased exhaled nitric oxide in children with asthma.

BACKGROUND: Research has shown associations between pediatric asthma outcomes and airborne particulate matter (PM). The importance of particle components remains to be determined. METHODS: We followed a panel of 45 schoolchildren with persistent asthma living in Southern California. Subjects were monitored over 10 days with offline fractional exhaled nitric oxide (FeNO), a biomarker of airway inflammation. Personal active sampler exposures included continuous particulate matter < 2.5 microm in aerodynamic diameter (PM2.5), 24-hr PM2.5 elemental and organic carbon (EC, OC), and 24-hr nitrogen dioxide. Ambient exposures included PM2.5, PM2.5 EC and OC, and NO2. Data were analyzed with mixed models controlling for personal temperature, humidity and 10-day period. RESULTS: The strongest positive associations were between FeNO and 2-day average pollutant concentrations. Per interquartile range pollutant increase, these were: for 24 microg/m3 personal PM2.5, 1.1 ppb FeNO [95% confidence interval (CI), 0.1-1.9]; for 0.6 microg/m3 personal EC, 0.7 ppb FeNO (95% CI, 0.3-1.1); for 17 ppb personal NO2, 1.6 ppb FeNO (95% CI, 0.4-2.8). Larger associations were found for ambient EC and smaller associations for ambient NO2. Ambient PM2.5 and personal and ambient OC were significant only in subjects taking inhaled corticosteroids (ICS) alone. Subjects taking both ICS and antileukotrienes showed no significant associations. Distributed lag models showed personal PM2.5 in the preceding 5 hr was associated with FeNO. In two-pollutant models, the most robust associations were for personal and ambient EC and NO2, and for personal but not ambient PM2.5. CONCLUSION: PM associations with airway inflammation in asthmatics may be missed using ambient particle mass, which may not sufficiently represent causal pollutant components from fossil fuel combustion.

Adolescent↗

PubMedDate not supplied

Incinerator fly ash provokes alteration of redox equilibrium and liberation of arachidonic acid in vitro.

Numerous epidemiological studies have associated exposure to ambient particulate matter (PM) with pulmonary and cardiovascular health effects. Macrophages as a part of the primary pulmonary defence system play a crucial role by generating pro- and anti-inflammatory mediators. The aim of the present study was to examine the effect of incinerator fly ash (MAF02) as a model of environmental particulate matter on the formation of reactive oxygen species (ROS) and their ability to induce oxidative stress in RAW264.7 macrophages. Furthermore, the liberation of arachidonic acid (AA) was observed. The interaction of MAF02 with macrophages caused increased mobilisation of AA, accompanied by enhanced expression of cyclooxygenase-2 (COX-2). The MAF02-induced AA liberation was found to depend on an increased intracellular calcium concentration. In addition, MAF02-induced liberation of AA was selectively blocked by an ERK1/2 pathway-specific inhibitor, while inhibition of the p38 MAPK activity had no effect. Fly ash was also observed to induce an increase in cellular glutathione (GSH) content and antioxidative enzyme haem oxygenase-1 (HO-1). In correlation, experiments with dichlorofluorescein demonstrated increased formation of ROS upon treatment with fly ash. In summary, incinerator fly ash induces oxidative stress to a certain extent, resulting in the onset of important mechanisms related to inflammation.

Animals↗

PubMedDate not supplied

Natural sources and heavy metals.

