Numerous studies have examined the hazards of living in areas with high levels of pollution. Whether one is residing near a factory, a condensed metropolis or a bustling roadway, living amid exhaust can be a risk factor for numerous health problems. But a new Tufts study examining life near crowded highways will go one step further by looking at specific links between pollutants emitted by cars and heart disease.
The Community Assessment of Freeway Exposure and Health (CAFEH) is a five-year project that began last summer. The CAFEH will be measuring both pollution levels in Boston communities near highways and the health of those communities. The study will be looking at rates of cardiovascular disease in the communities and at the levels of numerous pollutants produced by internal combustion engines, including ultrafine particles, black carbon and carbon monoxide.
The National Institute of Environmental Health Sciences, a division of National Institutes of Health (NIH), funded the study with a $2.5-million grant. Heading the study is Doug Brugge, associate professor of public health and family medicine at the medical school.
Rather than have researchers choose communities to be subjects in the study, a group of concerned citizens, the Somerville Transportation Equity Partnership (STEP), proposed the CAFEH. The idea for the study came up when STEP looked at ways to use land in Assembly Square for economic development.
"That led us to look at regional transportation systems, and that led us to look at air pollution and public health, first as a lever for getting better transportation in Somerville; but then after we started to do some research on particulate matter, we realized that we likely had a public health problem," STEP member Wig Zaimore said. Zaimore then looked at data relating to lung cancer and heart attack data in Eastern Massachusetts and found a strong correlation with increased incidence of lung cancer and heart attack mortality along major transportation corridors.
The group became concerned with the effect of traffic on nearby Interstate 93 and approached Brugge about the possibility of a study. Brugge, who had worked with other communities near I-93, proposed that other community partners be added to the study.
The full list of partners for CAFEH includes the STEP, the Latin American Health Institute, the Chinese Progressive Association, the Committee for Boston Public Housing and the Chinatown Resident Association. The communities and researchers are "full partners" in the study, Brugge said.
Although prior studies have looked for correlations between health and proximity to highways, what makes the CAFEH unique, according to Brugge, is its broad focus. "Narrowly speaking, I think it's the first study that is both measuring gradients of very tiny particles next to highways and looking for associations with health outcomes with those exposures," Brugge said. "Is it the first study of air pollution and health? Absolutely not," he added.
STEP President Ellen Risner agreed. "There's certainly been research done on proximity to highways and measuring health effects, and there [have] been researchers who've done air quality testing to measure the volume of pollution near highways, but ours is one of the first studies that does both together," Risner said.
No prior studies have measured both proximity to highways and health outcomes associated with ultrafine particles, such as asthma and cardiovascular disease. Another unique aspect of the study is the fact that it is being conducted in Massachusetts. According to Brugge, many American near-highway studies have been conducted in Southern California. "There's much less of that work of any sort in the Northeast or in Boston," Brugge said.
Distance from highways is one risk factor researchers will be looking at. "Presumably, people who live closer to the highway and spend more time at home and leave their windows open will have higher exposures than someone who is farther from the highway," Brugge said.
Although proximity to highways is certainly a risk factor, distance from highways is not necessarily the best measure of one's exposure to pollutants, according to Civil and Environmental Engineering Associate Professor John Durant. He is in charge of estimating near-highway residents' exposure to pollutants in the study.
"The thing most important after traffic volume is meteorology. Under certain meteorological conditions, you can have very low exposure. If you have wind coming off the ocean ... it can simply blow out all the pollution before it has a chance to expose people at high concentrations," Durant said. He added, however, that stable air that forms overnight can cause early-morning rush hour pollutant levels to "spike."
Because of the numerous factors that can affect pollution levels, CAFEH researchers go out into the communities and measure pollutant levels rather than simply predicting the pollutant levels based on distance from the highway.
Past studies on the subject have shown that ambient particulate pollution across large areas has been linked with cardiovascular disease. Furthermore, proximity to highways has been shown to increase risk of cardiovascular disease.
"If there's nothing wrong with those studies, then what we should see with much more clarity, because we're looking at it in a very fine-grained and detailed way, is an association with cardiovascular disease and exposure to these very fine particulates next to the highway," Brugge said.
The study will measure differences in health problems between people who are "more exposed and less exposed" to highway-produced ultrafine particles, Brugge said. "We'll end up with people at different levels of exposure and be able to look at a variety of health outcomes, including diagnosis of disease, but also blood markers of inflammation and blood pressure and so forth that would be risk factors for development of cardiovascular disease."
Brugge believes that the results of the study will be somewhat predictable but is not jumping to premature conclusions. "As a researcher, I have an idea of what is likely, but I'm not hoping or expecting to find something," he said.
