Diesel Pollution — Exposure to Diesel Exhaust on School buses

I came across a study by Dr John Wargo on “Children’s Exposure to Diesel Exhaust on School Buses”, which I found rather interesting. It has found that majority of school buses in the USA are powered by diesel fuel, and diesel exhaust has been identified as a probable human carcinogen. In this study, it was found that buses contain fine particulate concentrations (PM2.5) much higher than average levels along fixed monitoring stations in Connecticut. The study also highlighted several circumstances were highlighted in which level of fine particles were higher; these included situations where buses are running through high traffic, or when buses are running with windows closed, and when buses queued to load/unload children. The study, published under Environment and Human Health Inc (EHHI), can be accessed here! (There is a pretty useful summary report and a briefing note(?) by the US Environmental Protection Agency too, for those who want an overview of the issue)

The issue had a specific context that I can relate to — transport to school (I recall my own secondary school days where I had to squeeze on public buses that barely inched forward during peak hours). I never took a school bus on a frequent basis, but I suppose that the issues are similar; with so many people, be it children or adults, travelling along the roads everyday, diesel pollution is probably one aspect of pollution of the streets that we should be concerned with.

We have school buses in Singapore (that are not yellow) too! Just that they are under the service of various private bus companies and usually serve as tour buses too. Image Retrieved from: http://www.bedoktransport.com/data1/images/home3.jpg

Dr Wargo, together with a few other authors, have also written a report on “The harmful effects of vehicle exhaust“, which provided a broader discussion to the issue of vehicle exhaust pollution. Specific health problems are also highlighted (asthma and other respiratory problems), with children and elderly at much higher risk.

In Singapore, issues of diesel pollution exists too. For instance, the The Ministry of Environment and Water Resources, Singapore (MEWR) reports that the main sources of tiny particulate (such as PM10) are exhaust fumes from motor vehicles, in particular diesel vehicles. Some policies that have been in place to address this problem includes ensuring that the Euro VI standard for new diesel-powered vehicles are met starting from 1 January 2018 (National Environmental Agency, 2014). MEWR has also been encouraging the use of green vehicles (with the Green Vehicle Rebates since January 2001). Other measures in place includes the Chassis Dynamometer Smoke Test (CDST) for testing diesel vehicles that are found to not comply with NEA’s smoke emission threshold since 1 September 2000. Also, from 1 January 2007, All diesel-driven vehicles will also have to undergo the CDST during their mandatory inspections.

As a side note, I particularly liked how The New Scientist puts this particular study (Dr Wargo’s research on diesel exhausts) across as:

“The buses that take our children to school should be safe places. But… (these buses) are polluted by diesel exhausts.” (Source. Last Accessed 8 February 2015)

By describing the situation as such, it prompted us (or myself, at least) to take a look at the situation in more detail because it seemed counter-intuitive that a school-bus is supposed to take children to a place of safety and learning, but may instead be bringing them towards poor health (through the prolonged and cumulative exposure of diesel exhausts).


Environmental Protection Agency (n.d). ‘What you should know about Diesel Exhaust and School Bus Idling’. Retrieved from: http://www.epa.gov/reg3artd/diesel/School_bus_idling_MAR.pdf [Last accessed: 8 February 2015]

National Environmental Agency (2014). ‘Singapore will Usher in Duro VI Emission Standard for Diesel Vehicles from January 2018’. [Online] Retrieved from: http://www.nea.gov.sg/corporate-functions/newsroom/news-releases/singapore-will-usher-in-euro-vi-emission-standard-for-diesel-vehicles-from-january-2018 [Last accessed: 8 February 2015]

Ministry of the Environment and Water Resources (2008).  ‘Chapter 1 — Air’. State of the Environment 2008 Report Singapore. pp. 16-25. [Online] Retrieved from: https://app.mewr.gov.sg/data/ImgCont/1233/016-025%20Air.pdf [Last accessed: 8 February 2015]

Wargo, J. (2002). ‘Children’s Exposure to Diesel Exhaust on School Buses’. Retrieved from: http://www.ehhi.org/reports/diesel/diesel.pdf [Last accessed: 8 February 2015]

Wargo, J., Wargo, L. and Alderman, N. (2006). ‘The Harmful Effects of Vehicle Exhaust. A Case for Policy Change’. Retrieved from: http://www.ehhi.org/reports/exhaust/exhaust06.pdf [Last accessed: 8 February 2015]


One thought on “Diesel Pollution — Exposure to Diesel Exhaust on School buses

  1. Pingback: Diesel traffic — respiratory effects on asthmatic persons | Smoky Streets

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