Indoor PM2.5 Air Quality Dashboard

The default band is below ~12 µg/m³ (WHO 24-h guideline is 15 µg/m³; lower is better — there's no safe threshold). Treat it as a sensible starting point — your own specification, regulator, equipment manual or product datasheet sets the authoritative limits, and you can read your true band straight off the worst case those documents allow. Edit the readings against whatever band applies to you.

Lower is always better — the WHO sets a 24-hour guideline of 15 µg/m³ and an annual guideline of 5 µg/m³, with no threshold below which PM2.5 is harmless. Indoors, the big sources are cooking (especially frying, searing, gas burners), candles and incense, smoking, and infiltration of outdoor pollution or wildfire smoke. Spikes can dwarf the daily average, which is why a real-time monitor is useful: it tells you when to run the range hood, switch on a HEPA purifier, or close up and recirculate during an outdoor smoke event. Track the peaks here, and use them to time and size your filtration.

Match the interval to the consequence and the rate of change: where an excursion spoils product or risks safety, log continuously (or as often as you can sample); where it is merely informative, daily or per-shift spot checks suffice. The in-range % and excursion count only mean something if your sampling is regular — sparse, irregular readings hide the excursions between them.

Yes — every reading is stored in this browser's localStorage on your device and nothing is uploaded to any server, which also makes the dashboard usable on sites with strict data policies. For shared, audit-grade records across a team or for regulatory retention, export the values into your own system.