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PubMed2026

Prenatal exposure to particulate matter (PM) and autism spectrum disorder (ASD) among children: a systematic review and meta-analysis.

The global surge in Autism Spectrum Disorder (ASD) cases, coupled with evidence linking prenatal Particulate Matter (PM) exposure to developmental disruption, demands a comprehensive review to design targeted health interventions. This systematic review and meta-analysis aim to evaluate the strength and consistency of evidence linking prenatal PM exposure to ASD across studies, quantifying this relation to identify actionable environmental risk thresholds. This study employed PRISMA protocols to systematically extract and evaluate evidence from PubMed, Web of Science, Scopus, and ScienceDirect (2010-2024), and screened 4,013 articles to identify qualified case-control and cohort studies (n=29). Data synthesis employed random-effects modeling, accompanied by comprehensive assessment through I2 statistics, Q-tests, funnel plots, Duval and Tweedie's trim-and-fill analysis, and Egger's regression, to ensure validity. A meta-analysis of 16 case-control studies revealed a 34 % increased risk of ASD associated with prenatal PM exposure (pooled OR=1.34; 95 % CI: 1.13-1.54), despite substantial between-study heterogeneity (I2=94.02 %, p<0.001). Publication bias was not significant (Egger's test p value=0.114). Critical trimester-specific analysis uncovered that third-trimester exposure significantly increased ASD risk (OR=1.17; 95 % CI: 1.01-1.34), while first-trimester (OR=1.02; 95 % CI: 0.92-1.11; I2=49.18 %, p<0.10) and second-trimester exposures (OR=1.13; 95 % CI: 0.88-1.38; I2=92.59 %, p<0.001) showed non-significant associations. This review identified prenatal and early life exposure to PM as a risk factor for ASD, indicating a trimester-specific vulnerability. It highlighted the necessity of focused air quality interventions and targeted guidance to reduce prenatal PM exposure to alleviate ASD risk during the critical-window.

Child↗

PubMed1999

Urinary 1-hydroxypyrene and other PAH metabolites as biomarkers of exposure to environmental PAH in air particulate matter.

Humans are exposed to polycyclic aromatic hydrocarbons (PAHs) from occupational, environmental, medicinal and dietary sources. PAH metabolites in human urine can be used as biomarkers of internal dose to assess recent exposure to PAHs. The most widely used urinary PAH metabolites are 1-hydroxypyrene (1-OHP) or 1-hydroxypyrene-O-glucuronide (1-OHP-gluc), the major form of 1-OHP in human urine, because of their relatively high concentration and prevalence in urine and their relative ease of measurement. Elevated levels of 1-OHP or 1-OHP-gluc have been demonstrated in smokers, in patients receiving coal tar treatment (vs. pre-treatment), in postshift road pavers or coke oven workers, and in subjects ingesting charbroiled meat. This metabolite is found (at low levels) in most human urine samples, even in persons without apparent occupational or smoking exposure. Recent studies suggest that environmental exposure to PAHs (and air particles) is associated with increased excretion of 1-OHP-gluc or 1-OHP. These findings raise the possibility of using urinary concentration of 1-OHP-gluc, or another PAH metabolite, as a surrogate biomarker of exposure to airborne fine (sooty) particulate matter--the major source of PAHs in polluted air. Reported associations between ambient particulate matter concentrations and health effects among adults and children, including respiratory disease and mortality, indicate the need for biomarkers of fine particle exposure. If validated, such biomarkers would be useful in supplementing and refining exposure information obtained by ambient monitoring.

Adult↗

PubMed2005

Relationship between different size classes of particulate matter and meteorology in three European cities.

