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Certifying Smoke-Free Used Cars

Institution: San Diego State University Research Foundation
Investigator(s): Georg Matt, Ph.D.
Award Cycle: 2012 (Cycle 21) Grant #: 21RT-0142 Award: $686,734
Subject Area: Industry Influence/Policy
Award Type: Research Project Awards

Initial Award Abstract


This study will investigate the effects of certifying used cars as smoke-free on their value and the attitudes and behaviors of buyers and sellers in the private used car market. Specifically, this study aims to (1) promote the benefits of smoke-free cars and offer a smoke-free certification service via advertisements on the Autotrader, Craigslist, and San Diego Reader websites; (2) provide sellers or buyers with a written smoke-free certificate based on environmental samples collected in their cars; (3) examine the impact of smoke-free certification on car advertisements, asking and purchase prices, and decisions to purchase.


Smoking cigarettes in the small, enclosed space of a car cabin can lead to high levels of secondhand smoke (SHS) exposure. Because cars provide relatively large surface areas with materials that may absorb and trap tobacco smoke pollutants, car interiors are particularly susceptible to become reservoirs of tobacco smoke residue, also known as thirdhand smoke (THS). Our previous research has shown that 22% of used cars for sale in San Diego County were sold by smokers or had been smoked in, and used cars of smokers were offered for 7-9% less than comparable nonsmoker cars. This difference emerged in the absence of a formal recognition of tobacco use in valuation models or an objective assessment of THS in cars. Given existing consumer preferences for smoke-free environments, this study aims to help consumers make more informed decisions to increase the value of smoke-free cars, create incentives for establishing smoking bans and keeping cars smoke-free, and to contribute to the denormalization of tobacco use.


Advertisements for a smoke-free certification service will be placed online over a 24-month period. The advertisements will draw attention to consumer preferences for smoke-free cars and to concerns about smoke-polluted cars. Private sellers and buyers interested in a smoke-free certification will be invited to participate in a research study, and an appointment will be scheduled to collect environmental samples from cars and to interview the seller. Surface wipe samples will be analyzed using LCMS/MS analytic methods developed and validated by us in previous research. A smoke-free certificate will be issued within one week of sampling, indicating whether THS pollutants were within the range established in private used cars of nonsmokers with smoking bans (Matt et al., 2008). Print and online used car advertisements will be content-analyzed before, during, and after the smoke-free certification service is offered to determine whether frequency and content of references to tobacco use or smoke-free certifications have changed. Personal interviews with sellers and buyers will be conducted to investigate the relative importance of different factors influencing purchasing decisions and purchase or asking price.


We expect that sellers will use smoke-free certificates to advertise that a car is free of tobacco pollutants, set higher asking prices, and achieve a higher sales price than an equivalent car without smoke-free certification. We expect that buyers will use a smoke-free certificate to purchase smoke-free rather than smoke-polluted cars. We expect that this study will contribute to making tobacco-use an explicit part of the valuation of a used vehicle. This will make more explicit the long-term costs of tobacco use, create an incentive to keep a vehicle tobacco-free, and decrease smoking behavior in cars. In combination this will reduce SHS and THS exposure. If successful, this certification model could be transferred to other private and semi-private settings, where existing public policies currently do not apply (e.g., rental cars, hotels, real estate, multi-unit housing), contributing to the denormalization of tobacco use and protecting nonsmokers from exposure to the toxic effects of tobacco smoke and tobacco smoke residue.