SmogRank / Ireland / Leinster / Portlaoise

Portlaoise, month by month

Portlaoise has a measured daily mean on 201 days since 22 May 2025. Its worst month was August 2025, at 39 US AQI (7.0 µg/m³), 2,174th of 2,901 cities on that month's world ranking. Its cleanest was May 2026, at 32 US AQI (5.7 µg/m³).

Every month since 2025

2026too few days for a mean (a year needs 199)111 days measured
Jan4 daysFeb1 dayMar4 daysApr37#2,009May32#2,069Jun7 daysJul9 daysAug11 daysSep9 daysOct27#2,226
2025too few days for a mean (a year needs 256)90 days measured
JanFebMarAprMay8 daysJun13 daysJul19 daysAug39#2,174Sep16 daysOct7 daysNovnoneDecnone
Each square is a month's mean PM2.5 in US AQI from Portlaoise'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 Portlaoise marked; each year, the year's. A dashed square is the running month, so far.
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

14 months
MonthWhy
Sep 20269 of 30 days measured; a month needs 21. The others: 21 with readings for part of the day (a day needs 18 hours).
Aug 202611 of 31 days measured; a month needs 22. The others: 20 with under 18 hours of readings or readings that failed our checks.
Jul 20269 of 31 days measured; a month needs 22. The others: 22 with under 18 hours of readings or readings that failed our checks.
Jun 20267 of 30 days measured; a month needs 21. The others: 23 with under 18 hours of readings or readings that failed our checks.
Mar 20264 of 31 days measured; a month needs 22. The others: 27 with under 18 hours of readings or readings that failed our checks.
Feb 20261 of 28 days measured; a month needs 20. The others: 27 with under 18 hours of readings or readings that failed our checks.
Jan 20264 of 31 days measured; a month needs 22. The others: 27 with under 18 hours of readings or readings that failed our checks.
Dec 2025No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Nov 2025No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
Oct 20257 of 31 days measured; a month needs 22. The others: 24 with under 18 hours of readings or readings that failed our checks.
Sep 202516 of 30 days measured; a month needs 21. The others: 14 with under 18 hours of readings or readings that failed our checks.
Jul 202519 of 31 days measured; a month needs 22. The others: 12 with under 18 hours of readings or readings that failed our checks.
Jun 202513 of 30 days measured; a month needs 21. The others: 17 with under 18 hours of readings or readings that failed our checks.
May 20258 of 31 days measured; a month needs 22. The others: 2 with under 18 hours of readings or readings that failed our checks.

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

Portlaoise's worst months

MonthUS AQIDays measuredWorld rank
August 2025 397.0 µg/m³27 of 312,174thof 2,901
April 2026 376.6 µg/m³28 of 302,009thof 2,941
May 2026 325.7 µg/m³29 of 312,069thof 2,874

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.

Portlaoise's worst days

DayUS AQI
24 Jul 2025 7521.9 µg/m³
15 Jul 2026 6918.7 µg/m³
12 Aug 2025 6616.9 µg/m³
13 Aug 2025 6013.8 µg/m³
30 Mar 2026 5913.6 µg/m³
24 Apr 2026 5913.5 µg/m³
21 Jun 2025 5812.9 µg/m³
26 May 2026 5812.9 µg/m³
23 Apr 2026 5712.2 µg/m³
19 Aug 2025 5511.2 µg/m³

Daily means, the highest since 22 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, Portlaoise, Ireland, 22 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/portlaoise/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.

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

Updated 2026-10-12 18:07 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).