Biomedical subjects

Clifford P Weisel

Publications and source records attributed to Clifford P Weisel.

17 recordsLinked to original sources

PubMed2006

Source proximity and outdoor-residential VOC concentrations: results from the RIOPA study.

Ambient volatile organic compound concentrations outside residences were measured in Elizabeth, New Jersey as part of the Relationship of Indoor, Outdoor, and Personal A:r (RIOPA) study to assess the influence of proximity of the residences to known ambient emissions sources. The closest distances between the outdoor samplers and emission sources were determined using Geographic Information Systems (GIS)techniques. Multiple regression models were developed for residential ambient concentrations of aromatic hydrocarbons (BTEX), methyl tert butyl ether (MTBE), and tetrachloroethylene (PCE). The natural log transformed ambient concentrations of BTEX were inversely associated with distances to major roadways with high traffic densities and gasoline stations, atmospheric stability, temperature, and wind speed. Ambient MTBE levels were associated with inverse distance to gas stations and interstate highways. Residential ambient PCE concentration was inversely associated with distance to dry cleaning facilities, atmospheric stability, temperature, wind speed, and relative humidity. The linear regression models that include proximity to emission sources and meteorological variables explained 16-45% of the overall variation of ambient residential VOC concentrations. Meteorological conditions, especially atmospheric stability and temperature, explained 60-90% of the total variation in the regression models. The residential ambient air concentrations were 1.5-4 times higher than the urban background levels outside homes very close (<50 m) to ambient emission sources where approximately 7% of the population live. However, the relative increase of risk for disease is small and variations in air concentration in the background urban atmosphere are greater than those from the proximity to roadways.

Air Pollutants↗

PubMed2005

Human respiratory uptake of chloroform and haloketones during showering.

Inhalation is an important exposure route for volatile water contaminants, including disinfection by-products (DBPs). A controlled human study was conducted on six subjects to determine the respiratory uptake of haloketones (HKs) and chloroform, a reference compound, during showering. Breath and air concentrations of the DBPs were measured using gas chromatography and electron capture detector during and following the inhalation exposures. A lower percentage of the HKs (10%) is released from shower water to air than that of chloroform (56%) under the experiment conditions due to the lower volatility of the HKs. Breath concentrations of the DBPs were elevated during the inhalation exposure, while breath concentrations decreased rapidly after the exposure. Approximately 85-90% of the inhaled HKs were absorbed, whereas only 70% of the inhaled chloroform was absorbed for the experiment conditions used. The respiratory uptake of the DBPs was estimated using a linear one-compartment model coupled with a plug flow stream model for the shower system. The internal dose of chloroform normalized to its water concentration was approximately four times that of the HKs after a 30-min inhalation exposure. Approximately 0.3-0.4% of the absorbed HKs and 2-9% of the absorbed chloroform were expired through lung excretion after the 30-min exposure. The inhalation exposure from a typical 10-15 min shower contributes significantly to the total dose for chloroform in chlorinated drinking water but only to a moderate extent for HKs.

Adult↗

PubMed2005

Influence of ambient (outdoor) sources on residential indoor and personal PM2.5 concentrations: analyses of RIOPA data.

The Relationship of Indoor, Outdoor and Personal Air (RIOPA) study was designed to investigate residential indoor, outdoor and personal exposures to several classes of air pollutants, including volatile organic compounds, carbonyls and fine particles (PM2.5). Samples were collected from summer, 1999 to spring, 2001 in Houston (TX), Los Angeles (CA) and Elizabeth (NJ). Indoor, outdoor and personal PM2.5 samples were collected at 212 nonsmoking residences, 162 of which were sampled twice. Some homes were chosen due to close proximity to ambient sources of one or more target analytes, while others were farther from sources. Median indoor, outdoor and personal PM2.5 mass concentrations for these three sites were 14.4, 15.5 and 31.4 microg/m3, respectively. The contributions of ambient (outdoor) and nonambient sources to indoor and personal concentrations were quantified using a single compartment box model with measured air exchange rate and a random component superposition (RCS) statistical model. The median contribution of ambient sources to indoor PM2.5 concentrations using the mass balance approach was estimated to be 56% for all study homes (63%, 52% and 33% for California, New Jersey and Texas study homes, respectively). Reasonable variations in model assumptions alter median ambient contributions by less than 20%. The mean of the distribution of ambient contributions across study homes agreed well for the mass balance and RCS models, but the distribution was somewhat broader when calculated using the mass balance model with measured air exchange rates.

