Purple Turtle provides Real-time Air Quality Information for your precise location if there are PurpleAir sensors within 5 km / 3 miles around you. You can check the sensors at http://purpleair.com/map.
More information about AQI: https://cfpub.epa.gov/airnow/index.cfm?action=aqibasics.aqi
By default, Purple Turtle uses EPA correction that is more suitable for measuring wood smoke. More details on the wood smoke correction: https://thebolditalic.com/understanding-purpleair-vs-airnow-gov-measurements-of-wood-smoke-pollution-562923a55226