Herstal pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Herstal is none
Pollen Tomorrow
Tomorrow (21 September 2026) levels are similar to today.
7-Day Trend
Over the next week mugwort will increase; cypress, grass, and willow will remain stable.
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Features and forecast availability vary by region.
Pollen Risk
Today - 20 September
| Pollen species | Level | Value |
|---|---|---|
| Alder (Alnus) | None | 0/100 |
| Birch (Betula) | None | 0/100 |
| Hazel (Corylus) | None | 0/100 |
| Cypress (Cupressaceae) | None | 0/100 |
| Grass (Poaceae) | None | 0/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | None | 0/100 |
Tomorrow - 21 September
| Pollen species | Level | Value | 7-Day Trend |
|---|---|---|---|
| Alder (Alnus) | None | 0/100 | — |
| Birch (Betula) | None | 0/100 | — |
| Hazel (Corylus) | None | 0/100 | — |
| Cypress (Cupressaceae) | None | 0/100 | |
| Grass (Poaceae) | None | 0/100 | |
| Willow (Salicaceae) | None | 0/100 | |
| Mugwort (Artemisia) | None | 0/100 |
Local Environmental Conditions
oak and hornbeam are the dominant tree pollen source around Herstal, which sits on the Meuse river plain near Liège in Liège; grass and late-season herbs from nearby farmland and parks builds through spring into early summer. The balance between green space and built-up ground shapes how exposure differs across the town.
From an early alder and willow start, Herstal moves into a oak and hornbeam peak before grass and late-season herbs extends the season into early summer, with the January-to-August window covering the year's exposure in this part of Liège. ragweed adds a modest late-season tail in areas near farmland, a pattern shaped in part by the town's position on the Meuse river plain near Liège.
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Frequently Asked Questions About Pollen in Liège
Is pollen high in Herstal right now?
Currently, there is no significant pollen in Herstal.
Will pollen levels change in Herstal tomorrow?
On 21 September 2026, pollen conditions in Herstal will be similar to today with no significant pollen expected.
Is pollen expected to decrease in Herstal this week?
According to the five-day outlook, artemisia pollen levels will increase later in the week.
Which pollen types are currently active in Herstal?
On 20 September 2026, there are no significant pollen types in Herstal.
When is pollen season in Herstal?
How often is the Herstal pollen forecast updated?
The Herstal pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Herstal come from nearby or far away?
Studies show that most pollen exposure (often 70–90%) comes from nearby sources, such as local trees and vegetation. A good pollen forecast therefore depends on accurately representing local vegetation. Pollen can travel long distances, but this usually matters only early in the season or during specific wind events.
Are pollen levels in Herstal based on measurements or forecasts?
Pollen data is often misunderstood. Most "pollen levels" are not real-time measurements, but forecasts.
Direct pollen measurements are typically delayed by 1-2 days because they require manual analysis. To show current conditions in Herstal, modern forecasts combine recent measurements, weather data, and information about local vegetation.
This allows us to estimate pollen levels for today and the coming days, not just report the past.
Airmine’s atmospheric monitoring platform was developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team, using satellite and Earth observation technologies to improve emissions monitoring.
Understanding the Scale
The 0–100 scores represent risk levels, not direct measurements of pollen or air pollutant concentrations. Higher scores indicate higher risk. Pollen and air quality use different thresholds.
Pollen
| None | 0 | No or negligible risk of exposure. Pollen/mold exposure is expected to be minimal. |
| Low | 0-25 | Low risk of exposure. Small amounts of pollen or mold spores may be present. |
| Moderate | 25-50 | Moderate risk of exposure. Pollen/mold exposure is expected to be noticeable. |
| High | 50-75 | High risk of exposure. Elevated pollen/mold exposure is expected. |
| Very High | 75-100 | Very high risk of exposure. Pollen/mold exposure is expected to be at or near its highest levels. |
Get More in the Airmine Pollen app
Get 15-day pollen forecasts with morning, afternoon and evening detail, plus 5-day air quality forecasts. Explore interactive pollen risk maps, estimated pollen season start, route profiles and a symptoms diary.
Features and forecast availability vary by region. Currently covering Europe, the contiguous US, southern Canada, South Africa, Australia, Indonesia (Java & Bali), Brazil, Paraguay, Uruguay and the Buenos Aires area.
Developed with support from the European Space Agency (ESA) Business Applications and Space Solutions (BASS).