PTS, PM10 and PM2.5 samples have been collected at a rural site of south-east Italy (40 degrees 20' 13" N; 18 degrees 6' 47" E) from June to October, 2004 to investigate natural and anthropogenic contributions on particulate matter and heavy metal mass concentrations. It is shown that sharp-peak particulate-matter concentrations have been recorded during most African dust outbreaks occurred over south-east Italy. In particular, PM10 concentrations exceeding the 24-hour limit value of 50 microg/m3 have been monitored during dust events. Al, Cd, Cr, Cu, Fe, Mn, V, Ni, Pb, and Zn metal concentrations have been evaluated by an inductively coupled plasma atomic emission spectrometer and Al mass concentrations >500 ng/m3 have been observed in PTS and PM10 samples during the advection of African dust particles. Accordingly to geochemical calculations Al, Fe, and Mn, have a significant crustal origin while, Cd, Cu, Pb, and Zn are of anthropogenic origin. Moreover, Fe resulted predominant in the coarse particle fraction, while Ni, Pb, V, and Zn were predominant in the fine particle fraction. It is also shown that Cd, Mn, Ni, Pb, and V concentrations never exceeded guide and/or limit values recommended by the World Health Organization and the European Council Directives.

Air Pollutants↗

PubMed1975

Persistence of parathion and its oxidation to paraoxon on the soil surface as related to worker reentry into treated crops.

Soil and dust samples from beneath citrus trees contained relatively high concentrations of paraoxon and parathion for at least 45 days after parathion was applied at normal rates. These data indicate that parathion dripping on dry soil from sprayed crops, or sprayed directly on the soil surface, can persist for long periods and be oxidized to the highly toxic paraoxon. The residue concentrations are much higher on the loose dust particles than in the bulk soil. The data indicate that the soil or grove floor should be considered as a possible contributing source of toxicant along with foliage, or dust on foliage, to workers reentering treated fields. In any event, the data confirmed the high rates of oxidation of parathion to paraoxon on particulate matter, whether on foliage (SPEAR et al., 1974) or at the soil surface. The particulate matter appears to contribute to the accumulation of paraoxon, either by enhancing oxidation of parathion to paraoxon or by decreasing dissipation of paraoxon.

Agricultural Workers' Diseases↗

PubMed2000

Airway inflammation after controlled exposure to diesel exhaust particulates.

Epidemiologic evidence suggests a link between morbidity and mortality and levels of particulate matter in the atmosphere. We studied the inflammatory response to inhalation of diesel exhaust particulates (DEP) in normal volunteers. DEP were collected from the exhaust of a stationary diesel engine and were resuspended in an exposure chamber. Ten nonsmoking healthy volunteers were exposed for 2 h at rest to a controlled concentration of DEP (monitored at 200 microg/m(3) particulate matter of less than 10 microm aerodynamic diameter [PM(10)]) or air in a double-blind, randomized, crossover study. Exposures were followed by serial spirometry and measurement of pulse, blood pressure, exhaled carbon monoxide (CO), and methacholine reactivity, as well as sputum induction and venesection for up to 4 h after exposure, and a repeat of all these procedures at 24 h after exposure. There were no changes in cardiovascular parameters or lung function following exposure to DEP. Levels of exhaled CO were increased ater exposure to DEP, and were maximal at 1 h (air: 2.9 +/- 0.2 ppm [mean +/- SEM]; DEP: 4.4 +/- 0.3 ppm; p < 0.001). There was an increase in sputum neutrophils and myeloperoxidase (MPO) at 4 h after DEP exposure as compared with 4 h after air exposure (neutrophils: 41 +/- 4% versus 32 +/- 4%; MPO: 151 ng/ml versus 115 ng/ml, p < 0.01), but no change in concentrations of inflammatory markers in peripheral blood. Exposure to DEPs at high ambient concentrations leads to an airway inflammatory response in normal volunteers.

Adult↗

PubMedDate not supplied

[The work process and occupational health risks in a cement factory].

The authors evaluate the work process and its effect on workers' health in a cement factory in the State of Rio de Janeiro. The interactive methodology consisted of different approaches to assessing the workplace through the incorporation of various institutions working in the field of Workers' Health, professionals from different backgrounds, and the trade union, valorizing the workers' experience and actively contributing to the surveillance process under the Unified National Health System (SUS). Levels of particulate matter and noise were measured. The mean level of free crystalline silica in the particulate matter was 2%, resulting in a tolerance limit as specified under Brazilian legislation (NR-15), or 2.0mg/m3. The concentration of particles both in samples collected in the workers' respiratory zone and in area samples varied from 3.59 to 52.44mg/m3. Noise varied from 83dB to 110dB. The majority of the values were higher than the maximum limits set by Brazilian legislation. These results, together with the opinions expressed by the workers themselves, showed an unhealthy workplace and work process, placing the workers' health at risk.

