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PubMed2006

The contribution from distant dust sources to the atmospheric particulate matter loadings at XiAn, China during spring.

Mass concentration data for PM(10) (particulate matter, PM, less than 10 mum) combined with an air mass back-trajectory clustering technique, a potential source contribution function (PSCF) model, and a concentration-weighted trajectory (CWT) method were used to evaluate the transport pathways and sources of XiAn PM(10) in spring 2001 to 2003. Three dust source areas: "Northwesterly Sources," "Northerly Sources," and a "Loess Plateau Source" and an anthropogenic "Southerly Source" contributing to the high particulate matter concentrations at XiAn were identified using these methods. The CWT method provided more compelling information on dust sources than the PSCF model, but there are clear advantages to using multiple interpretive tools. A comparison of the major dust transport pathways shows differences for XiAn versus Beijing, with "Northwesterly Sources" more important for XiAn and arid and semi-arid regions in Mongolia more important for Beijing.

Air Movements↗

PubMed2005

Prescribed burns and wildfires in Colorado: impacts of mitigation measures on indoor air particulate matter.

Wildfires and prescribed burns are receiving increasing attention as sources of fine particulate matter (PM2.5). The goal of this research project was to understand the impact of mitigation strategies for residences impacted by scheduled prescribed burns and wildfires. Pairs of residences were solicited to have PM2.5 concentrations monitored inside and outside of their houses during four fires. The effect of using air cleaners on indoor PM2.5 was investigated, as well as the effect of keeping windows closed. Appropriately sized air cleaners were provided to one of each pair of residences; occupants of all of the residences were asked to keep windows shut and minimize opening of exterior doors. Additionally, residents were asked to record all of the activities that may be a source of particulate matter, such as cooking and cleaning. Measurements were made during one prescribed burn and three wildfires during the 2002 fire season. Outdoor 24-hr average PM2.5 concentrations ranging from 6 to 38 microg/m3 were measured during the fires, compared with levels of 2-5 microg/m3 during background measurements when no fires were burning. During the fires, PM2.5 was < 3 microg/m3 inside all of the houses with air cleaners installed. This corresponds with a decrease of 63-88% in homes with the air cleaners operating when compared with homes without air cleaners. In the homes without the air cleaners, measured indoor concentrations were 58-100% of the concentrations measured outdoors.

Air Pollution, Indoor↗

PubMed2006

Temperature modifies the health effects of particulate matter in Brisbane, Australia.

A few epidemiological studies have examined whether there was an interactive effect between temperature and ambient particulate matter on cardiorespiratory morbidity and mortality, but the results were inconsistent. The present study used three time-series approaches to explore whether maximum temperature modified the impact of ambient particulate matter less than 10 microm in diameter (PM(10)) on daily respiratory hospital admissions, cardiovascular hospital admissions, respiratory emergency visits, cardiovascular emergency visits, non-external cause mortality and cardiovascular mortality in Brisbane between 1996 and 2001. The analytical approaches included a bivariate response surface model, a non-stratification parametric model and a stratification parametric model. Results show that there existed a statistically significant interaction between PM(10) and temperature on most health outcomes at various lags. PM(10) exhibited more adverse health effects on warm days than cold days. The choice of the degree of freedom for smoothers to adjust for confounders and the selection of arbitrary cut-offs for temperature affected the interaction estimates to a certain extent, but did not change the overall conclusion. The results imply that it is important to control and reduce the emission of air particles in Brisbane, particularly when temperature increases.

Air Pollutants↗

PubMed1992

Polycyclic aromatic hydrocarbons, nickel and vanadium in air particulate matter in Bahrain during the burning of oil fields in Kuwait.

