Glen Carbon pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Glen Carbon is moderate; ragweed is moderate; grass is low.
Pollen Tomorrow
Tomorrow (21 September 2026) levels are similar to today.
7-Day Trend
Over the next week grass, mugwort, and ragweed will increase.
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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) | Low | 25/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | None | 0/100 |
| Ragweed (Ambrosia) | Moderate | 50/100 |
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) | Low | 13/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | None | 0/100 | |
| Ragweed (Ambrosia) | Moderate | 37/100 |
Local Environmental Conditions
Glen Carbon lies in the Ohio-Mississippi confluence country of southern Illinois, not far from the Mississippi River and Cache River State Natural Area. The surrounding landscape is dominated by southern floodplain hardwoods and upland oak-hickory forest. The Mississippi River winds through the wider area, its banks favoring moisture-loving trees such as willow and alder.
Streamside willow and alder near the Cache River kick off the local pollen calendar, usually strongest in the weeks before spring fully arrives. The wooded areas near Giant City State Park woodlots then carry the tree pollen load into its sharpest phase, typically centered on April and May. Farther out toward the Ohio River and Shawnee National Forest, tree pollen tends to follow this same rough schedule.
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Frequently Asked Questions About Pollen in Illinois
Is pollen high in Glen Carbon right now?
On 20 September 2026, overall pollen levels in Glen Carbon are moderate. Ambrosia is the main contributor to airborne pollen, while grass remain at lower levels
Will pollen levels change in Glen Carbon tomorrow?
On 21 September 2026, pollen conditions in Glen Carbon will be similar to today, with ambrosia at moderate levels, grass at low levels
Is pollen expected to decrease in Glen Carbon this week?
According to the five-day outlook, ambrosia, artemisia, and grass pollen levels will increase later in the week.
Which pollen types are currently active in Glen Carbon?
On 20 September 2026, Ambrosia is the dominant pollen source in Glen Carbon. grass are also present but at lower levels. artemisia are not currently active.
When is pollen season in Glen Carbon?
How often is the Glen Carbon pollen forecast updated?
The Glen Carbon pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Glen Carbon 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 Glen Carbon 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 Glen Carbon, 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).
