Private Pollution Monitors: Gimmick or Game Changer?

State and federal government agencies have traditionally been the primary source of air quality data, but the high cost of monitoring has limited the scope of publicly available information. In the United States there are fewer than 1,000 regulatory-grade compliance monitors measuring PM2.5—the very small particles that pose significant health risks.

There can be big differences in the levels of pernicious local pollutants like PM2.5 over short distances, so the sparseness of this monitoring network really matters for anyone looking to understand or limit their exposure. Recently, though, low-cost, consumer-grade sensors from companies like PurpleAir have started to fill some big information gaps.

Here in California, private citizens have deployed more than three times as many air pollution sensors as the government agencies charged with monitoring our air quality. Although the technology is not as reliable as regulatory-grade monitors, our colleagues at the Lawrence Berkeley National Laboratory have found that it works surprisingly well. And once connected to Wi-Fi, privately owned PurpleAir devices link up with a global network that displays their data on a map in real time for all to see. This crowdsourcing of air quality information marks an important shift away from the status quo and opens the door for citizen scientists who want to know more about the air they breathe.

During the Camp Fire in November 2018, Northern California was clouded with smoke for over a week. Outdoor particulate concentrations reached dangerous levels. Using real-time feedback from our PurpleAir monitor, my family and I started experimenting with adaptation. This little sensor made invisible air pollution visible to us, and we were able to identify and make adjustments—like replacing our furnace filters and constantly running the fan—that measurably improved our indoor air quality.

A 2017 California law, AB 617, mandates that community-level air monitoring be put in place by mid-2019 to improve conditions in communities that are disproportionately affected by outdoor air pollution. To keep implementation costs manageable, low-cost sensors will likely play an important role. These monitors aren’t a perfect substitute for regulatory-grade ones, but they could be important complements. If well-crafted policy implementation and community mobilization can catch up with innovations in sensor technology, these cool gadgets could become a real game changer.