Inhalable air particulate matter (APM) was collected in Bahrain from July 31, 1991 to August 4, 1991, during the burning of the oil fields in Kuwait. The filters collected were black and the levels of APM ranged from 139 to 673 micrograms m-3 with an average value of 199 micrograms m-3. APM were analysed for their contents of PAHs, Ni and V. Analysis was carried out for 32 PAHs and total PAHs ranged from 3.1 to 9.1 ng m-3 and averaged 5.3 ng m-3. The highest individual PAH levels were benzo[ghi]perylene, benzo[b]fluoranthene, benzo[a]pyrene and indeno[1,2,3-cd]pyrene. The concentration of Ni and V ranged from 7 to 42 and 11 to 42 ng m-3, with an average value of 22 and 26 ng m-3, respectively. A strong correlation was found between Ni and V (r = 0.98, P less than 0.01). The results show that the smoke from burning oil wells in Kuwait has contributed to the concentrations of particulate matter, PAHs, Ni and V in APM in Bahrain.

Air Pollutants↗

PubMed2006

Comparison of particle light scattering and fine particulate matter mass in central California.

Particle light scattering (Bsp) from nephelometers and fine particulate matter (PM2.5) mass determined by filter samplers are compared for summer and winter at 35 locations in and around California's San Joaquin Valley from December 2, 1999 to February 3, 2001. The relationship is described using particle mass scattering efficiency (sigmasp) derived from linear regression of Bsp on PM2.5 that can be applied to estimated PM2.5 from nephelometer data within the 24-hr filter sampling periods and between the every-6th-day sampling frequency. An average of sigmaSp = 4.9 m2/g was found for all of the sites and seasons; however, sigmasp averaged by site type and season provided better PM2.5 estimates. On average, the sigmasp was lower in summer than winter, consistent with lower relative humidities, lower fractions of hygroscopic ammonium nitrate, and higher contributions from fugitive dust. Winter average sigmasp were similar at non-source-dominated sites, ranging from 4.8 m2/g to 5.9 m2/g. The sigmasp was 2.3 m2/g at the roadside, 3.7 m2/g at a dairy farm, and 4.1 m2/g in the Kern County oilfields. Comparison of Bsp from nephelometers with and without a PM2.5 inlet at the Fresno Supersite showed that coarse particles contributed minor amounts to light scattering. This was confirmed by poorer correlations between Bsp and coarse particulate matter measured during a fall sampling period.

Air Pollutants, Occupational↗

PubMed2006

Characterization of major chemical components of fine particulate matter in North Carolina.

This paper presents measurements of daily sampling of fine particulate matter (PM2.5) and its major chemical components at three urban and one rural locations in North Carolina during 2002. At both urban and rural sites, the major insoluble component of PM2.5 is organic matter, and the major soluble components are sulfate (SO4(2-)), ammonium (NH4(+)), and nitrate (NO3(-)). NH4(+) is neutralized mainly by SO4(2-) rather than by NO3(-), except in winter when SO4(2-) concentration is relatively low, whereas NO3(-) concentration is high. The equivalent ratio of NH4(+) to the sum of SO4(2-) and NO3(-) is < 1, suggesting that SO4(2-) and NO3(-) are not completely neutralized by NH4(+). At both rural and urban sites, SO4(2-) concentration displays a maximum in summer and a minimum in winter, whereas NO3(-) displays an opposite seasonal trend. Mass ratio of NO3(-) to SO4(2-) is consistently < 1 at all sites, suggesting that stationary source emissions may play an important role in PM2.5 formation in those areas. Organic carbon and elemental carbon are well correlated at three urban sites although they are poorly correlated at the agriculture site. Other than the daily samples, hourly samples were measured at one urban site. PM2.5 mass concentrations display a peak in early morning, and a second peak in late afternoon. Back trajectory analysis shows that air masses with lower PM2.5 mass content mainly originate from the marine environment or from a continental environment but with a strong subsidence from the upper troposphere. Air masses with high PM2.5 mass concentrations are largely from continental sources. Our study of fine particulate matter and its chemical composition in North Carolina provides crucial information that may be used to determine the efficacy of the new National Ambient Air Quality Standard (NAAQS) for PM fine. Moreover, the gas-to-particle conversion processes provide improved prediction of long-range transport of pollutants and air quality.

