SmogRank / Greece / Attica / Khalándrion

Khalándrion, month by month

Khalándrion has a measured daily mean on 1,060 days since 1 January 2023. Its worst month was July 2023, at 61 US AQI (14.7 µg/m³), 155th of 1,432 cities on that month's world ranking. Its cleanest was December 2024, at 43 US AQI (7.7 µg/m³). 2025 averaged 52 US AQI (9.7 µg/m³), against 55 US AQI (11.4 µg/m³) in 2023.

Every month since 2023

2026too few days for a mean (a year needs 199)195 days measured
Jan49#1,266Feb50#1,670Mar55#1,401Apr51#1,137May50#998Jun13 daysJul15 daysAug21 daysSep17 daysOctnone
202552 for the year277 days measured1,077th of 2,681 in the world
Jan52#1,045Feb48#1,410Mar55#1,366Apr20 daysMay52#942Jun19 daysJul56#839Aug52#1,254Sep51#824Oct13 daysNov45#1,509Dec52#1,404
2024too few days for a mean (a year needs 257)240 days measured
Jan48#1,092Feb53#640Mar15 daysApr56#763May54#609Jun55#402Jul52#766Aug14 daysSepnoneOctnoneNov16 daysDec43#1,465
202355 for the year348 days measured284th of 1,355 in the world
Jan54#407Feb59#446Mar52#263Apr53#419May55#335Jun54#661Jul61#155Aug56#375Sep58#271Oct59#140Nov51#845Dec48#1,044
Each square is a month's mean PM2.5 in US AQI from Khalándrion'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 Khalándrion 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

13 months
MonthWhy
Oct 2026No day measured. The others: 10 with no readings from the monitor, 1 with under 18 hours of readings or readings that failed our checks.
Sep 202617 of 30 days measured; a month needs 21. The others: 7 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.
Aug 202621 of 31 days measured; a month needs 22. The others: 10 with under 18 hours of readings or readings that failed our checks.
Jul 202615 of 31 days measured; a month needs 22. The others: 16 with under 18 hours of readings or readings that failed our checks.
Jun 202613 of 30 days measured; a month needs 21. The others: 17 with under 18 hours of readings or readings that failed our checks.
Oct 202513 of 31 days measured; a month needs 22. The others: 18 with under 18 hours of readings or readings that failed our checks.
Jun 202519 of 30 days measured; a month needs 21. The others: 11 with under 18 hours of readings or readings that failed our checks.
Apr 202520 of 30 days measured; a month needs 21. The others: 10 with under 18 hours of readings or readings that failed our checks.
Nov 202416 of 30 days measured; a month needs 21. The others: 14 with under 18 hours of readings or readings that failed our checks.
Oct 2024No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Sep 2024No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
Aug 202414 of 31 days measured; a month needs 22. The others: 17 with under 18 hours of readings or readings that failed our checks.
Mar 202415 of 31 days measured; a month needs 22. The others: 16 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.

Khalándrion's worst months

MonthUS AQIDays measuredWorld rank
July 2023 6114.7 µg/m³26 of 31155thof 1,432
February 2023 5913.5 µg/m³28 of 28446thof 1,129
October 2023 5913.4 µg/m³31 of 31140thof 2,012
September 2023 5812.8 µg/m³30 of 30271stof 2,176
July 2025 5612.0 µg/m³27 of 31839thof 2,889
August 2023 5611.7 µg/m³28 of 31375thof 1,980

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.

Khalándrion's worst days

DayUS AQI
24 Apr 2024 16676.4 µg/m³
12 Aug 2024 14151.7 µg/m³
15 Feb 2026 11340.4 µg/m³
23 Sept 2023 8326.5 µg/m³
24 Sept 2023 8326.3 µg/m³
19 May 2024 8326.3 µg/m³
25 May 2025 8225.6 µg/m³
26 Oct 2023 8024.5 µg/m³
1 Mar 2023 7723.3 µg/m³
26 Jul 2023 7722.9 µg/m³

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, Khalándrion, Greece, 1 Jan 2023 – 21 Sep 2026. Monitor data from EEA, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/gr/khalandrion/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.

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

Updated 2026-10-12 17:07 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).