SmogRank / United States / Wisconsin

Air quality in Greendale

Wisconsin, United States. Over the last 24 hours its air rated Good, the 1,090th most polluted of 1,322 cities measured.

24-hour average23US AQI
Good

PM2.5 4.2 µg/m³, 0.3× the WHO 24-hour guideline. The figure the 24-hour ranking uses.

Latest hour: 18 US AQI (3.3 µg/m³), local time

Below its usual for early October (5.6 µg/m³).

Where Greendale ranks

24 hours#1,090of 1,322, at 23 US AQI (4.2 µg/m³)
7 days#1,617of 2,660, at 35 US AQI (6.3 µg/m³)
30 days#2,207of 2,883, at 28 US AQI (5.1 µg/m³)
This year#1,212of 2,736, at 51 US AQI (9.3 µg/m³)

Why it ranks here

Seasonal. Over the past year its worst months were July, averaging up to 25.5 µg/m³ against 4.3 in its cleanest month. Seasonal peaks usually come from heating, crop burning, fire or dust seasons.

Based on Greendale's own measurements; causes are the usual kinds for a pattern like this, not a confirmed source.

Bad-air episodes that reached Greendale

Times when Greendale and many cities around it had PM2.5 at twice their usual or more on the same days. Latest 8 of 13. All episodes.

