Click on a label to read posts from that part of the world.
May 23rd 2008 4:13PM There have been several previous reports showing high pollutant levels inside vehicles.
Dr. Scott Fruin, who currently works at the California Air Resource Board (CARB), did his graduate school research on pollutant levels inside cars (at UCLA). The abstract of his 2003 presentation at CARB sums it up:
"On a per-time basis, time spent in vehicles is the most important route of exposure to air pollutants for most people. Air pollution concentrations inside vehicles are often an order of magnitude higher than ambient air, and Californians average over an hour and a half per day in vehicles. This talk describes results of a recent in-vehicle diesel exhaust particulate matter (DPM) exposure assessment performed for the first time for California driving, and its implications for overall exposure. The assessment found that the six percent of our day we spend in vehicles causes about one-third of our total DPM exposures. This high relative importance of in-vehicle exposures means on-road diesel emissions contribute three times more exposure on an equal mass basis than off-road diesel emissions."
His presentation is on-line (link below). There are probably quite a few other reports about his work on-line for free, and a few in non-free scientific journals.
There is also a far less rigorous study of truck drivers by the National Resources Defense Council also showed higher pollant concentrations inside the cab than outside.
Link to Fruin's seminar: http://www.arb.ca.gov/research/seminars/fruin/fruin.htm
A PDF of his presentation: ftp://ftp.arb.ca.gov/carbis/research/seminars/fruin/fruin.pdf
Link to NRDC report: http://www.nrdc.org/health/effects/driving/contents.asp
Oct 12th 2007 12:24PM bioburner -- you're right that different engines have different emissions performance on biodiesel. I neglected to mention that the results I presented were for heavy-duty engines (e.g., large trucks and buses). I haven't seen similar studies on passenger cars, but also haven't looked very hard for them.
Oct 11th 2007 6:56PM Whether the new diesel engines will meet SULEV targets, I think we need to wait and see what appears in the spring. If you have information comparing the expected emissions for diesel cars against the SULEV standards, please provide a link so we can check it out.
Some of the emissions claims above don't match what I have seen in the technical literature. Generally, the expectation for biodiesel is a mild decrease in PM, HC and CO and a slight increase in NOx.
Here is some emissions information that comes from comprehensive literature reviews, one by the U.S. EPA, the other by researchers at the National Renewable Energy Laboratory.
For 1991-97 engines, the EPA's review of the technical literature found the following changes in emissions:
* For B20 (20% biodiesel, 80% petrodiesel): 12% decrease in PM, 2% increase in NOx, 21% decrease in HC, 11% decrease in CO.
* For B100: 47% decrease in PM, 10% increase in NOx, 67% decrease in HC, 48% decrease in CO.
Reference: A Comprehensive Analysis of Biodiesel Impacts on Exhaust Emissions - Draft Technical Report, EPA420-P-02-001 (available on-line)
For newer engines, there is a paper from NREL published by the Society of Automotive Engineers that found:
* For B20 (20% biodiesel, 80% petrodiesel): 25% decrease in PM, 3% increase in NOx, no change in HC, no change in CO.
* For B100: 75% decrease in PM, 25% increase in NOx, 40% decrease in HC, no change in CO.
Reference: Dr. Robert McCormick et al., "Regulated Emissions from Biodiesel Tested in Heavy-Duty Engines Meeting 2004 Emission Standards," SAE 2005-01-2200. (not available on-line, but perhaps the results are in a report somewhere in the archives of NREL.gov, where McCormick works)
Another work by McCormick might be of interest, Effects of Biodiesel on Pollutant Emissions - A Clean Cities Webcast, link: http://www.eere.energy.gov/biomass/progs/searchdb2.cgi?9036
Aug 29th 2007 10:55AM Thanks for the link to my post. I'm gratified that this tip has been found so useful.
In response to RobynT's question about the bag, my theory is that the bag helps the plant retain moisture in my particular climate, which is fairly dry (San Francisco Bay Area). The holes in the bag keep it from being too moist. In a humid area like Washington, D.C. or Houston, you might not need the bag at all (unless you run the A/C all the time, which dries out the air). A potential downside of storing the basil in the refrigerator is that the very dry air in the fridge can be tough on the plant.
I tried this trick with cilantro recently. The results are so-so. The cilantro started to grow delicate, ferny leaves, like it is getting ready to bolt and go to seed. It is not putting out roots like the basil does. Overall, possibly slightly better than keeping it in the refrigerator (where it tends to get slimy).
Jul 9th 2007 6:24PM The companies that supply precious metals for catalytic converters have very active recycling and recovery programs. It must be easier to extract the platinum from a junked catalytic converter than from freshly mined ore.
A few years ago I ran across a scientific paper about levels of catalytic converter precious metals (platinum, palladium, and rhodium) in road dust. The authors found that the levels were almost high enough to be economical to recover. Since then, the price of platinum has doubled. The full paper is not available for free, but you can read the abstract here: http://pubs.acs.org/cgi-bin/abstract.cgi/esthag/2001/35/i19/abs/es001989s.html
It might make sense for streetsweepers to regularly send samples of the collected dust for precious metal measurement.
Jan 16th 2007 11:46AM Tiara wrote: "Mangosteens are banned in USA? Why?"
It's not the mangosteen itself that is the problem in the USA, but the insects, fungi, mites and other pests about which the U.S. Dept of Agriculture is concerned. The NY Times had a story a few months ago on the mangosteen, and a devoted grower in Puerto Rico who will soon be selling his crop in the U.S. It also said that Thailand would be irradiating mangosteen and exporting them to the USA.
When I have traveled to Asia, I always am sure to enjoy mangosteens.
I agree with Willy's comment: there is no "right" to eat endangered species.
Jan 1st 2007 3:13PM For more audio on Burma by Emma Larkin, the San Francisco-based World Affairs Council audio archives have an MP3 of Emma Larkin's speech. It is quite interesting and includes some Q&A with the audience. Link: http://wacsf.vportal.net/detail.cfm?fileid=3950
Nov 29th 2006 1:48PM In the United States, it is usually easy to find a buyer of catalytic converters, who will then sell them back to the catalyst manufacturer, which often has a division devoted to recovery of precious metals. Johnson-Matthey, for example, has a huge precious metals division that includes mining, refining and recycling. But I don't know how the dealers assign a price to a catalytic convertor or box of beads. Every year the car manufacturers demand lower and lower precious metal content in the catalytic converters from the catalyst suppliers, and somehow they manage to do it through improved technology (a combination catalyst technology and engine controls).
I don't know where that photo came from, but it is my understanding that catalyst beads or pellets haven't been used for many years, and that current catalytic converters are on honeycomb monoliths (of ceramic or metal).
Nov 25th 2006 12:06AM Can anyone recommend a good podcast to help with learning Spanish?
Nov 12th 2006 2:28PM I second the opinion that the Teaching Company puts out some great material, and I would consider buying more series if they were offered in MP3 format. My favorites are History of Ancient Rome, History of Science from pre-history to 1700, The U.S. and the Middle East since 1910, and Robert Greenberg's classical music lectures. The History of Asia Minor, on the other hand, was unbearable, as the lecturer provides far too many details and sounds like Dr. Marvin Monroe of The Simpsons.
Most of my collection is on cassette, which proved impractical to put on my MP3 player (it has an audio in, but too much time and effort would be needed), so they have not traveled with me on long flights.