Simple nitrogen dioxide (NO2) chart card with background

Who it’s for

Environmental health officers, traffic managers, and smart city operators ask “how has NO₂ trended recently?” The simple chart with background combines compact trend visualization with full-card color coding so the current status is visible at a distance.

What it does

A monitoring station streams nitrogen telemetry and the widget renders a time-series trend chart on a card whose background color reflects the current severity: green for Good (0–40 µg/m³), light green for Moderate (40–90 µg/m³), orange for Elevated (90–120 µg/m³), dark orange for High (120–230 µg/m³), and red for Hazardous (above 230 µg/m³).

• Full-card background color communicates current severity at a glance from a distance
• Trend chart of NO₂ concentration over the selected dashboard time window
• Shows one sensor’s data per widget; add multiple widgets to compare trends and current status across stations

How to set up

Data keys

Key	Role	Type	Description
nitrogen	Chart series	Timeseries	Nitrogen dioxide concentration in µg/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 Nitrogen dioxide, 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	Level	Color
0–40	Good	Green
40–90	Moderate	Light Green
90–120	Elevated	Orange
120–230	High	Dark Orange
230+	Hazardous	Red

How to customize

• To change the time window — adjust the dashboard time filter to show the last hour, day, or week of NO₂ readings.
• To change the severity thresholds — edit the color ranges on the Latest data key.
• 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 severity from across the room while the embedded chart gives the trend context when someone approaches the screen.
• Use consistent severity colors across all air quality widgets so operators can interpret a red background anywhere on the dashboard without reading the label.
• A sustained upward NO₂ trend over several days usually indicates increased vehicle traffic or a shift in prevailing wind that is bringing industrial emissions closer to the sensor.