SmogRank / Spain / La Rioja / Alfaro

Alfaro, month by month

Alfaro, La Rioja has a measured daily mean on 385 days since 6 May 2023. Its worst month was September 2023, at 49 US AQI (8.8 µg/m³), 838th of 2,176 cities on that month's world ranking. Its cleanest was May 2024, at 20 US AQI (3.6 µg/m³).

Every month since 2023

2026too few days for a mean (a year needs 199)12 days measured
Jan3 daysFebnoneMarnoneAprnoneMay1 dayJun1 dayJulnoneAugnoneSep5 daysOct2 days
2025too few days for a mean (a year needs 256)1 day measured
JannoneFebnoneMarnoneAprnoneMaynoneJunnoneJulnoneAug1 daySepnoneOctnoneNovnoneDecnone
2024too few days for a mean (a year needs 257)156 days measured
Jan41#1,435Feb33#1,870Mar15 daysApr33#1,711May20#2,505Jun15 daysJul6 daysAug4 daysSepnoneOctnoneNovnoneDec2 days
2023too few days for a mean (a year needs 256)216 days measured
JanFebMarAprMay37#1,203Jun34#1,312Jul35#1,050Aug21 daysSep49#838Oct45#738Nov24#2,087Dec38#1,583
Each square is a month's mean PM2.5 in US AQI from Alfaro's measured days, with its place on that month's world ranking under it. A month has a mean once 70% of its days are measured, the rule the monthly rankings use; under that, the square gives the days measured. Each square opens that month's ranking with Alfaro marked; each year, the year's.
Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

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

31 months
MonthWhy
Oct 20262 of 11 days measured; a month needs 8. The others: 3 with no readings from the monitor, 5 with readings for part of the day (a day needs 18 hours), 1 with under 18 hours of readings or readings that failed our checks.
Sep 20265 of 30 days measured; a month needs 21. The others: 1 with no readings from the monitor, 24 with readings for part of the day (a day needs 18 hours).
Aug 2026No day measured. The others: 6 with no readings from the monitor, 25 with readings for part of the day (a day needs 18 hours).
Jul 2026No day measured. The others: 3 with no readings from the monitor, 28 with readings for part of the day (a day needs 18 hours).
Jun 20261 of 30 days measured; a month needs 21. The others: 3 with no readings from the monitor, 26 with readings for part of the day (a day needs 18 hours).
May 20261 of 31 days measured; a month needs 22. The others: 20 with no readings from the monitor, 10 with readings for part of the day (a day needs 18 hours).
Apr 2026No day measured. The others: 30 with no readings from the monitor.
Mar 2026No day measured. The others: 31 with no readings from the monitor.
Feb 2026No day measured. The others: 19 with no readings from the monitor, 9 with readings for part of the day (a day needs 18 hours).
Jan 20263 of 31 days measured; a month needs 22. The others: 2 with no readings from the monitor, 26 with readings for part of the day (a day needs 18 hours).
Dec 2025No day measured. The others: 7 with no readings from the monitor, 24 with readings for part of the day (a day needs 18 hours).
Nov 2025No day measured. The others: 2 with no readings from the monitor, 28 with readings for part of the day (a day needs 18 hours).
Oct 2025No day measured. The others: 31 with readings for part of the day (a day needs 18 hours).
Sep 2025No day measured. The others: 1 with no readings from the monitor, 29 with readings for part of the day (a day needs 18 hours).
Aug 20251 of 31 days measured; a month needs 22. The others: 30 with readings for part of the day (a day needs 18 hours).
Jul 2025No day measured. The others: 1 with no readings from the monitor, 30 with readings for part of the day (a day needs 18 hours).
Jun 2025No day measured. The others: 3 with no readings from the monitor, 27 with readings for part of the day (a day needs 18 hours).
May 2025No day measured. The others: 1 with no readings from the monitor, 30 with readings for part of the day (a day needs 18 hours).
Apr 2025No day measured. The others: 1 with no readings from the monitor, 29 with readings for part of the day (a day needs 18 hours).
Mar 2025No day measured. The others: 3 with no readings from the monitor, 28 with readings for part of the day (a day needs 18 hours).
Feb 2025No day measured. The others: 2 with no readings from the monitor, 26 with readings for part of the day (a day needs 18 hours).
Jan 2025No day measured. The others: 15 with readings for part of the day (a day needs 18 hours), 16 with under 18 hours of readings or readings that failed our checks.
Dec 20242 of 31 days measured; a month needs 22. The others: 17 with no readings from the monitor, 12 with readings for part of the day (a day needs 18 hours).
Nov 2024No day measured. The others: 5 with no readings from the monitor, 25 with readings for part of the day (a day needs 18 hours).
Oct 2024No day measured. The others: 3 with no readings from the monitor, 28 with readings for part of the day (a day needs 18 hours).
Sep 2024No day measured. The others: 30 with readings for part of the day (a day needs 18 hours).
Aug 20244 of 31 days measured; a month needs 22. The others: 5 with no readings from the monitor, 22 with readings for part of the day (a day needs 18 hours).
Jul 20246 of 31 days measured; a month needs 22. The others: 3 with no readings from the monitor, 22 with readings for part of the day (a day needs 18 hours).
Jun 202415 of 30 days measured; a month needs 21. The others: 2 with no readings from the monitor, 13 with readings for part of the day (a day needs 18 hours).
Mar 202415 of 31 days measured; a month needs 22. The others: 10 with no readings from the monitor, 6 with readings for part of the day (a day needs 18 hours).
Aug 202321 of 31 days measured; a month needs 22. The others: 2 with no readings from the monitor, 8 with readings for part of the day (a day needs 18 hours).

A day counts once 18 hours of it are measured; a month needs 70% of its days.

Alfaro's worst months

MonthUS AQIDays measuredWorld rankEpisode
September 2023 498.8 µg/m³30 of 30838thof 2,176North-eastern Spain and France, September 2023
October 2023 458.1 µg/m³27 of 31738thof 2,012–
January 2024 417.3 µg/m³31 of 311,435thof 2,385–
December 2023 386.9 µg/m³31 of 311,583rdof 2,247–
May 2023 376.6 µg/m³25 of 311,203rdof 1,600–
July 2023 356.3 µg/m³24 of 311,050thof 1,432–

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.

Alfaro's worst days

DayUS AQIEpisode
5 Sept 2023 9733.7 µg/m³North-eastern Spain and France, September 2023
29 Dec 2023 8024.5 µg/m³–
4 Sept 2023 7823.5 µg/m³North-eastern Spain and France, September 2023
11 Aug 2025 7723.0 µg/m³–
23 Aug 2023 6918.9 µg/m³–
28 Dec 2023 6818.4 µg/m³–
7 Apr 2024 6617.1 µg/m³–
11 Jul 2023 6617.0 µg/m³–
6 Oct 2023 6516.6 µg/m³–
9 Jun 2024 6416.0 µg/m³–

Daily means, the highest since 6 May 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, Alfaro, La Rioja, Spain, 6 May 2023 – 9 Oct 2026. Monitor data from EEA, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/es/alfaro/history (accessed 12 Oct 2026).

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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.

Alfaro now: the last 24 hours, its ranks today and the last 12 months day by day.

Updated 2026-10-12 19:07 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).