SmogRank / United States / New Jersey / Mendham
Mendham, month by month
Mendham has a measured daily mean on 838 days since 3 January 2024. Its worst month was July 2026, at 61 US AQI (14.4 µg/m³), 560th of 2,784 cities on that month's world ranking. Its cleanest was January 2024, at 18 US AQI (3.2 µg/m³). 2025 averaged 33 US AQI (6.0 µg/m³), against 28 US AQI (5.1 µg/m³) in 2024.
Every month since 2024
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
| Month | Why |
|---|---|
| Jun 2026 | 20 of 30 days measured; a month needs 21. The others: 10 with under 18 hours of readings or readings that failed our checks. |
| Jan 2026 | 8 of 31 days measured; a month needs 22. The others: 23 with under 18 hours of readings or readings that failed our checks. |
| Dec 2025 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Nov 2025 | 11 of 30 days measured; a month needs 21. The others: 19 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.
Mendham's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| July 2026 | 6114.4 µg/m³ | 560thof 2,784 | Northern United States and Canada, July 2026 |
| February 2026 | 519.3 µg/m³ | 1,589thof 2,866 | – |
| June 2025 | 519.2 µg/m³ | 1,543rdof 2,508 | – |
| July 2025 | 498.8 µg/m³ | 1,560thof 2,889 | North-eastern United States and Canada, 29 July to 9 August 2025 North-eastern United States and Canada, 24 to 28 July 2025 |
| August 2025 | 488.6 µg/m³ | 1,605thof 2,901 | North-eastern United States and Canada, 29 July to 9 August 2025 |
| June 2024 | 437.8 µg/m³ | 1,392ndof 2,563 | – |
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.
Mendham's worst days
| Day | US AQI | Episode |
|---|---|---|
| 16 Jul 2026 | 17082.4 µg/m³ | Northern United States and Canada, July 2026 |
| 18 Jul 2026 | 14352.7 µg/m³ | Northern United States and Canada, July 2026 |
| 17 Jul 2026 | 12746.2 µg/m³ | Northern United States and Canada, July 2026 |
| 5 Aug 2025 | 9532.5 µg/m³ | North-eastern United States and Canada, 29 July to 9 August 2025 |
| 7 Feb 2026 | 8728.5 µg/m³ | – |
| 27 Jul 2025 | 8627.9 µg/m³ | North-eastern United States and Canada, 24 to 28 July 2025 |
| 15 Jul 2026 | 8527.4 µg/m³ | Northern United States and Canada, July 2026 |
| 18 Feb 2026 | 8024.7 µg/m³ | – |
| 4 Aug 2025 | 7722.9 µg/m³ | North-eastern United States and Canada, 29 July to 9 August 2025 |
| 6 Aug 2025 | 7521.9 µg/m³ | North-eastern United States and Canada, 29 July to 9 August 2025 |
Daily means, the highest since 3 Jan 2024; 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, Mendham, United States, 3 Jan 2024 – 11 Oct 2026. Monitor data from AirNow, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/us/mendham/history (accessed 12 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.
Mendham 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).