Air Pollutants↗

PubMed2005

Relationship of Indoor, Outdoor and Personal Air (RIOPA) study: study design, methods and quality assurance/control results.

The Relationship of Indoor, Outdoor and Personal Air (RIOPA) Study was undertaken to evaluate the contribution of outdoor sources of air toxics, as defined in the 1990 Clean Air Act Amendments, to indoor concentrations and personal exposures. The concentrations of 18 volatile organic compounds (VOCs), 17 carbonyl compounds, and fine particulate matter mass (PM(2.5)) were measured using 48-h outdoor, indoor and personal air samples collected simultaneously. PM2.5 mass, as well as several component species (elemental carbon, organic carbon, polyaromatic hydrocarbons and elemental analysis) were also measured; only PM(2.5) mass is reported here. Questionnaires were administered to characterize homes, neighborhoods and personal activities that might affect exposures. The air exchange rate was also measured in each home. Homes in close proximity (<0.5 km) to sources of air toxics were preferentially (2:1) selected for sampling. Approximately 100 non-smoking households in each of Elizabeth, NJ, Houston, TX, and Los Angeles, CA were sampled (100, 105, and 105 respectively) with second visits performed at 84, 93, and 81 homes in each city, respectively. VOC samples were collected at all homes, carbonyls at 90% and PM(2.5) at 60% of the homes. Personal samples were collected from nonsmoking adults and a portion of children living in the target homes. This manuscript provides the RIOPA study design and quality control and assurance data. The results from the RIOPA study can potentially provide information on the influence of ambient sources on indoor air concentrations and exposure for many air toxics and will furnish an opportunity to evaluate exposure models for these compounds.

Air Movements↗

PubMed2005

Dermal uptake of chloroform and haloketones during bathing.

Dermal contact with some organic disinfection by-products (DBPs) such as trihalomethanes in chlorinated drinking water has been established to be an important exposure route. We evaluated dermal absorption of two haloketones (1,1-dichloropropanone and 1,1,1-trichloropropanone) and chloroform while bathing, by collecting and analyzing time profiles of expired breath samples of six human subjects during and following a 30-min bath. The DBP concentrations in breath increased towards a maximum concentration during bathing. The maximum haloketone breath concentration during dermal exposure ranged from 0.1 to 0.9 microg / m(3), which was approximately two orders of magnitude lower than the maximum chloroform breath concentration during exposure. Based on a one-compartment model, the in vivo permeability of chloroform, 1,1-dichloropropanone, and 1,1,1-trichloropropanone were approximated to be 0.015, 7.5 x 10(- 4), and 4.5 x 10(- 4) cm / h, respectively. Thus, haloketones are much less permeable across human skin under normal bathing conditions than is chloroform. These findings will be useful for future assessment of total human exposure and consequent health risk of these DBPs.

Acetone↗

PubMed2005

Relationships of Indoor, Outdoor, and Personal Air (RIOPA). Part I. Collection methods and descriptive analyses.

