I haven’t seen snow for three years and had forgotten what 35 degree weather is like. Over the last 4 days, I ate at three different Legal Seafoods in Boston and lost 10 pounds. While the last statement is false, I did have a great time in Boston. The Cambridge area is a serious cluster of economic talent and it was great to see my old friends and co-authors (5 of them) who all attended the National Bureau of Economic Research's environmental economics meetings. These meetings were bundled with a 1.5 day session on agricultural economics. UC Berkeley's Agricultural and Resource Economics was well represented at this conference. I had never talked research with David Zilberman before and had a great time learning agricultural economics from him. Everyone knows that I love to talk and over these four days, I sat down and talked and talked to over 30 star economists who ranged in age from 25to 75. I’m willing to talk to anybody who will teach me about economics and answer my strange questions!
What research did I see? The future of agricultural economics and environmental economics is bright but let me just talk about one paper by two young Columbia stars. Now, I had thought that when I left Columbia in 2000 that no more research would emerge from that liberal arts school but I was wrong. Here is a salient counter-example offered by Reed Walker and Wolfram Schlenker .
What are the health impacts from exposure to air pollution? This is a deceptively hard causal question. In a world without human subject’s protection, I would take my current Ph.D. students and randomly choose a subset (Neil?) to be exposed to some air pollution and then track his later health outcomes. Assuming that my graduate students are randomly sampled from the greater population (and this may be true), this experimental design (while nasty) would help to answer the question of how the average person’s health is affected by short term exposure to air pollution. Given that I can’t run such an experiment, how do we go about measuring the causal impact of pollution on health? We can wait for volcanoes to explode or the 4 year Olympic cycle which stops traffic and shuts down dirty factories near the athletic Olympic Village, but Reed and Wolfram have a better design.
Here is their logic; Step #1: Airports are major urban polluters, 2. Airports produce more emissions when plans “taxi” for long periods of time; just running their engines getting from the gate and stop and go before getting to the runway. 3. The taxi period is longer when there is bad weather and delays on the east coast. 4. So, random delays on the East Coast raise taxi times at California Air ports which yields exogenous air pollution variation within a 5 mile radius around the airports, 5. This increase at random times in nox and carbon monoxide yields variation for testing the health impacts. To measure health impacts, they examine hospital admissions for people over age 65 on Medicare. They observe Emergency Room admissions per 100,000 by zipcode/year. While this work is still in a preliminary stage, the current results indicate that unexpected carbon monoxide blasts do cause health impacts. Since the exposed population cannot anticipate these elevated levels, they cannot take defensive actions to self protect. So, this study is a very nice contribution to the public health literature.
Another economist at Columbia named Matt Neidell has devoted effort to documenting that when people are given information about elevated pollution levels (Smog Alerts) that they do preempt and take costly self protection actions (such as not going to the Zoo) that reduces their ambient pollution exposure.
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