Exposure to Secondhand Smoke in Homes and Vehicles among US Youths, United States, 2011–2019.

Walton K, Gentzke AS, Murphy-Hoefer R, Kenemer B, Neff LJ.  
Exposure to Secondhand Smoke in Homes and Vehicles among US Youths, United States, 2011–2019.  
Prev Chronic Dis 2020;17:200107. DOI: http://dx.doi.org/10.5888/pcd17.200107external icon 

In this study, we report the prevalence of self-reported secondhand smoke (SHS) exposure in homes and vehicles among US middle and high school students in 2019 and changes in SHS exposure over time. Data were from 7 years of the National Youth Tobacco Survey (NYTS; 2011, 2013, and 2015–2019). In 2019, 25.3% (an estimated 6.7 million) of students reported home SHS exposure and 23.3% (6.1 million) reported vehicle SHS exposure. Home and vehicle SHS exposure significantly declined during 2011 through 2018, except for home exposure among non-Hispanic black students. Implementation of smoke-free policies in public and private settings can reduce SHS exposure. 
Results: In 2019, 25.3% (an estimated 6.7 million) of middle and high school students reported home SHS exposure, and 23.3% (6.1 million) reported vehicle SHS exposure (Table). A significant difference in home SHS exposure was observed by race/ethnicity; non-Hispanic black (28.4%; 980,000) and non-Hispanic white (27.4%; 4 million) students both had a higher prevalence than Hispanic (20.0%; 1.3 million) and non-Hispanic other (20.2%; 290,000) students (P < .001). 

For vehicles, a significant difference was observed by school level (high school: 24.9%, 3.6 million; vs middle school: 21.4%, 2.5 million; P = .01). Non-Hispanic black (26.4%; 880,000) and non-Hispanic white (26.1%; 3.8 million) students had higher prevalences of SHS exposure in vehicles than Hispanic (17.6%; 1.1 million) and non-Hispanic other (14.0%; 200,000) students (P < .001). SHS exposure in homes and vehicles was highest among students currently using combustible tobacco products (homes: 52.5%; vehicles: 56.3%), followed by noncombustible tobacco product only users (homes: 31.7%; vehicles: 34.7%) and nonusers of tobacco products (homes: 20.8%; vehicles: 17.4%) (P < .001) (Table). 

Overall, home SHS exposures declined from 26.8% in 2011 to 20.9% in 2018 (P < .001); vehicle SHS exposures declined from 30.2% in 2011 to 19.8% in 2018 (P < .001) (Figure). For all characteristics, SHS exposure in homes and vehicles significantly declined during 2011 through 2018, except for SHS exposure in homes among non-Hispanic black students, in which it did not change.