This study on the relationships of indoor, outdoor, and personal air (RIOPA) was undertaken to collect data for use in evaluating the contribution of outdoor sources of air toxics and particulate matter (PM) to personal exposure. The study was not designed to obtain a population-based sample, but rather to provide matched indoor, outdoor, and personal concentrations in homes that varied in their proximity to outdoor pollution sources and had a wide range of air exchange rates (AERs). This design allowed examination of relations among indoor, outdoor, and personal concentrations of air toxics and PM across a wide range of environmental conditions; the resulting data set obtained for a wide range of environmental pollutants and AERs can be used to evaluate exposure models. Approximately 100 households with residents who do not smoke participated in each of three cities in distinct locations expected to have different climates and housing characteristics: Elizabeth, New Jersey; Houston, Texas; and Los Angeles County, California. Questionnaires were administered to characterize homes, neighborhoods, and personal activities that might affect exposures. The concentrations of a suite of volatile organic compounds (VOCs) and carbonyl compounds, as well as the fraction of airborne particulate matter with a mass median aerodynamic diameter < or = 2.5 microm (PM2.5), were measured during continuous 48-hour sessions in which indoor, outdoor, and personal air samples were collected simultaneously. During the same 48-hour period, the AER (exchanges/hr; x hr(-1)) was determined in each home, and carbonyl compounds were measured inside vehicle cabins driven by a subset of the participants. In most of the homes, measurements were made twice, during two different seasons, to obtain a wide distribution of AERs. This report presents in detail the data collection methods, quality control measures, and initial analyses of data distributions and relations among indoor, outdoor, and personal concentrations. The results show that indoor sources dominated personal and indoor air concentrations of many measured VOCs and carbonyl compounds. For several measured species, personal concentrations were higher than either indoor or outdoor concentrations, indicating the presence of some sources closely related to personal activities. For some species there were no significant indoor sources in the majority of the homes; thus indoor concentrations were mainly determined by outdoor concentrations in these homes. The range of distributions of air concentrations for the measured VOCs, formaldehyde and acetaldehyde, PM2.5, and AERs were generally consistent with values reported previously in the literature. Thus associations derived from or models based on this data set that may link the influence of outdoor sources with indoor air concentrations of air toxics and PM2.5 can be relevant to other urban settings. The simultaneous measurements of indoor concentrations, outdoor concentrations, AERs, and room volumes allowed the use of a mass balance model, under the steady-state approximation, to mechanistically examine the relative contributions of indoor and outdoor sources to measured indoor concentrations on a home-by-home basis. Estimated indoor source strengths for VOCs and carbonyl compounds varied widely from home to home, consistent with the indoor-outdoor concentration patterns, as shown in scatter plots. The indoor source estimations agreed with published values for PM2.5 and with the general understanding of sources of VOCs and carbonyl compounds. The source strengths reported here, derived from hundreds of homes, are an important contribution to the literature on exposure to air toxics. For the first time for many compounds, these estimates present a cohesive set of measurements across a range of air toxics in paired indoor, outdoor, and personal samples along with AER and questionnaire results that can be used for future analyses of indoor air quality. The estimation of outdoor contributions to measured indoor concentrations provides insights about the relative importance of indoor and outdoor sources in determining indoor concentrations, the main determinant of personal exposure for most of the measured compounds. In this report simple statistical tests mainly of the pooled data were used to analyze differences by sampling site, emission source type, season, home type, and home age. Paired adult-child personal concentrations within the same home were also compared using the pooled data set. These analyses generated some intriguing results that warrant more in-depth investigation in the future.

Air Movements↗

PubMed2004

Simultaneous and sensitive measurement of anabasine, nicotine, and nicotine metabolites in human urine by liquid chromatography-tandem mass spectrometry.

BACKGROUND: Determination of nicotine metabolism/pharmacokinetics provides a useful tool for estimating uptake of nicotine and tobacco-related toxicants, for understanding the pharmacologic effects of nicotine and nicotine addiction, and for optimizing nicotine dependency treatment. METHODS: We developed a sensitive method for analysis of nicotine and five major nicotine metabolites, including cotinine, trans-3'-hydroxycotinine, nicotine-N'-oxide, cotinine-N-oxide, and nornicotine, in human urine by liquid chromatography coupled with a TSQ Quantum triple quadrupole tandem mass spectrometer (LC/MS/MS). Urine samples to which deuterium-labeled internal standards had been added were extracted with a simple solid-phase extraction procedure. Anabasine, a minor tobacco alkaloid, was also included. RESULTS: The quantification limits of the method were 0.1-0.2 microg/L, except for nicotine (1 microg/L). Cotinine-N-oxide, trans-3'-hydroxycotinine, nicotine, and anabasine in urine were almost completely recovered by the solid-phase extraction, whereas the mean extraction recoveries of nicotine-N'-oxide, cotinine, and nornicotine were 51.4%, 78.6%, and 78.8%, respectively. This procedure provided a linearity of three to four orders of magnitude for the target analytes: 0.2-400 microg/L for nicotine-N'-oxide, cotinine-N-oxide, and anabasine; 0.2-4000 microg/L for cotinine, nornicotine, and trans-3'-hydroxycotinine; and 1.0-4000 microg/L for nicotine. The overall interday method imprecision and recovery were 2.5-18% and 92-109%, respectively. CONCLUSIONS: This sensitive LC/MS/MS procedure can be used to determine nicotine metabolism profiles of smokers, people during nicotine replacement therapy, and passively exposed nonsmokers. This method avoids the need for a time-consuming and labor-intensive sample enrichment step and thus allows for high-throughput sample preparation and automation.

