SmogRank / United States / Texas / Highlands
Highlands, month by month
Highlands has a measured daily mean on 1,236 days since 1 January 2023. Its worst month was March 2024, at 65 US AQI (16.4 µg/m³), 211th of 1,698 cities on that month's world ranking. Its cleanest was September 2024, at 42 US AQI (7.5 µg/m³). 2025 averaged 54 US AQI (10.6 µg/m³), against 54 US AQI (10.6 µg/m³) in 2024.
Every month since 2023
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
2 months
| Month | Why |
|---|---|
| Mar 2023 | 10 of 31 days measured; a month needs 22. The others: 20 missing from OpenAQ's archive, 1 with under 18 hours of readings or readings that failed our checks. |
| Feb 2023 | 2 of 28 days measured; a month needs 20. The others: 25 missing from OpenAQ's archive, 1 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.
Highlands's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| March 2024 | 6516.4 µg/m³ | 211thof 1,698 | Southern United States and Mexico, March 2024 |
| October 2025 | 6315.8 µg/m³ | 338thof 2,614 | – |
| May 2024 | 6315.3 µg/m³ | 266thof 2,684 | Southern United States and Mexico, 19 to 28 May 2024 Southern United States and Mexico, 7 to 10 May 2024 |
| July 2023 | 6215.2 µg/m³ | 136thof 1,432 | Texas, United States, July 2023 |
| May 2023 | 6114.7 µg/m³ | 149thof 1,600 | Southern United States, May 2023 |
| July 2026 | 6014.1 µg/m³ | 585thof 2,784 | – |
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.
Highlands's worst days
| Day | US AQI | Episode |
|---|---|---|
| 14 Mar 2024 | 13549.5 µg/m³ | – |
| 9 May 2024 | 11240.0 µg/m³ | Southern United States and Mexico, 7 to 10 May 2024 |
| 27 May 2024 | 11039.3 µg/m³ | Southern United States and Mexico, 19 to 28 May 2024 |
| 31 Jul 2024 | 9231.2 µg/m³ | Southern and eastern United States and Mexico, July and August 2024 |
| 15 Mar 2024 | 9130.5 µg/m³ | – |
| 7 Mar 2024 | 8929.5 µg/m³ | – |
| 24 May 2023 | 8627.9 µg/m³ | Southern United States, May 2023 |
| 5 Mar 2024 | 8527.3 µg/m³ | Southern United States and Mexico, March 2024 |
| 12 Mar 2024 | 8527.3 µg/m³ | – |
| 23 May 2023 | 8326.3 µg/m³ | Southern United States, May 2023 |
Daily means, the highest since 1 Jan 2023; 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, Highlands, United States, 1 Jan 2023 – 11 Oct 2026. Monitor data from AirNow, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/us/highlands/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.
Highlands 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).