Regulation of goods associated with negative environmental externalities may decrease consumption of the targeted product, but may be ineffective at reducing the externality itself if close substitutes are left unregulated. We find evidence that plastic bag bans, the most common disposable bag regulation in the U.S., led retailers to circumvent the regulation by providing free thicker plastic bags, which are not covered by the ban. In contrast, a regulation change that replaced the ban with a small tax on all disposable bags generated large decreases in disposable bag use and overall environmental costs. Our results suggest that narrowly defined regulations (such as plastic bag bans) may be less effective than policies that target a more comprehensive set of products, even in the case when the policy instrument itself (a tax rather than a ban) is not as strict.

中文翻译：

---

跳过袋子：一次性袋子监管的有意和无意后果

对与负面环境外部性相关的商品进行监管可能会减少目标产品的消费，但如果对相近的替代品不予监管，则可能无法有效减少外部性本身。我们发现证据表明，塑料袋禁令是美国最常见的一次性塑料袋法规，导致零售商通过免费提供该禁令未涵盖的较厚塑料袋来规避该法规。相比之下，一项以对所有一次性袋子征收小额税来取代禁令的监管变化导致一次性袋子的使用和整体环境成本大幅下降。我们的结果表明，狭义的法规（例如塑料袋禁令）可能不如针对更全面的产品的政策有效，