Anabasine↗

PubMed2004

Chlordanes in the indoor and outdoor air of three U.S. cities.

Indoor and outdoor concentrations of six chlordane components (trans-chlordane, cis-chlordane, trans-nonachlor, cis-nonachlor, oxychlordane, and MC5) were measured at 157 residences, all of which were inhabited by nonsmoking individuals, in three urban areas during June 1999-May 2000. The analyses were conducted on a subset of 48 h integrated samples collected in Los Angeles County, CA, Houston, TX, and Elizabeth, NJ within the Relationship of Indoor, Outdoor, and Personal Air (RIOPA) study. Both particle-bound (PM2.5; quartz fiber filter) and vapor-phase (PUF sorbant) chlordane concentrations were separately measured by GC/EI MS after solvent extraction. The outdoor (gas + particle) total chlordane (trans-chlordane + cis-chlordane + trans-nonachlor + cis-nonachlor) concentrations ranged from 0.036 to 4.27 ng m(-3) in Los Angeles County, from 0.008 to 11.00 ng m(-3) in Elizabeth, and from 0.062 to 1.77 ng m(-3) in Houston. The corresponding indoor total chlordane concentrations ranged from 0.037 to 112.0 ng m(-3) in Los Angeles County, from 0.260 to 31.80 ng m(-3) in Elizabeth, and from 0.410 to 38.90 ng m(-3) in Houston study homes. Geometric mean concentrations were higher in indoor air than outdoor air (1.98 vs 0.58 ng m(-3) in CA; 1.30 vs 0.17 ng m(-3) in NJ; 4.18 vs 0.28 ng m(-3) in TX), which suggests there are significant indoor sources of chlordane species in a subset of homes in each of the three cities. Calculated source strengths relate to home age, with the highest apparent indoor source strengths occurring in unattached single-family homes built during the period from 1945 to 1959. Principle indoor sources of chlordanes likely include volatilization from residues of indoor application of chlordanes and infiltration from subsurface and foundation application of chlordane-containing termiticides during home construction.

Air Pollutants↗

PubMed2004

Selective detection of monohydroxy metabolites of polycyclic aromatic hydrocarbons in urine using liquid chromatography/triple quadrupole tandem mass spectrometry.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitously present in the environment and associated with a variety of adverse health effects. Monohydroxylated PAHs (OH-PAHs), metabolites of PAHs, have been employed as biomarkers for human exposure assessment of PAHs. This manuscript describes new, selective detection methods for OH-PAHs using liquid chromatography and tandem mass spectrometry (LC/MS/MS). Electrospray ionization was operated in the negative ion mode to detect the deprotonated PAH metabolites ([M-H](-)). Hydroxylated metabolites of naphthalene, fluorene, phenanthrene, fluoranthene, pyrene, benzo[c]phenanthrene, chrysene, benzo[a]anthracene, and benzo[a]pyrene were selected for the method development. Based on the collision-induced dissociation MS/MS spectra of the selected OH-PAHs, a characteristic ion fragmentation, loss of 28 Da from the [M--H](-) ion, was identified for all of these OH-PAHs. This characteristic fragmentation was exploited for selective screening for OH-PAHs in human urine by incorporating a constant neutral loss (CNL) scan with data-dependent scanning, using a triple quadruple mass spectrometer. Selected reaction monitoring (SRM) was also used to tentatively identify isomers of the target OH-PAHs in human urine. The excellent linearity (3-4 orders of magnitude) and signal-to-noise performance provided by the SRM method allowed development of a sensitive LC/MS/MS method for measuring OH-PAHs in urine samples. The limits of detection of the SRM method ranged from approximately 0.1-5 pg on column for a suite of OH-PAHs tested in the study. The LC-SRM method was applied, following enzymatic deconjugation and solid-phase extraction of the urine, to preliminarily determine the OH-PAH concentrations in urine specimens from six Chinese non-occupationally exposed workers and seven Chinese coke oven workers.

