I live in San Francisco and regularly check purple air because we sometimes get bad AQI due to fires. The data is very helpful and I’m really thankful for this community! But I’ve noticed one device is almost always significantly higher than any other device nearby and even higher than any other device in the whole city.
It got me wondering… can one device throw off a city’s avg? And does it matter?
Hi Liam, PurpleAir ¶ sensors are not used for regulatory purposes so the sensor in question will not affect an average in a regulatory sense.
The EPA Fire and Smoke map doesn’t create averages for an area. Fire and Smoke Map
The EPA Fire and Smoke map does gray out a PA sensor if it doesn’t meet certain criteria in reporting. I am not familiar with all the different ways PA data is used by other websites or users so it is possible different websites could be ‘averaging’.
Regarding the ‘higher then surrounding’ PA sensor, it is difficult to say from the map why its values are higher then others. It might not be functioning properly or it might be functioning just fine, but was placed near an exhaust - so the high values could be a siting issue.
Ahh, ok good. I’m relieved these wouldn’t affect regulatory decisions. Thank you for your thorough answer!
Hello refactornator,
Thank you for letting us know! We are attempting to contact the owner of the sensor to collect more information and see if we can correct the issue.
@Jasmine_Bootman is correct that our sensors are not used for regulatory purposes. We have downgraded the sensor so it will not affect the map graph. However, the data will still appear in the API.
