Both biodiesel and veggy-oil have the virtue of repurposing existing carbon in the biosphere (taking growing plant matter which took carbon from the air, and returning it to the atmosphere by burning) whereas petroleum uses carbon which was sequestered from the atmosphere millions of years ago and adds it to the existing burden.

Ah. So, in a manner it's recycling pollution, not creating new.

In cat-related news, The world's oldest LOLCat. From 1905.

Depends on how you define pollution. Nitrogen Oxide (NOx) emissions are a problem with biodiesel and diesel in general. NOx is a major cause of smog, so it's a problem. Diesel engine technology keeps improving the pollution problem, but yeah, gas engines are cleaner in that respect.

I hope your MiL recovers well Cash.

~ma to your MiL and family, Cash.

Speaking of new diesel cars: A High-Mileage Masterpiece

But like many new clean diesels, which meet even California’s tough emissions rules, the Jetta scoffs at its sticker. Hoarding fuel like a mobile Scrooge, I averaged a remarkable 48 m.p.g. over more than 150 miles of freeway driving. That’s the best mileage of any American-market car I’ve tested — gas, diesel or hybrid. I never knew that driving a steady 60 m.p.h. could be so gratifying, and I vowed to try it more often.

...

Among a wave of diesel cars and trucks — whose advanced emissions systems let them meet pollution rules in all 50 states -- the Jetta is the people’s choice, costing half as much as diesels from Audi, BMW and Mercedes-Benz. The VW is also the current champion of diesel economy. And its 4-cylinder engine achieves impressively low emissions without the need to carry several gallons of liquid urea, which helps to cleanse the emissions of larger diesel cars and S.U.V.’s.

Health-ma to your MIL, Cashmere.

~ma for your MiL, Cash.

Health~ma for your MIL, Cash.