Students target air pollution from Boston to Sub-Saharan Africa

Kathie Dionisio Photo, Kent Dayton/HSPH

[Fall 2009]

Kathie Dionisio and Emmanuel Baja

A pair of HSPH doctoral students look at air pollution in new ways. For one, the goal is to describe unique air pollution challenges in the developing world. For the other, the aim is to measure more precisely the effects of air pollution on the heart, to understand how it causes damage.

Kathie Dionisio has the mind of an engineer but a heart devoted to global health. The graduate student’s technical know-how and problem-solving drive came in handy when she arrived in Accra, Ghana, in 2006, charged with launching research with her HSPH faculty adviser Majid Ezzati. The goal: to understand the detailed patterns of air pollution throughout the city and its neighborhoods—one of the first such studies in urban areas of the developing world.

“We had to do everything from making personal connections in the neighborhoods to building a battery backup system to keep the equipment running on an unreliable power supply,” Dionisio says. Now a doctoral candidate in the departments of Global Health and Population and Environmental Health, she spent a year in Accra as a research assistant before beginning her studies at HSPH, and returned periodically during the following year to manage data collection. “I had to solve problems without the benefit of overnight delivery for the parts I needed—just whatever I could get from the local market,” she says.

Dionisio studied biomedical engineering as an undergraduate at Columbia University and earned a master’s degree in mechanical engineering at the Massachusetts Institute of Technology. Eager for an international experience and curious about exploring research with a more direct application to health, Dionisio pursued an MIT-funded service project with a community-based health care organization in Zambia following graduation. The experience stoked her interest in public health, and the data-driven Accra project seemed like an ideal next step.

Currently, Dionisio is analyzing reams of measurements from the stationary and mobile monitors she and other student-researchers carried around Accra. The devices captured airborne particulate matter, registering differences between neighborhoods caused by traffic patterns, widespread burning of charcoal or wood for fuel, and other factors.

“Kathie is tremendously motivated, with great scientific and personal judgment,” says Ezzati, associate professor of international health at HSPH. “We spoke regularly about research and the project’s operation during Kathie’s field research in Accra. It was clear her decisions were the right ones for both the scientific and social aspects of our work.”

Dionisio and her colleagues aim to create a detailed profile of the unique air pollution challenges faced by cities in developing countries, laying the groundwork for future monitoring efforts and interventions.


Emmanuel BajaPhoto, Kent Dayton/HSPH
Emmanuel Baja
Photo, Kent Dayton/HSPH

“It’s fairly well accepted that air pollution is bad for your heart,” says Helen Suh, associate professor of environmental chemistry at HSPH. “But what is not as well understood is how it causes damage.”

The key may prove to be in the measurement of the heart’s electrical cycle known as the QT interval, says environmental health doctoral student Emmanuel Baja, who is advised by Suh. Exposure to traffic pollution has been associated with longer QT intervals in the elderly. Abnormally long or short QT intervals suggest a risk of developing abnormal electrical activity (arrhythmias) in the heart. Baja hypothesizes that pollution may trigger arrhythmias, leading to heart attack or even sudden death.

To explore this idea, he set up a study drawing on pollution data he gathered from monitoring devices located on the roof of Harvard Medical School’s Countway Library, as well as air quality data from Massachusetts’ Department of Environmental Protection and health data from a long-running cohort of elderly veterans. His study garnered top honors in HSPH’s student research poster competition in April. The judges praised Baja’s “novel approach,” but he is reluctant to take sole credit. “Studies are always a collaboration,” he says.

When pressed, Baja will admit he was determined to help develop a computer program that more accurately measures the QT interval than the conventional method—measuring by hand the distance between blips on a paper chart. Baja collaborated with colleagues to supply the statistical model used to analyze the study’s data. Dipping into  applied mathematics skills acquired earlier in his academic career, Baja realized that a model from economics could be a good fit for measuring cumulative exposures over a period of time.

“It’s fascinating to me that certain theories cut across disciplines,” Baja says. “I can take models from economics and psychology and apply them to epidemiology to create something different.”

Baja’s passion for math has taken him down several different paths, including jobs in banking and consulting. But while earning his master’s degree in applied mathematics from the University of the Philippines, he worked on an analysis of the toxicity of pesticides and discovered that his skills could be put to use in making the world a healthier place.

After he graduates, Baja hopes to continue working in air pollution research, perhaps for a nongovernmental organization in Southeast Asia where he sees a strong need for data collection. Or, he says, he may find another way to pull together his wide-ranging background. “I’d love to create public service campaigns for public health issues.”

Amy Roeder is the development communications coordinator in the Office for External Relations at HSPH.

Now recognized as a dangerous form of air pollution, particulate matter is the complex mixture of extremely small particles and liquid droplets suspended in air. It includes dust and pollen, as well as diesel soot and other potentially harmful substances produced by fires and fossil fuel combustion. Current air pollution standards regulate particles as small as 2.5 microns in diameter-hundreds of times smaller than the width of a human hair. These particles, called PM2.5 for short, easily deposit deep in the lungs.

Launched by faculty members in HSPH’s Department of Environmental Health 35 years ago, the Harvard Six Cities Study evaluated the effects of air pollution on the respiratory health of thousands of Americans and found a strong link to premature death. Its findings, released in 1993, led to the revision of air quality standards by the U.S. Environmental Protection Agency (EPA). Data produced by the study and its many spin-offs continue to strongly influence American air quality policy, including further strengthening particulate emissions standards by the EPA in 2006 and recognizing indoor air pollution as a significant contributor to health problems. Follow-up studies have shown that people are now living longer in cities where fine airborne particulate matter has been reduced.
Read more about the original study in “A Tale of Six Cities”.