SmogRank / Ireland / Leinster / Longford
Longford, month by month
Longford has a measured daily mean on 368 days since 23 May 2025. Its worst month was December 2025, at 57 US AQI (12.1 µg/m³), 963rd of 3,006 cities on that month's world ranking. Its cleanest was September 2026, at 28 US AQI (5.0 µg/m³).
Every month since 2025
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
6 months
| Month | Why |
|---|---|
| Jun 2026 | 20 of 30 days measured; a month needs 21. The others: 10 with readings for part of the day (a day needs 18 hours). |
| Oct 2025 | 5 of 31 days measured; a month needs 22. The others: 8 with no readings from the monitor, 18 with readings for part of the day (a day needs 18 hours). |
| Sep 2025 | 12 of 30 days measured; a month needs 21. The others: 18 with readings for part of the day (a day needs 18 hours). |
| Jul 2025 | 18 of 31 days measured; a month needs 22. The others: 13 with readings for part of the day (a day needs 18 hours). |
| Jun 2025 | 10 of 30 days measured; a month needs 21. The others: 20 with readings for part of the day (a day needs 18 hours). |
| May 2025 | 9 of 31 days measured; a month needs 22. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Longford's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| December 2025 | 5712.1 µg/m³ | 963rdof 3,006 | – |
| March 2026 | 5410.6 µg/m³ | 1,515thof 2,971 | Europe, 18 to 25 March 2026 |
| January 2026 | 529.9 µg/m³ | 1,117thof 2,617 | – |
| February 2026 | 529.7 µg/m³ | 1,482ndof 2,866 | – |
| November 2025 | 498.9 µg/m³ | 1,276thof 2,715 | – |
| April 2026 | 397.1 µg/m³ | 1,867thof 2,941 | – |
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.
Longford's worst days
| Day | US AQI | Episode |
|---|---|---|
| 20 Mar 2026 | 9331.4 µg/m³ | Europe, 18 to 25 March 2026 |
| 21 Mar 2026 | 8929.7 µg/m³ | Europe, 18 to 25 March 2026 |
| 23 Dec 2025 | 8125.1 µg/m³ | – |
| 22 Dec 2025 | 7622.7 µg/m³ | – |
| 1 Feb 2026 | 7521.8 µg/m³ | – |
| 27 Aug 2026 | 7120.0 µg/m³ | – |
| 5 Jan 2026 | 7019.1 µg/m³ | – |
| 3 Mar 2026 | 6918.7 µg/m³ | – |
| 31 Dec 2025 | 6918.6 µg/m³ | – |
| 24 Jul 2025 | 6818.1 µg/m³ | – |
Daily means, the highest since 23 May 2025; 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, Longford, Ireland, 23 May 2025 – 11 Oct 2026. Monitor data from EEA, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/ie/longford/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.
Longford now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 21:07 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).