Nitrogen dioxide (NO2) chart card with background

Who it’s for

Environmental health officers, traffic managers, and smart city operators ask “what is the NO₂ level right now and has it been rising — and can I see the severity status from across the room?” The background-color chart variant combines real-time trend visibility with high-contrast room-level status communication.

What it does

A monitoring station reporting nitrogen = 28 µg/m³ displays the current value and a historical trend chart on a card whose background fills with the severity color: 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 severity at a glance from a distance
• Historical trend chart shows how NO₂ concentration has evolved over the selected time window
• Shows one sensor’s data per widget; add multiple widgets to track stations across a network

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
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 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 severity thresholds — edit the color ranges on the Latest data key to match your local regulatory limits.
• To change the band colors — edit the background color for each severity level in the widget settings.
• To change the time window — adjust the dashboard time filter to show the last hour, day, or week of NO₂ readings.

Tips

• On a wall display, the colored background signals the current severity from a distance while the embedded chart gives analysts the context they need when they approach the screen.
• Use consistent severity colors across all air quality widgets on the same dashboard.
• NO₂ peaks sharply during rush hours; a 24-hour chart in view alongside the current reading helps operators quickly distinguish a predictable traffic peak from an unusual emission event.