Publications

This report describes a study to develop detailed personal exposure models that take various microenvironments into account. To develop the models, Dr. Harrison and colleagues made repeated measurements of exposure to selected air toxics for each of 100 healthy adult nonsmoking participants residing in urban, suburban, and rural areas of the United Kingdom expected to have different traffic exposures.

This report describes a study to explore novel electrocardiogram (ECG) parameters to improve our understanding of how air pollution may affect cardiovascular health. Drs. Robert Lux and Arden Pope used ECGs obtained in a previous study by Dr. Pope that found a decrease in heart rate variability associated with increased levels of particulate matter, and analyzed them for changes in novel parameters of another important potential change - ventricular repolarization.

Research Report 137, The Influence of Improved Air Quality on Mortality Risks in Erfurt, Germany, is the first study to come out of HEI's program on the health impact of regulatory and other actions to improve air quality, known as accountability. The report describes sweeping changes in the economy and energy use that occurred in the former East Germany after the 1990 reunification as a result of stricter environmental controls and modernization of industry, transportation, and household heating. Dr.

Research Report 136, Uptake and Inflammatory Effects of Nanoparticles in a Human Vascular Endothelial Cell Line, is one part of HEI's larger program on the health effects of particulate matter and its various components. This report describes a one-year study to evaluate which physicochemical characteristics of metal nanoparticles may contribute to their toxicity.

The September issue of Environmental Health Perspectives published the first systematic presentation of the HEI-funded PAPA studies in Bangkok, Hong Kong, Shanghai, and Wuhan, as well as a combined analysis and accompanying editorial. These articles have been reprinted and are currently available as HEI Communication 13. The detailed studies and accompanying HEI commentaries will be published by the Institute this spring.

A Special Report of the Institute's Air Toxics Review Panel. Special Report 16 summarizes the health effects of exposure to the 21 mobile-source air toxics (MSATs) defined by the 2001 EPA mobile-source rulemaking and critically analyzes the literature for a subset of seven MSATs (acetaldehyde, acrolein, benzene, 1,3-butadiene, formaldehyde, naphthalene, and polycyclic organic matter). The report also assesses and summarizes research gaps and unresolved questions, as understood in the context of the current regulatory agenda. The report focuses on MSATs for which mobile sources are a sizable source of human exposure and for which existing data suggest that health effects might be observed at concentrations approaching those found in ambient air. For each MSAT, the following questions are addressed: (1) To what extent are mobile sources a significant source of exposure to this MSAT? (2) Does this MSAT affect human health? (3) Does this MSAT affect human health at environmental conditions?

HEI Communication 12 describes a project by Dr Scott Zeger and colleagues at the Johns Hopkins Bloomberg School of Public Health that was funded by HEI to make data and software from the National Morbidity, Mortality, and Air Pollution Study (NMMAPS) available to the wider research and policy communities. This Communication contains the Project Report, which describes the Internet-Based Health and Air Pollution Surveillance System (iHAPSS), along with Comments from some members of the HEI Health Research and Review Committees and other experts who had used the data.

To answer important questions about possible sources of metal exposure from both tailpipe and non-tailpipe emissions, Dr. James Schauer and his colleagues at the University of Wisconsin - Madison collected and characterized metals in fine and coarse particles from a variety of sources, including tailpipe emissions, dust from brake and tire wear, and roadway dust.

The RIOPA project comprised three studies, one funded by the Mickey Leland National Urban Air Toxics Research Center (NUATRC) and two funded by HEI, that investigated seasonal concentrations of 16 VOCs, 10 carbonyls, and PM_2.5 in homes in Los Angeles CA, Houston TX, and Elizabeth NJ. The project was jointly funded and reviewed by a Special Review Panel of the two organizations. It generated a rich database on concentrations of air toxics and PM_2.5 in the personal breathing zone of 100 adults in each city as well as inside and outside their homes.

Dr. Hahn and colleagues systematically examined lung inflammation in young adult and old rats after inhalation of fine particles (< 2.5 µm in aerodynamic diameter) and ultrafine particles (< 0.1 µm in aerodynamic diameter) of different composition: relatively inert carbon and vanadium pentoxide (V₂O₅), which contains the transition metal vanadium, known to cause toxic effects upon inhalation in humans in occupational settings. In addition, they examined the effect of a short-term increase (spike) in particle exposure concentration on inflammatory response.

Dr. Brunekreef and his colleagues assessed the correlation between personal, indoor, and outdoor PM_2.5 concentrations for elderly people with cardiovascular disease living in Amsterdam, The Netherlands, and Helsinki, Finland. Measurements were taken between November 1998 and June 1999 using fixed monitoring sites near the subjects' residences and inside their homes using the same type of monitor. Personal exposures were monitored with a different type of sampler that the subjects kept with them at all times.

Dr. Frampton and his colleagues evaluated the effects of exposing healthy and mildly asthmatic men and women to laboratory-generated ultrafine carbon particles. They hypothesized that ultrafine particle exposure would activate leukocytes and endothelial cells and lead to an inflammatory response in the airway and in the blood; and that it also might affect respiration and cardiac electrophysiologic function. They further hypothesized that effects would be greater in people with asthma than in healthy people.