The last 12 months, day by day

1102031Nov 2025DecJan 2026FebMarAprMayJunJulAugSepOct2025-11-01: 6.4 µg/m³2025-11-02: 4.0 µg/m³2025-11-03: 3.3 µg/m³2025-11-04: 5.0 µg/m³2025-11-05: 6.0 µg/m³2025-11-06: 5.4 µg/m³2025-11-07: 5.8 µg/m³2025-11-08: 1.3 µg/m³2025-11-09: 2.3 µg/m³2025-11-10: 2.5 µg/m³2025-11-11: 5.2 µg/m³2025-11-12: 3.9 µg/m³2025-11-13: 8.0 µg/m³2025-11-14: no daily value, under 18 hours of readings, or readings that failed our checks2025-11-15: no daily value, under 18 hours of readings, or readings that failed our checks2025-11-16: no daily value, under 18 hours of readings, or readings that failed our checks2025-11-17: no daily value, under 18 hours of readings, or readings that failed our checks2025-11-18: no daily value, under 18 hours of readings, or readings that failed our checks2025-11-19: no daily value, under 18 hours of readings, or readings that failed our checks2025-11-20: no daily value, under 18 hours of readings, or readings that failed our checks2025-11-21: 9.6 µg/m³2025-11-22: 9.9 µg/m³2025-11-23: 8.1 µg/m³2025-11-24: 15.3 µg/m³2025-11-25: 14.1 µg/m³2025-11-26: 1.8 µg/m³2025-11-27: 2.0 µg/m³2025-11-28: 4.3 µg/m³2025-11-29: 5.8 µg/m³2025-11-30: 4.9 µg/m³2025-12-01: 8.5 µg/m³2025-12-02: 12.9 µg/m³2025-12-03: 13.0 µg/m³2025-12-04: 7.9 µg/m³2025-12-05: 11.6 µg/m³2025-12-06: 12.7 µg/m³2025-12-07: 8.8 µg/m³2025-12-08: 7.9 µg/m³2025-12-09: 14.2 µg/m³2025-12-10: 6.3 µg/m³2025-12-11: 9.1 µg/m³2025-12-12: 13.7 µg/m³2025-12-13: 9.8 µg/m³2025-12-14: 5.7 µg/m³2025-12-15: 9.3 µg/m³2025-12-16: 15.7 µg/m³2025-12-17: 12.8 µg/m³2025-12-18: 8.9 µg/m³2025-12-19: 4.8 µg/m³2025-12-20: 3.9 µg/m³2025-12-21: 4.4 µg/m³2025-12-22: 5.3 µg/m³2025-12-23: 10.2 µg/m³2025-12-24: 12.1 µg/m³2025-12-25: 9.9 µg/m³2025-12-26: 10.8 µg/m³2025-12-27: 10.1 µg/m³2025-12-28: 4.0 µg/m³2025-12-29: 3.5 µg/m³2025-12-30: 4.7 µg/m³2025-12-31: 6.9 µg/m³2026-01-01: 4.5 µg/m³2026-01-02: 10.4 µg/m³2026-01-03: 8.2 µg/m³2026-01-04: 7.8 µg/m³2026-01-05: 16.1 µg/m³2026-01-06: 24.9 µg/m³2026-01-07: 12.0 µg/m³2026-01-08: 10.9 µg/m³2026-01-09: 4.6 µg/m³2026-01-10: 5.7 µg/m³2026-01-11: 5.7 µg/m³2026-01-12: 6.0 µg/m³2026-01-13: 4.7 µg/m³2026-01-14: 3.5 µg/m³2026-01-15: 4.4 µg/m³2026-01-16: 6.0 µg/m³2026-01-17: 4.5 µg/m³2026-01-18: 5.7 µg/m³2026-01-19: no daily value, under 18 hours of readings, or readings that failed our checks2026-01-20: no daily value, under 18 hours of readings, or readings that failed our checks2026-01-21: 11.2 µg/m³2026-01-22: 8.1 µg/m³2026-01-23: 11.6 µg/m³2026-01-24: 11.3 µg/m³2026-01-25: 5.5 µg/m³2026-01-26: 11.5 µg/m³2026-01-27: 13.4 µg/m³2026-01-28: 10.5 µg/m³2026-01-29: 8.6 µg/m³2026-01-30: 5.9 µg/m³2026-01-31: 6.2 µg/m³2026-02-01: 16.4 µg/m³2026-02-02: 14.3 µg/m³2026-02-03: 13.6 µg/m³2026-02-04: 9.2 µg/m³2026-02-05: 14.5 µg/m³2026-02-06: 8.7 µg/m³2026-02-07: 5.0 µg/m³2026-02-08: 4.1 