SmogRank / Ireland / Leinster / Birr

Birr, month by month

Birr has a measured daily mean on 232 days since 22 May 2025. Its worst month was April 2026, at 39 US AQI (7.1 µg/m³), 1,867th of 2,941 cities on that month's world ranking. Its cleanest was September 2026, at 29 US AQI (5.3 µg/m³).

Every month since 2025

2026too few days for a mean (a year needs 200)175 days measured

Jan4 daysFebnoneMar3 daysApr39#1,867 May32#2,069Jun20 daysJul32#2,469 Aug33#2,509 Sep29#2,171 Oct32#1,866

2025too few days for a mean (a year needs 256)57 days measured

JanFebMarAprMay4 daysJun6 daysJul12 daysAug21 daysSep9 daysOct5 daysNovnoneDecnone

Each square is a month's mean PM2.5 in US AQI from Birr'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 Birr 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

12 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).
Mar 2026	3 of 31 days measured; a month needs 22. The others: 28 with readings for part of the day (a day needs 18 hours).
Feb 2026	No day measured. The others: 28 with readings for part of the day (a day needs 18 hours).
Jan 2026	4 of 31 days measured; a month needs 22. The others: 27 with readings for part of the day (a day needs 18 hours).
Dec 2025	No day measured. The others: 31 with readings for part of the day (a day needs 18 hours).
Nov 2025	No day measured. The others: 30 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: 4 with no readings from the monitor, 22 with readings for part of the day (a day needs 18 hours).
Sep 2025	9 of 30 days measured; a month needs 21. The others: 4 with no readings from the monitor, 17 with readings for part of the day (a day needs 18 hours).
Aug 2025	21 of 31 days measured; a month needs 22. The others: 10 with readings for part of the day (a day needs 18 hours).
Jul 2025	12 of 31 days measured; a month needs 22. The others: 19 with readings for part of the day (a day needs 18 hours).
Jun 2025	6 of 30 days measured; a month needs 21. The others: 4 with no readings from the monitor, 20 with readings for part of the day (a day needs 18 hours).
May 2025	4 of 31 days measured; a month needs 22. The others: 3 with no readings from the monitor, 3 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.

Birr's worst months

Month	US AQI	Days measured	World rank
April 2026	397.1 µg/m³	29 of 30	1,867thof 2,941
August 2026	335.9 µg/m³	27 of 31	2,509thof 2,896
July 2026	325.8 µg/m³	29 of 31	2,469thof 2,784
May 2026	325.7 µg/m³	28 of 31	2,069thof 2,874
September 2026	295.3 µg/m³	26 of 30	2,171stof 2,981

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.

Birr's worst days

Day	US AQI
27 Aug 2026	7320.8 µg/m³
24 Jul 2025	6918.6 µg/m³
16 Jul 2026	6818.1 µg/m³
12 Aug 2025	6516.7 µg/m³
28 Aug 2026	6315.7 µg/m³
21 Jan 2026	6315.5 µg/m³
15 Jul 2026	6215.1 µg/m³
17 Jul 2026	6114.7 µg/m³
30 Mar 2026	6114.2 µg/m³
26 Aug 2026	5913.6 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, Birr, 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/birr/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.

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

Updated 2026-10-12 22:07 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).