Realtime, Granular Air Quality Data from

So it’s wildfire season again (a little early this year), and with Covid, we need to be more mindful of the air quality–both because poor air quality makes us more susceptible to infection, and also because it’s hard to do outdoor socially-distant activities when the air is too crappy to breathe.  In San Francisco, the Bay Area Air Quality Management District (BAAQMD) maintains 4 air quality sensors, but only one with 2.5 micron particulate (PM2.5) measurement capabilities–on Arkansas St at 16th St in the Dogpatch.  It’s hard to extrapolate what the rest of the city’s air quality looks like based on a single sensor.

Enter PurpleAir–they have a network of thousands of their individually-owned sensors world-wide, and around 100 sensors across San Francisco.  Whereas the BAAQMD says that the AQI in SF is 64 right now, PurpleAir’s network shows that pretty much only the Mission, Potrero Hill, Dogpatch, and Mission Bay have AQI levels higher than 64–the rest of the city is clear.  The PurpleAir data is realtime also, whereas the BAAQMD data gets updated hourly.  And the PurpleAir map’s interface seems easier to use.

Very cool stuff–I’m considering purchasing the outdoor version of their models to help us know when we can keep the windows open at the office to improve ventilation and reduce Covid risk.