SmogRank / United States / Maryland / Essex
Essex, month by month
Essex has a measured daily mean on 418 days since 8 March 2025. Its worst month was February 2026, at 57 US AQI (12.3 µg/m³), 990th of 2,866 cities on that month's world ranking. Its cleanest was October 2025, at 24 US AQI (4.4 µg/m³).
Every month since 2025
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
7 months
| Month | Why |
|---|---|
| Oct 2026 | No day measured. The others: 12 with no readings from the monitor. |
| Sep 2026 | No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks. |
| Aug 2026 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Jul 2026 | 4 of 31 days measured; a month needs 22. The others: 27 with under 18 hours of readings or readings that failed our checks. |
| Jun 2026 | 11 of 30 days measured; a month needs 21. The others: 19 with under 18 hours of readings or readings that failed our checks. |
| Aug 2025 | 15 of 31 days measured; a month needs 22. The others: 16 with under 18 hours of readings or readings that failed our checks. |
| Mar 2025 | 21 of 31 days measured; a month needs 22. The others: 3 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.
Essex's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| February 2026 | 5712.3 µg/m³ | 990thof 2,866 | – |
| January 2026 | 529.5 µg/m³ | 1,157thof 2,617 | – |
| June 2025 | 519.3 µg/m³ | 1,512thof 2,508 | Northern United States and Canada, June 2025 |
| December 2025 | 519.2 µg/m³ | 1,536thof 3,006 | – |
| July 2025 | 468.2 µg/m³ | 1,729thof 2,889 | North-eastern United States, July 2025 |
| March 2026 | 458.1 µg/m³ | 2,114thof 2,971 | – |
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.
Essex's worst days
| Day | US AQI | Episode |
|---|---|---|
| 14 Jun 2025 | 9230.9 µg/m³ | Northern United States and Canada, June 2025 |
| 4 Jul 2025 | 8326.2 µg/m³ | North-eastern United States, July 2025 |
| 28 Feb 2026 | 7923.9 µg/m³ | – |
| 2 Jul 2026 | 7723.0 µg/m³ | – |
| 6 Jan 2026 | 7421.7 µg/m³ | – |
| 26 Feb 2026 | 7421.5 µg/m³ | – |
| 21 Nov 2025 | 7421.2 µg/m³ | – |
| 5 Mar 2026 | 7320.7 µg/m³ | – |
| 13 Jun 2025 | 7220.3 µg/m³ | Northern United States and Canada, June 2025 |
| 18 Feb 2026 | 7220.3 µg/m³ | – |
Daily means, the highest since 8 Mar 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, Essex, United States, 8 Mar 2025 – 5 Jul 2026. Monitor data from AirNow, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/us/essex/history (accessed 13 Oct 2026).
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.
Essex now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-13 04:07 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).