Effects of AIR pollution on cardiopuLmonary disEaSe in urban and peri-urban reSidents in Beijing: protocol for the AIRLESS study

Abstract. Beijing, as a representative megacity in China, is experiencing some of the most severe air pollution in the world, and its fast urbanization has led to a substantial urban and peri-urban disparities in both health status and air quality. Uncertainties remain regarding the possible causal links between individual air pollutants and health outcomes, with spatial comparative investigations of these links lacking, particularly in developing megacities. In light of this challenge, Effects of AIR pollution on cardiopuLmonary disEaSe in urban and peri-urban reSidents in Beijing (AIRLESS) was initiated with the aim of addressing the complex issue of multipollutant exposures on cardiopulmonary outcomes. The two panel studies deployed included urban and peri-urban elderly Beijing residents recruited from two established cohorts. The project was strengthened further through the measurement of an extensive range of ambient and indoor pollutants during two intensive monitoring campaigns undertaken simultaneously with the collection of health data from the panel participants. This paper presents the novel elements and methodology deployed in the AIRLESS project that addressed gaps in current understanding: namely (1) contrast of the exposure to air pollution in peri-urban and urban areas in a developing megacity, (2) a nested case (hypertensive) – control (healthy) study design to identify potential susceptible population, (3) the detailed assessments of personal exposure to air pollution in diverse indoor and outdoor environments using miniaturised portable platforms; (4) detailed assessment of the chemical composition of particulate matter; and (5) a rich collection of biological markers to understand the underlying mechanisms of health responses to air pollution.