Saturday, April 14, 2007

disposable or reusable revisited

Back in October I posted something about how many times you'd need to reuse a ceramic (or glass) mug to use less energy per use than drinking from a disposable cup.

There was something today on digg about the topic. Since digg can be annoying, here is the link to the cited report. This is probably where the "you'd need to use a ceramic mug a thousand times to break even" comes from -- according to professor Martin Hocking's calculations, the ceramic-foam "break even" point is 1006. A quote:

The results are extremely sensitive to the amount of energy the dishwasher requires for cleaning each cup. Hocking's choice for the dishwasher, requiring 0.18 MJ/cup-wash, is barely less than the manufacturing energy of the foam cup, 0.19 MJ/cup. If Hocking had chosen even a slightly less energy-efficient dishwasher as his standard, then the reusable cups would never have broken even with the foam cup.

The lesson of this life-cycle energy analysis is that the choice between reusable and disposable cups doesn't matter much in its overall environmental impact. One should use one's best judgement.

Bonus tidbit: earlier in the week I was in a meeting where someone who knows a lot about local health statistics opined that contrary to popular local belief, the number of emergency room visits for "asthma" don't peak during "bad air" (high ozone) days. The visits peak during high allergy days :)


Here is a page of statistics that looks ... misleading. For example, the central valley has a higher percentage of kids with asthma. OK, how much higher. The rate for the valley is 11%, the bay area 10%, the state (9%), and LA (8%). Three percent difference? Is that statistically significant? Could there be something else going on here, like, oh, family income? Access to health care? Living where there is a ton of pollen in the air? :)

Also, when you look at "all ages" and see that Fresno County is 13%, yet Kern, Tulare, and San Joaquin counties (two out of three with at least as bad air quality :) are 9%, well that makes you wonder about the data :)

I've always thought it interesting that living around cockroaches is bad for asthma.

Back to ages 0-17. As above, the central valley rate is 11%. Assignment: What's the national average for ages 0-17?

How about this (emphasis added):

In 2003, most U.S. children under 18 years of age had excellent or very good health (83%). However, 10% of children had no health insurance coverage, and 5% of children had no usual place of health care. Thirteen percent of children had ever been diagnosed with asthma. An estimated 8% of children 3-17 years of age had a learning disability, and an estimated 6% of children had ADHD.

Isn't data interesting :)