Brazil↗

PubMed2006

Air quality measurements for the aerosol research and inhalation epidemiology study.

Measurements of pollutant gases, airborne particulate matter mass and composition, and meteorology have been made at a core site near downtown Atlanta, GA, since August 1998 in support of the Aerosol Research and Inhalation Epidemiology Study (ARIES). This site is one of eight in the Southeastern Aerosol Research and Characterization network. The measurement objective is to provide a long-term, multivariate dataset suitable for investigating statistical associations of respiratory and cardiovascular disease with airborne particulate matter composition, meteorology, and copollutant gases through epidemiologic modeling. Measurements are expected to continue through 2010. Ancillary multiyear measurements at additional sites in the Atlanta metropolitan area and in short-term exposure assessments have been used to estimate the exposure/measurement error associated with using data from a central site to approximate human exposures for the entire area. To date, 13-, 25-, and 53-month air quality datasets have been used in epidemiologic analyses.

Aerosols↗

PubMed2026

Breathing carcinogens: PM2.5 air pollution and lung cancer in never-smokers, a narrative review.

BACKGROUND AND OBJECTIVE: Lung cancer in never-smokers (LCINS) disproportionately affects women and younger individuals, and its incidence has increased over recent decades. Environmental respiratory hazards, such as particulate matter ≤2.5 µm (PM2.5), are associated with lung cancer incidence and mortality, but the mechanisms by which PM2.5 increases lung cancer susceptibility remain incompletely understood. This review summarizes the current evidence linking PM2.5 exposure to LCINS and identifies priorities for future research. METHODS: A narrative review was conducted using PubMed/MEDLINE to identify English-language studies published from 2000 through May 2026 using combinations of the terms "PM2.5", "fine particulate matter", "air pollution", "lung cancer", "never-smokers", "environmental respiratory hazards", "genomic alterations", and "tumor microenvironment". Additional relevant studies were identified through manual review of the reference lists of included articles. Studies were selected based on their relevance to the epidemiology, biological mechanisms, genomic and immune landscape, and clinical implications of PM2.5-associated LCINS, with emphasis on original investigations, high-quality reviews, and landmark publications. KEY CONTENT AND FINDINGS: PM2.5 exposure promotes inflammatory signaling, metabolic reprogramming, and tumor progression. Emerging evidence suggests that PM2.5 functions primarily as a tumor promoter rather than a direct mutagen and is associated with genomic and epigenetic alterations, more advanced disease, and worse survival following lung cancer diagnosis and surgical resection. LCINS also exhibits distinct molecular and immunologic characteristics with important implications for screening, molecular profiling, and targeted therapies. CONCLUSIONS: PM2.5 is an increasingly recognized contributor to lung carcinogenesis in never-smokers. Improved understanding of the biologic mechanisms linking environmental respiratory hazards to LCINS may inform future screening strategies, precision oncology approaches, and novel therapeutic targets for this growing and understudied patient population.

Fine particulate matter ≤2.5 µm in dia↗

PubMed2006

Enhanced biogas recovery by applying post-digestion in large-scale centralized biogas plants.

