Publications

This report describes semiparametric methods for epidemiologic investigations of the short-term effects of air pollution on health, intended specifically to improve the reliability of point estimates and confidence intervals. Dr. James Robins of the Harvard School of Public Health and colleagues developed the new methods, used simulations to compare them with other methods, and applied them to a large epidemiologic data set from the National Morbidity, Mortality, and Air Pollution Study (NMMAPS) to assess their effectiveness. The report is accompanied by a short editorial to assist the reader in understanding this study and its contributions to epidemiologic methods for air pollution.

This report describes the results of a study of long-term effects of PM components in the American Cancer Society's Cancer Prevention Study II cohort; a time-series study of short-term effects of PM components on cardiovascular and other diseases in people living in 150 U.S. cities; and two toxicologic studies in animals exposed by inhalation to concentrated ambient particles, and in animals and human cells exposed to particles collected on filters from five different airsheds across the United States. This report, along with Research Report 178 (Vedal et al.), is one of HEI's National Particle Component Toxicity (NPACT) studies, which describe the most systematic multidisciplinary studies to date to investigate the health effects of PM components in humans and animal models at locations across the United States where the effects of PM sources and components may differ. The report includes a Commentary and a Synthesis by the NPACT Review Panel.

This report revisits an earlier study of the air pollution and health impacts of a coal ban in Dublin, Ireland, and then extends the analysis to coal bans in 11 additional Irish cities. Dr. Douglas W. Dockery of the Harvard School of Public Health and colleagues evaluated changes in black smoke and sulfur dioxide concentrations for the 5 years before and after the coal bans and examined how those changes related to mortality and hospitalization rates in the counties affected by the bans, as compared with other counties where coal bans were not implemented. They also included in their analysis other trends in health and social factors that were occurring at the same time.

This newsletter reports on an expert panel named to review diesel epidemiology studies, two HEI Asia workshops on the global health impact of air pollution, and a meeting of HEI's Research Committee and sponsors reviewing progress and priorities, as well as HEI in the news.

This report describes a study in which a nano aerosol mass spectrometer (NAMS) was used to study composition of nanoparticles in real time near a major roadway intersection. Dr. Murray V. Johnston of the University of Delaware, Newark, and colleagues conducted a field test in Wilmington, Delaware, to evaluate performance of the instrument in a real-world setting and to assess whether it could aid in identifying the major source contributions to nanoparticle spikes and background levels, including distinguishing diesel from gasoline vehicles.

Perspectives 3 is the third of a series produced by HEI to describe and interpret results from HEI and other research bearing on important and timely issues for a broad audience interested in environmental health. Perspectives 3 focuses on the health effects of ambient ultrafine particles (UFPs) and was developed under the guidance of a special HEI Review Panel. It examines the contribution of motor vehicles within the broader context of the multiple sources of ambient UFPs and explores the evidence from experimental studies in animals and in humans, as well as observational epidemiologic studies of people exposed to UFPs in the environment. It also identifies some of the broader lessons about both the specific health effects associated with exposure to UFPs and possible directions for future studies that could enhance our understanding of emissions, exposures, and effects of UFPs.

This report describes a study that analyzed the relationships between reductions in pollutants from power plants and fine particulate matter (PM_2.5) concentrations in the eastern United States between 1999 and 2005. Dr. Richard D. Morgenstern of Resources for the Future and colleagues used a novel data-driven source-receptor model to explore the statistical relationships between source emissions of sulfur dioxide (SO₂) and nitrogen oxides and monitored concentrations of PM_2.5. They performed various external comparisons of their models, and compared the reductions to an estimated counterfactual scenario in which no mandated reductions in SO₂ occurred.

This report describes the first-ever multicity study to estimate the effect of short-term exposures to particulate matter (PM₁₀) and to ozone on mortality in nine Latin American cities. Led by Dr. Isabelle Romieu in Mexico, in collaboration with Dr. Nelson Gouveia in Brazil and Dr. Luis Cifuentes in Chile, the researchers evaluated mortality from all causes and in different age groups, using a common analytic framework. They analyzed mortality in each city and the region as a whole, and explored two pollutant models in individual cities. They also used two meta-analytic statistical techniques to further analyze the effects from individual cities.

This report describes a study to explore the role that specific chemical constituents of particulate air pollution may have played in effects on daily mortality observed after the 1990 Hong Kong restriction on sulfur in fuels. The study was part of HEI's Outcomes Research program, which aims to assess the health impacts of actions taken to improve air quality. Dr. Chit-Ming Wong of the University of Hong Kong and his team also developed methods to estimate the impacts on life expectancy of the 1990 sulfur restriction.

This report describes a study to investigate the relationships among daily variations in air pollution in Ho Chi Minh City (HCMC), Vietnam, hospital admissions for acute lower respiratory infections in children under age 5, and poverty. The study was part of HEI's Public Health and Air Pollution in Asia (PAPA) program and is the first study of air quality and health to be performed in Vietnam. The team of investigators, led by Drs. Le Truong Giang, Long Ngo, and Sumi Mehta, collected daily pollutant data for PM₁₀, sulfur dioxide, nitrogen dioxide, and ozone at multiple locations throughout the city and obtained admissions data from the two pediatric hospitals in HCMC. They then performed statistical analysis on the data using Poisson time-series and case–crossover methods.

