Avoidance behavior against air pollution: evidence from online search indices for anti-PM<inf>2.5</inf> masks and air filters in Chinese cities

Abstract

This study investigates people’s behavioral responses to air pollution information in China. We find that elevated air pollution levels are positively associated with higher online searches for anti-PM2.5 masks and air filters. A 10 µg/m3 increase in PM2.5 is associated with a 3.6–8.4% increase of mobile queries for anti-PM2.5 masks, and 1.1–4.7% for air filters. Using a regression discontinuity design, we find that a haze alert issued when PM2.5 concentration exceeds 250 µg/m3 would double online queries for anti-PM2.5 masks and air filters. Online searches are also positively correlated with online sales. One day of severe pollution would induce a cost of 0.2 million USD on online expenditure on anti-PM2.5 masks. Some suggestive evidence shows that people in richer and polluted cities tend to search more for anti-PM2.5 masks and air filters than those in poorer and cleaner cities.