Remote sensing of PM2.5 exposure and change in air pollution-related awareness measured by Google Trends in Asian megacities

In recent years, air pollution mitigation policies have become stricter, but air pollution is still worsening in many areas. From this example, we hypothesize that public awareness of air pollution is a more important factor in mitigating air pollution than the strictness of air pollution mitigation policies. This study analyzed air pollution levels and public awareness of air pollution in Southeast and South Asia, where air pollution is severe, by comparing changes over time. Regarding air pollution levels, time-series data on PM2.5 pollution levels, which are the most harmful to the human body, were generated from MODIS products. As for the public awareness of air pollution, we obtained time-series data on the popularity of a search query meaning air pollution from GoogleTrends. These two time-series data were decomposed into seasonal, trend, and residual components by STL decomposition, and compared. As a result, it was found that time-series data on public awareness of air pollution is broadly classified into two patterns. The first is a consistently increasing pattern and the second is a temporary decline pattern. The U-shaped temporary decline in environmental awareness suggests the influence of new Google users. However, in many areas, the increase in public awareness of air pollution did not lead to an improvement in air pollution levels, and research on the relationship between mitigation policies and air pollution levels is warranted.