Sensing a Planet in Crisis

Abstract

Wildfires in California contributed to some of the worst air quality in the world during late 2018. The fires were considered to be among the most extreme in California's history and were attributed in part to changes in climate and land use. In the process of burning hundreds of thousands of acres of land, the fires created pollution that led to an air quality emergency. At one point, during mid-November 2018, the media widely reported that cities including San Francisco, Sacramento, and Stockton had higher levels of pollution than Delhi or Beijing (Azad 2018). While varying data sources were referenced to support these claims, the most common source reported was from the PurpleAir sensor map and platform, which produced an animation to demonstrate the elevated levels of particulate matter in California (figure 1) (Jeung 2018). With a worldwide network of around two thousand sensors and growing, PurpleAir provides air quality measurements in locations that might be remote or lacking in air quality infrastructure. What is notable about this network is that it is not the product of governmental intervention but rather is driven by individuals and community groups seeking to monitor environmental pollution.