Air quality index chart card

Who it’s for

Dashboard authors monitoring outdoor air quality stations or smart city sensors ask “is the AQI trending up or down, and by how much compared to last week?” A single reading does not say whether air quality is improving; the trend does.

What it does

A sensor averaging 85 AQI this week, down from 112 AQI last week, shows a -24% delta in green — air quality has improved. The chart below confirms the downward trend over the selected period.

• Large current AQI value in the center, color-coded across six severity bands from Good to Hazardous
• Percentage change vs. the previous period, with a colored arrow — green when AQI is falling (better air), red when rising (worse air)
• Absolute AQI change shown below the delta percentage
• Time-series chart of AQI readings over the selected time window, averaged per interval
• Shows one sensor’s data; it does not compare multiple stations or locations

How to set up

Data keys

Key	Role	Type	Description
air	Chart series	Timeseries	Numeric AQI reading; drives the chart. The Latest, Delta percent, and Delta absolute overlays are automatically derived from this same key
Latest	Latest value	Timeseries	The headline figure above the chart. Its own color ranges are where the band colors are edited
Delta percent	Percentage change	Timeseries	Change against the previous period, as a percentage
Delta absolute	Absolute change	Timeseries	Change against the previous period, in the key’s own unit

The widget ships with a simulated function datasource key labeled Air Quality Index, so it draws random values until you point the datasource at a device and rename the key.

To point it at your own device: open the dashboard in edit mode, open the widget’s Datasources, pick the entity or entity alias, and replace the function key with the key your device reports.

If the key has never reported for the selected time window, the chart is empty and all overlays show no data.

Value ranges

Range	Level	Color
0–50	Good	Green
50–100	Moderate	Orange
100–150	Unhealthy (sensitive)	Orange
150–200	Unhealthy	Red
200–300	Very Unhealthy	Purple
300+	Hazardous	Maroon

How to customize

• To use your own AQI color bands — edit the color ranges on the Latest data key; adjust the six default levels to match your monitoring thresholds.
• To hide or show the chart — toggle Show chart in the widget settings.
• To change the chart line color — set Chart color.
• To show min, max, or total in the legend instead of avg — edit the Legend settings.
• To hide the entity name subtitle or the timestamp — turn off Show subtitle or Show date.
• To match your dashboard’s fonts — set the font options under each data key’s appearance settings.

Tips

• For AQI, a falling delta means better air quality. The arrow turns green when AQI drops vs. the previous period and red when it rises.
• The aggregation interval controls chart granularity. For a weekly view, an hourly interval makes trends visible without too many data points.
• The default upper range starts at 300 with no upper limit. The card colors the value correctly even when a reading goes above 500.