PARIS (AFP) — More than 2.7 billion people worldwide, including 767 million children, were exposed to second-hand smoke in 2023, contributing to nearly 1.7-million deaths, according to a study published Tuesday in The Lancet.

“Exposure to second-hand smoke is a globally recognized health risk, with no safe level of inhalation,” the study said.

Researchers reviewed studies and population surveys covering 204 countries and territories from 1990 to 2023.

Second-hand smoke exposure was estimated to have caused 1.66 million premature deaths in 2023, with ischemic heart disease among the leading health effects.

Among children ages 0 to 14, exposure was estimated to have caused 5.2 million respiratory tract infections.

“The sidestream component, which dominates the air non-smokers breathe, is unfiltered... carrying higher per-unit concentrations of the toxic and carcinogenic compounds” than smoke inhaled by active smokers, the study said.

Despite declines in global smoking prevalence since 1990, the number of people exposed to second-hand smoke has remained relatively stable due to population growth and increased exposure in Africa and the Middle East.