This dissertation, "A Study on Second and Third Hand Smoke Exposure and Self-protection Behaviors Among Sick School-aged Children in Guangzhou, China" by Xuan, Zhou, 周璇, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Introduction: Due to the high prevalence of smoking in China, exposure to second hand smoke (SHS) is a serious public health issue. However, school-aged children's behavioral responses to SHS exposure and the associated factors are unclear. Aims: This study aims to (a) identify the sources and settings of SHS exposure among school-aged sick children and their mothers in Guangzhou, China; (b) describe the behavioral responses of those children and mothers when exposed to SHS; and (c) examine the personal and environmental factors associated with children's responses to SHS exposure. Methods: Qualitative and quantitative methods were combined in this study. Forty-five in-depth individual interviews were conducted to investigate sick school-aged children and their mothers' understanding of and responses to SHS. A pilot survey was used to assess the validity and reliability of the questionnaire and the feasibility of the study. A cross-sectional survey was conducted with the children and their mothers at three hospitals in Guangzhou in 2012. All sick children who were aged 6 to 12 years, able to communicate in Mandarin Chinese, and not acutely or severely ill, along with their nonsmoking mothers, were invited to join this study. Results: A total of 339 pairs of sick children and their mothers were included in the data analysis. Of these pairs, 169 (49.9%) lived with smokers. All sick children and their mothers experienced high-level SHS and third hand smoke (THS) exposure inside or outside the home. Those living with nonsmokers were also at risk of household SHS and THS exposure from guests. Most of the sick school-aged children were unaware of the dangers of SHS and THS, while the mothers had a better understanding of SHS and THS. The majority of children would adopt self-protective behaviors when exposed to SHS. The regression model for children's behavioral responses to SHS exposure by family smokers found two significant factors: amount of social support and family smoke-free policy. Five factors were associated with children's behavioral responses to SHS exposure by guest smokers, including boys, living with smokers, amount of social support, family members informed of the dangers of smoking, and fathers protecting children from SHS. The amount of social support, and fathers protecting children from SHS were also associated with children's behavioral responses to SHS exposure by stranger smokers. Conclusions: To our knowledge, this is the first study to describe self-protective behavioral responses to SHS exposure among sick school-aged children in mainland China and the personal and environmental factors associated with these responses. Boys, living with smokers, and a partial smoke-free policy at home were negatively related to children's responses to SHS exposure; however, more information about smoking, fathers' protection from SHS, and information about the harms of smoking by family members were associated with greater self-protection among sick school-aged children. Therefore, multiple-direction interventions should be considered for children's health promotion about smoking and SHS. DOI: 10.5353/th_b5053423 Subjects: Passive smoking - Health aspects - China - Guangzhou School children - China - Guangzhou - Health and hygiene