SmogRank / United States / Pennsylvania / Warren

Warren, month by month

Warren, Pennsylvania has a measured daily mean on 401 days since 12 August 2025. Its worst month was July 2026, at 72 US AQI (20.3 µg/m³), 322nd of 2,784 cities on that month's world ranking. Its cleanest was October 2025, at 21 US AQI (3.8 µg/m³).

Every month since 2025

202643 so far274 days measured1,963rd of 2,793 in the world
Jan31#2,222Feb48#1,771Mar30#2,627Apr32#2,307May28#2,348Jun38#1,550Jul72#322Aug41#1,948Sep27#2,432Oct23#2,452
2025too few days for a mean (a year needs 256)127 days measured
JanFebMarAprMayJunJulAug17 daysSep36#1,887Oct21#2,448Nov29#2,349Dec32#2,530
Each square is a month's mean PM2.5 in US AQI from Warren'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 Warren 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

1 month
MonthWhy
Aug 202517 of 31 days measured; a month needs 22. The others: 2 with no readings from the monitor, 1 with readings for part of the day (a day needs 18 hours).

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

Warren's worst months

MonthUS AQIDays measuredWorld rankEpisode
July 2026 7220.3 µg/m³31 of 31322ndof 2,784Northern United States and Canada, July 2026
February 2026 488.7 µg/m³28 of 281,771stof 2,866–
August 2026 417.3 µg/m³31 of 311,948thof 2,896–
June 2026 386.8 µg/m³27 of 301,550thof 2,497–
September 2025 366.5 µg/m³30 of 301,887thof 3,104–
December 2025 325.7 µg/m³27 of 312,530thof 3,006–

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.

Warren's worst days

DayUS AQIEpisode
16 Jul 2026 199124.0 µg/m³Northern United States and Canada, July 2026
17 Jul 2026 190111.0 µg/m³Northern United States and Canada, July 2026
18 Jul 2026 16068.9 µg/m³Northern United States and Canada, July 2026
19 Jul 2026 8929.4 µg/m³Northern United States and Canada, July 2026
1 Jul 2026 7421.7 µg/m³–
2 Jul 2026 7019.2 µg/m³–
15 Aug 2025 6919.0 µg/m³–
17 Feb 2026 6918.9 µg/m³–
20 Jul 2026 6717.9 µg/m³Northern United States and Canada, July 2026
21 Jul 2026 6717.9 µg/m³Northern United States and Canada, July 2026

Daily means, the highest since 12 Aug 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, Warren, Pennsylvania, United States, 12 Aug 2025 – 11 Oct 2026. Monitor data from AirNow, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/us/warren-pennsylvania/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.

Warren 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).