AirStatus is a free app that shows the current AQI in macOS's status menu bar. Data is provided by PurpleAir. The app updates every 10 minutes, displaying the 10-min average PurpleAir sensors report converted to EPA's AQI scale. The AQI is the median of all PurpleAir's sensors in the given Zip Code and Radius. Supports macOS 10.15 or higher.

AQI stands for Air Quality Index. See EPA's AQI Basics for more info.

See this article for more information: Understanding PurpleAir vs. AirNow.gov Measurements of Smoke Pollution (Thanks Sara for the article)

Two reasons why there is no AQI displaying:

1. PurpleAir rate limits the number of request in a given minute. If there is no data, please wait until the next update. 

2. Ensure the number of sensors is greater than 0 by adjusting the Sensor Filter Distance.

AirStatus will filters out certain sensors and converts PurpleAir's raw data values to a close approximate to EPA PM.2.5 value. The conversion becomes less accurate the higher the AQI (> 150). 

You can quit the App by right-clicking the AQI and going to "Quit". After quitting, you can just delete the Airstatus.app file.

1.0.3

• Bandwidth optimization to lower overall data usage 

• Now shows Median of all sensors in filter area