Chromatography, Liquid↗

PubMed2004

Comparisons of the dust/smoke particulate that settled inside the surrounding buildings and outside on the streets of southern New York City after the collapse of the World Trade Center, September 11, 2001.

The collapse of the World Trade Center (WTC) on September 11, 2001, generated large amounts of dust and smoke that settled in the surrounding indoor and outdoor environments in southern Manhattan. Sixteen dust samples were collected from undisturbed locations inside two uncleaned buildings that were adjacent to Ground Zero. These samples were analyzed for morphology, metals, and organic compounds, and the results were compared with the previously reported outdoor WTC dust/smoke results. We also analyzed seven additional dust samples provided by residents in the local neighborhoods. The morphologic analyses showed that the indoor WTC dust/smoke samples were similar to the outdoor WTC dust/smoke samples in composition and characteristics but with more than 50% mass in the <53-microm size fraction. This was in contrast to the outdoor samples that contained >50% of mass above >53 microm. Elemental analyses also showed the similarities, but at lower concentrations. Organic compounds present in the outdoor samples were also detected in the indoor samples. Conversely, the resident-provided convenience dust samples were different from either the WTC indoor or outdoor samples in composition and pH, indicating that they were not WTC-affected locations. In summary, the indoor dust/smoke was similar in concentration to the outdoor dust/smoke but had a greater percentage of mass <53 microm in diameter.

Air Pollutants↗

PubMed2003

Inhalation exposure to haloacetic acids and haloketones during showering.

Inhalation exposure to haloacetic acids (HAAs) and haloketones (HKs) in contaminated drinking water occurs during showering. The size distribution of the aerosols generated by a shower was determined using an eight size-range particle counter, which measured particles from 0.1 to >2 microm. An exponential increase in aerosol numbers was observed while the shower water was on, while the aerosol numbers declined exponentially once the water was turned off. The half-lives of the shower aerosols were longer than 5 min after the shower water was turned off. Although the majority of the shower-generated aerosols were smaller than 0.3 microm, these aerosols only contributed approximately 2% to the measured total aerosol mass. The total shower-generated particulate HAA and HK concentrations collected on an open face filter were approximately 6.3 and 0.13 microg/m3, respectively, for shower water HAA and HK concentrations of 250 and 25 microg/L, respectively. The vapor-phase HK concentrations were 25-50 microg/m3. The estimate of the dose from inhalation exposure of disinfection byproducts (DBPs) in the particulate phase indicate that they represent less than 1% of the ingestion dose, so inhalation is not expected to be an important exposure route to nonvolatile water contaminants or the portion of volatile DBPs that stay in the particulate phase, unless the lung is the target organ. The vapor-phase levels of volatile HKs, though, are significantly higher and can contribute greater than 10% of the ingestion dose during a shower. Thus, risk assessment to the these DBPs needs to consider the inhalation route.

Acetates↗

PubMed2003

Use of stable isotopically labeled benzene to evaluate environmental exposures.

The use of stable, isotopically labeled compounds in controlled exposure experiments at environmentally relevant levels allows for the distinguishing of urinary metabolites associated with known exposure from background levels generally present in the urine. Exposures of volunteers to (13)C-benzene for 2 h at 40+/-10 p.p.b. were conducted after obtaining informed consent, and urinary phenol, catechol, hydroquinone and trans,trans- muconic acid were measured. Each isotopically labeled urinary metabolite was determined in the presence of significantly higher concentrations of the unlabeled metabolite. Following exposure, free and acid hydrolyzed phenol, acid hydrolyzed catechol and hydroquinone, and free trans,trans-muconic acid were determined by GC/MS. The percentage of trans,trans-muconic acid excreted was higher than reported following exposure at occupational levels. The use of isotopically labeled compounds has the potential to investigate the metabolism of common environmental contaminants for validation of toxicokinetic models and improve risk extrapolation from high concentration occupational exposures and animal studies to environmentally relevant pollutant levels.

Adult↗

PubMed2002

Percutaneous absorption of trihalomethanes, haloacetic acids, and haloketones.