Air Pollutants, Occupational↗

PubMed1996

Trace elements in vegetables grown in an industrial area in relation to soil and air particulate matter.

The relationships between the trace element content of vegetables, agricultural soil and airborne particulate matter were investigated in the greater industrial area of Thessaloniki, northern Greece. Most elements were found at concentrations normally observed in vegetables grown in uncontaminated areas, however, elevated concentrations of Pb, Zn, Cr and Mn were found particularly in leafy vegetables. The trace element content of agricultural soil was low, despite the airborne particulate matter that was highly enriched with Zn, Cd, Pb and Mn. Multivariate statistical analysis indicated that the compositional patterns of the vegetables, the soil and the atmospheric particulates were largely different. The dominant pathway for most trace elements to vegetable roots was from the soil, while trace elements in vegetable leaves appeared to originate mostly from the atmosphere. High accumulation due to atmospheric deposition was found for Pb, Cr and Cd, especially in leafy vegetables. Root vegetables were found to accumulate soil Cd more efficiently than the other trace elements.

Journal Article↗

PubMed2005

Seasonal evaluation and spatial variability of suspended particulate matter in the vicinity of a large coal-fired power station in India--a case study.

Coal combustion in the power sector gives rise to the emission of primary and secondary particulate pollutants. Since the emission of pollutants depends on coal quality and combustion technology, and given that transport, transformation and deposition of contaminants depend on regional climatic conditions, specific studies for the power stations is needed to evaluate their environmental impacts. Monitoring of ambient respirable suspended particulate matter (RSPM) and suspended particulate matter (SPM) levels around a large coal-fired power station in India was carried out. The specific objectives were the determination of spatial and seasonal variability in RSPM and SPM levels, and their relationship with meteorological parameters such as wind velocity and relative humidity. The results have shown a marked seasonal trend and spatial variability in RSPM and SPM levels in the study area. Higher concentrations of ambient RSPM and SPM were found in downwind monitoring stations compared to upwind direction. Ratios of RSPM to SPM and correlation coefficient values between RSPM and SPM along with meteorological parameters were also worked out. Relative humidity and wind velocity have shown an inverse relation with particulate deposition pattern.

Air Pollutants↗

PubMed2002

Real-world particulate matter and gaseous emissions from motor vehicles in a highway tunnel.

Recent studies have linked atmospheric particulate matter with human health problems. In many urban areas, mobile sources are a major source of particulate matter (PM) and the dominant source of fine particles or PM2.5 (PM smaller than 2.5 pm in aerodynamic diameter). Dynamometer studies have implicated diesel engines as being a significant source of ultrafine particles (< 0.1 microm), which may also exhibit deleterious health impacts. In addition to direct tailpipe emissions, mobile sources contribute to ambient particulate levels by brake and tire wear and by resuspension of particles from pavement. Information about particle emission rates, size distributions, and chemical composition from in-use light-duty (LD) and heavy-duty (HD) vehicles is scarce, especially under real-world operating conditions. To characterize particulate emissions from a limited set of in-use vehicles, we studied on-road emissions from vehicles operating under hot-stabilized conditions, at relatively constant speed, in the Tuscarora Mountain Tunnel along the Pennsylvania Turnpike from May 18 through 23, 1999. There were five specific aims of the study. (1) obtain chemically speciated diesel profiles for the source apportionment of diesel versus other ambient constituents in the air and to determine the chemical species present in real-world diesel emissions; (2) measure particle number and size distribution of chemically speciated particles in the atmosphere; (3) identify, by reference to data in years past, how much change has occurred in diesel exhaust particulate mass; (4) measure particulate emissions from LD gasoline vehicles to determine their contribution to the observed particle levels compared to diesels; and (5) determine changes over time in gas phase emissions by comparing our results with those of previous studies. Comparing the results of this study with our 1992 results, we found that emissions of C8 to C20 hydrocarbons, carbon monoxide (CO), and carbon dioxide (CO2) from HD diesel emissions substantially decreased over the seven-year period. Particulate mass emissions showed a similar trend. Considering a 25-year period, we observed a continued downward trend in HD particulate emissions from approximately 1,100 mg/km in 1974 to 132 mg/km (reported as PM2.5) in this study. The LD particle emission factor was considerably less than the HD value, but given the large fraction of LD vehicles, emissions from this source cannot be ignored. Results of the current study also indicate that both HD and LD vehicles emit ultrafine particles and that these particles are preserved under real-world dilution conditions. Particle number distributions were dominated by ultrafine particles with count mean diameters of 17 to 13 nm depending on fleet composition. These particles appear to be primarily composed of sulfur, indicative of sulfuric acid emission and nucleation. Comparing the 1992 and 1999 HD emission rates, we observed a 48% increase in the NOx/CO2 emissions ratio. This finding supports the assumption that many new-technology diesel engines conserve fuel but increase NOx emissions.

