WordsPM2.5
ฝุ่น PM2.5 · fun PM song chut ha
Particles under 2.5 micrometres across — small enough to go past the nose and into the lungs.
What it is
Particles under 2.5 micrometres across — small enough to go past the nose and into the lungs.
The long version
It is measured in micrograms per cubic metre. The United States set its 24-hour standard at 35.4 µg/m³ and, in a 2024 revision, moved the annual standard to 9.0; the AQI figures on this site use that revision's breakpoints.
Inference — the reason it is the number that matters here rather than visibility is that the size is what makes it dangerous, and the size is also what makes it invisible individually. A hazy day and a dangerous day are not the same list.
Runs with
- storyThe smoke — Four years of it, measured.
- hazardRiding in the smoke — What it does on a bike.
Named here by
- hazardRiding in the smoke — What is actually in the air.
- storyThe smoke — What the number measures.
Where each claim comes from
| Field | Tier | Source | Note |
|---|---|---|---|
| default | cited | Final Reconsideration of the National Ambient Air Quality Standards for Particulate Matter — US Environmental Protection Agency | |
| text.story | cited | Final Reconsideration of the National Ambient Air Quality Standards for Particulate Matter — US Environmental Protection Agency | |
| text_th | inference | written in Thai by this project, not machine-translated |
Sources
- Final Reconsideration of the National Ambient Air Quality Standards for Particulate Matter — US Environmental Protection Agency
- Open-Meteo Air Quality API (Copernicus CAMS) — Open-Meteo
- Southeast Asian haze — Wikipedia (en)
cited Cited — a named source, linked · harvested Harvested — fetched from an open dataset, with its licence · tradition Tradition — general knowledge of the tradition, hedged · inference Inference — this project's own reasoning from the above · field Field — someone stood there