ROUTES Scholar Sarah Gibbs’s Research suggests diesel trains increase the levels of Particulate Matter concentrations at 3 Boston Commuter Rail Stations

ROUTES Scholar Sarah Gibbs is an Environmental Science student currently on her first co-op working in Dr. Matthew Eckelman’s lab on a project titled “Integrated Assessment Modeling of Energy, Air Quality, and Health Links.” In this role, Sarah has focused mainly on collecting, cleaning, and analyzing data using R from air monitoring sessions at three heavily trafficked Commuter Rail Stations (Back Bay, Ruggles, and Roxbury Crossing). Additionally, she has gained experience in research by preparing literature reviews for PhD students in their lab and by advancing her knowledge of ArcGIS.

Her data suggests that there is a statistically significant increase in Particulate Matter (PM) concentrations when a diesel train is present versus when an electric train is present, as well as between when a diesel train is present versus when no train is present. “The increase in concentration after the passing of a diesel train was almost immediate (about 10 seconds after the train passed.) Surprisingly, PM concentrations after an electric train passed also increased, but there was a delay of about 30 seconds due to the wake that the trains created. Electric trains do not emit any particles themselves, but their wake resuspends particles already on the tracks. These resuspended particles are likely from diesel trains as well as from the gravel that the tracks are built on.”

Whilst carrying out the study, Sarah would place an aerosol monitor on or around the platforms of the chosen MBTA Stations for multiple hours a day. Data analysis required the investigation of multiple statistical tests to determine the most appropriate one for the data collected.  When asked how this was carried out, Sarah explained, “This was done in R, which I had no prior experience with and spent a significant amount of time learning.” Sarah was able to train herself in this software which is impressive due to the fact it is not an easy program to use and she had no previous experience with programming languages. Since R is a program so widely used within the science and research community when interacting with data, this skill will be invaluable to her career development.

Particulate Matter can be defined as a mixture of solid and liquid particles found in the air which can contribute to respiratory health issues. PM is measured in micrometers; smaller particles are more dangerous to human health. The two most commonly studied and regulated particle sizes are PM2.5 (fine inhalable particles such as metals or organic compounds that can also be formed by combustion) and PM10 (inhalable particles such as dust, pollen, or mold). Additionally, chronic exposure to PM can cause coughing, difficulty breathing, aggravated asthma, decreased lung function, or even premature death. Children, the elderly, and those with heart or lung disease are the most sensitive to exposure.

Since ROUTES has a public and environmental health focus, we wanted to know how Sarah’s research findings could potentially impact the general population and our lifestyles. This is what she had to say:

“People living in urban areas should be mindful of the PM pollution that they are exposed to on a daily basis, especially if they are predisposed to respiratory issues. PM exposure can occur from many different transportation methods, not just the commuter rail trains studied. People who are concerned about their respiratory health can wear face masks during their commute or while walking outside. Many commuters do not realize that they are exposed to PM every day. This chronic exposure can lead to health complications, especially to those in sensitive groups. I believe that the key findings of this study can be used to help inform people of the risks they face so they can take action to reduce their exposure.”

Sarah will be completing her co-op this December and plans to graduate with her Bachelor of Science in May 2021. After completing her degree, she plans to stay in Boston to pursue her PhD focusing on fisheries and socio-ecological systems.