This report describes a study evaluating the effects of exposure to diesel exhaust (DE) and nitrogen dioxide (NO₂) on the lower airways and blood of allergic asthmatic participants. The study by Dr. Riedl and colleagues was funded as part of HEI's research program looking at diesel exhaust and other particle exposures and allergic response. The participants were exposed in random order to 100 µg/m³ diesel exhaust or 0.35 ppm nitrogen dioxide for 2 hours, with or without an allergen inhalation challenge. The investigators measured multiple physiologic and pulmonary function endpoints, including specific airway resistance, oxygen saturation, bronchial reactivity, and inflammatory and immunologic endpoints.

Contents: Effects of Exposure to Diesel Exhaust Particles in Persons with Asthma and Allergy; Workshop Brings Experts Together: Atmospheric Chemists and Health Effects Scientists Meet at HEI to Discuss Common Goals; Symposium Sheds Light on Air Toxics Hot Spots; Wood Stove Changeout Program Brings Some Improvements in Health, Air Quality; Three New HEI Studies Launched: Ozone Exposure and Inflammatory Cells / PM Exposure and Heart Rhythm / Impact of Exposure in Early Life; ACES Reaches Important Milestones; New Investigator

This report describes a study that evaluated whether exposure to fine or nano-titanium dioxide (TiO₂) particles may affect cardiovascular endpoints, in particular endothelium-dependent vascular dilation. Dr. Nurkiewicz and colleagues exposed rats via inhalation to 0.5 to 20 mg/m³ TiO₂ for up to 12 hours and evaluated them for vascular dilation and for markers of oxidative stress, coagulation, and inflammation. This study was funded under the Walter A. Rosenblith New Investigator Award.   

This report describes a study that tested whether an air toxics "hot spot" existed in Camden, NJ. Dr. Lioy and colleagues evaluated ambient and personal exposures of nonsmoking residents to PM_2.5, VOCs, aldehydes, and PAHs in two neighborhoods in Camden, NJ, one of which was hypothesized to be a regional air toxics "hot spot." The investigators compared concentrations of air pollutants in the two neighborhoods with each other and then with concentrations at other locations in the United States. They also assessed the effects of seasonality, contributions from mobile sources, and spatial variability.

This report evaluates airway inflammatory responses and expression of the enzyme neprilysin in response to diesel exhaust particle exposure. Dr. Wong and colleagues hypothesized that components of diesel exhaust decrease neprilysin levels in airways, leading to airway function disorders and heightened responses to diesel exhaust. They exposed normal mice, mice genetically deficient in neprilysin, human subjects, and human airway epithelial cells to diesel exhaust particles and measured airway inflammation, neprilysin expression, and any unique responses in neprilysin-deficient mice.

This report contains studies in Chennai and Delhi led by Dr. Kalpana Balakrishnan and Dr. Uma Rajarathnam, respectively. These time-series studies of air pollution and mortality in India were funded under HEI's PAPA Program to provide information to inform regulatory and other decisions that would be relevant to local populations, with the added goal of supporting scientific capacity building in the region.

This report describes research funded under HEI's Air Toxics Hot Spot program. Dr. Eric Fujita and colleagues characterized concentrations of mobile-source air toxics (MSATs) and other pollutants in potential Los Angeles County pollution hot spots, including on urban highways with a varying mix of gasoline- and diesel-powered traffic and sites at various distances from the highways and close to other roads.

This report explores how land-use regression and source-apportionment techniques can be used to characterize individual-level exposure to both indoor and outdoor air pollution sources. Dr. Levy and colleagues utilized health and air monitoring data from an ongoing prospective cohort study on childhood asthma in Boston, Massachusetts to model variability in outdoor and indoor residential air pollution, identify potential sources, and evaluate the effectiveness of various indoor exposure surrogates for predicting childhood asthma development.

This report describes the first set of coordinated time-series studies ever undertaken in Asian cities: four time-series studies of the health effects of air pollution in Bangkok, Hong Kong, Shanghai, and Wuhan. These studies were intended to help bridge the gaps between studies conducted in different locations around the globe.

Communication 15, Proceedings of an HEI Workshop on Further Research to Assess the Health Impacts of Actions Taken to Improve Air Quality, summarizes the findings of a workshop held in December 2009 that reviewed the current state of research to evaluate the impact of air quality interventions (also known as accountability or air quality outcomes research).

This report describes a study by Dr. Thomas Cahill and colleagues to create and evaluate a new method to measure acrolein and other volatile carbonyls present at low concentrations in ambient air. Acrolein is an important aldehyde that is very difficult to measure accurately, so developing better methods for measuring levels and exposure is critical to better risk assessment for the chemical. The investigators developed a sampler that traps acrolein using sodium bisulfite in an aqueous medium.

This report is the latest in HEI's program of studies to assess the health impacts of air quality actions. Research Report 148 describes a study to evaluate the effect of a short-term, temporary intervention to reduce traffic congestion during the 1996 Summer Olympic Games in Atlanta, Georgia. A previous study had shown a decrease in acute care visits for pediatric asthma and a concomitant decrease in concentrations of ozone, particulate matter, and carbon monoxide.

This report describes a study to investigate the role of two subpopulations of T cells in the airway response to inhaled acrolein, a toxic pollutant in ambient air, which US EPA's National Air Toxics Assessment has identified as having broad effects. Dr. Michael Borchers and colleagues measured inflammation and injury in response to acrolein in the lungs of mice that are genetically deficient in the specific T-cell subpopulations. He also measured changes in gene expression in the T-cell subpopulations after acrolein exposure. This study was funded under the Walter A.