Air Pollutants↗

PubMed2005

The effect of diesel fuel sulfur content on particulate matter emissions for a nonroad diesel generator.

The effect of sulfur content on diesel particulate matter (DPM) emissions was studied using a diesel generator (Generac Model SD080, rated at 80 kW) as the emission source to simulate nonroad diesel emissions. A load simulator was used to apply loads to the generator at 0, 25, 50, and 75 kW, respectively. Three diesel fuels containing 500, 2100, and 3700 ppm sulfur by weight were selected as generator fuels. The U.S. Environmental Protection Agency sampling Method 5 "Determination of Particulate Matter Emissions from Stationary Sources" together with Method 1A "Sample and Velocity Traverses for Stationary Sources with Small Stacks or Ducts" was adopted as a reference method for measurement of the exhaust gas flow rate and DPM mass concentration. The effects of various parameters on DPM concentration have been studied, such as fuel sulfur contents, engine loads, and fuel usage rates. The increase of average DPM concentrations from 3.9 mg/Nm3 (n cubic meter) at 0 kW to 36.8 mg/Nm3 at 75 kW is strongly correlated with the increase of applied loads and sulfur content in the diesel fuel, whereas the fuel consumption rates are only a function of applied loads. An empirical correlation for estimating DPM concentration is obtained when fuel sulfur content and engine loads are known for these types of generators: Y = Zm(alphaX + beta), where Y is the DPM concentration, mg/m3, Z is the fuel sulfur content, ppm(w) (limited to 500-3700 ppm(w)), X is the applied load, kW, m is the constant, 0.407, alpha and beta are the numerical coefficients, 0.0118 +/- 0.0028 (95% confidence interval) and 0.4535 +/- 0.1288 (95% confidence interval), respectively.

Air Pollution↗

PubMedDate not supplied

Pro-inflammatory effects of Dunkerque city air pollution particulate matter 2.5 in human epithelial lung cells (L132) in culture.

Exposure to urban airborne particulate matter (PM) has been associated with adverse health effects. The majority of research articles published on air pollution PM relate to PM10. However, increasing emphasis and stringent regulations have been placed on PM2.5. The mechanisms for PM-induced adverse health effects are not well understood, but inflammation seems to be of importance. We focused our attention also on the capacity of air pollution PM2.5 to induce cytotoxic and inflammatory responses in human epithelial lung cells (L132) in culture. Particulate matter was collected in Dunkerque, a French seaside city characterized by the proximity of industrial activity and heavy motor vehicle traffic. Size distribution results showed that the cumulative frequency of PM2.5 was 92.15% and their specific surface area was 1 m2 g(-1). Inorganic and organic chemicals usually associated with the natural environment but also so-called anthropogenic elements were found in PM, suggesting that much of the PM was derived from wind-borne dust from the industrial complex and the heavy diesel motor vehicle. We observed PM concentration-dependent cytotoxic effects in L132 cells (LC10 = 18.84 microg PM ml(-1); LC50 = 75.36 microg PM ml(-1)). We showed that exposure to Dunkerque City's PM2.5 induced significant increases (in a concentration- and time-dependent manner) in protein secretion and/or gene expression of inflammatory cytokines (i.e. TNF-alpha, IL-1beta, IL-8, GM-CSF, IL-6, TGF-beta1). We hypothesized also that the occurrence of the acute inflammatory response might rely on the capacity of such air pollutants to generate oxidative species, which have been implicated in the stringent regulation of the cytokine network. Hence, we suggest that the development of inflammatory effects that worsen over time stems from the cytotoxicity in Dunkerque City's PM2.5-exposed L132 cells in culture.

