Background Second-hand smoke (SHS) exposure at work is a cause of serious ill-health. Consequently, many countries have implemented smoke-free workplace laws designed to protect most workers. However, workers who work in other people’s homes (such as home-care workers, tradespeople and nannies) are not protected by these laws, as smoking is not prohibited inside private homes. Previous research has suggested that domiciliary care workers, such as nurses making home visits to patients, are particularly heavily exposed to SHS. This research project sought to quantify that exposure in the context of wider occupational exposure to SHS.

Methods Through a programme of expert assessment, we developed a job exposure matrix (JEM) for SHS exposure among all classes of worker in the UK. Three raters assessed exposure to SHS for all UK occupations by 4-digit Standard Occupational Classification (SOC), rating likelihood, intensity and frequency of exposure.

To assess the extent of exposure to SHS among home-care workers, we conducted surveys of these workers in the NHS, two local authorities and a private organisation in Scotland. We conducted personal exposure monitoring with these groups of home-care workers, assessing their exposure to SHS by monitoring fine particulate matter (PM_2.5), air nicotine and changes in salivary cotinine over the course of a shift.

Results Our JEM indicated that around ten million workers in the UK may be occupationally exposed to SHS. Overall, 84 of 412 four-digit SOC codes (20.4%) were considered likely to have at least 10% of workers experiencing some degree of non-incidental exposure to SHS during their duties. Exposure is estimated to be most severe among lower SES workers, particularly care workers. Our survey results indicated that many home-care workers are occupationally exposed to SHS. Local authority workers were more likely to be exposed than NHS workers, with 84% of council respondents reporting exposure during their work vs 15% of NHS respondents. Measurements revealed highly variable patterns of SHS exposure based on shift pattern and visit duration. Visits to smoking homes included peak PM_2.5 concentrations in excess of 400µg/m³, sixteen times the WHO guideline limit for 24h periods.

Discussion SHS exposure remains a serious health concern for a considerable fraction of the UK working population. People in lower paid jobs are disproportionately affected by SHS at work, potentially a cause of health inequality. Home-care workers can experience frequent and high SHS exposure, and new policies are necessary to protect them from associated health harms.