µg/m³2026-02-09: 26.5 µg/m³2026-02-10: 13.9 µg/m³2026-02-11: 8.5 µg/m³2026-02-12: 7.4 µg/m³2026-02-13: 14.9 µg/m³2026-02-14: 26.2 µg/m³2026-02-15: 22.9 µg/m³2026-02-16: 13.0 µg/m³2026-02-17: 17.8 µg/m³2026-02-18: 7.7 µg/m³2026-02-19: 4.5 µg/m³2026-02-20: 4.8 µg/m³2026-02-21: 4.6 µg/m³2026-02-22: 3.9 µg/m³2026-02-23: 4.8 µg/m³2026-02-24: 8.6 µg/m³2026-02-25: 8.0 µg/m³2026-02-26: 10.1 µg/m³2026-02-27: 9.8 µg/m³2026-02-28: 4.4 µg/m³2026-03-01: 4.0 µg/m³2026-03-02: 5.3 µg/m³2026-03-03: 10.2 µg/m³2026-03-04: 16.3 µg/m³2026-03-05: 13.7 µg/m³2026-03-06: 7.2 µg/m³2026-03-07: 3.9 µg/m³2026-03-08: 4.9 µg/m³2026-03-09: 5.1 µg/m³2026-03-10: 4.8 µg/m³2026-03-11: 3.3 µg/m³2026-03-12: 4.0 µg/m³2026-03-13: 2.5 µg/m³2026-03-14: 2.6 µg/m³2026-03-15: 3.2 µg/m³2026-03-16: 2.5 µg/m³2026-03-17: 5.5 µg/m³2026-03-18: 9.3 µg/m³2026-03-19: 17.6 µg/m³2026-03-20: 17.3 µg/m³2026-03-21: 12.5 µg/m³2026-03-22: 5.1 µg/m³2026-03-23: 3.0 µg/m³2026-03-24: 7.6 µg/m³2026-03-25: 12.0 µg/m³2026-03-26: 16.3 µg/m³2026-03-27: 3.5 µg/m³2026-03-28: 4.5 µg/m³2026-03-29: 7.0 µg/m³2026-03-30: 10.4 µg/m³2026-03-31: 8.0 µg/m³2026-04-01: 2.4 µg/m³2026-04-02: 4.4 µg/m³2026-04-03: 3.2 µg/m³2026-04-04: 2.9 µg/m³2026-04-05: 2.7 µg/m³2026-04-06: 3.3 µg/m³2026-04-07: 2.5 µg/m³2026-04-08: 5.7 µg/m³2026-04-09: 5.0 µg/m³2026-04-10: 6.0 µg/m³2026-04-11: 5.5 µg/m³2026-04-12: 9.3 µg/m³2026-04-13: 5.4 µg/m³2026-04-14: 4.7 µg/m³2026-04-15: 4.8 µg/m³2026-04-16: 3.7 µg/m³2026-04-17: 6.2 µg/m³2026-04-18: 3.7 µg/m³2026-04-19: 3.6 µg/m³2026-04-20: 3.7 µg/m³2026-04-21: 8.1 µg/m³2026-04-22: 7.7 µg/m³2026-04-23: 7.7 µg/m³2026-04-24: 6.0 µg/m³2026-04-25: 4.5 µg/m³2026-04-26: 6.4 µg/m³2026-04-27: 6.7 µg/m³2026-04-28: 2.6 µg/m³2026-04-29: 2.9 µg/m³2026-04-30: 4.2 µg/m³2026-05-01: 2.9 µg/m³2026-05-02: 5.7 µg/m³2026-05-03: 6.4 µg/m³2026-05-04: 6.4 µg/m³2026-05-05: 2.8 µg/m³2026-05-06: 5.7 µg/m³2026-05-07: 6.3 µg/m³2026-05-08: 8.6 µg/m³2026-05-09: 5.2 µg/m³2026-05-10: 3.1 µg/m³2026-05-11: 1.6 µg/m³2026-05-12: 5.1 µg/m³2026-05-13: no daily value, under 18 hours of readings, or readings that failed our checks2026-05-14: no daily value, under 18 hours of readings, or readings that failed our checks2026-05-15: 5.1 µg/m³2026-05-16: 6.7 µg/m³2026-05-17: 7.8 µg/m³2026-05-18: 7.8 µg/m³2026-05-19: 3.8 µg/m³2026-05-20: 3.2 µg/m³2026-05-21: 2.2 µg/m³2026-05-22: 4.0 µg/m³2026-05-23: 5.9 µg/m³2026-05-24: 10.6 µg/m³2026-05-25: 10.1 µg/m³2026-05-26: 5.7 µg/m³2026-05-27: 6.4 µg/m³2026-05-28: 3.2 µg/m³2026-05-29: 6.1 µg/m³2026-05-30: 7.2 µg/m³2026-05-31: 3.6 µg/m³2026-06-01: 3.8 µg/m³2026-06-02: 4.0 µg/m³2026-06-03: 5.5 µg/m³2026-06-04: 7.1 µg/m³2026-06-05: 9.8 µg/m³2026-06-06: 8.2 µg/m³2026-06-07: 7.8 µg/m³2026-06-08: 6.7 µg/m³2026-06-09: 4.6 µg/m³2026-06-10: 5.1 µg/m³2026-06-11: 3.5 µg/m³2026-06-12: 5.4 µg/m³2026-06-13: 4.4 µg/m³2026-06-14: 2.9 µg/m³2026-06-15: 3.0 