The main objective of this study was to investigate the degradation efficiency of centralized biogas plants and provide guidance for the design of more efficient digester and post-digestion systems. These centralized biogas plants in Denmark digest manure together with organic waste from the food industry to generate biogas, which is used for electricity and thermal energy. A total of 20 such plants are currently active in Denmark, most of which were included in the investigation. From the plants, samples were obtained from various steps of the process. Samples were analysed and the residual biogas potential determined by batch post-digestion at various temperature levels. Results were correlated with plant characteristics and production statistics in order to judge the efficiency of various digestion concepts. A simplified model based on a two-step biogas production process was developed and experimental data were used to determine kinetic constants. Experimental results and analysis combined with model simulations showed that the residual biogas potential in the main digestion step effluent is originating mainly from undegraded particulate matter in the biomass. For thermophilic plants 93% of the residual biogas potential was originating from particulate matter and 88% for the mesophilic biogas plants. This indicates that the residual biogas potential is mainly due to insufficient retention time in the main digestion step for hydrolysis of particulate material and that the hydrolysis step is the methane yield limiting factor, while conversion of soluble material such as VFA is the rate limiting factor critical for achieving a stable process.

Denmark↗

PubMed2026

MASLD Exacerbates Chronic Low-dose PM2.5-induced Lung Injury, Inflammation, and Fibrosis.

BACKGROUND/AIM: Fine particulate matter (PM2.5) and metabolic dysfunction-associated steatotic liver disease (MASLD) are independent risk factors for respiratory disease. However, the combined impact of chronic, low-dose PM2.5 exposure and Western diet (WD)-induced metabolic dysfunction on pulmonary health remains poorly understood. We investigated whether this metabolic state exacerbates PM2.5-driven pathologies using an environmentally relevant PM2.5 dosage (~50 μg/m3). MATERIALS AND METHODS: C57BL/6J mice were fed a WD or normal diet (ND) for 28 weeks and concurrently received intratracheal instillations of PM2.5 (0.5 mg/kg diesel particulate matter) or vehicle three times per week. The MASLD phenotype was confirmed through metabolic and histological analyses. Pulmonary injury, fibrosis, and inflammation were assessed via histology (hematoxylin and eosin, and Masson's trichrome staining) and cytokine quantification in both bronchoalveolar lavage fluid using Luminex multiplex assay and lung tissue using enzyme-linked immunosorbent assay and quantitative polymerase chain reaction. RESULTS: The WD successfully induced MASLD characterized by weight gain, hepatic steatosis, and dyslipidemia. While PM2.5 exposure did not significantly worsen the primary features of MASLD, its combination with a WD markedly exacerbated pulmonary injury and fibrosis compared to PM2.5 exposure alone. This exacerbation was driven by a surge in pro-inflammatory chemokines, including C-X-C motif chemokine ligands 1 and 2 (CXCL1 and CXCL2), and C-C motif chemokine ligand 5 (CCL5), confirmed by Luminex analysis of lavage fluid and mRNA/protein quantification in lung tissue. CONCLUSION: Diet-induced metabolic dysfunction primes the lung for a hyper-inflammatory response to chronic PM2.5 exposure. These findings identify individuals with MASLD as a population with heightened susceptibility to air pollution-related respiratory diseases and underscore the critical interplay between metabolic health and environmental toxicology.

Animals↗

PubMed2006

The composition of PM10 as collected by a conventional TEOM, a modified TEOM and a Partisol gravimetric monitor at a kerbside site in the North East of England.

The composition of airborne particulate matter sampled by a conventional TEOM, an experimental modified TEOM, operated at a lower temperature but fitted with a drier to remove moisture and a Partisol, installed at a kerbside site in the North East of England, has been investigated. The results indicate that there is a seasonal variation in the composition of PM(10) as sampled by the three monitors, with chloride concentration being significantly higher in the winter. The Partisol was found to sample a higher mass of chloride and nitrate, however the differences between the monitors was only significant for chloride. Both TEOM's were found to sample a greater mass of sulphate, although the variability in the data collected meant that significance of the results was not proven statistically. The range of artifacts associated with PM(10) monitors is reviewed. Difficulties in the interpretation of results due to the variable nature of airborne particulate matter and the ability of filter based systems to accurately represent the composition of atmospheric particles are considered.

Aerosols↗