SmogRank / Sweden / Stockholm / Upplands Väsby

Upplands Väsby, month by month

Upplands Väsby has a measured daily mean on 585 days since 11 January 2023. Its worst month was February 2025, at 45 US AQI (8.1 µg/m³), 1,556th of 2,633 cities on that month's world ranking. Its cleanest was August 2025, at 17 US AQI (3.0 µg/m³).

Every month since 2023

2026too few days for a mean (a year needs 200)72 days measured
Jan8 daysFeb32#2,465Mar44#2,137Apr7 daysMay6 daysJun2 daysJulnoneAugnoneSepnoneOctnone
2025too few days for a mean (a year needs 256)247 days measured
Jan21#2,396Feb45#1,556Mar19 daysApr24#2,713May21 daysJun15 daysJul29#2,571Aug17#2,884Sep24#2,839Oct19 daysNov18 daysDec7 days
2024too few days for a mean (a year needs 257)210 days measured
Jan3 daysFeb28#2,131Mar15 daysApr22#2,229May29#2,202Jun23#2,355Jul19#2,491Aug12 daysSepnoneOct9 daysNov18#2,554Dec14 days
2023too few days for a mean (a year needs 256)56 days measured
Jan7 daysFeb24#1,083Mar20 daysApr3 daysMaynoneJunnoneJul1 dayAugnoneSepnoneOctnoneNovnoneDecnone
Each square is a month's mean PM2.5 in US AQI from Upplands Väsby'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 Upplands Väsby 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

31 months
MonthWhy
Oct 2026No day measured. The others: 1 with no readings from the monitors, 11 with readings for part of the day (a day needs 18 hours).
Sep 2026No day measured. The others: 30 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 20267 of 30 days measured; a month needs 21. The others: 23 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 20257 of 31 days measured; a month needs 22. The others: 24 with under 18 hours of readings or readings that failed our checks.
Nov 202518 of 30 days measured; a month needs 21. The others: 12 with under 18 hours of readings or readings that failed our checks.
Oct 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 202515 of 30 days measured; a month needs 21. The others: 15 with under 18 hours of readings or readings that failed our checks.
May 202521 of 31 days measured; a month needs 22. The others: 10 with under 18 hours of readings or readings that failed our checks.
Mar 202519 of 31 days measured; a month needs 22. The others: 12 with under 18 hours of readings or readings that failed our checks.
Dec 202414 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 202412 of 31 days measured; a month needs 22. The others: 19 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.
Jan 20243 of 31 days measured; a month needs 22. The others: 28 with under 18 hours of readings or readings that failed our checks.
Dec 2023No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Nov 2023No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
Oct 2023No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Sep 2023No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
Aug 2023No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Jul 20231 of 31 days measured; a month needs 22. The others: 30 with under 18 hours of readings or readings that failed our checks.
Jun 2023No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
May 2023No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Apr 20233 of 30 days measured; a month needs 21. The others: 27 with under 18 hours of readings or readings that failed our checks.
Mar 202320 of 31 days measured; a month needs 22. The others: 11 with under 18 hours of readings or readings that failed our checks.
Jan 20237 of 31 days measured; a month needs 22. The others: 14 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.

Upplands Väsby's worst months

MonthUS AQIDays measuredWorld rank
February 2025 458.1 µg/m³22 of 281,556thof 2,633
March 2026 448.0 µg/m³26 of 312,137thof 2,971
February 2026 325.8 µg/m³23 of 282,465thof 2,866
May 2024 295.3 µg/m³29 of 312,202ndof 2,684
July 2025 295.2 µg/m³26 of 312,571stof 2,889
February 2024 285.0 µg/m³28 of 292,131stof 2,486

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.

Upplands Väsby's worst days

DayUS AQI
23 Feb 2025 8024.6 µg/m³
22 Feb 2025 7924.3 µg/m³
11 Mar 2026 7823.5 µg/m³
21 Feb 2025 7421.4 µg/m³
18 Mar 2023 6617.3 µg/m³
8 Mar 2025 6516.8 µg/m³
9 Mar 2025 6215.2 µg/m³
18 Jun 2024 6114.5 µg/m³
8 Mar 2026 6114.3 µg/m³
9 Mar 2026 6014.0 µg/m³

Daily means, the highest since 11 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, Upplands Väsby, Sweden, 11 Jan 2023 – 27 Jun 2026. Monitor data from EEA, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/se/upplands-vaesby/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.

Upplands Väsby 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).