Publications

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.