Health impacts of natural gas or other engines in buses in Helsinki
GASBUS - Health Effects Caused by Primary Fine Particulate Matter (PM2.5) Emitted from Buses in the Helsinki Metropolitan Area, Finland.
Research team at KTL: Marko Tainio, M.Sc; Jouni Tuomisto, D.Med.Sc; Juha Pekkanen, D.Med.Sc, prof; Matti Jantunen, PhD, prof; Kimmo Koistinen, PhD, Otto Hänninen, M.Sc; Päivi Aarnio, Lic.Tech.
Funding: The Finnish Ministry of Social Affairs and Health, Finland
Contact person: Marko Tainio, tel. +358-17-201-162
Background & objectives: Particle emissions from many individual sources have been reduced. Recently attention has been focused on traffic-generated particulate matter. The need to develop low-emission vehicles has led to a number of improvements in engine design, fuel composition, and particle-trapping systems. As a consequence, authorities and decisionmakers now face the opportunity of choosing bus technologies from several options. To support the decision-making process, The Finnish Ministry of Social Affairs and Health commissioned a risk analysis to compare the health effects of particulate matter emissions from alternative bus technologies for use in the Helsinki Metropolitan Area.
Results: The mortality due to primary fine particles from buses ranged from 3 to 18 cases per year in the different bus strategies. Of the examined options, diesel with particles trap and natural gas bus strategies showed similar reduction in mortality, while with the modern diesel strategy the mortality remained at a higher level. The uncertainties in the mortality estimates were high and included a zero-effect possibility.
Conclusions: The corresponding health effects can be affected to some extent by changing bus types. The difference in the excess mortality between natural gas buses and the present diesel engines with proper trapping systems is not large. Thus it is questionable whether the costs and alternative risks associated with the more complicated fuel storage and delivery systems for compressed natural gas would be covered by the marginal health benefits from the lower PM emissions. Emissions from buses in Helsinki are only a small fraction of the total traffic and other combustion particle emissions in the area and thus there are also possibilities for acquiring similar or larger reductions in ambient PM concentrations and corresponding reductions in health effects.
Analytica-based model: Gasbus model.ANA. (56 KiB) To view the model graphically, save it to your computer (press the right mouse button and chose the Save target as… -option), download the free Analytica-player from Lumina and open the saved model with the program. The model identifier is: URN:NBN:fi-fe20051170
Reference: Tainio, M., Tuomisto, J.T., Hänninen, O., Aarnio, P., Koistinen, K.J., Jantunen, M.J., and Pekkanen J. Health effects caused by primary particulate matter (PM2.5) emitted from buses in the Helsinki Metropolitan Area, Finland. Risk Analysis, Vol. 25, No.1, 2005. pp. 151-160.