SmogRank / Chile / Biobio / Nacimiento
Nacimiento, month by month
Nacimiento has a measured daily mean on 1,272 days since 1 January 2023. Its worst month was May 2024, at 182 US AQI (100.3 µg/m³), 5th of 2,684 cities on that month's world ranking. Its cleanest was February 2026, at 65 US AQI (16.7 µg/m³). 2025 averaged 132 US AQI (48.0 µg/m³), against 126 US AQI (45.6 µg/m³) in 2024.
Every month since 2023
The US EPA's Air Quality Index for PM2.5 (2024 breakpoints). Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales
Months without a mean, and why
4 months
| Month | Why |
|---|---|
| Oct 2026 | No day measured. The others: 10 with no readings from the monitors, 1 with readings for part of the day (a day needs 18 hours). |
| Nov 2025 | 19 of 30 days measured; a month needs 21. The others: 11 with under 18 hours of readings or readings that failed our checks. |
| Mar 2023 | 11 of 31 days measured; a month needs 22. The others: 20 missing from OpenAQ's archive. |
| Feb 2023 | 3 of 28 days measured; a month needs 20. The others: 25 missing from OpenAQ's archive. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Nacimiento's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| May 2024 | 182100.3 µg/m³ | 5thof 2,684 | South-western Chile, 24 to 28 May 2024 South-western Chile, 14 to 19 May 2024and 1 more |
| June 2025 | 17792.5 µg/m³ | 2ndof 2,508 | Southern Chile, 29 June to 4 July 2025 South-western Chile, June 2025 |
| July 2023 | 17285.0 µg/m³ | 2ndof 1,432 | Southern Chile, July 2023 |
| July 2024 | 17184.3 µg/m³ | 4thof 2,566 | Southern Chile, July 2024 South-western Chile, July 2024and 1 more |
| July 2025 | 17082.0 µg/m³ | 3rdof 2,889 | Southern Chile, 29 June to 4 July 2025 |
| June 2023 | 16575.5 µg/m³ | 2ndof 1,603 | South-western Chile, June 2023 |
Monthly means over the days measured; finished months only. World rank: its place on that month's world ranking of every city with enough days. Each month opens that ranking.
Nacimiento's worst days
| Day | US AQI | Episode |
|---|---|---|
| 17 May 2024 | 251175.8 µg/m³ | South-western Chile, 14 to 19 May 2024 |
| 3 Jul 2025 | 244169.0 µg/m³ | Southern Chile, 29 June to 4 July 2025 |
| 19 Jun 2023 | 243167.5 µg/m³ | South-western Chile, June 2023 |
| 12 Jul 2024 | 236160.7 µg/m³ | Chile, July 2024 |
| 27 May 2024 | 232157.0 µg/m³ | South-western Chile, 24 to 28 May 2024 |
| 4 Jul 2025 | 232156.5 µg/m³ | Southern Chile, 29 June to 4 July 2025 |
| 20 May 2026 | 229153.4 µg/m³ | Southern Chile, May 2026 |
| 30 May 2023 | 227151.5 µg/m³ | – |
| 18 Jul 2023 | 227151.5 µg/m³ | Southern Chile, July 2023 |
| 23 Jul 2024 | 226150.9 µg/m³ | South-western Chile, July 2024 |
Daily means, the highest since 1 Jan 2023; the WHO's daily guideline is 15 µg/m³. Each date opens that day's world ranking, and each episode the bad-air spell it was part of.
Use this history
SmogRank, PM2.5 monthly and daily means, Nacimiento, Chile, 1 Jan 2023 – 30 Sep 2026. Monitor data from Chile - SINCA via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/cl/nacimiento/history (accessed 12 Oct 2026).
You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.
Nacimiento now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 23:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index. Some low-cost readings: Sensor.Community, ODbL (data and licence). Some readings: Uzhydromet (Uzbekistan's Hydrometeorological Service); Department of Environment, Nepal; Vietnam's government monitors; Aurassure; Umhverfisstofnun (Environment Agency of Iceland); RMCAB (Secretaría Distrital de Ambiente, Bogotá); Love My Air (City and County of Denver), no reuse terms published (why we use them).