Background

To date, 69 cities or counties within California have adopted ordinances to ban single-use plastic bags¹ with Los Angeles City’s upcoming implementation to bring the total affected to 25% of the state population². Ban proponents have emphasized the negative environmental and economic impacts of plastic bags, noting that volunteer recycling efforts recover less than 5% of the produced material^3,4,5. The plastics industry and pro-plastic affiliates have responded that recycling rates are rising, and that bans exacerbate environmental and economic impacts by increasing paper bag usage (i.e., problem shifting)^6,7,8. Meanwhile, few comprehensive studies have quantitatively assessed: (1) the effectiveness of bag bans in eliminating plastic bags, (2) pre- and post-ban trends in carryout bag choice, (3) potential problem shifting to paper bags, and (4) the effects of age and gender on bag selection. Such data are needed for municipalities to make informed decisions about implementing ban ordinances and are critical to the success or failure of future bans at all levels of government.

Summary

We conducted a 19-month study over two years to examine the effects of the City of Santa Monica’s plastic bag ban (implemented September 1, 2011 with a ten cent fee per paper bag) on consumer bag choice. Spanning ten months prior to the bag ban and 12 months after, we observed a total of 50,400 grocery store patrons exiting five Santa Monica grocery stores to visually estimate their age, gender, and carryout bag type (plastic, reusable, paper, or no bag). We performed separate analyses for both “eco-friendly” stores (Whole Foods and Trader Joes), which used few if any plastic bags prior to the ban, and “regular” stores, which used primarily plastic bags prior to the ban. The results show that at regular grocery stores, mean plastic bag usage went from 69% pre-ban to 0% post-ban, with reusable, paper, and no bag usage increasing from 10%, 5%, and 15% pre-ban to 41%, 23%, and 36% post-ban, respectively. At eco-friendly grocery stores, the ban not only eliminated plastic bags and increased reusable and no bag options, paper bag usage dropped by 23%. Our results also indicate the oldest age group was that most inclined to use plastic bags pre-ban and reusable bags post-ban, while the youngest patrons used more paper bags and no bags. Furthermore, at both eco-friendly and regular stores, a higher percentage of females used reusable bags than males, while males were inclined to use more paper bags or no bag than females.

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