Abstract
BACKGROUND: The number of food delivery workers engaging in online food delivery (OFD) services has soared recently. While they are exposed to air pollutants from traffic exhaust frequently, their exposure to carbon monoxide (CO) is seldom assessed. This study aimed to assess the CO exposure of food delivery workers using exhaled air with consideration of smoking habits. METHODS: We recruited food delivery workers from OFD services and compared their CO concentrations in exhaled air with those of a reference group. In addition, we used a questionnaire to gather data on sociodemographic characteristics, health behaviors, health status, and work-related conditions. RESULTS: We enrolled 156 food delivery workers and a reference group of 49 members. The results showed that food delivery workers had a higher mean CO concentration in exhaled air (4.79 ppm vs. 1.51 ppm, p < 0.001) as well as a higher proportion of smokers (25.0% vs. 4.1%, p < 0.001). While food delivery workers with smoking habits had a much higher mean CO concentration in exhaled air than those without smoking habits (14.46 ppm vs. 1.57 ppm, p < 0.001), amongst non-smokers, the CO concentration was still higher in food delivery workers than in the reference group (1.57 ppm vs. 1.13 ppm, p = 0.002). Among smokers, smoking might contribute 89% of the CO in exhaled air. CONCLUSIONS: Food delivery workers had higher CO concentrations in exhaled air than the reference group, indicating higher exposure levels. Smoking is an important contributing factor when using exhaled air for CO exposure assessment.