http://ens-news.com/ens/apr2003/2003-04-15-09.asp
The Battle Between Natural Gas and Diesel BOSTON, Massachusetts, April 15, 2003 (ENS) - A new study from the Harvard Center for Risk Analysis finds that compressed natural gas technologies deployed on urban transit buses offer more health benefits than competing "clean diesel" technologies but at greater cost. The analysis of the two technologies showed that compressed natural gas (CNG) provides one third more health benefits than emission controlled diesel (ECD)" but the cost per unit of health improvement is six to nine times higher. The study, published in the current issue of the journal "Environmental Science and Technology," measures the public health damages of air pollution from urban transit buses in units of Quality Adjusted Life Years (QALYs). According to the research team, the study finds that new ECD buses reduce health damages by 40 percent, and that new CNG buses cuts health damages by 55 percent, compared with new conventional diesel buses. Both technologies reduce emissions of fine particles by some 75 percent, but CNG also reduces emissions of nitrogen oxides, which contributes to smog and the formation of fine particles. Yet the cost per QALY saved using CNG would be six to nine times greater than for ECD because of the higher cost of acquiring and maintaining these vehicles, as well as installing and maintaining infrastructure to fuel them, and paying more for fuel to run them. The study did not take into account the safety risk of CNG, which is readily ignitable, nor does it consider some of the drawbacks of diesel technology, including a strong odor and noisier operation. The authors say this analysis is the "the first to compute and compare aggregate incremental costs and health benefits for bus propulsion technologies." "These first order ball-park estimates of the costs and benefits of these alternative propulsion systems provide an important way to think about the pros and cons of different ways to address this important environmental issue," said senior research associate Joshua Cohen. ------------------------ Yahoo! Groups Sponsor ---------------------~--> Make Money Online Auctions! Make $500.00 or We Will Give You Thirty Dollars for Trying! http://us.click.yahoo.com/yMx78A/fNtFAA/i5gGAA/9bTolB/TM ---------------------------------------------------------------------~-> Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://webconx.green-trust.org/2000/biofuel/biofuel.htm List messages are archived at the Info-Archive at NNYTech: http://archive.nnytech.net/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
