AirNow's fire map Contains data from PurpleAir sensors (this is what the small circles represent), and Watch Duty, a non-profit app for tracking firesAlso displays PurpleAir data. But the air quality index reported by the same sensor can vary significantly from map to map, possibly due to different calculations and processing delays. Known as PM2.5 pollution, or tiny respirable particles of smoke and dust, a PurpleAir sensor located south of Los Angeles International Airport on Monday reported 28 on AirNow's website, 20 on WatchDuty and 20 on PurpleAir. Returned an air quality index of 5. Official page.
Each of those values generally indicates healthy air, but things can get more complicated when other types of data are added to the calculations. This is what companies like Breezeometer and Ambi do, in hopes of providing accurate “hyperlocal” estimates across distances of several miles between a few sensor locations.
Breezometer was founded in Israel and raised millions of dollars in venture capital funding before being acquired by Google in 2022 for more than $200 million. israeli media(Google declined to comment on the value of the deal.) It powers air quality data seen in the Weather app on Apple devices and the Google Maps app. Indian startup Ambi, meanwhile, is responsible for the air quality data in the WeatherBug app, one of the most popular weather apps in the world.
Breezeometer says Yael Maguire, vice president of geo sustainability at Google estimates air quality More data is generated than many government systems, on an hourly basis across a wide range of pollutants and locations. To make its calculations, the company uses information not only from EPA and PurpleAir sensors, but also from satellites and other sources like weather and traffic reports. According to its CEO Jaideep Singh Bachher, similar data is incorporated into Ambi's proprietary algorithms. “We want to give people the right data whenever and wherever they need it,” he says.
Volkens says he doesn't trust these systems. They say the low-cost PurpleAir sensors they use in part are not suitable for the situations where they are often deployed in the US, including wildfires. But he acknowledges that although they are weak in terms of raw numbers, these sensors can be about 90 percent accurate in determining the advisory level — that green-to-maroon scale that people often use to make decisions. Enough about how to protect their health.
PurpleAir representative Andrew White says its sensors has been found to be accurate And it doesn't control how other services run calculations using its data. Google's Maguire says the company “provides industry-leading, highly accurate air quality information,” including “even in areas with limited monitoring.”
Jennifer Richmond-Bryant, associate professor of forestry and environmental resources at North Carolina State University, who has studied the PurpleAir sensor, says the safest bet for anyone concerned about air quality is to get the highest number among different services or Have to rely on color level. “I have more confidence in the AirNow numbers because I understand them,” she says, but “making overly conservative decisions can never hurt when it comes to protecting yourself.”