Environmental Policy Behavioral Spillovers : The Impact of California's Single-Use Bag Ban on the Use of Unregulated Single-Use Plastics

Spillover occurs when an intended behavior change causes other unintended behavior changes. Single-use bag bans, a consumption-based environmental intervention, are designed to reduce the use of disposable plastic bags and, in turn, decrease plastic pollutants in the environment. This paper examines the spillover effect of the bag ban and whether the intervention serves as an environmental behavior-changing measure by spilling over into the use of similar but unregulated single-use plastics (SUPs). Using California counties under the intervention with the implementation of a statewide bag ban in 2016, we found decreased sales of unregulated single-use plastics. The sales of single-use plastic significantly decreased by 9.0% in the second post year following the ban, compared to counties in the control group. However, further analysis indicates that when the impact of a general sales decline was accounted for, the sales drop in the same year was only marginally significant at 10%. Overall, the results show relatively weak evidence of environmental policy interventions causing behavioral spillover effects, which reflects the increasing number of regulations adopted on disposable products across regions