Why Is Air Quality in Los Angeles So Confused Now?

of AirNow fire map Data from the PurpleAir sensors (that’s what the small circles represent) and Watch Duty, a non-profit program for monitoring wildfiresalso displays PurpleAir data. But it is likely that the air quality index reported by the same sensors can vary greatly from map to map due to different calculations and processing delays. For PM2.5 pollution, or what’s known as inhalable tiny smoke and dust particles, the PurpleAir sensor south of Los Angeles International Airport simultaneously returned an air quality index of 28 on AirNow’s website, 20 on WatchDuty and 5 on PurpleAir on Monday. . official page.

Each of these values ​​generally indicates healthy weather, 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” calculations over many miles between some 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. Israeli media. (Google declined to comment on the value of the deal.) It powers the air quality data that appears in the Weather app on Apple devices and in the Google Maps app. And Indian startup Ambee is responsible for air quality data in one of the world’s most popular weather apps, WeatherBug.

Yael Maguire, Google’s vice president of geosustainability, 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 the calculations, the company uses data collected 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 CEO Jaideep Singh Bachher. “We want to give people the right information, wherever they need it, when they need it,” he says.

Volckens says he doesn’t trust these systems. He says the low-cost PurpleAir sensors, which they rely on in part, aren’t suitable for the conditions they’re often deployed in the U.S., including wildfires. But he admits that while they’re impossible in terms of raw numbers, these sensors can be accurate 90 percent of the time in determining the advisory level — the range from green to dark red that’s often enough for people to make decisions. on how to protect their health.

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

Jennifer Richmond-Bryant, an associate professor of forestry and environmental resources at North Carolina State University who researched the PurpleAir sensors, says the safest option for anyone concerned about air quality is to rely on the highest number or color level among the various services. “I trust the AirNow numbers more because I understand them,” he says. But “it never hurts to make an overly conservative decision to protect yourself.”