Evidence on the correlation between particle mass and (ultrafine) particle number concentrations is limited. Winter- and spring-time measurements of urban background air pollution were performed in Amsterdam (The Netherlands), Erfurt (Germany) and Helsinki (Finland), within the framework of the EU funded ULTRA study. Daily average concentrations of ambient particulate matter with a 50% cut off of 2.5 microm (PM2.5), total particle number concentrations and particle number concentrations in different size classes were collected at fixed monitoring sites. The aim of this paper is to assess differences in particle concentrations in several size classes across cities, the correlation between different particle fractions and to assess the differential impact of meteorological factors on their concentrations. The medians of ultrafine particle number concentrations were similar across the three cities (range 15.1 x 10(3)-18.3 x 10(3) counts cm(-3)). Within the ultrafine particle fraction, the sub fraction (10-30 nm) made a higher contribution to particle number concentrations in Erfurt than in Helsinki and Amsterdam. Larger differences across the cities were found for PM2.5(range 11-17 microg m(-3)). PM2.5 and ultrafine particle concentrations were weakly (Amsterdam, Helsinki) to moderately (Erfurt) correlated. The inconsistent correlation for PM2.5 and ultrafine particle concentrations between the three cities was partly explained by the larger impact of more local sources from the city on ultrafine particle concentrations than on PM2.5, suggesting that the upwind or downwind location of the measuring site in regard to potential particle sources has to be considered. Also, relationship with wind direction and meteorological data differed, suggesting that particle number and particle mass are two separate indicators of airborne particulate matter. Both decreased with increasing wind speed, but ultrafine particle number counts consistently decreased with increasing relative humidity, whereas PM2.5 increased with increasing barometric pressure. Within the ultrafine particle mode, nucleation mode (10-30 nm) and Aitken mode (30-100 nm) had distinctly different relationships with accumulation mode particles and weather conditions. Since the composition of these particle fractions also differs, it is of interest to test in future epidemiological studies whether they have different health effects.

Air Pollutants↗

PubMed1993

Particulate matter of smoke inhalation.

Smoke inhalational injury is a common event, which often complicates cutaneous burns, markedly increasing mortality, especially when it is associated with facial burning. The primary source of injury in the upper respiratory tract is heat, but thermal injury does not usually extend beyond the bifurcation of the trachea. Within the lung, it is the deposition of particles, derived from the substrate burnt, together with the toxic gases given off which causes the injury. The way in which the injuries are caused is not completely understood, but it appears to be a direct response to the stimulation of the inflammatory response. This seems to give rise to a feedback mechanism. The continued presence of particulate matter may lead to continuing damage and thus to impaired respiratory function in survivors. The nature of the particulate matter, like the toxic fumes given off, reflects the chemical nature of the substances burnt, and is not as is commonly assumed, merely carbon.

Fires↗

PubMed2003

DDT-related compounds bound to the nonextractable particulate matter in sediments of the Teltow Canal, Germany.

Sediment samples of the Teltow Canal (Berlin, Germany) were analyzed with respect to extractable and nonextractable organic compounds. The study focused on the identification and quantitation of bound 2,2-bis(chlorophenyl)-1,1,1-trichlorethane (DDT) residues in order to obtain further information about the fate of DDT-derived compounds within the particulate matter of the aquatic environment. Various chemical degradation techniques and a complementary online pyrolysis-GC/MS method were applied to the pre-extracted sediment residues. Generally, the distribution of the bound DDT-related compounds was found to differ distinctly from the substances distribution within the extractable fraction. The main metabolite of the anaerobic degradation pathway (2,2-bis(chlorophenyl)-1,1-dichlorethane, DDD) is most abundant in the sediment extracts but occurred only in insignificant concentrations in the degradation products of all procedures applied. The most abundant DDT-metabolites released after the degradation procedures were 4,4'-DBP, 4,4'-DDA, and 4,4'-DDM. In addition, 4,4'-DDM was detected at rather high concentrations by pyrolytic analysis. The results imply a weak association to the nonextractable particulate matter based on noncovalent interactions for the observed DDT-related contaminants. The release of these compounds was initiated by the modification and degradation of the organic macromolecular matrix as well as of the inorganic material. Furthermore, numerous methoxychlor-related compounds were detected not only in the extracts but also in parts of the hydrolysis products.

DDT↗

PubMed2005

Application of satellite remote-sensing data for source analysis of fine particulate matter transport events.

