SmogRank / Brazil / Rio de Janeiro / Acari

Acari, month by month

Acari has a measured daily mean on 384 days since 23 July 2025. Its worst month was August 2025, at 54 US AQI (10.8 µg/m³), 1,044th of 2,901 cities on that month's world ranking. Its cleanest was September 2026, at 35 US AQI (6.3 µg/m³).

Every month since 2025

202643 so far277 days measured1,911th of 2,791 in the world
Jan43#1,586Feb37#2,298Mar36#2,477Apr42#1,717May42#1,449Jun52#688Jul48#1,689Aug52#938Sep35#1,585Oct42#1,133
2025too few days for a mean (a year needs 256)107 days measured
JanFebMarAprMayJunJul9 daysAug54#1,044Sep46#1,119Oct13 daysNovnoneDec41#2,030
Each square is a month's mean PM2.5 in US AQI from Acari'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 Acari 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

3 months
MonthWhy
Nov 2025No day measured. The others: 30 with no readings from the monitor.
Oct 202513 of 31 days measured; a month needs 22. The others: 11 with no readings from the monitor, 7 with readings for part of the day (a day needs 18 hours).
Jul 20259 of 31 days measured; a month needs 22.

A day counts once 18 hours of it are measured; a month needs 70% of its days.

Acari's worst months

MonthUS AQIDays measuredWorld rank
August 2025 5410.8 µg/m³31 of 311,044thof 2,901
June 2026 529.8 µg/m³29 of 30688thof 2,497
August 2026 529.8 µg/m³31 of 31938thof 2,896
July 2026 488.7 µg/m³30 of 311,689thof 2,784
September 2025 468.3 µg/m³30 of 301,119thof 3,104
January 2026 437.7 µg/m³28 of 311,586thof 2,617

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.

Acari's worst days

DayUS AQI
8 Aug 2025 7924.1 µg/m³
4 Aug 2026 7823.8 µg/m³
1 Jan 2026 7823.6 µg/m³
11 Jun 2026 7723.1 µg/m³
17 Oct 2025 7522.1 µg/m³
7 Aug 2025 7421.7 µg/m³
23 Jul 2025 7421.4 µg/m³
22 Aug 2025 7321.0 µg/m³
20 Aug 2026 7220.4 µg/m³
27 Jul 2025 7120.0 µg/m³

Daily means, the highest since 23 Jul 2025; 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, Acari, Brazil, 23 Jul 2025 – 11 Oct 2026. Monitor data from Rio City Hall via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/br/acari/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.

Acari 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).