SmogRank / United States / California / Ceres

Ceres, month by month

Ceres has a measured daily mean on 65 days since 8 August 2026. Its worst month was August 2026, at 24 US AQI (4.4 µg/m³), 2,811th of 2,896 cities on that month's world ranking. Its cleanest was September 2026, at 17 US AQI (3.0 µg/m³).

Every month since 2026

2026too few days for a mean (a year needs 199)65 days measured

JanFebMarAprMayJunJulAug24#2,811 Sep17#2,912 Oct48#835

Each square is a month's mean PM2.5 in US AQI from Ceres'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 Ceres 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

Ceres's worst months

Month	US AQI	Days measured	World rank
August 2026	244.4 µg/m³	24 of 31	2,811thof 2,896
September 2026	173.0 µg/m³	30 of 30	2,912thof 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.

Ceres's worst days

Day	US AQI
3 Oct 2026	7019.4 µg/m³
4 Oct 2026	6315.8 µg/m³
19 Aug 2026	5812.7 µg/m³
8 Aug 2026	5511.3 µg/m³
24 Sept 2026	5310.2 µg/m³
6 Oct 2026	5310.0 µg/m³
11 Aug 2026	529.9 µg/m³
2 Oct 2026	529.5 µg/m³
9 Aug 2026	509.0 µg/m³
12 Aug 2026	427.6 µg/m³

Daily means, the highest since 8 Aug 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, Ceres, United States, 8 Aug 2026 – 11 Oct 2026. Monitor data from AirGradient via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/us/ceres/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.

Ceres 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).