Preliminary Study Using Sensor Measurements in Selected Homes in Cornwall, England, over a One-Year Period Confirms Increased Indoor Exposure from Second-Hand Smoking but Not from Second-Hand Vaping

Introduction: Increased exposure to air pollution poses a burden to society and healthcare systems worldwide, with increased risk of morbidity and mortality. Indoor concentrations of air pollutants, such as particulate matter, are a public health concern because they can be present in higher concentrations than outside. Unlike the effects of indoor environmental tobacco smoke (ETS), there is a dearth of research that includes the impact of e-cigarettes on particulate matter concentrations in the home, which is the focus of this study. Method: Participant, household, and sensor information were obtained from 164 lower-income households located in Cornwall, South West of England. Daily sensor readings were obtained for PM2.5 for one year. Descriptive statistics were used to describe study participant characteristics and health status. Mean indoor averages, median PM2.5 measurements, and two-tailed tests were used to assess differences in concentrations of PM2.5. Results: The 164 surveyed households included 315 residents (67% female) with a mean adult age of 57 (22–92). Half of all homes were in the 10% most deprived neighbourhoods in England. Thirty-four per cent of participants were current smokers, and of these 36% have asthma and had seen a doctor in the last year (cf. never smokers 14%, ex-smokers 25%). Mean annual PM2.5 was highest in smoking households (14.07 µg/m3) and smoking and vaping households (9.18 µg/m3), and lower in exclusive vaping households (2.00 µg/m3) and smoke and vape-free households (1.28 µg/m3). Monthly levels of PM2.5 fluctuated seasonally for all groups, with the highest recordings in winter and the lowest in summer. Discussion and Conclusion: In this preliminary study, we conducted secondary data analyses using monitoring data from a large health and housing study to assess factors leading to elevated indoor concentrations of particulate matter. Indoor concentrations appeared to be highest in homes where residents smoked indoors. The use of e-cigarettes in the home also appeared to modify concentrations of particulate matter, but levels were lower than in homes with tobacco smoke. We were not able to determine the relationship between smoking and/or vaping indoors and particulate matter, which supports the need for studies of larger sample sizes and more complex longitudinal monitoring. This will help assess the timing and extent of exposures resulting from smoking and vaping indoors, along with a range of other chemical and biological exposures and their corresponding health effects.