Harrison Township, Pennsylvania pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Harrison Township, Pennsylvania is high; ragweed is high; grass and mugwort are low.
Pollen Tomorrow
Tomorrow (21 September 2026) ragweed declining, grass no longer expected, 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 | 19/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | Low | 11/100 |
| Ragweed (Ambrosia) | High | 51/100 |
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 | |
| Ragweed (Ambrosia) | Low | 20/100 |
Local Environmental Conditions
With woodland and water both absent nearby, grass and ragweed growing on unmanaged or agricultural land likely dominate the pollen mix. Comparable land cover in surrounding areas tends to produce a similar pollen mix overall. Local microclimate and soil conditions can push these figures slightly higher or lower. The broader area tends to mirror this pattern, with only minor local variation.
Grass pollen rises through late spring toward a June high point, before ragweed pollen takes center stage across mid-August into October. Warmer or wetter years can pull these peaks a week or two earlier or later. This general pattern holds fairly steady across the surrounding county from year to year.
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Pollen forecast neighborhoods 3 neighborhoods
Frequently Asked Questions About Pollen in Pennsylvania
Is pollen high in Harrison Township, Pennsylvania right now?
On 20 September 2026, overall pollen levels in Harrison Township, Pennsylvania are high. Ambrosia is the main contributor to airborne pollen, while artemisia and grass remain at lower levels
Will pollen levels change in Harrison Township, Pennsylvania tomorrow?
On 21 September 2026, pollen conditions in Harrison Township, Pennsylvania will be different from today, with ambrosia continuing to decline
Is pollen expected to decrease in Harrison Township, Pennsylvania 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 Harrison Township, Pennsylvania?
On 20 September 2026, Ambrosia is the dominant pollen source in Harrison Township, Pennsylvania. artemisia and grass are also present but at lower levels.
When is pollen season in Harrison Township, Pennsylvania?
How often is the Harrison Township, Pennsylvania pollen forecast updated?
The Harrison Township, Pennsylvania pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Harrison Township, Pennsylvania 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 Harrison Township, Pennsylvania 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 Harrison Township, Pennsylvania, 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).