Bathing in chlorinated drinking water causes significant exposure to potentially toxic disinfection by-products (DBPs). In the present studies, we measured the permeation coefficients (K(p)) of three important classes of DBPs, trihalomethanes (THMs), haloketones (HKs), and haloacetic acids (HAAs), in aqueous solution across human skin using in vitro diffusion chambers. Linear mixed-effects model was utilized to calculate the steady-state permeability coefficients. The permeability coefficients of THMs ranged from 0.16 to 0.21 cm/h when the donor solution was at 25 degrees C. Bromoform had the highest K(p) value, while chloroform was the least permeable through the skin. THMs were approximately 10 times more permeable than HKs, while the permeability of HAAs through the skin was very low (1 to 3 x 10(-3) cm/h, pH 7). The permeability of HKs tripled as the temperature was increased from room temperature (20 degrees C) to bathing temperature (40 degrees C). A direct relationship was found between the permeability of THMs, but not HKs and HAAs, and their octanol/water partition coefficients. The dermal dose from daily bathing activities was approximated for an average adult using U.S. EPA recommended methods and found to be 40-70% of the daily ingestion dose for the THMs, 10% of the ingestion dose for HKs, and an insignificant percentage of the ingestion dose for the HAAs. In addition to ingestion, dermal absorption is an important route of exposure to THMs and HKs and must be considered in models of risk assessment.

Acetates↗

PubMed2002

Polycyclic aromatic hydrocarbons in the indoor and outdoor air of three cities in the U.S.

The indoor and outdoor concentrations of 30 polycyclic aromatic hydrocarbons (PAHs) were measured in 55 nonsmoking residences in three urban areas during June 1999-May 2000. The data represent the subset of samples collected within the Relationship of Indoor, Outdoor, and Personal Air study (RIOPA). The study collected samples from homes in Los Angeles, CA, Houston, TX, and Elizabeth, NJ. In the outdoor samples, the total PAH concentrations (sigmaPAH) were 4.2-64 ng m(-3) in Los Angeles, 10-160 ng m(-3) in Houston, and 12-110 ng m(-3) in Elizabeth. In the indoor samples, the concentrations of sigmaPAH were 16-220 ng m(-3) in Los Angeles, 21-310 ng m(-3) in Houston, and 22-350 ng m(-3) in Elizabeth. The PAH profiles of low molecular weight PAHs (3-4 rings) in the outdoor samples from the three cities were not significantly different. In contrast, the profiles of 5-7-ring PAHs in thesethree citieswere significantlydifferent, which suggested different dominant PAH sources. The signatures of 5-7-ring PAHs in the indoor samples in each city were similar to the outdoor profiles, which suggested that indoor concentrations of 5-7-ring PAHs were dominated by outdoor sources. Indoor-to-outdoor ratios of the PAH concentrations showed that indoor sources had a significant effect on indoor concentrations of 3-ring PAHs and a smaller effect on 4-ring PAHs and that outdoor sources dominated the indoor concentrations of 5-7-ring PAHs.

Air Pollutants↗

PubMed2002

Concepts in developing health-based indicators for ozone.

OBJECTIVES: The traditional manner to evaluate whether regulatory controls meet their public health goals of reducing adverse health effects associated with exposure to environmental pollutants is to compare measured concentrations of the target pollutant in the environment with a standard. A complementary approach is also to measure health-based indicators, e.g., changes in the prevalence of adverse health outcomes attributed to the pollutant. This manuscript presents the concepts of using asthma emergency room (ER) visits and hospital admission as potential health-based indicators for ozone. METHODS: The frequency of ER visits and hospital admissions for asthma in New Jersey in 1995 was compared with daily ozone concentrations, to establish the consistency of the relationship and the presence of potential confounders, and to establish whether routinely documented adverse outcomes in asthmatics could serve as health-based indicators. RESULTS: A mathematical model relating ER visits and hospital admissions of asthmatics to ozone concentration was developed for 1995, which was to be used as a baseline year within a health-based indicator program. A coherent relationship was found between same-day ambient air ozone concentrations and ER visits and 2-day time-lagged ambient ozone and hospital admissions during 1995; pollen was identified as a confounder and the association between ER visits and ozone concentration was similar to that determined for 1986 to 1990. CONCLUSIONS: Sufficient databases exist for ER visits by asthmatics in Northern and Central New Jersey, and throughout the state for hospital admissions, for these health outcomes to be used as health-based indicators, complementing air-monitoring data in assessing whether improvements in public health are occurring because of reduction in emissions of precursors of ozone.