Air Pollutants↗

PubMed2000

Some analytical problems encountered for trace elements determination in the airborne particulate matter of urban and rural areas.

The determination of trace elements (TE) in airborne particulate matter collected onto filters requires an accurate evaluation of the entire analytical procedure. Since many elements have to be determined at a few milligrams of air dust at nanogram levels, possible sources of error can arise from uncontrolled parameters such as blank of the filters, sample homogeneity, pre-analytical treatment, primary and comparator standards. These potential critical points are presented here and discussed on the basis of the experience developed in our laboratory in previous studies where several TE monitoring campaigns have been performed for air particulate matter collected in urban as well as in rural residential areas of north Italy. Instrumental neutron activation analysis (INAA) and electrothermal atomic absorption spectroscopy (ET-AAS) have been used for the investigation of more than 30 trace elements.

Air Pollution↗

PubMed2005

[Mass size distribution of Beijing particulate matters and its inorganic water-soluble ions in winter and summer].

To understand one of the important characteristics of Beijing particulate matter pollution, the mass size distribution of particulate matters and its water-soluble ions, the particle samples were collected by a MOUDI cascade impactor in Beijing during July 2001, March 2002, July 2002 and January 2003 and every sampling period lasted a week. By analysis, the results indicate that there is "two modes" in the diameter range of the fine particle, one called "condensation mode" and another called "droplet mode", and the reasons of the peak of the accumulation mode appearing in the diameter range of 1 - 1. 8 microm was discussed in this paper. And there was a relatively strong correlation between PM1.8 and PM10 (R2 > 80%), the same to PM(1.8-10) (PM10 minus PM1.8); the ratio of PM1.8s/PM10 varietied between 40% and 60% during the sampling periods; as a result, the mass concentration of PM10 can be decreased by decreasing the concentration of coarse particles; sulfate, nitrate and ammonium are the main component of the inorganic water-soluble ions and the percentage of these three ions in PM1.8 was above 70% when the concentration of fine particle was more than 70 microg x m(-3) and they are the main reason increasing particle concentration.

Air Pollutants↗

PubMed2006

Evaluation of the recursive model approach for estimating particulate matter infiltration efficiencies using continuous light scattering data.

Quantifying particulate matter (PM) infiltration efficiencies (F(inf)) in individual homes is an important part of PM exposure assessment because individuals spend the majority of time indoors. While F(inf) of fine PM has most commonly been estimated using tracer species such as sulfur, here we evaluate an alternative that does not require particle collection, weighing and compositional analysis, and can be applied in situations with indoor sources of sulfur, such as environmental tobacco smoke, gas pilot lights, and humidifier use. This alternative method involves applying a recursive mass balance model (recursive model, RM) to continuous indoor and outdoor concentration measurements (e.g., light scattering data from nephelometers). We show that the RM can reliably estimate F(inf), a crucial parameter for determining exposure to particles of outdoor origin. The RM F(inf) estimates showed good agreement with the conventional filter-based sulfur tracer approach. Our simulation results suggest that the RM F(inf) estimates are minimally impacted by measurement error. In addition, the average light scattering response per unit mass concentration was greater indoors than outdoors; after correcting for differences in light scattering response the median deviation from sulfur F(inf) was reduced from 15 to 11%. Thus, we have verified the RM applied to light scattering data. We show that the RM method is unable to provide satisfactory estimates of the individual components of F(inf) (penetration efficiency, air exchange rate, and deposition rate). However, this approach may allow F(inf) to be estimated in more residences, including those with indoor sources of sulfur. We show that individual homes vary in their infiltration efficiencies, thereby contributing to exposure misclassification in epidemiological studies that assign exposures using ambient monitoring data. This variation across homes indicates the need for home-specific estimation methods, such as the RM or sulfur tracer, instead of techniques that give average estimates of infiltration across homes.