Dr James Ultman and colleagues at Pennsylvania State University recruited 32 men and 28 women to examine differences in ozone uptake in the lung. The subjects (all non smokers) first took a series of single breaths of air–ozone mixtures, which allowed the investigators to examine how ozone was distributed in the airways and where the major fraction of ozone was taken up. In a follow-up test, the subjects pedaled a bicycle ergometer to produce conditions of moderate exercise for one hour while breathing clean air, followed by a third test while breathing ozone at 0.25 ppm).

Dr. Beverly Cohen and her colleagues at New York University School of Medicine tested the performance of iron nanofilms to collect and measure sulfuric acid particles of different sizes under a variety of temperature and humidity conditions. The iron nanofilm detector is a thin iron-coated silicon chip. Particles would react with the iron, creating an elevated site or bump on the film surface, which can be visualized using an atomic force microscope.

In Part III of the National Morbidity, Mortality, and Air Pollution Study (NMMAPS), Dr. Daniels and colleagues at Johns Hopkins University and Harvard University evaluated the shape of the relation between PM₁₀ concentrations measured at fixed monitoring sites and daily mortality among residents from all causes (excluding accidental causes), from all cardiovascular and respiratory causes combined, and from causes other than cardiovascular-respiratory disease.

Drs. Yokel and Crossgrove at the University of Kentucky Medical Center studied the mechanisms by which manganese enters and leaves the brain across the blood–brain barrier and, in particular, whether transporter molecules are involved. The investigators used in vivo brain perfusion in rats as well as in vitro tests in several cell lines to assess specific characteristics of manganese transport, such as pH and energy dependence. Manganese transport rates were compared with those of sucrose and dextran, which do not easily cross the blood–brain barrier.

Stephen Holgate and his colleagues at the University of Southampton proposed that inflammatory changes in lung fluids and blood from humans exposed to PM were related to the chemical composition of the particles. He obtained samples from two human studies in which participants were exposed to diesel exhaust and concentrated ambient particles (CAPs). At a Swedish laboratory 25 healthy and 12 asthmatic participants were exposed to diesel exhaust or filtered air on separate days. At a US laboratory, 12 healthy participants were exposed to filtered air and 30 different healthy participants were exposed to a range of CAPs concentrations. All participants underwent bronchoscopy to obtain lung tissues and fluids to analyze inflammatory markers, including numbers of specific white blood cells, expression of activation markers, and levels of cytokines in addition to analysis of lung function, lung fluids, and blood.

A document from the HEI Accountability Working Group. Evaluating the extent to which air quality regulations improve public health is part of a broad effort—termed accountability—to assess the performance of all environmental regulatory policies. Communication 11 sets out a conceptual framework for accountability research and identifies types of evidence required and methods by which the evidence can be obtained.

Dr. Albertini and colleges organized a group of researchers from the United States, Czech Republic, The Netherlands, and the United Kingdom to determine whether biomarkers in the blood and urine of workers exposed to butadiene in occupational settings correlated with their personal exposure. Samples were collected from male workers employed either in a plant that used butadiene and styrene to produce rubber polymer in Prague. They also collected blood and urine from male administrative workers at the plant who had no direct occupational exposure to butadiene and served as control subjects.

Over the past decade, time-series studies conducted in many cities have contributed information about the association between daily changes in concentrations of airborne particulate matter (PM) and daily morbidity and mortality. In 2002, however, investigators at Johns Hopkins University and at Health Canada identified issues in the statistical model used in the majority of time-series studies. This HEI Special Report details attempts to address several questions raised by these discoveries.

Dr. Susanne Hering of Aerosol Dynamics Inc and her colleagues set out to design and validate a personal monitoring sampler for particles smaller than 2.5 µm (PM_2.5) that is suitable for subsequent chemical speciation work. The sampler intended to meet the measurement needs for PM_2.5 mass concentration and several of its major constituents including elemental carbon, organic carbon, sulfates, and nitrates.

Dr. Aust and her colleagues at Utah State University and Ford Motor company hypothesized that transition metals (metals that can participate in possibly toxic oxidative reactions) associated with particulate matter are released within lung epithelial cells and catalyze the formation of reactive oxygen species. The investigators focused their study on coal fly ash that was produced in the laboratory and separated into four size fractions.

Dr. Schlesinger and colleagues at the New York University School of Medicine used a well-established animal model of airway hyperresponsiveness (a heightened tendency of the bronchial airways to constrict) and allergic asthma to determine whether ozone can induce airway hyperresponsiveness or exacerbate existing airway hyperresponsiveness. Male and female guinea pigs were exposed to ozone concentrations comparable to levels to which humans are exposed during periods of ozone pollution.

Perspectives 2 is the second of a series produced by the HEI Health Review Committee to integrate findings across several HEI studies or entire research programs. The intent is to describe and interpret results bearing on important and timely issues for a broad audience interested in environmental health.