Satellite sensors have provided new datasets for monitoring regional and urban air quality. Satellite sensors provide comprehensive geospatial information on air quality with both qualitative imagery and quantitative data, such as aerosol optical depth. Yet there has been limited application of these new datasets in the study of air pollutant sources relevant to public policy. One promising approach to more directly link satellite sensor data to air quality policy is to integrate satellite sensor data with air quality parameters and models. This paper presents a visualization technique to integrate satellite sensor data, ground-based data, and back trajectory analysis relevant to a new rule concerning the transport of particulate matter across state boundaries. Overlaying satellite aerosol optical depth data and back trajectories in the days leading up to a known fine particulate matter with an aerodynamic diameter of <2.5 microm (PM2.5) event may indicate whether transport or local sources appear to be most responsible for high PM2.5 levels in a certain location at a certain time. Events in five cities in the United States are presented as case studies. This type of analysis can be used to help understand the source locations of pollutants during specific events and to support regulatory compliance decisions in cases of long distance transport.

Aerosols↗

PubMed2002

Effects of birch pollen and traffic particulate matter on Th2 cytokines, immunoglobulin E levels and bronchial hyper-responsiveness in mice.

BACKGROUND: Health effects due to air pollution arising from motor vehicles are a major public and political concern world-wide. Epidemiological studies have shown that the manifestations of asthma are increased by air pollution in already affected individuals. OBJECTIVE: To investigate the potential role of air-polluted tunnel dust (traffic particulate matter, TPM) or pure carbon core particles in the initiation and persistence of experimental allergic inflammation. METHODS: BP2 mice were immunized with birch pollen alone (group B) or pollen together with TPM (group A), or with birch pollen and Al(OH)3 (group C), or with birch pollen and carbon core particles (group D). Before methacholine challenge they were challenged intranasally and thereafter bronchial hyper-reactivity (BHR) was evaluated in a whole-body plethysmograph. Levels of Th2 cytokines, fibronectin and lactate dehydrogenase (LDH) were determined, and differential counts were performed in the bronchoalveolar lavage (BAL) fluid. Sera were collected for determination of antibody titres and cytokine levels. RESULTS: Specific IgE titres, BHR, the number of recruited eosinophils and levels of fibronectin and LDH in BAL were increased in mice immunized and challenged with a mixture of birch pollen and TPM. However, mice immunized with birch pollen alone and challenged intranasally with pollen or a mixture of pollen and TPM demonstrated the highest levels of IL-4 and IL-5. CONCLUSION: This study highlights the importance of the exposure to a combination of particulate matters and pollen allergens, in the induction of allergic disease in the airways, and we have demonstrated that polluted tunnel dust has an effect on both the inflammatory and immunological components of experimental allergy. Immunization and challenge with carbon core particles together with birch pollen increased neither the BHR nor the specific IgE production significantly. Our results therefore strongly suggest that it is most likely to be the organic phase bound to the carbon core of the diesel exhaust particles that might have an important adjuvant effect in the induction of experimental allergy.

Allergens↗

PubMed2001

Comparison of real-time instruments used to monitor airborne particulate matter.

Measurements collected using five real-time continuous airborne particle monitors were compared to measurements made using reference filter-based samplers at Bakersfield, CA, between December 2, 1998, and January 31, 1999. The purpose of this analysis was to evaluate the suitability of each instrument for use in a real-time continuous monitoring network designed to measure the mass of airborne particles with an aerodynamic diam less than 2.5 microns (PM2.5) under wintertime conditions in the southern San Joaquin Valley. Measurements of airborne particulate mass made with a beta attenuation monitor (BAM), an integrating nephelometer, and a continuous aerosol mass monitor (CAMM) were found to correlate well with reference measurements made with a filter-based sampler. A Dusttrak aerosol sampler overestimated airborne particle concentrations by a factor of approximately 3 throughout the study. Measurements of airborne particulate matter made with a tapered element oscillating microbalance (TEOM) were found to be lower than the reference filter-based measurements by an amount approximately equal to the concentration of NH4NO3 observed to be present in the airborne particles. The performance of the Dusttrak sampler and the integrating nephelometer was affected by the size distribution of airborne particulate matter. The performance of the BAM, the integrating nephelometer, the CAMM, the Dusttrak sampler, and the TEOM was not strongly affected by temperature, relative humidity, wind speed, or wind direction within the range of conditions encountered in the current study. Based on instrument performance, the BAM, the integrating nephelometer, and the CAMM appear to be suitable candidates for deployment in a real-time continuous PM2.5 monitoring network in central California for the range of winter conditions and aerosol composition encountered during the study.

