SmogRank / Portugal / Lisbon / Cacém

Cacém, month by month

Cacém has a measured daily mean on 406 days since 11 January 2023. Its worst month was December 2023, at 58 US AQI (13.1 µg/m³), 355th of 2,247 cities on that month's world ranking. Its cleanest was September 2023, at 32 US AQI (5.8 µg/m³).

Every month since 2023

2026too few days for a mean (a year needs 199)14 days measured
Jan3 daysFeb1 dayMarnoneAprnoneMaynoneJunnoneJulnoneAugnoneSep5 daysOct5 days
2025too few days for a mean (a year needs 256)1 day measured
JannoneFebnoneMarnoneAprnoneMaynoneJunnoneJulnoneAug1 daySepnoneOctnoneNovnoneDecnone
2024too few days for a mean (a year needs 257)71 days measured
Jan57#645Feb52#688Mar8 daysApr2 daysMay1 dayJun2 daysJulnoneAug1 daySepnoneOctnoneNovnoneDecnone
202346 for the year320 days measured815th of 1,355 in the world
Jan7 daysFeb55#586Mar43#518Apr33#1,207May44#958Jun43#1,134Jul34#1,087Aug41#1,177Sep32#1,837Oct45#738Nov48#941Dec58#355
Each square is a month's mean PM2.5 in US AQI from Cacém'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 Cacém 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

33 months
MonthWhy
Oct 20265 of 11 days measured; a month needs 8. The others: 2 with readings for part of the day (a day needs 18 hours), 4 with readings left out by our checks.
Sep 20265 of 30 days measured; a month needs 21. The others: 25 with readings left out by our checks.
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 2026No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
May 2026No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Apr 2026No day measured. The others: 30 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 20263 of 31 days measured; a month needs 22. The others: 28 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 2025No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Sep 2025No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
Aug 20251 of 31 days measured; a month needs 22. The others: 30 with under 18 hours of readings or readings that failed our checks.
Jul 2025No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Jun 2025No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
May 2025No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Apr 2025No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
Mar 2025No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Feb 2025No day measured. The others: 28 with under 18 hours of readings or readings that failed our checks.
Jan 2025No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Dec 2024No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Nov 2024No day measured. The others: 30 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 20241 of 31 days measured; a month needs 22. The others: 30 with under 18 hours of readings or readings that failed our checks.
Jul 2024No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Jun 20242 of 30 days measured; a month needs 21. The others: 28 with under 18 hours of readings or readings that failed our checks.
May 20241 of 31 days measured; a month needs 22. The others: 30 with under 18 hours of readings or readings that failed our checks.
Apr 20242 of 30 days measured; a month needs 21. The others: 28 with under 18 hours of readings or readings that failed our checks.
Mar 20248 of 31 days measured; a month needs 22. The others: 23 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.

Cacém's worst months

MonthUS AQIDays measuredWorld rankEpisode
December 2023 5813.1 µg/m³31 of 31355thof 2,247Spain, France and 2 more countries, December 2023 to January 2024
January 2024 5712.5 µg/m³31 of 31645thof 2,385Spain, France and 2 more countries, December 2023 to January 2024
February 2023 5511.3 µg/m³27 of 28586thof 1,129–
February 2024 529.8 µg/m³26 of 29688thof 2,486–
November 2023 488.7 µg/m³30 of 30941stof 2,243–
October 2023 458.1 µg/m³27 of 31738thof 2,012–

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.

Cacém's worst days

DayUS AQIEpisode
25 Dec 2023 9834.2 µg/m³Spain, France and 2 more countries, December 2023 to January 2024
1 Jan 2024 8929.7 µg/m³Spain, France and 2 more countries, December 2023 to January 2024
16 Apr 2024 8527.4 µg/m³–
30 Dec 2023 8426.8 µg/m³Spain, France and 2 more countries, December 2023 to January 2024
24 Dec 2023 8326.3 µg/m³–
14 Jan 2023 7522.2 µg/m³–
26 Dec 2023 7522.2 µg/m³Spain, France and 2 more countries, December 2023 to January 2024
8 Jan 2024 7421.6 µg/m³–
5 Feb 2024 7421.5 µg/m³–
10 Jan 2024 7220.2 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, Cacém, Portugal, 11 Jan 2023 – 11 Oct 2026. Monitor data from EEA, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/pt/cacem/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.

Cacém 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).