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Ny rapport, LA skulle drabbas av mer cancer vid 100% E85 http://etanol.nu/forum/viewtopic.php?f=31&t=2912 |
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Författare: | karlmb [ tis 08-04-29 13:35 ] |
Inläggsrubrik: | Ny rapport, LA skulle drabbas av mer cancer vid 100% E85 |
http://pubs.acs.org/cgi-bin/sample.cgi/ ... 62085v.pdf Rapporten ger sken av att ha kommit på att det 2020 skulle kunna ge stora problem om större delen av bilparken i LA drevs av E85 jfrt med bensin. Efter ett antal linjär regressions resonemang och fina färgglada bilder ser det inte alls bra ut för E85 (eller E80 som de menar E85 är i USA?). Men om man läser tabell1 på sid 2 blir man lite mer fundersam: Citat: (4) percent
change from gasoline to E85 Under den kolumnen minskar alla cancerogena ämnen utom CO, formaldehyde, Acetaldehyde och TOG Alla andra som bensen, NO2, paraffin bond group, toluene bond group, xylene bond group, isoprene bond group reduceras mkt kraftigt, oftast med omkring 80%. Hur kommer de egentligen fram till att det blir fler cancerfall med E85 då? De gör ett stort nummer av 2000% ökning av aldehyder samt ozon t.ex., men aldehyder bryts ju ned kort efter bildandet, finns det några uppgifter på hur snabbt egentligen, i kaliforniensol? Ozon, hur är det med den? |
Författare: | karlmb [ tis 08-04-29 14:30 ] |
Inläggsrubrik: | |
OK, lite research...: http://www.cleanfuelsdc.org/pubs/docume ... dStudy.pdf Citat: While the model used in this study by Mark Z. Jacobson is very extensive and sophisticated, the quality of the results from any modeling study always dependant on the quality of the inputs used for the model. In the present case, these inputs are questionable, mainly due to the time projection out to 2020. The California Air Resources Board (CARB) is currently struggling with an emissions inventory to be used in air quality models that will attempt to predict 2010; yet Professor Jacobson is attempting to predict 2020. Furthermore, the differences in air quality predicted for 2020 between ethanol and gasoline fuels are much smaller than the differences expected in California for just gasoline vehicles in the four years between now and 2010. Thus, even the base gasoline predictions are uncertain for a year so far in the future as 2020, let alone the potential emissions using E85. As a group of sensitivity simulations, future expected trends in various emissions categories might be a useful addition to a study comparing gasoline with E85. However, this reviewer believes a more convincing comparison would be based on a simulation of a near term year (e.g. 2006 or 2010) using the latest current gasoline emissions and a compilation of currently available E85 emissions data. To be sure, as discussed below, this would still be a “fictional” exercise because so few vehicles now can use E85, but it would be based on the best emissions estimates currently available. Even though a total use of E85 might be assumed in one of these near-term scenarios, the results could be used to provide an approximation to the impact of any level of E85 utilization. Trying to project 14 years into the future for all emissions adds too many uncertainties due to changes in gasoline and ethanol technology, let alone potential differences between them. Currently only about 1 percent of vehicles are capable of using E85 nationwide. Thus, any vehicles remaining on the road in 2020 would need to be retrofitted. All new vehicles sold between now and then would have to be either flex-fuel capable between gasoline and E85 (or perhaps even dedicated E85) or they too would have to be retrofitted. There really is a paucity of data now on the emissions of existing E85- capable vehicles. Also new emissions-technology improvements and catalyst formulations are being developed every year. Rapid developing technologies are a major source of uncertainty for the emissions for each fuel themselves, let alone the differences between gasoline and E85 by 2020. Given such uncertainties and the fact that this study by Professor Jacobson showed results that actually were very small (less than 2 ppb ozone) impacts, it is reasonable to state that zero impact could be considered to be within the range of uncertainty for this study. Citat: ACE Statement in Response to Stanford University Ethanol Report
Sioux Falls, SD (April 12, 2007) – In response to a paper released today by Mark Z. Jacobson of Stanford University and published in the online edition of the journal Environmental Science & Technology, the American Coalition for Ethanol (ACE) issued the following statement: “Air quality has improved in every city, county, and state that has switched from straight gasoline use to ethanol blended fuel. Those are real world results, not predictions. In a way, it is refreshing to see that the anti-ethanol naysayers continue to be relegated to making dire predictions of what 'might happen if' - because it shows they have no negative real-world experience to report. Ethanol’s record as a clean air fuel is unmatched. The track record for the predictive models issued by ethanol opponents – especially with respect to California predictions – has been less than stellar. |
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