Why is it so confusing to determine the air quality in Los Angeles right now

AirNow’s fire map includes data from PurpleAir sensors (that’s what the small circles represent), and Watch Duty, a non-profit fire tracking appalso shows PurpleAir data. But probably due to different calculations and processing delays, the air quality index reported by the same sensors can vary greatly from map to map. For what is known as PM2.5 pollution, or tiny inhalable particles of smoke and dust, a PurpleAir sensor located south of Los Angeles International Airport simultaneously returned on Monday an air quality index air of 28 on the AirNow site, 20 on WatchDuty and 5 on PurpleAir. 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. That’s exactly what companies like BreezoMeter and Ambee are doing in hopes of providing what they describe as accurate “hyperlocal” estimates in the many miles between certain sensor locations.

BreezoMeter was founded in Israel and raised tens of millions of dollars in venture capital funding before Google acquired it in 2022 for more than $200 million, according to the The Israeli media. (Google declined to comment on the value of the deal.) You can view air quality data in the Weather app on Apple devices and 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 estimate air quality every hour on a wide range of pollutants and locations, generating more data than many government systems. To make its calculations, the company uses information collected not only from EPA and PurpleAir sensors, but also satellites and other sources, such as weather and traffic reports. Similar data is incorporated into Ambee’s own algorithm, according to its CEO, Jaideep Singh Bachher. “We want to give people the right data when, where they need it,” he says.

Volckens says he doesn’t trust these systems. The low-cost PurpleAir sensors they rely on are not well-suited to the conditions where they are often deployed in the United States, including during wildfires, he says. But recognize that while they tend to be off in terms of raw numbers, these sensors can be accurate about 90 percent of the time in determining the advisory level — that green to brown scale that is often enough for people to take decisions. how to protect their health.

Andrew White, a representative of PurpleAir, says that its sensors were found to be accurate and that it is not in control of how other services perform calculations using its data. Google’s Maguire says the company “provides industry-leading and highly accurate air quality information,” including “even in areas with limited monitoring.”

Jennifer Richmond-Bryant, an associate professor of forestry and environmental resources at North Carolina State University who studied the PurpleAir sensors, says the safest bet for anyone concerned about air quality is to trust the most high number or level of color between different services. “I trust the AirNow numbers more because I understand them,” he says. But “it can never hurt to make an overly conservative decision when it comes to protecting yourself.”