Simple radon level chart card

Who it’s for

Building managers, property owners, and occupational health officers ask “how has radon trended at this location over the past day or week?” They want a compact chart that fits into a multi-zone overview without the overhead of a full chart card.

What it does

A sensor reporting radon = 45 Bq/m³ renders a time-series chart of those readings, color-coded by risk band: green for Safe (0–100 Bq/m³), orange for Elevated (100–200 Bq/m³), and red for High (above 200 Bq/m³). The chart fills the card without a large numerical readout, maximizing the visible time window.

• Trend chart of radon concentration over the selected dashboard time window
• Color-coded by severity at each point in time across three bands
• Shows one sensor’s data per widget; add multiple widgets to compare trends across floors or zones

How to set up

Data keys

Key	Role	Type	Description
radon	Chart series	Timeseries	Radon concentration in Bq/m³; change the key name to match your device’s telemetry key
Latest	Latest value	Timeseries	The headline figure above the chart. Its own color ranges are where the band colors are edited

The widget ships with a simulated function datasource key labeled Radon level, 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.

Value ranges

Range (Bq/m³)	Level	Color
0–100	Safe	Green
100–200	Elevated	Orange
200+	High	Red

How to customize

• To change the time window — adjust the dashboard time filter to show the last hour, day, or week of radon readings.
• To change the severity thresholds — edit the color ranges on the Latest data key to match your national regulatory reference levels.
• To change the chart colors — edit the color of each range on the Latest data key.

Tips

• Use this chart in a grid alongside simple chart cards for CO2, humidity, and other air quality metrics to give managers a side-by-side multi-parameter trend view without cluttering the dashboard with large value cards.
• A 24-hour time window makes the natural radon diurnal cycle visible — low in the afternoon, rising overnight — so deviations from that pattern stand out immediately.
• A 7-day trend with a gradually rising overnight baseline rather than isolated spikes indicates structural seepage that ventilation alone cannot resolve.