Skip Ribbon Commands
Skip to main content

Exposure to particles pollution

See Photos, Videos And Publications

Investigators: Erik Velasco

Description: We investigate the exposure to particle pollution during daily activities and commuting trips.

Particle pollution in urban microenvironments

​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​CENSAM stopped activities on Dec. 2017. For updates and information contact to Erik Velasco (

At city scale, air quality monitoring is performed by networks of monitoring stations. They provide information on the average ambient pollution at district scale to which the general population is exposed, which is used for both, regulatory and advisory purposes. The monitoring stations are usually placed above the urban canopy layer (i.e. rooftops), where pollution measurements are not directly impacted by local emissions or obstructed by wind flow. However, the ambient pollutants reported by these stations do not always represent the pollution to which people are exposed during their daily activities.  The highest outdoor exposure to pollutants for many dwellers occurs while commuting or carrying out activities in proximity to emission sources at ground level (e.g., walking along busy streets).

On this account, a series of field observations using portable and battery operated monitors have been designed to evaluate the exposure concentration of particles to which people are exposed in selected public environments and transport modes. Results will provide information to evaluate existing air quality regulations, as well as identify areas of potential improvement in public health.

Current and past studies

- Commuter exposure to aerosol pollution on public transport in Singapore.

- Characterization of airborne particles at bus-stops.

- Use of data-driven methodology for the design of air quality monitoring networks at street level.

- Performance evaluation of black carbon monitors.

- Particle characterization in traffic microenvironments of HCMC, Vietnam.

- Masks efficiency against pollutant particles.

Lead researcher

- Erik Velasco (SMART, Singapore;


- Sok Huang Tan (NUS-Geography, Singapore; now at MEWR, Singapore)

- Vahid Moosavi (FCL-ETH, Singapore; now at ETH, Switzerland)

- Gideon Aschwanden (FCL-ETH, Singapore; now at Univ. of Melbourne, Australia)

- Oscar Peralta (National Autonomous University of Mexico, Mexico)

- Soheil Rastan (Canada Statistics, Canada)

- Matthias Roth (NUS-Geography, Singapore)

- Phạm Anh Đức (Ton Duc Thang University, Vietnam)

- Tony Huang (Ton Duc Thang University, Vietnam)

Peer-reviewed articles
- Tan SH. Commuter exposure to aerosol pollution on public transport in Singapore. Master Thesis. National University of Singapore, 2015.
- Moosavi V. Pre-Specific Modeling: Computational Machines in Coexistence with Urban Data Streams. PhD Thesis. ETH Zurich, 2015.
Aschwanden GDPA. Health and Place: an analysis of the built environments impact on walking behavior and health. PhD Thesis. ETH Zurich, 2015.
- Tan SH. Personal exposure to aerosol pollution at bus stops in Singapore. Honors Thesis. National University of Singapore, 2011.

Approximately 64% of Singapore's population commute to work by bus every day. Just how much pollution are we breathing while we're waiting at the bus stops?

Did you know that bus stops are hotspots of personal exposure to tiny particles, known as ultrafine, which permeates the bloodstream and can produce or exacerbate existing pulmonary and cardiovascular diseases? You could be exposed to these particles while standing at bus stops for nearly 7 hours per month! Catch the news report on Channel NewsAsia (20 Sep 2016) here.
SMART CENSAM Dr Erik Velasco explains the risk of breathing particles expelled by vehicular traffic at bus stops to Chinese News on Channel 8, 20 Sep 16.
Photo Gallery Upload
Publications Upload

Back to Top