Unavoidable exposure to secondhand smoke in indoor places: a cross-sectional comparison to the Health Japan 21 (second term) objectives, 2022.

Daily unavoidable SHS exposure was disproportionately high among adolescents, less-educated individuals, and HTP users. The prevalence of unavoidable SHS exposure did not reach the national target in any of the assessed indoor places; home and workplace were the dominant sources of unavoidable SHS exposure. The lack of comprehensive smoke-free laws provides inadequate protection against SHS that cannot be complemented by individual efforts. The authorities must ensure smoke-free environments for all.