Healthy living in cities: my Personal Exposure Quality (MyPEQ)

Professor Rajasekhar Balasubramanian

Adverse health effects from exposure to air pollution are a global challenge of widespread concern. The project “Healthy living in cities: my Personal Exposure Quality (MyPEQ)” brought together three Universities (National University of Singapore, University of California, Berkeley and University of Cambridge) to pursue collaborative research based on their respective strengths. Urban dwellers are frequently exposed to elevated levels of particulate matter (PM) and potentially toxic constituents, which are emitted from anthropogenic activities (e.g., industry, road transport). The personal exposure (PE) to PM across microenvironments endangers the health and well-being of urban residents who form a sizeable part (55%) of the world’s population.  The major goal of the research is to provide insights into the exposure of individuals to airborne pollutants such as fine particulate matter (PM_2.5, PM less than 2.5 micrometers in aerodynamic diameter), black carbon (BC) and ultrafine particles (UFPs, PM less than 100 nm in diameter).

The human health risk, experienced by city residents, is influenced by particulate pollution in both outdoor and indoor microenvironments. However, until recently the emphasis on health risk assessment has been placed on outdoor air quality data collected from fixed air quality monitoring stations. As people spend a significant amount of their time indoors (about 90%), their exposure to PM emissions from cooking, cleaning agents, paints etc. should also be considered. To address this knowledge gap, an alternative health risk assessment framework, linking the extent, place, duration, and frequency of human exposure to PM in diverse microenvironments (e.g., home, office, restaurant, bus, car) was developed as part of the project.

Systematic field studies involving real-time measurements of PM_2.5, BC and UFPs using portable sensors were carried out in cities with different PM emission characteristics, weather conditions and topography (Singapore, Berkeley, San Francisco and London). Chemical characterization of PM and subsequent health risk assessment were also performed as part of the research. Our key findings are summarized: (i) Short-term PE to high levels of PM is significantly high, and these data are not captured in the conventional outdoor measurement of PM at fixed locations environments for health risk estimates; (ii) Active modes of commuting such as cycling and walking to work from home and back are encouraged in the context of mitigating traffic-related carbon footprints, but health concerns due to high inhaled doses of PM_2.5, BC, and UFPs emitted from motorized transport merit consideration; (iii) Traffic emissions adversely affect indoor air quality in naturally-ventilated apartments and hence the health of building occupants. Indoor cooking activities can further exacerbate the health condition of exposed individuals. Human health risk in such exposure scenarios can be mitigated with the use of a portable air purifier.

This project revealed that the 24-hour time-integrated assessment of personal exposure to air pollutants in both outdoor and indoor microenvironments is an effective tool for urban air quality improvement as well as personal air quality management. The outcomes of this project are useful in formulating effective strategies to minimize personal exposure to PM and its potentially toxic constituents and to provide long-term health benefits.

Poster presentation

Tran P.T.M., Adam M.G., Chiang A., Tham K.W., Schiavon S., Linden P.F., Balasubramanian R., 2019. ‘Healthy Living in Cities - The Way Forward’ at Association of Pacific Rim Universities (APRU) Global Health Conference 2019, Hong Kong.

Publications in international journals

[1] Tran, P.T., Nguyen, T. and Balasubramanian, R., 2020a. Personal Exposure to Airborne Particles in Transport Micro-Environments and Potential Health Impacts: A Tale of Two Cities. Sustainable Cities and Society: 102470.

[2] Tran, P.T., Ngoh, J.R. and Balasubramanian, R., 2020b. Assessment of Integrated Personal Exposure to Particulate Emissions in Urban Microenvironments: A Pilot Study. Aerosol and Air Quality Research: 341-357.

[3] Tran, P.T., Adam, M.G. and Balasubramanian, R., 2020c. Mitigation of Indoor Human Exposure to Airborne Particles of Outdoor Origin in an Urban Environment During Haze and Non-Haze Periods. J. Hazard. Mater.: 123555.

[4] Tran, P.T., Zhao, M., Yamamoto, K., Laura, M., Ngyuen, T., and Balasubramanian, 2020d. R. Cyclists’ personal exposure to traffic-related air pollution and its influence on bikeability, Transportation Research D: Transport and Environment, in press.

Articles submitted for publication

[5] Tran P.T.M., Adam M.G., Tham K.W., Schiavon S., Pantelic J., Linden P.F., Sekhar C., Cheong D.K.W., Balasubramanian R., 2020. ‘Assessment and mitigation of personal exposure to particulate air pollution in cities: an exploratory study’.

[6] Adam M.G., Tran P.T.M., Balasubramanian R., 2020. ‘Assessment of home-based and mobility-based exposure to black carbon in an urban environment: health implications’.