Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Children on school buses may face increased exposure to diesel pollution

19.04.2005


Diesel particle pollution inside urban school buses may be worse than levels found in the surrounding roadway air, according to a study by scientists at the University of California. The report appears in the April 15 issue of the American Chemical Society’s journal Environmental Science & Technology. ACS is the world’s largest scientific society.



It has generally been assumed that other vehicles on the road are the source of elevated particle levels. But a study of school buses in the Los Angeles area shows that much of the pollution inside a school bus comes from the bus itself, and children on board may be inhaling more diesel particles than previously believed.

Diesel particles are extremely small and can deposit deep in the lungs, whereas larger particles are filtered out by the nose, mouth and throat. A number of studies have linked diesel particles to adverse health effects. For example, a large assessment of air pollution in the Los Angeles area found that diesel particles are responsible for most of the cancer risk from outdoor air pollution.


Children are especially susceptible to air pollution because they have high inhalation rates and large lung surface area per body weight, as well as narrow airways and immature immune systems, the researchers say.

They analyzed results from a UCLA school bus experiment where the researchers took out the seats and essentially turned the buses into mobile chemistry labs, driving them along actual school bus routes in the greater Los Angeles area. Six buses were involved in the study: two older high-emitting diesel buses from 1975 and 1985; two diesel buses that are more representative of current fleets; one diesel bus outfitted with a particle trap; and one bus powered by compressed natural gas.

The researchers released a tracer gas into the engine exhaust and measured concentrations of that gas inside the buses. They then calculated the "intake fraction" — the fraction of the bus’s exhaust that is inhaled by students on that bus, assuming an average population of 40 people on each bus.

The levels turned out to be substantial for all six buses, but older buses and close-windowed buses were higher, according to the researchers. The average value for intake fraction across all bus runs was 27 grams inhaled per million grams emitted, with the highest value at around 100 per million.

"This may not sound like a lot," says Julian Marshall, a doctoral candidate in the Energy and Resources Group at UC Berkeley and lead author of the study. "But intake fraction values for vehicle emissions are 5-15 per million in a typical U.S. urban area, and about 50 per million in a large urban area like Los Angeles."

The fact that these values are comparable is "shocking," according to Marshall. "This means that for every ton of pollution emitted by a school bus, the cumulative mass of pollution inhaled by the 40 or so kids on that bus is comparable to — or in many cases larger than — the cumulative mass inhaled by all the other people in an urban area."

The California Air Resources Board, which sponsored the original study by UCLA, recommends minimizing commute times, using the cleanest buses for the longest commutes, accelerating the retirement of older buses, and decreasing bus caravanning and idling time to reduce children’s exposure to bus-related air pollutants.

"Based on our work, if a policymaker wants to reduce health effects from diesel for the population as a whole, then school buses are a good source to target," Marshall says.

The American Chemical Society is a nonprofit organization, chartered by the U.S. Congress, with an interdisciplinary membership of more than 158,000 chemists and chemical engineers. It publishes numerous scientific journals and databases, convenes major research conferences and provides educational, science policy and career programs in chemistry. Its main offices are in Washington, D.C., and Columbus, Ohio.

Michael Bernstein | EurekAlert!
Further information:
http://www.acs.org

More articles from Studies and Analyses:

nachricht Physics of bubbles could explain language patterns
25.07.2017 | University of Portsmouth

nachricht Obstructing the ‘inner eye’
07.07.2017 | Friedrich-Schiller-Universität Jena

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Physicists Design Ultrafocused Pulses

Physicists working with researcher Oriol Romero-Isart devised a new simple scheme to theoretically generate arbitrarily short and focused electromagnetic fields. This new tool could be used for precise sensing and in microscopy.

Microwaves, heat radiation, light and X-radiation are examples for electromagnetic waves. Many applications require to focus the electromagnetic fields to...

Im Focus: Carbon Nanotubes Turn Electrical Current into Light-emitting Quasi-particles

Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers

Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...

Im Focus: Flexible proximity sensor creates smart surfaces

Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.

At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

 
Latest News

Programming cells with computer-like logic

27.07.2017 | Life Sciences

Identified the component that allows a lethal bacteria to spread resistance to antibiotics

27.07.2017 | Life Sciences

Malaria Already Endemic in the Mediterranean by the Roman Period

27.07.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>