How Do People Perceive Air Quality in Different Geographic Contexts? A Case Study of Hong Kong, China

Perception of air pollution is subjective and context-dependent. Previous studies exploring the association between measured air pollution and perceived air quality mainly focused on air pollution levels measured in the residence-based (RB) or regional context, overlooking the mobility-based (MB) context in which people are exposed to air pollution. This study measures air pollution levels in MB, RB, and regional contexts and examines their relationships with perceived air quality across different neighborhoods and gender sub-groups of Hong Kong, China to investigate how people perceive air quality. The results indicate that particulate matter 2.5 (PM_2.5) measured in RB and the regional context significantly contributes to people’s perceived air quality compared to MB PM_2.5. Individuals in Central and Western district of Hong Kong rely on RB, regional and MB PM_2.5 to assess air pollution. In Sham Shui Po, RB PM_2.5 exhibits the highest influence on people’s perceived air quality, followed by regional PM_2.5. Women’s perceived air quality is strongly related to their RB PM_2.5 exposure, while men’s perceived air quality is associated with both RB PM_2.5 and regional PM_2.5 levels. We conclude that neighborhood effects and mobility levels are the two most important factors influencing the association between measured air pollution and perceived air quality. We reveal that the neighborhood effect averaging problem (NEAP) influences the association between perceived air quality and measured air pollution levels in a way that differs from health outcome-related studies. Effective measures are needed to improve the public’s awareness of air pollution, and scientific control should be implemented to reduce public exposure.