AQI is Air Quality Index (basically a measurement of how polluted the air is)
Currently all Luna does (when online) is leverage the aqicn.org API to respond to two slash commands:
/aqi {city} Takes a string argument to search for the AQI measurement of a city.
/aqi_all Gathers the AQI reading of a list of hard-coded locations where I am personally invested in knowing the air quality of.
A visual element that LunaBot adds is adding circle emojis of the color corresponding to the AQI reading.