Air Pollutants↗

PubMed2002

Characterization of the dust/smoke aerosol that settled east of the World Trade Center (WTC) in lower Manhattan after the collapse of the WTC 11 September 2001.

The explosion and collapse of the World Trade Center (WTC) was a catastrophic event that produced an aerosol plume impacting many workers, residents, and commuters during the first few days after 11 September 2001. Three bulk samples of the total settled dust and smoke were collected at weather-protected locations east of the WTC on 16 and 17 September 2001; these samples are representative of the generated material that settled immediately after the explosion and fire and the concurrent collapse of the two structures. We analyzed each sample, not differentiated by particle size, for inorganic and organic composition. In the inorganic analyses, we identified metals, radionuclides, ionic species, asbestos, and inorganic species. In the organic analyses, we identified polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls, polychlorinated dibenzodioxins, polychlorinated dibenzofurans, pesticides, phthalate esters, brominated diphenyl ethers, and other hydrocarbons. Each sample had a basic pH. Asbestos levels ranged from 0.8% to 3.0% of the mass, the PAHs were > 0.1% of the mass, and lead ranged from 101 to 625 microg/g. The content and distribution of material was indicative of a complex mixture of building debris and combustion products in the resulting plume. These three samples were composed primarily of construction materials, soot, paint (leaded and unleaded), and glass fibers (mineral wool and fiberglass). Levels of hydrocarbons indicated unburned or partially burned jet fuel, plastic, cellulose, and other materials that were ignited by the fire. In morphologic analyses we found that a majority of the mass was fibrous and composed of many types of fibers (e.g., mineral wool, fiberglass, asbestos, wood, paper, and cotton). The particles were separated into size classifications by gravimetric and aerodynamic methods. Material < 2.5 microm in aerodynamic diameter was 0.88-1.98% of the total mass. The largest mass concentrations were > 53 microm in diameter. The results obtained from these samples can be used to understand the contact and types of exposures to this unprecedented complex mixture experienced by the surviving residents, commuters, and rescue workers directly affected by the plume from 11 to 12 September and the evaluations of any acute or long-term health effects from resuspendable dust and smoke to the residents, commuters, and local workers, as well as from the materials released after 11 September until the fires were extinguished. Further, these results support the need to have the interior of residences, buildings, and their respective HVAC systems professionally cleaned to reduce long-term residential risks before rehabitation.

Aerosols↗

PubMed2002

Assessing exposure to air toxics relative to asthma.

Asthma is a respiratory disease whose prevalence has been increasing since the mid 1970s and that affects more than 14.6 million residents of the United States. Environmental triggers of asthma include air pollutants that are respiratory irritants. Air toxics emitted into the ambient air are listed in the 1990 Clean Air Act Amendments as hazardous air pollutants (HAPs) if they can adversely affect human health, including the respiratory tract. HAPs include particulate and gaseous-phase pollutants, individual organic compounds and metals, and mixtures. Associations between asthma exacerbation and both particles and indoor volatile organic compounds (VOCs), often referred to as indoor air quality, have been reported. Studies conducted in the United States, Canada, and Europe over the past two decades have shown that most people living in the developed countries spend the majority of their time indoors and that the air concentrations of many air toxics or HAPs are higher indoors than in the ambient air in urban, suburban, and rural settings. Elevated indoor air concentrations result from emissions of air toxics from consumer products, household furnishings, and personal activities. The Relationship of Indoor, Outdoor and Personal Air (RIOPA) study was designed to oversample homes in close proximity to ambient sources, excluding residences where smokers lived, to determine the contribution of ambient emissions to air toxics exposure. The ratios of indoor to outdoor air concentrations of some VOCs in homes measured during RIOPA were much greater than one, and for most other VOCs that had indoor-to-outdoor ratios close to unity in the majority of homes, elevated ratios were found in the paired samples with the highest concentration. Thus, although ambient emissions contribute to exposure of some air toxics indoors as well as outdoors, this was not true for all of the air toxics and especially for the higher end of exposures to most volatile organic air toxics examined. It is therefore critical, when evaluating potential effects of air toxics on asthma or other adverse health end points, to determine where the exposure occurs and the source contributions for each air toxic and target population separately and not to rely solely on ambient air concentration measurements.

Air Pollutants↗