from AirNow fire map includes data from PurpleAir sensors (that’s what the little circles represent), and Watch Duty, a nonprofit app to track firesalso displays PurpleAir data. But probably due to different calculations and processing delays, the air quality index reported by the same sensors can vary significantly from map to map. For so-called PM2.5 pollution, or tiny inhalable particles of smoke and dust, a PurpleAir sensor south of Los Angeles International Airport simultaneously returned an air quality index of 28 on Monday on the AirNow website, 20 on WatchDuty and 5 on the PurpleAir website. official page.
Each of these values generally indicates healthy air, but things can get more complicated when other types of data are added to the calculations. That’s exactly what companies like BreezoMeter and Ambee are doing, hoping to provide what they describe as accurate “hyperlocal” estimates across the many miles between certain sensor locations.
BreezoMeter was founded in Israel and raised tens of millions of dollars in venture capital before Google acquired it in 2022 for more than $200 million, according to Israeli media. (Google declined to comment on the value of the deal.) It powers air quality data displayed in the Weather app on Apple devices and in the Google Maps app. Indian startup Ambee, meanwhile, is responsible for air quality data in the WeatherBug app, which is among the most popular weather apps in the world.
Yael Maguire, vice president of geo-sustainability at Google, says BreezoMeter assesses air quality on an hourly basis across a wide range of pollutants and locations, generating more data than many government systems. To make its calculations, the company uses information gleaned not only from EPA and PurpleAir sensors, but also from satellites and other sources such as weather and traffic reports. Similar data is incorporated into Ambee’s proprietary algorithm, according to its CEO Jaideep Singh Bachher. “We want to provide people with the right data anytime, anywhere,” he says.
Volckens says he doesn’t trust these systems. The low-cost PurpleAir sensors they partly rely on aren’t well suited to the conditions they’re often deployed in in the United States, including during wildfires, he says. But he acknowledges that while they tend to be wrong in terms of raw numbers, these sensors can be accurate about 90 percent of the time in determining alert level — that scale from green to brown that is often enough for people to make decisions. on how to protect their health.
PurpleAir representative Andrew White talks about his sensors proved to be accurate and that it does not control how other services perform calculations using its data. Google’s Maguire says the company “provides cutting-edge, highly accurate air quality information,” including “even in areas where monitoring is limited.”
Jennifer Richmond-Bryant, an associate professor of forestry and environmental resources at North Carolina State University who has studied the PurpleAir sensors, says the safest bet for anyone concerned about air quality is to trust the highest color number or level across different services. “I have more confidence in AirNow’s numbers because I understand them,” she says. But “it can never hurt to make a decision that is too conservative when it comes to protecting yourself.”