µg/m³2026-06-16: 3.4 µg/m³2026-06-17: 4.7 µg/m³2026-06-18: 4.7 µg/m³2026-06-19: 4.2 µg/m³2026-06-20: 3.9 µg/m³2026-06-21: 5.1 µg/m³2026-06-22: 3.6 µg/m³2026-06-23: 4.1 µg/m³2026-06-24: 6.1 µg/m³2026-06-25: 6.2 µg/m³2026-06-26: 6.3 µg/m³2026-06-27: 7.6 µg/m³2026-06-28: 6.7 µg/m³2026-06-29: 8.8 µg/m³2026-06-30: 17.4 µg/m³2026-07-01: 22.9 µg/m³2026-07-02: 5.8 µg/m³2026-07-03: 5.3 µg/m³2026-07-04: 11.9 µg/m³2026-07-05: 11.2 µg/m³2026-07-06: 7.8 µg/m³2026-07-07: 11.7 µg/m³2026-07-08: 9.6 µg/m³2026-07-09: 5.4 µg/m³2026-07-10: 7.3 µg/m³2026-07-11: 11.6 µg/m³2026-07-12: 11.8 µg/m³2026-07-13: 11.6 µg/m³2026-07-14: 9.2 µg/m³2026-07-15: 36.7 µg/m³2026-07-16: 248.0 µg/m³2026-07-17: 128.0 µg/m³2026-07-18: 45.4 µg/m³2026-07-19: 62.2 µg/m³2026-07-20: 43.0 µg/m³2026-07-21: 7.1 µg/m³2026-07-22: 4.4 µg/m³2026-07-23: 6.2 µg/m³2026-07-24: 7.5 µg/m³2026-07-25: 7.5 µg/m³2026-07-26: 11.2 µg/m³2026-07-27: 9.6 µg/m³2026-07-28: 8.8 µg/m³2026-07-29: 5.5 µg/m³2026-07-30: 8.8 µg/m³2026-07-31: 8.7 µg/m³2026-08-01: 8.7 µg/m³2026-08-02: 8.8 µg/m³2026-08-03: 6.6 µg/m³2026-08-04: 10.0 µg/m³2026-08-05: 17.7 µg/m³2026-08-06: 15.1 µg/m³2026-08-07: 7.5 µg/m³2026-08-08: 6.9 µg/m³2026-08-09: 5.3 µg/m³2026-08-10: 8.1 µg/m³2026-08-11: 8.7 µg/m³2026-08-12: 10.7 µg/m³2026-08-13: 10.5 µg/m³2026-08-14: 8.7 µg/m³2026-08-15: 7.4 µg/m³2026-08-16: 5.5 µg/m³2026-08-17: 3.9 µg/m³2026-08-18: 6.0 µg/m³2026-08-19: 5.9 µg/m³2026-08-20: 13.8 µg/m³2026-08-21: 11.3 µg/m³2026-08-22: 7.6 µg/m³2026-08-23: 11.2 µg/m³2026-08-24: 5.0 µg/m³2026-08-25: 6.6 µg/m³2026-08-26: 9.1 µg/m³2026-08-27: 7.7 µg/m³2026-08-28: 10.4 µg/m³2026-08-29: 12.4 µg/m³2026-08-30: 9.5 µg/m³2026-08-31: 11.6 µg/m³2026-09-01: 11.4 µg/m³2026-09-02: 11.0 µg/m³2026-09-03: 8.0 µg/m³2026-09-04: 3.8 µg/m³2026-09-05: 5.2 µg/m³2026-09-06: 4.6 µg/m³2026-09-07: 4.8 µg/m³2026-09-08: 6.3 µg/m³2026-09-09: 5.4 µg/m³2026-09-10: 3.5 µg/m³2026-09-11: 4.3 µg/m³2026-09-12: 6.8 µg/m³2026-09-13: 3.9 µg/m³2026-09-14: 4.0 µg/m³2026-09-15: 4.4 µg/m³2026-09-16: 2.6 µg/m³2026-09-17: 4.1 µg/m³2026-09-18: 3.4 µg/m³2026-09-19: 4.4 µg/m³2026-09-20: 3.0 µg/m³2026-09-21: 2.5 µg/m³2026-09-22: no daily value, under 18 hours of readings, or readings that failed our checks2026-09-23: no daily value, under 18 hours of readings, or readings that failed our checks2026-09-24: 3.8 µg/m³2026-09-25: 4.2 µg/m³2026-09-26: 7.3 µg/m³2026-09-27: 10.1 µg/m³2026-09-28: 5.8 µg/m³2026-09-29: 8.2 µg/m³2026-09-30: 9.2 µg/m³2026-10-01: 8.4 µg/m³2026-10-02: 3.8 µg/m³2026-10-03: 4.5 µg/m³2026-10-04: 4.3 µg/m³
23 of 350 measured days were over the WHO 24-hour guideline (15 µg/m³). 15 days without a value, all with under 18 hours of readings or readings that failed our checks; point at a grey square for its reason (why days go blank). One row per month, one square per local day.
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

