PM2.5 chart card

Who it’s for

Air quality engineers, city planners, and environmental health officers ask “how has PM2.5 changed over the selected period, and is the fine particle load trending up or down?” They want the current concentration, a trend line, and a period-over-period delta in one card to support regulatory reporting and public health decisions.

What it does

A sensor averaging 28 µg/m³ this week versus 14 µg/m³ last week shows an orange value — Moderate — with a +100% delta and a +14 µg/m³ absolute change, plus a chart of readings over the period.

• Large current PM2.5 value color-coded across four bands from Good to Hazardous
• Delta percentage and absolute delta comparing the current period to the previous one
• Time-series chart of PM2.5 readings averaged per interval
• Shows one sensor’s data; it does not compare multiple monitoring sites

How to set up

Data keys

Key	Role	Type	Description
pm2.5	Chart series	Timeseries	PM2.5 concentration in µg/m³; drives the chart and all derived overlays
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 PM2.5, 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
0–10	Good	Green
10–35	Moderate	Orange
35–75	High	Dark Orange
75+	Hazardous	Red

How to customize

• To use your own PM2.5 thresholds — edit the color ranges on the Latest data key; adjust the four default bands to match your regulatory limits.
• To change the comparison period — adjust the Time window on the dashboard; the delta automatically compares to the equivalent preceding period.
• 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.

Tips

• PM2.5 spikes after calm, cold nights (temperature inversions trap combustion particles at ground level) are a common pattern — a positive delta on winter mornings often points to this cause rather than new emission sources.
• Use this card when the period-over-period change matters. If you only need the trend shape without a delta, use the simple PM2.5 chart card instead.