Air Pollution↗

PubMed2005

Elucidating a particulate matter deposition episode by combining scanning electron microscopy and X-ray fluorescence spectrometry.

Multielemental composition and morphology of particulate matter samples were examined to detect the presence of two potential responsible pollutant emitters at four sites impacted during a pollution episode in the City of Campana, Argentina. Coke and smoke black are the main constituents associated to the industrial plants that were considered, a priori, as responsible pollutant emitters. Wavelength dispersive X-ray fluorescence (WDXRF) was employed for the analysis of metals in samples coming from both, suspected sources and four sites. On the basis of multielemental composition profiles, a screening analysis was undertaken for exploring similarities among sources and sample sites adopting the average concentration profile of the crustal rock as soil surrogate. Particle morphology was studied by scanning electron microscopy (SEM) in source samples and in those environmental samples selected through the screening analysis. Two types of collected samples were analyzed: 1) those with composition profiles closer to the potential sources and 2) those closer to the cluster rock. This strategy was adequate to identify the responsible source of the contamination episode.

Air Pollutants↗

PubMed2006

Determination of oxygenated polycyclic aromatic hydrocarbons in particulate matter using high-performance liquid chromatography-tandem mass spectrometry.

A high-performance liquid chromatography-tandem mass spectrometric (LC-MS/MS) method with a rapid and simple sample preparation was optimized and validated for the determination of phenanthrene-9,10-dione, chrysene-5,6-dione, benzo[a]pyrene-1,6-dione, benzo[a]pyrene-3,6-dione, benzo[a]pyrene-4,5-dione, benzo[a]pyrene-6,12-dione, benzo[a]pyrene-7,8-dione, benzo[a]pyrene-11,12-dione and 6-oxo-7-oxa-benzo[a]pyrene in particulate matter. The mass spectrometer was operated in the multiple reaction monitoring (MRM) mode leading to high sensitivity and selectivity. The limits of quantification (S/N=10) ranged from ca. 0.1 pg/microl to ca. 5.8 pg/microl and matrix dependent recoveries varied between 49 and 92%. The applicability of the LC-MS/MS method was shown by the analysis of particulate matter (PM(2.5)) collected during the course of 2005 in the Munich area, Germany. All oxy-PAHs determined exhibited higher mean and peak concentrations in the winter months compared to the concentration levels in the warmer season.

Chromatography, High Pressure Liquid↗

PubMed2003

Determination of Cr(VI) in ambient airborne particulate matter by a species-preserving scrubber-sampling technique.

Airborne particulate matter has been sampled at a location close to a metallurgical plant in North-Rhine-Westphalia, Germany, and first results on the chromium(VI) content in the collected dust are presented. A special procedure using a scrubber as sampling device was used to preserve Cr(VI) during the sampling procedure. The scrubber solution which consisted of 0.1 mol L(-1) TRIS-buffer solution was adjusted to a slightly alkaline pH of 8.6 to reduce the oxidation potential of Cr(VI) and to avoid possible oxidation of Cr(III) to Cr(VI), for example by oxygen (or ozone at ambient concentrations). After sampling Cr(VI) was pre-concentrated on an anion-exchange material and eluted with aqueous 0.6 mol L(-1) sodium perchlorate solution. After elution, a species-selective complex of Cr(VI) with diphenylcarbazide (DPC) was prepared; this was extracted into n-hexanol and quantified by UV-visible spectrophotometry. A detection limit of 0.9 ng m(-3) for Cr(VI) in ambient aerosols can be achieved with this method.

Journal Article↗

PubMed1996

Carcinogenicity study of outdoor airborne particulate matter in newborn male NMRI mice.

An organic extract of airborne particulate matter (APM) was tested for carcinogenicity at two dose levels in the newborn mouse bioassay. The samples used were taken under specific polluted conditions. The doses tested corresponded with 0.75 and 1.5 times the amount of air man inhales during lifetime. Benzo(a)pyrene, which was used as a positive control, significantly increased the lung tumor incidence. No evidence was found for a carcinogenic activity of the organic extract of APM. Considering the high dose of APM applied in this animal model and the much lower actual cumulative dose to which man is exposed to in many areas, the conclusion can be drawn that exposure to APM alone probably does not represent an important cancer risk for man.

