- Pollen count = grains of pollen per cubic meter of air over 24 hours
- Four severity levels: Low (0–14), Moderate (15–89), High (90–1,499), Extreme (1,500+)
- Species composition matters as much as the total number
- Counts lag up to 24 hours — forecasts use atmospheric modeling to fill the gap
The Simple Definition
A pollen count is the number of pollen grains found in one cubic meter of air, measured over a 24-hour period. The higher the number, the more pollen is in the air around you. What gets complicated is understanding what those numbers mean for a real person living a real day.
How Pollen Is Measured
Pollen is captured using a rotorod sampler — a rotating arm coated in adhesive that collects airborne particles over 24 hours. A trained aerobiologist counts and identifies the grains under a microscope. This is why pollen counts are always reported as yesterday's data. Forecast apps supplement this measured data with atmospheric modeling to project today's conditions.
Anthos uses Google's Pollen API combined with Claude AI-generated daily readings that interpret this data in the context of your personal sensitivity — not just a generic number.
The Four Severity Levels
| Level | Grains/m³ | What It Means | Anthos Guidance |
|---|---|---|---|
| Low | 0–14 | Minimal exposure. Most people with mild allergies feel fine. | Enjoy your day outside. |
| Moderate | 15–89 | Noticeable exposure. Sensitive individuals may feel symptoms. | Heads up — carry your antihistamine. |
| High | 90–1,499 | Action recommended. Limit outdoor time. Close windows at home. | Plan around your lowest-exposure window. |
| Extreme | 1,500+ | Avoid all exposure. Stay indoors. HEPA filter on high. | Stay inside. Your best window is after 3 PM. |
What Makes Counts Vary Day to Day
Wind
Windy days dramatically increase airborne pollen. Even trees not currently blooming can have settled pollen redistributed by strong winds.
Rain
Rain temporarily washes pollen from the air — but the 24–48 hours following rain often sees a sharp spike as trees release accumulated pollen all at once.
Temperature
Warm temperatures accelerate bloom cycles. Climate Central data shows pollen season has extended by 20 days since 1990 due to warming trends.
Time of Day
Pollen peaks between 6–9 AM most days. Grass pollen also peaks at midnight to 2 AM specifically. Knowing your window is half the battle.
Thunderstorms
"Thunderstorm asthma" is real — storms break pollen into ultra-fine particles that penetrate deeper into airways, causing acute symptoms even in people with mild allergies.
Local Geography
Counts vary block by block. A park or stand of oak trees nearby can elevate your local count significantly above the regional number you see in weather apps.
Pollen Count vs Pollen Index
A pollen count is the raw measurement in grains/m³. A pollen index is a scaled score (typically 0–12) combining pollen count with weather and forecast modeling into a single number. Anthos shows you both — the exact count in grains/m³ and a plain-language action directive for your day.
Your pollen count, personalized.
Every morning, Anthos interprets the pollen count in the context of your specific sensitivities, your sleep data, and your local conditions.
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Anthos provides general wellness information only. Nothing in this article constitutes medical advice, diagnosis, or treatment. Always consult a licensed healthcare professional before making health decisions.