Personal Vehicle Secondhand Smoke Exposure for Various Ventilation Modes

Abstract

Objectives: In this study we measured secondhand smoke (SHS) particulate concentrations under a variety of driving conditions to document exposure levels in a smoking-permitted vehicle.

Methods: We conducted 46 unique trials for each of 3 vehicle types, including 2 driving speeds, 4 window positions, and multiple ventilation configurations. The monitoring included continuous photometer measurements of fine particles (PM2.5) while a participant smoked one cigarette and drove until the SHS dissipated.

Results: For trials with windows closed, the 30-second peak PM2.5 concentration ranged from 359 to 5612 with an average of 2013 μg/m3. After smoking stopped, it took between 4 and 25 minutes for the particulate level to decrease to the background level. The average SHS exposure was roughly equal to sitting in a typical smoky bar for 3 hours. Opening windows just 2 inches reduced exposure by almost a factor of 10 and fully opening at least one window reduced exposure by a factor of 34.

Conclusions: The measurements highlight the importance of regulations to protect passengers from high SHS exposure that often occurs in vehicles. Only 8 US states have policies prohibiting smoking with youth in vehicles.