Last 4 days, hour by hour

15303 Oct 20:00 local, 2026-10-04 01:00 UTC: 4.5 µg/m³3 Oct 21:00 local, 2026-10-04 02:00 UTC: 5.1 µg/m³3 Oct 22:00 local, 2026-10-04 03:00 UTC: 4.5 µg/m³3 Oct 23:00 local, 2026-10-04 04:00 UTC: 4.3 µg/m³4 Oct 00:00 local, 2026-10-04 05:00 UTC: 4.2 µg/m³4 Oct 01:00 local, 2026-10-04 06:00 UTC: 4.9 µg/m³4 Oct 02:00 local, 2026-10-04 07:00 UTC: 5.5 µg/m³4 Oct 03:00 local, 2026-10-04 08:00 UTC: 6.3 µg/m³4 Oct 04:00 local, 2026-10-04 09:00 UTC: 6.7 µg/m³4 Oct 05:00 local, 2026-10-04 10:00 UTC: 6.8 µg/m³4 Oct 06:00 local, 2026-10-04 11:00 UTC: 6.6 µg/m³4 Oct 07:00 local, 2026-10-04 12:00 UTC: 5.5 µg/m³4 Oct 08:00 local, 2026-10-04 13:00 UTC: 4.3 µg/m³4 Oct 09:00 local, 2026-10-04 14:00 UTC: 3.3 µg/m³4 Oct 10:00 local, 2026-10-04 15:00 UTC: 3.6 µg/m³4 Oct 11:00 local, 2026-10-04 16:00 UTC: 4.0 µg/m³4 Oct 12:00 local, 2026-10-04 17:00 UTC: 3.6 µg/m³4 Oct 13:00 local, 2026-10-04 18:00 UTC: 3.4 µg/m³4 Oct 14:00 local, 2026-10-04 19:00 UTC: 3.1 µg/m³4 Oct 15:00 local, 2026-10-04 20:00 UTC: 2.9 µg/m³4 Oct 16:00 local, 2026-10-04 21:00 UTC: 2.7 µg/m³4 Oct 17:00 local, 2026-10-04 22:00 UTC: 2.6 µg/m³4 Oct 18:00 local, 2026-10-04 23:00 UTC: 3.6 µg/m³4 Oct 19:00 local, 2026-10-05 00:00 UTC: 3.5 µg/m³4 Oct 20:00 local, 2026-10-05 01:00 UTC: 4.7 µg/m³4 Oct 21:00 local, 2026-10-05 02:00 UTC: 4.8 µg/m³4 Oct 22:00 local, 2026-10-05 03:00 UTC: 3.9 µg/m³4 Oct 23:00 local, 2026-10-05 04:00 UTC: 3.6 µg/m³5 Oct 00:00 local, 2026-10-05 05:00 UTC: 3.4 µg/m³5 Oct 01:00 local, 2026-10-05 06:00 UTC: 3.3 µg/m³Oct 2Oct 3Oct 4
Greendale's local time; hover a bar for UTC. Dashed line: WHO 24-hour guideline (15 µg/m³).

Where it stood each day

Top 10Top 100#1#10#100#1,000#3,193NovDecJanFebMarAprMayJunJulAugSep#1,937
Its rank on each day's world board, #1 being the most polluted city that day. Higher is worse. Each gridline down is ten times the rank above it (#1, #10, #100, #1,000), so the top places get the most room. See it among every city.

2026 against 2025, month by month

15Jan 2025: 7.1 µg/m³Jan 2026: 8.6 µg/m³JanFeb 2025: 8.2 µg/m³Feb 2026: 11.0 µg/m³FebMar 2025: 5.6 µg/m³Mar 2026: 7.5 µg/m³MarApr 2025: 5.7 µg/m³Apr 2026: 4.9 µg/m³AprMay 2025: 4.7 µg/m³May 2026: 5.5 µg/m³MayJun 2025: 12.0 µg/m³Jun 2026: 5.8 µg/m³JunJul 2025: 14.5 µg/m³Jul 2026: 25.5 µg/m³JulAug 2025: 13.2 µg/m³Aug 2026: 9.0 µg/m³AugSep 2025: 7.2 µg/m³Sep 2026: 5.6 µg/m³SepOct 2025: 4.2 µg/m³OctNov 2025: 5.9 µg/m³NovDec 2025: 9.0 µg/m³Dec
Faded bars: 2025. A month shows once it has 10 measured days.

This week against past years

This weekThis week: 6.3 µg/m³6.320252025: 5.6 µg/m³5.620242024: 5.1 µg/m³5.120232023: 8.9 µg/m³8.9
Mean PM2.5 for 28 Sept to 4 Oct in each year. Dashed line: WHO 24-hour guideline.

Monitors

PM2.5 from 1 reference monitor, updated hourly.

StationOperatorType
Milwaukee College AvUS Public DomainAirNowReference

The city's value is the median of its reference monitors each hour, when at least a third of them report (three are always enough); low-cost sensors are listed but not counted when reference monitors exist. Data via OpenAQ; licences as listed. How we rank. Embed this on your site.

Use this page

SmogRank, PM2.5 daily means, Greendale, United States, 7 Oct 2025 – 4 Oct 2026, smogrank.com/us/greendale (accessed 5 Oct 2026).

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Other cities in United States

30-day averages, US AQI. All of United States.

Updated 2026-10-05 07:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index.