Adenoma↗

PubMed2005

Particulate matter and heart disease: evidence from epidemiological studies.

The association between particulate matter and heart disease was noted in the mid-nineties of last century when the epidemiological evidence for an association between air pollution and hospital admissions due to cardiovascular disease accumulated and first hypotheses regarding the pathomechanism were formulated. Nowadays, epidemiological studies have demonstrated coherent associations between daily changes in concentrations of ambient particles and cardiovascular disease mortality, hospital admission, disease exacerbation in patients with cardiovascular disease and early physiological responses in healthy individuals consistent with a risk factor profile deterioration. In addition, evidence was found that annual average PM(2.5) exposures are associated with increased risks for mortality caused by ischemic heart disease and dysrhythmia. Thereby, evidence is suggesting not only a short-term exacerbation of cardiovascular disease by ambient particle concentrations but also a potential role of particles in defining patients' vulnerability to acute coronary events. While this concept is consistent with the current understanding of the factors defining patients' vulnerability, the mechanisms and the time-scales on which the particle-induced vulnerability might operate are unknown.

Air Pollutants↗

PubMed2002

Monitoring of particulate matter outdoors.

Recent studies of the size and composition of atmospheric particulate matter (PM) have demonstrated the usefulness of separating atmospheric PM into its fine and coarse components. The need to measure the mass and composition of fine and coarse PM separately has been emphasized by research in exposure, epidemiology, and toxicology of atmospheric PM. This paper provides a background on the size distribution and properties of PM relevant to the differences between fine and coarse particles. Various decisions that must be made when deciding how to separate, collect, and measure PM are discussed. Techniques for monitoring fine and coarse particles, including the US Federal Reference Method for PM2.5 and several techniques for PM10-2.5, are presented. Problems encountered in collecting semivolatile PM and in weighing atmospheric PM collected on a filter are described. Continuous monitoring methods for PM mass and for PM components (carbon, nitrate, and sulfate) are described and brief descriptions are given of analytical techniques for the chemical characterization of collected PM. This information should be especially useful for environmental workers familiar with monitoring methods for total suspended particles or PM10 but who will need to measure PM2, and PM10-2.5 in the future.

Air Pollutants↗

PubMed2004

Source strengths for indoor human activities that resuspend particulate matter.

A mathematical model was applied to continuous indoor and outdoor particulate matter (PM) measurements to estimate source strengths for a variety of prescribed human activities that resuspend house dust in the home. Activities included folding blankets, folding clothes, dry dusting, making a bed, dancing on a rug, dancing on a wood floor, vacuuming, and walking around and sitting on upholstered furniture. Although most of the resuspended particle mass from these activities was larger than 5 microm in diameter, the resuspension of PM2.5 and PM5 was substantial, with source strengths ranging from 0.03 to 0.5 mg min(-1) for PM2.5 and from 0.1 to 1.4 mg min(-1) for PM5. Source strengths for PM > 5 microm could not be quantified due to instrument limitations. The source strengths were found to be a function of the number of persons performing the activity, the vigor of the activity, the type of activity, and the type of flooring.

Activities of Daily Living↗

PubMed2002

Incorporating exposure models in probabilistic assessment of the risks of premature mortality from particulate matter.

