Fine and ultrafine particles concentrations in vape shops

Abstract

Vape shops are widespread due to the popularity of electronic cigarettes (e-cigs) as an alternative to tobacco cigarettes. In this study, sixty-seven Southern California vape shops were randomly surveyed for building characteristics, ventilation, and business patterns. Based on the survey results, six representative shops were recruited for real-time measurements of indoor and outdoor fine and ultrafine particles concentrations on a busy and less busy day. Occupancy, vaping frequency, and opening and closing of doors were recorded, and shop air exchange rate was determined. Indoor CO2, relative humidity, and temperature were also recorded. In addition, simultaneous measurements were taken at increasing distances away from a vaping area to assess the mixing and spatial profiles of particle levels inside the shops. During active vaping, real-time indoor particle number concentration and gravimetric-corrected PM2.5 mass concentration across the six vape shops varied from 1.3 × 104 to 4.8 × 105 particles/cm3 and from 15.5 to 37,500 μg/m3, respectively. The spatial profiles of particle number and mass were more uniformly mixed than expected in an indoor environment. Total vaping frequency was the main predictor of particle concentrations inside the vape shops when indoor-outdoor particle mass transfer is minimal (doors closed).