SmogRank / United States / South Dakota / Pierre
Pierre, month by month
Pierre has a measured daily mean on 1,273 days since 1 January 2023. Its worst month was May 2023, at 59 US AQI (13.5 µg/m³), 184th of 1,600 cities on that month's world ranking. Its cleanest was April 2024, at 11 US AQI (1.9 µg/m³). 2025 averaged 28 US AQI (5.1 µg/m³), against 20 US AQI (3.6 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 | 11 of 31 days measured; a month needs 22. The others: 20 missing from OpenAQ's archive. |
| Feb 2023 | 3 of 28 days measured; a month needs 20. The others: 25 missing from OpenAQ's archive. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Pierre's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| May 2023 | 5913.5 µg/m³ | 184thof 1,600 | Northern United States and Canada, May 2023 |
| September 2023 | 529.9 µg/m³ | 607thof 2,176 | Northern United States and Canada, August and September 2023 |
| July 2023 | 529.7 µg/m³ | 693rdof 1,432 | United States and Canada, July 2023 |
| September 2025 | 488.6 µg/m³ | 1,015thof 3,104 | – |
| August 2025 | 478.5 µg/m³ | 1,639thof 2,901 | North-eastern United States and Canada, 29 July to 9 August 2025 |
| August 2023 | 478.4 µg/m³ | 911thof 1,980 | Northern United States and Canada, August and September 2023 Northern United States, August 2023 |
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.
Pierre's worst days
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, Pierre, 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/pierre/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.
Pierre 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).