SmogRank / Czechia / Ústí nad Labem Region / Most

Most, month by month

Most has a measured daily mean on 634 days since 1 January 2023. Its worst month was January 2024, at 72 US AQI (20.3 µg/m³), 263rd of 2,385 cities on that month's world ranking. Its cleanest was May 2024, at 44 US AQI (8.0 µg/m³).

Every month since 2023

2026too few days for a mean (a year needs 199)25 days measured
Jan8 daysFeb1 dayMarnoneApr2 daysMay6 daysJun2 daysJulnoneAugnoneSep1 dayOct5 days
2025too few days for a mean (a year needs 256)77 days measured
Jan14 daysFeb17 daysMar8 daysApr10 daysMay8 daysJun1 dayJul1 dayAug3 daysSep7 daysOct5 daysNov2 daysDec1 day
2024too few days for a mean (a year needs 257)215 days measured
Jan72#263Feb53#661Mar15 daysApr44#1,307May44#1,314Jun1 dayJul52#804Aug1 daySepnoneOct9 daysNov65#356Dec55#752
202358 for the year317 days measured171st of 1,355 in the world
Jan55#384Feb65#266Mar59#118Apr59#200May56#267Jun59#461Jul54#585Aug56#375Sep61#195Oct56#196Nov44#1,143Dec21 days
Each square is a month's mean PM2.5 in US AQI from Most'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 Most 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

28 months
MonthWhy
Oct 20265 of 11 days measured; a month needs 8. The others: 6 with readings for part of the day (a day needs 18 hours).
Sep 20261 of 30 days measured; a month needs 21. The others: 29 with readings for part of the day (a day needs 18 hours).
Aug 2026No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Jul 2026No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Jun 20262 of 30 days measured; a month needs 21. The others: 28 with under 18 hours of readings or readings that failed our checks.
May 20266 of 31 days measured; a month needs 22. The others: 25 with under 18 hours of readings or readings that failed our checks.
Apr 20262 of 30 days measured; a month needs 21. The others: 28 with under 18 hours of readings or readings that failed our checks.
Mar 2026No day measured. The others: 31 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 20268 of 31 days measured; a month needs 22. The others: 23 with under 18 hours of readings or readings that failed our checks.
Dec 20251 of 31 days measured; a month needs 22. The others: 30 with under 18 hours of readings or readings that failed our checks.
Nov 20252 of 30 days measured; a month needs 21. The others: 28 with under 18 hours of readings or readings that failed our checks.
Oct 20255 of 31 days measured; a month needs 22. The others: 26 with under 18 hours of readings or readings that failed our checks.
Sep 20257 of 30 days measured; a month needs 21. The others: 23 with under 18 hours of readings or readings that failed our checks.
Aug 20253 of 31 days measured; a month needs 22. The others: 28 with under 18 hours of readings or readings that failed our checks.
Jul 20251 of 31 days measured; a month needs 22. The others: 30 with under 18 hours of readings or readings that failed our checks.
Jun 20251 of 30 days measured; a month needs 21. The others: 29 with under 18 hours of readings or readings that failed our checks.
May 20258 of 31 days measured; a month needs 22. The others: 23 with under 18 hours of readings or readings that failed our checks.
Apr 202510 of 30 days measured; a month needs 21. The others: 20 with under 18 hours of readings or readings that failed our checks.
Mar 20258 of 31 days measured; a month needs 22. The others: 23 with under 18 hours of readings or readings that failed our checks.
Feb 202517 of 28 days measured; a month needs 20. The others: 11 with under 18 hours of readings or readings that failed our checks.
Jan 202514 of 31 days measured; a month needs 22. The others: 17 with under 18 hours of readings or readings that failed our checks.
Oct 20249 of 31 days measured; a month needs 22. The others: 22 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 20241 of 31 days measured; a month needs 22. The others: 30 with under 18 hours of readings or readings that failed our checks.
Jun 20241 of 30 days measured; a month needs 21. The others: 29 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.
Dec 202321 of 31 days measured; a month needs 22. The others: 10 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.

Most's worst months

MonthUS AQIDays measuredWorld rankEpisode
January 2024 7220.3 µg/m³29 of 31263rdof 2,385Europe, 27 January to 2 February 2024
Europe, 28 to 31 January 2024and 3 more
February 2023 6516.4 µg/m³27 of 28266thof 1,129Europe, 28 February to 4 March 2023
Europe, 6 to 25 February 2023
November 2024 6516.4 µg/m³27 of 30356thof 2,624Eastern Europe, 25 to 29 November 2024
Europe, November 2024
September 2023 6114.4 µg/m³28 of 30195thof 2,176–
April 2023 5913.4 µg/m³26 of 30200thof 1,622–
June 2023 5913.4 µg/m³30 of 30461stof 1,603Germany, Slovakia and 2 more countries, June 2023

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.

Most's worst days

DayUS AQIEpisode
22 Jan 2024 15764.7 µg/m³Europe, 8 to 27 January 2024
6 Dec 2023 14754.1 µg/m³Europe, December 2023
8 Feb 2023 13750.3 µg/m³Europe, 6 to 25 February 2023
7 Feb 2023 13448.9 µg/m³Europe, 6 to 25 February 2023
21 Feb 2025 13348.5 µg/m³Europe, 14 February to 1 March 2025
10 Jan 2024 13147.5 µg/m³Europe, 8 to 27 January 2024
31 Mar 2024 12846.5 µg/m³Europe, March and April 2024
31 Jan 2024 12545.4 µg/m³Europe, 27 January to 2 February 2024
Europe, 28 to 31 January 2024
25 Jan 2026 12545.2 µg/m³Europe, January and February 2026
20 Feb 2025 12445.0 µg/m³Europe, 14 February to 1 March 2025

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, Most, Czechia, 1 Jan 2023 – 11 Oct 2026. Monitor data from EEA, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/cz/most/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.

Most 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).