Reported PM₁₀ Concentrations Before and After Automation
Note: This figure illustrates changes in reported PM₁₀ concentration before and after automation. Monitoring station fixed effects, month fixed effects, and weather conditions are absorbed before plotting the figure.
Less than a decade ago, China suffered from a bleak challenge: Not only was air pollution a recognized problem, but many didn’t trust the data being reported by local officials. The central government knew it needed to improve air quality, but that it would be impossible without knowing true pollution levels. The challenge was that local officials often prioritized economic growth and so had strong incentives to manipulate air pollution concentrations before reporting them to the central government.
So, the central government turned to technology. On the heels of declaring a “war on pollution,” the government installed an automatic pollution monitoring system throughout the country that collects pollution data from local stations, releases the data in real-time to the public, and critically is very difficult to tamper with. Results from a new study show that the increased transparency and improved data quality rooted out manipulation and led people to better protect themselves.
Comparing pollution data from before and after the installation of the technology, the researchers found that the installation of automatic monitors significantly improved the quality of pollution data being reported. They discovered that reported particulate pollution concentrations increased by 37 percent immediately after the technology was installed, though satellite measurements indicated no change in true air quality before and after the installation. This suggests air pollution concentrations were being underreported by local government officials. The degree of underreporting was greater in heavily polluted and lower income cities.
When the reliable information on pollution was released, people appeared to respond by taking greater measures to protect themselves. Specifically, online searches for masks—a strong correlator for purchasing behaviors—increased by as much as 300 percent after the monitors were installed. Searches for air filters increased by around 20 percent. The implication is that the manipulated data led people to have a false sense of security and insufficiently protect themselves from air pollution’s dangers. This finding underscores the human costs of inaccurate data, as well as the central role that people play in protecting themselves from air pollution.