What is the air quality trend in Herstal?

Over the past 15 days, Herstal had an average AQI of 33 based on station measurements. The worst day was 2026-05-20 with AQI 40.

How is Herstal air quality measured?

Air quality in Herstal is measured by ground-level monitoring stations that report PM2.5 and PM10 concentrations hourly. CERNS.IO aggregates readings from nearby stations and converts PM2.5 to the US EPA Air Quality Index (AQI) scale.

Air Quality History for Herstal, Belgium

Name: Herstal Air Quality History
Creator: CERNS.IO
License: https://creativecommons.org/licenses/by/4.0/

Historical PM2.5 and AQI trend from monitoring stations near Herstal, Belgium.

Current AQI
Good Station

48 Hours 7 Days 14 Days 20 Days

CSV JSON

Air Quality Index Station

337h

PM2.5 Station

337h · 15 stations

Temperature GFS model

56pt

Precipitation GFS model

mm/day

Daily Summary Station

Date	AQI	Range	PM2.5 avg	PM10 avg	Hours	Stations
2026-05-29	40	25–58	9.7 µg/m³	32.2	23h	19
2026-05-28	30	23–44	7.2 µg/m³	22.3	24h	19
2026-05-27	38	25–58	9.2 µg/m³	23.3	24h	20
2026-05-26	34	22–47	8.2 µg/m³	16.0	24h	20
2026-05-25	33	22–46	7.9 µg/m³	12.3	24h	19
2026-05-24	39	24–58	9.3 µg/m³	17.1	24h	21
2026-05-23	36	24–49	8.7 µg/m³	17.0	24h	20
2026-05-22	34	23–58	8.2 µg/m³	15.1	24h	20
2026-05-21	32	26–55	7.7 µg/m³	14.3	24h	20
2026-05-20	40	17–155	11.4 µg/m³	12.1	24h	19
2026-05-19	28	16–39	6.8 µg/m³	7.5	24h	18
2026-05-18	35	18–55	8.4 µg/m³	8.0	24h	19
2026-05-17	29	17–78	7.3 µg/m³	6.7	24h	17
2026-05-16	34	12–53	8.2 µg/m³	10.9	24h	17
2026-05-15	18	4–31	4.2 µg/m³	8.3	2h	12

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