摘要：Objectives. This study assessed progress in achieving clean indoor air in California. Methods. Data were from large, cross-sectional population-based surveys (1990–1999). Results. Indoor workers reporting smoke-free workplaces increased from 35.0% (95% confidence interval [CI] = 33.7, 36.3) in 1990 to 93.4% (95% CI = 92.6, 94.2) in 1999. Exposure of nonsmoking indoor workers to secondhand tobacco smoke decreased from 29.0% (95% CI = 27.2, 30.8) to 15.6% (95% CI = 14.1, 17.1). Adults with smoke-free homes increased from 37.6 % (95% CI = 35.1, 40.1) in 1992 to 73.7% (95% CI = 73.2, 74.2) in 1999; nearly half of smokers in 1999 had smoke-free homes. In 1999, 82.2% (95% CI = 81.5, 82.9) of children and adolescents (0–17 years) had smoke-free homes, up from 38.0% (95% CI = 35.1, 40.9) in 1992. Conclusions. California's advances highlight an important opportunity for tobacco control. The health hazards of secondhand smoke to nonsmokers were first recognized in the 1972 US surgeon general's report. 1 Following numerous population and laboratory investigations, the 1986 surgeon general's report reviewed all of the accumulated evidence and confirmed the health threat. 2 Ordinances restricting smoking in public places, including the workplace, became increasingly common. 3 Advocacy for clean air came largely from private organizations such as Americans for Nonsmokers' Rights. The first comprehensive state governmental tobacco control program was initiated in California in 1988, funded by the $0.25 per pack excise tax increase passed by voters as Proposition 99. 4 This program was based on accumulated knowledge concerning the most effective tobacco use prevention strategies documented to date, as eventually outlined by the National Cancer Institute. 5 Although the importance of clean indoor air was recognized, smoking restrictions in public places, including worksites, were mainly viewed as a means for promoting smoking cessation and for establishing societal antismoking norms. Worksites were seen as a venue for delivery of smoking cessation assistance, and smoking restrictions were promoted as economically beneficial to the employer. 5 Another early study suggested that smoke-free workplaces and college settings might interrupt smoking initiation. 6 Initially, the California Tobacco Control Program did not include nonsmokers among its “target populations” for whom it established goals. 7 Prompted by the release in 1992 of the US Environmental Protection Agency report on the dangers of secondhand smoke, 8 protection of nonsmokers from secondhand smoke in the workplace became a program goal. 9 A further review published in 1995 by the California Environmental Protection Agency 10 and later more widely circulated as a National Cancer Institute monograph 11 implicated secondhand smoke not only as a cause of cancer but also as a cause of heart disease and as a contributing cause of respiratory and auricular morbidity in young children. In 1997, clean indoor air in the workplace and for children at school and in the home were touted as program accomplishments, and protection of all nonsmokers from secondhand smoke became a clearly articulated program goal. 12 The first statewide law (Assembly Bill 13) mandating clean air in indoor workplaces was enacted in California in 1994; however, application of this law to gaming clubs, bars and taverns, and bar areas of restaurants was delayed until January 1, 1998. Compliance with this law may be problematic in some settings, so monitoring exposure of nonsmokers to secondhand smoke in the workplace is important. Whereas smoke-free workplaces are now mandated by law in California, smoking restrictions in the home are by agreement among household members. National data indicate that smokers who have smoke-free workplaces are more likely to live in smoke-free homes. 13 Workplace smoking restrictions may help establish norms against smoking around nonsmokers and make people more aware of the dangers of secondhand smoke. Having a smoke-free home is the most effective step parents can take to reduce their children's exposure to secondhand smoke. 14 A recent study indicated that protection of adolescents with smoking parents occurred in smoke-free homes but not in homes with lesser or no restrictions. 15 In this article, we present trends from large population-based surveys of Californians, conducted in 1990, 1992, 1993, 1996, and 1999, indicating that the California Tobacco Control Program has been highly successful in its goal of promoting clean indoor air both in the workplace and in the home.
