SmogRank / Sierra Leone / Western Area / Freetown

Freetown, month by month

Freetown has a measured daily mean on 52 days since 20 May 2026. Its worst month was September 2026, at 61 US AQI (14.5 µg/m³), 393rd of 2,981 cities on that month's world ranking.

Every month since 2026

2026too few days for a mean (a year needs 199)52 days measured
JanFebMarAprMay3 daysJun3 daysJul5 daysAug9 daysSep61#393Oct59#313
Each square is a month's mean PM2.5 in US AQI from Freetown'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 Freetown 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

4 months
MonthWhy
Aug 20269 of 31 days measured; a month needs 22. The others: 22 with under 18 hours of readings or readings that failed our checks.
Jul 20265 of 31 days measured; a month needs 22. The others: 26 with under 18 hours of readings or readings that failed our checks.
Jun 20263 of 30 days measured; a month needs 21. The others: 27 with under 18 hours of readings or readings that failed our checks.
May 20263 of 31 days measured; a month needs 22. The others: 9 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.

Freetown's worst months

MonthUS AQIDays measuredWorld rank
September 2026 6114.5 µg/m³23 of 30393rdof 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.

Freetown's worst days

DayUS AQI
28 Sept 2026 8024.7 µg/m³
24 Aug 2026 7522.0 µg/m³
28 Jun 2026 7521.8 µg/m³
25 Aug 2026 7421.3 µg/m³
21 May 2026 7321.0 µg/m³
30 Sept 2026 6918.9 µg/m³
22 Sept 2026 6818.3 µg/m³
15 Sept 2026 6818.1 µg/m³
29 Sept 2026 6717.5 µg/m³
7 Oct 2026 6717.5 µg/m³

Daily means, the highest since 20 May 2026; 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, Freetown, Sierra Leone, 20 May 2026 – 11 Oct 2026. Monitor data from Clarity via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/sl/freetown/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.

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

Updated 2026-10-12 20:07 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).