Chestnuthill Township pollen forecast — Merwinsburg neighborhood
Pollen Today
Today (20 September) pollen in Merwinsburg, Chestnuthill Township is low; grass, mugwort, and ragweed are low.
Pollen Tomorrow
Tomorrow (21 September 2026) grass remains low, ragweed remains low, mugwort no longer expected.
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 | 15/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | Low | 3/100 |
| Ragweed (Ambrosia) | Low | 23/100 |
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 | 8/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | None | 0/100 | |
| Ragweed (Ambrosia) | Low | 16/100 |
Local Environmental Conditions
This area, in the wider area, has hazel and willow grow along the bank, contributing some of the season's earliest allergenic pollen. A park where mown turf grass and ornamental trees add grass and ragweed pollen, within easy reach. Local microclimate and soil conditions can push these figures slightly higher or lower.
Hazel and willow along the water get the season underway before other species, usually peaking sometime between late winter and the end of March. Grass pollen counts rise through late spring, reaching their peak around June, before ragweed becomes the more dominant allergen from mid-August into October. This general pattern holds fairly steady across the surrounding county from year to year.
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Frequently Asked Questions About Pollen in Pennsylvania
Is pollen high in Chestnuthill Township right now?
On 20 September 2026, overall pollen levels in Chestnuthill Township are low. Grass is the main contributor to airborne pollen, while ambrosia and artemisia remain at lower levels
Will pollen levels change in Chestnuthill Township tomorrow?
On 21 September 2026, pollen conditions in Chestnuthill Township will be different from today, with grass at low levels, ambrosia at low levels
Is pollen expected to decrease in Chestnuthill Township this week?
According to the five-day outlook, grass, ambrosia, and artemisia pollen levels will increase later in the week.
Which pollen types are currently active in Chestnuthill Township?
On 20 September 2026, Grass is the dominant pollen source in Chestnuthill Township. ambrosia and artemisia are also present but at lower levels.
When is pollen season in Chestnuthill Township?
How often is the Chestnuthill Township pollen forecast updated?
The Chestnuthill Township pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Chestnuthill Township 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 Chestnuthill Township 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 Chestnuthill Township, 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. |
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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).