Air Pollution↗

PubMed2002

Temporal association between pulmonary and systemic effects of particulate matter in healthy and cardiovascular compromised rats.

Exposure to particulate matter (PM) has been associated with increased morbidity and mortality among individuals with cardiovascular disease. It is hypothesized that systemic alterations occur concurrent to pulmonary injury/inflammation, and contribute to cardiac events in compromised hosts. We explored this hypothesis using a rat model for human hypertension and cardiovascular disease (spontaneously hypertensive, SH), and normotensive Wistar Kyoto (WKY) rats. SH and WKY rats (12-13 wk old) were exposed either intratracheally (IT; 0.0, 1.0, or 5.0 mg/kg in saline) or nose-only (15 mg/m(3) x 6 h/d x 3 d/wk x 1, 2 or 4 wk) to combustion source residual oil fly ash (ROFA) with low metal content, and examined 1, 2 or 4 d later. Bronchoalveolar lavage fluid (BALF) albumin and neutrophils increased (SH approximately equal WKY) at d 1 following ROFA IT. With inhalation exposure, both strains experienced progressive histological lung damage and increases in BALF albumin and neutrophils during 1 to 4 wk (SH > WKY). Acute lung injury from ROFA IT was temporally associated with increases in plasma fibrinogen in both strains, but only the SH rats responded to the acute 1-wk ROFA inhalation. Longer term (2 or 4 wk) ROFA caused progressive lung injury (SH > WKY), but did not sustain the increase in fibrinogen. BALF glutathione increased in a temporal fashion similar to fibrinogen; however, only WKY rats demonstrated this response. There was a small but consistent decrease in blood lymphocytes and an increase in blood neutrophils in SH rats exposed to ROFA acutely. In conclusion, acute PM exposure can provoke an acute systemic thrombogenic response associated with pulmonary injury/inflammation and oxidative stress in cardiovascular compromised rats. This evidence is consistent with greater cardiovascular events during acute PM episodes in compromised humans.

Administration, Inhalation↗

PubMed2000

Exposure of chronic obstructive pulmonary disease patients to particulate matter: relationships between personal and ambient air concentrations.

Mot time-series studies of particulate air pollution and acute health outcomes assess exposure of the study population using fixed-site outdoor measurements. To address the issue of exposure misclassification, we evaluate the relationship between ambient particle concentrations and personal exposures of a population expected to be at risk of particle health effects. Sampling was conducted within the Vancouver metropolitan area during April-September 1998. Sixteen subjects (non-smoking, ages 54-86) with physician-diagnosed chronic obstructive pulmonary disease (COPD) wore personal PM2.5 monitors for seven 24-hr periods, randomly spaced approximately 1.5 weeks apart. Time-activity logs and dwelling characteristics data were also obtained for each subject. Daily 24-hr ambient PM10 and PM2.5 concentrations were measured at five fixed sites spaced throughout the study region. SO4(2-), which is found almost exclusively in the fine particle fraction and which does not have major indoor sources, was measured in all PM2.5 samples as an indicator of accumulation mode particulate matter of ambient origin. The mean personal and ambient PM2.5 concentrations were 18 micrograms/m3 and 11 micrograms/m3, respectively. In analyses relating personal and ambient measurements, ambient concentrations were expressed either as an average of the values obtained from five ambient monitoring sites for each day of personal sampling, or as the concentration obtained at the ambient site closest to each subject's home. The mean personal to ambient concentration ratio of all samples was 1.75 (range = 0.24 to 10.60) for PM2.5, and 0.75 (range = 0.09 to 1.42) for SO4(2-). Regression analyses were conducted for each subject separately and on pooled data. The median correlation (Pearson's r) between personal and average ambient PM2.5 concentrations was 0.48 (range = -0.68 to 0.83). Using SO4(2-) as the exposure metric, the median r between personal and average ambient concentrations was 0.96 (range = 0.66 to 1.0). Use of the closest ambient site did not improve the median correlation of the group for either PM2.5 or SO4(2-). All pooled analyses resulted in lower correlation coefficients than the median correlation coefficient of individual regressions. Personal SO4(2-) was more highly correlated with all ambient measures than PM2.5. Inclusion of time-activity and dwelling characteristics data did not result in a useful predictive regression model for PM2.5 personal exposure, but improved the model fit from simply regressing against ambient concentration (R2 = 0.27). The model for SO4(2-) was predictive (R2 = 0.82), as personal exposures were largely explained by ambient levels. These results indicate a relatively low correlation between personal exposure and ambient PM2.5 that is not improved by assigning exposure to the closest ambient monitor. The correlation between personal exposure and ambient concentration is high, however, when using SO4(2-), an indicator of accumulation mode particulate matter of ambient origin.

