I don’t think the download tool will have “AQI”. The tool will download the raw data only. You can look at PM2.5 or PM10.0 etc to get an idea at what is in the air at the moment. I’d have to look around, but I think there are formulas to take raw data from the download tool and convert it to more useful stuff like AQI.
Take a look at this post: How to Calculate the US EPA PM2.5 AQI
It may have what you’re looking for.