Radon level chart card with background

Who it’s for

Building managers, property owners, and occupational health officers ask “how has radon trended in this zone recently?” The chart with background combines a compact trend line with a full-card color signal so the current status is visible at a distance.

What it does

A sensor reporting radon = 45 Bq/m³ renders a time-series trend chart on a card whose entire background fills with the risk color: green for Safe (0–100 Bq/m³), orange for Elevated (100–200 Bq/m³), and red for High (above 200 Bq/m³).

• Full-card background color makes radon risk readable across a room without reading the number
• Historical trend chart shows how radon concentration has evolved over the selected time window
• Shows one sensor’s data per widget; add multiple widgets to monitor different 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
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 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 background colors — edit the color of each range on the Latest data key.

Tips

• On a wall display, the colored background signals the current radon risk from across the room while the embedded chart shows whether overnight accumulation is still building or already clearing.
• Radon concentrations typically rise overnight as buildings are closed and fall during the working day as air circulates; a chart spanning 24–48 hours makes this natural cycle visible and helps distinguish it from a genuine accumulation problem.
• A 7-day trend showing a gradual upward baseline — not just overnight spikes — indicates radon is seeping through floors or foundations and building up faster than ventilation can clear it.