This paper examines the link between the ambient level of particulate pollution and subsequent human health effects and various sources of uncertainty when total exposure is taken into consideration. The exposure simulation model statistically simulates daily personal total exposure to ambient PM and nonambient PM generated from indoor sources. It incorporates outdoor-indoor penetration of PM, contributions of PM from indoor sources, and time-activity patterns for target groups of the population. The model is illustrated for Los Angeles County using recent 1997 monitoring data for both PM(10) and PM(2.5). The results indicate that, on average, outdoor-source PM contributes about 20-25% of the total PM exposure to Los Angeles County individuals not exposed to environmental tobacco smoking (ETS), and about 15% for those who are exposed to ETS. The model computes both the fractional contribution of outdoor concentrations to total exposure and the effect of exposure uncertainties on the estimated slope of the (linear) concentration-response curve in time-series studies for PM health effects. The latter considers the effects of measurement and misclassification error on PM epidemiological time-series studies. The paper compares the predictions of a conventional PM epidemiological model, based solely on ambient concentration measurements at a central monitoring station, and an exposure simulation model, which considers the quantitative relationship between central-monitoring PM concentrations and total individual exposures to particulate matter. The results show that the effects of adjusting from outdoor concentrations to personal exposures and correcting dose-response bias are nearly equal, so that roughly the same premature mortalities associated with short-term exposure to both ambient PM(2.5) and PM(10) in Los Angeles County are predicted with both models. The uncertainty in the slope of the concentration-response curve in the time-series studies is the single most important source of uncertainty in both the ambient- and the exposure-health model.

Air Pollutants↗

PubMed2007

Inhalation of ultrafine and fine particulate matter disrupts systemic vascular function.

This study investigated the effects of particulate matter (PM) with aerodynamic diameter 0.02-1 microm (noted as PM1) inhalation during exercise on conduit artery and microvascular function. Inhalation of internal combustion-derived PM is associated with cardiovascular mortality and morbidity. Direct action of PM on the vascular endothelium is likely, as a substantial fraction of ultrafine PM translocates from the alveoli to the circulatory system. Sixteen intercollegiate athletes performed 30 min of exercise while inhaling low or high PM1. Flow-mediated brachial artery dilation (FMD) using high-resolution ultrasonography with simultaneous measurements of forearm oxygen kinetics using near infrared spectrophotometry (NIRS) was done before and after exercise. Basal brachial artery vasoconstriction was found after high PM1 exercise (4.0%, 4.66 +/- 0.609 to 4.47 +/- 0.625 mm diameter; p = .0002), but not after low PM1 exercise (-0.3%, 4.66 +/- 0.626 to 4.68 +/- 0.613 mm diameter). FMD was impaired after high PM1 exercise (6.8 +/- 3.58% for preexercise FMD and 0.30 +/- 2.74% for postexercise FMD, p = .0001), but not after low PM1 exercise (6.6 +/- 4.04% for preexercise FMD and 4.89 +/- 4.42% for postexercise FMD). Reduction in forearm muscle reperfusion estimated by reoxygenation slope-to-baseline after 4 min cuff ischemia was observed for high PM1 exercise (55% vs. 3%, p = .0006); no difference was noted for low PM1 exercise. Brachial artery FMD was significantly correlated to muscle reoxygenation slope-to-baseline (r = .50, p = .005). Acute inhalation of high [PM1] typical of urban environments impairs both systemic conduit artery function and microcirculation. The observed decrease reoxygenation slope-to-baseline after cuff release is consistent with reduced blood flow in the muscle microvasculature.

Administration, Inhalation↗

PubMed2005

Emissions of organic compounds and trace metals in fine particulate matter from motor vehicles: a tunnel study in Houston, Texas.

Fine particulate matter (PM) samples collected in a highway tunnel in Houston, TX, were analyzed to quantify the concentrations of 14 n-alkanes, 12 polycyclic aromatic hydrocarbons, and nine petroleum biomarkers, as well as 21 metals, with the ultimate aim of identifying appropriate tracers for diesel engines. First, an exploratory multivariate dimensionality reduction technique called principal component analysis (PCA) was employed to identify all potential candidates for tracers. Next, emission indices were calculated to interpret PCA results physically. Emission indices of n-heneicosane, n-docosane, n-tricosane, n-tetracosane, n-pentacosane, fluoranthene, and pyrene were correlated highly and increased strongly with percentage carbon present in the tunnel emanating from diesel vehicles. This suggests that these organic compounds are useful molecular markers to separate emissions from diesel and gasoline engines. Additionally, the results are the first quantification of the metal composition of PM with aerodynamic diameters smaller than 2.5 microm (PM2.5) emissions from mobile sources in Houston. PCA of trace metal concentrations followed by emission index calculations revealed that barium in fine airborne particles can be linked quantitatively to diesel engine emissions, demonstrating its role as an elemental tracer for heavy-duty trucks.

Air Pollutants↗