Aged↗

PubMed2003

Evaluation of the efficiency of extraction of PAHs from diesel particulate matter with pressurized solvents.

Pressurized Fluid Extraction (PFE) was evaluated for the extraction of polycyclic aromatic hydrocarbons (PAHs) and nitro-derivatives from diesel particulate matter. Extraction conditions were set up by performing several tests in which temperature, solvent strength, pressure, and static time were gradually increased. The results obtained on a laboratory test material made of a "lean" (low content of soluble fraction) Diesel particulate matter indicate that very severe conditions were needed in order to obtain better recoveries of the higher molecular weight molecules. Moreover, extraction efficiency seems to be influenced by the amount of soluble matter in the particulate, so that a "lean" particulate appears more difficult to extract. Recoveries of the deuterated standards of certain PAHs (i.e. indeno[1,2,3- cd]pyrene) were incomplete even with the toughest conditions tested. Experiments carried out on a certified material (SRM 1650 from NIST) also indicate that PFE can perform a better extraction of some of the PAHs than the method used for certification, but still incomplete. Comparison of results obtained on the SRM with different extraction techniques suggests that the composition of the extract varies considerably with the extraction technique and conditions. It is relevant to notice that recent Diesel engines produce leaner particulate: for future materials more drastic extraction conditions will be required.

Chemical Fractionation↗

PubMed2004

Fine particulate matter and wheezing illnesses in the first year of life.

BACKGROUND: Recent evidence implicates fine particulate matter (PM2.5), principally from vehicular exhaust, as a major cause of increased mortality and morbidity. However, there are limited data on the impact of PM2.5 on infant respiratory illnesses. METHODS: We conducted a cohort study of 504 infants recruited at 4 months of age from primary health care units in southeastern Santiago, Chile. Project physicians followed infants through the first year of life via monthly check-ups and by appointments on demand. We obtained data for fine particulate matter, sulfur dioxide (SO2), and nitrogen dioxide (NO2) from the governmental monitoring network. RESULTS: The most frequent diagnosis during follow-up was wheezing bronchitis, occurring 19.5 times per 100 infants per month. After adjusting for sex, socioeconomic level, family history of asthma, minimum temperature, and number of older siblings, we found that an increase of 10 microg/m of PM2.5 24-hour average was related to a 5% increase (95% confidence interval 0-9%) in the risk for wheezing bronchitis (1-day lag). This association was present for different lags, with a maximum observed for a 9-day lag (9%; 6-12%). No consistent association was detected with NO2 or SO2 ambient levels. Lower socioeconomic status and having older siblings were also associated with the risk of wheezing bronchitis. The association of PM2.5 and wheezing bronchitis was stronger among infants with a family history of asthma than among infants without. CONCLUSIONS: Air pollution in the form of fine particulates, mostly from vehicular exhaust, may adversely affect infants' respiratory health with potential for chronic effects later in life.

Air Pollutants↗