Urban air pollution and time losses: Evidence from cyclists in London
研究臭氧污染对伦敦骑行者速度的影响，发现臭氧浓度超过20 ppb时骑行速度下降，每增加10 ppb速度降低0.3-0.4%，提示空气污染可能对户外活动造成时间损失。
We provide novel evidence of the immediate impact of air pollution on time delays in urban outdoor activities. We focus on ambient ozone, which is known to reduce lung capacity. We estimate its effect on cycling speed in London using several estimation strategies, and find that ozone reduces speed for concentrations above 20 ppb, which is far below the minimum threshold suggested by other studies. A 10 ppb increase in ozone concentration leads to a 0.3–0.4% reduction in cycling speed, despite that most cycling trips are short, so that exposure to ozone tends to be short. It seems plausible that ozone induces time losses of similar magnitude of other outdoor activities, such as walking.