Air-quality standards

Every demo declares one standard: the set of limits its forecast is evaluated against. Santiago’s is cl-mma. The standard says, per species, which average is used and which value must not be exceeded; the demo computes that average and the margin against the limit.

The registered standards

Chile — Primary air-quality standards (cl-mma), Ministry of the Environment.

Species	Average	Limit	Decree
SO₂	1 hour	350 µg/m³N	D.S. 104/2018
NO₂	1 hour	200 µg/m³N	D.S. 40/2024
PM₁₀	24 hours	130 µg/m³N	D.S. 12/2022
PM₂.₅	24 hours	50 µg/m³	D.S. 12/2011
CO	8-hour moving	10,000 µg/m³N	D.S. 115/2002
O₃	8-hour moving	120 µg/m³N	D.S. 112/2002

Indonesia — Government Regulation PP 22/2021, Annex VII (id-pp22-2021).

Species	Average	Limit
SO₂	1 hour	150 µg/m³
NO₂	1 hour	200 µg/m³

The table states each standard as the law writes it, including the 24-hour particulate limits. The platform evaluates only the hourly and 8-hour moving forms: it does not compute a 24-hour mean of the forecast, because that figure is complete only once the day is over — see averaged series. A limit’s legal statistical form is usually an annual percentile over a full year, which no 4-day forecast can compute either; the Regulatory panel says the form beside the norm. The Indonesian particulate limits are not registered yet.

A standard and an alert level are not the same thing

The demo’s alert levels — warning, alert, critical — are instantaneous thresholds of the demo’s own, chosen so the forecast reads; the standard is the legal limit, with its averaging. A demo can show alerts without exceeding its standard, and the reverse. The standard is read in the Regulatory panel and as the norm line on the Series chart; the demo’s thresholds colour the markers, the timebar and the Alerts panel.

Against what was measured

The same 1-hour and 8-hour limits are also held against the monitoring stations’ measured data, in the dashboard’s Monitoring → Standards: the highest measured mean at each station, its share of the limit and the hours over it. There too it is an exceedance review, not a compliance verdict — and it says whether a station measured anything near a modelled exceedance.

Units

The Chilean limits are in µg/m³N — normal conditions, 25 °C and 1 atm —; the Indonesian ones in µg/m³. The model delivers µg/m³ at the modelled atmosphere’s conditions, and the regulatory comparison converts the modelled value to normal conditions before it is set against a limit stated in µg/m³N, so the margin shown is the legal one. Detail in units and species.

→ Averaged series · This demo