Reviewed by Lexie CornerJul 30 2024
A recent study published in Nature Cities and co-authored by MIT scholars finds considerable disparities in how much people are exposed to air pollution based on their daily mobility.
The research, based in the Bronx, New York, does more than just estimate air pollution exposure based on where people live or work; it also utilizes mobile data to investigate where individuals go throughout a typical day, allowing for a more detailed assessment of the environment’s influence.
According to the study, exposure to particulate matter 2.5 millimeters or higher rises by around 2.4 percent when daily travel patterns are considered.
One of the main strengths of the study is that we try to improve the information we use on the air quality side and also from the fine-grained estimation of people’s mobility. That allows us to build trajectories of people’s movement. So, it was the first time we were able to combine these data to come up with a new measure of exposure.
Paolo Santi, Study Co-Author and Principal Research Scientist, Massachusetts Institute of Technology
After all, people's daily pollution exposure might be a complicated combination of living close to, working near, or commuting near sources of particulate matter.
People move around the city for jobs, and education, and more, and studying that is where we get this better information about exposure.
An Wang, Study Co-Author and Assistant Professor, Hong Kong Polytechnic
Iacopo Testi of the Senseable City Lab; An Wang of Hong Kong Polytechnic University; Sanjana Paul, a graduate student in DUSP; Simone Mora of the Senseable City Lab; Erica Walker, an associate professor at the Brown University School of Public Health; Marguerite Nyhan, a senior lecturer/associate professor at the National University of Ireland, University College Cork; Fábio Duarte of the Senseable City Lab; Santi; and Carlo Ratti, director of the Senseable City Lab are the other study authors.
The researchers gathered air pollution by installing solar-powered environmental sensors, such as optical particle counts, temperature and humidity sensors, and GPS, aboard New York City’s civic services vehicles in the Bronx.
This strategy shows that cities can use their existing fleet as environmental sensors.
Simone Mora, Research Scientist, Massachusetts Institute of Technology
The researchers analyzed 500 million daily location records in New York and anonymized phone records of 500,000 distinct people to evaluate how people passing through the Bronx are exposed to pollution at different times.
Based on statistics from ground-level pollution, the southeast section of the Bronx, where expressways and businesses converge most frequently, has the highest concentration of particulate matter.
When the mobility data was analyzed in terms of demographics, it also showed differences in exposure; the differences by ethnicity were greater than those by income. For example, certain communities that are predominately Hispanic have some of the greatest levels of exposure. However, the data also revealed significant variations in exposure levels across groups of Hispanic descent.
Duarte points out that exposure to pollution has a significant impact on health. For example, the Bronx has the poorest air quality of any borough in New York City, contributing to 2.5 times the city’s asthma cases.
Fábio Duarte of the Senseable City Lab added, “You see the consequences of exposure to pollution in the hospitalization of adults in the Bronx.”
As the researchers note, there could be slightly different mobility patterns in the Bronx today because the study was done in the fall of 2021, while the global COVID-19 pandemic was still impacting business and commuting. Nevertheless, they think this approach might result in further studies on pollution exposure in the future.
Ratti stated that mobile data, including automobile pollution sensors, can serve as “a huge monitoring system. It is not expensive, we have the infrastructure in terms of cars and buses, and just putting sensors on them, you can have better air quality monitoring.”
Wang also observed that granular studies like this one could be expanded to include other types of air-quality problems besides PM 2.5 particles.
Wang stated, “This actually opens the door for new analysis for many kinds of toxicity studies combined with exposure.”
MIT Senseable City Lab Consortium supported the study.
Journal Reference:
Testi, I., et. al. (2024) Big mobility data reveals hyperlocal air pollution exposure disparities in the Bronx, New York. Nature Cities. doi:10.1038/s44284-024-00093-x