Paradise Lost - A Community Struggling to Survive
Alternative Giving Christmas Fair

Understanding Purple Air Data

Screen Shot 2018-11-15 at 4.10.29 PMA lot of people are now turning to PurpleAir.com for real-time air quality measurements.  But everyone should know that, in their default setting, they show higher PM2.5 readings than the government's sensors.  To obtain more realistic readings, use the box in the lower left hand corner of your web page to change the conversion from "none" to "LRAPA."  You can read more about the LRAPA settings here and here

Please pass along this information.  Our situation is serious and people should be appropriately cautious (stay inside if possible, use filters if possible, obtain N95 masks from the Davis Fire Department), but no purpose is served by thinking that things are worse than they actually are.

(Screen shot in this post taken at around 4:10 PM, Thursday, November 15).

Note: One of the links above recommends using raw PM 2.5 data before selecting the conversion to LRAPA.  My experience, however, is that the default US EPA PM2.5 AQI setting gives numbers that are closer to the Spare the Air values.

Comments

Sarah Perrault

Thank you.

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