Individual Daily Exposure To Black Carbon In Shanghai, China

Abstract

Background and Aims: The vast majority of personal exposure to Black Carbon (BC) studies has taken place in developed countries. However, the population activity patterns in China are completely different from those in Western countries. We aimed to identify the activities and microenvironments that make the greatest concentration to individual daily exposure dose in Shanghai, China. Method: We recruited 51 graduate students in a university located in Shanghai, from December 2014 to March 2015. Personal BC was measured using aethalometers every 5 minutes. The Nork software was installed on a small handheld computer, to fill in executed activities and trips (such as studying, eating, transportation, sleeping etc.) and where time is spent each day. The accuracy of Nork software was also checked by consulting the GPS logs. The inhaled dose received by volunteers was determined for each microenvironment/activity. “Exposure (dose) intensity”, which is defined as the ratio of the daily exposure dose fraction to the daily time fraction, was calculated for each activity. Results: Overall mean BC exposure concentration was 5.3 ug/m3. High daily inhaled doses were also observed and were equal to 40.6 ug/day. An in-depth analysis of the exposure/dose experienced by participant revealed that indoor during general activity time made significant contributions to the students' daily dose, due to the time exposured to indoor was substantially longer than that of Western countries. Eating accounted for a lowest contribution of BC exposure. In particular, outdoor activities presented the highest BC dose intensity. Conclusion: Our study generated the prospective evidence that the microenvironment /activity contribution to BC personal exposure in China is very different from Western countries. These data contribute to the scientific literature on effects of air pollution for high exposure settings.