Unpredictable Weather & Pollen: A Perfect Health Storm

Climate change doesn’t just make weather more extreme and unpredictable, it wreaks havoc on pollen season too. Here we explore the ways changing weather can impact pollen production and spread, and why new forms of pollen forecasting may hold the key to improving allergy management – both now and in the future.

Pollen’s Ideal Weather Conditions

The main method of airborne pollen distribution is the wind, so the weather definitely plays a big role in how high the pollen count will be on a particular day. Made up of incredibly small and light particles, dry and windy weather provides the ideal conditions for pollen to spread and travel long distances.

This is part of what makes pollen so hard to monitor; it can encroach on a lovely warm day and cause allergy attacks even if there’s no pollen-producing plant in sight.  Wind plays a major role in how pollen grains travel, and their small dimensions make these allergenic particles liable to enter our airways, irritate our eyes, and cause various other allergic responses

Learn More: What is Pollen?

Does Rain Make Pollen Worse?

Some plants release more pollen during dry weather, and lower moisture in the air can help pollen grains travel farther with greater ease. Conversely, light rain and the resulting humidity can help wash pollen away and restrict its spread to some degree. 

Weather and plant pollen

However, the pollen-rain connection is not always positive. During thunderstorms, pollen grains can be broken up into smaller-than-usual particles through a process called Osmotic shock, which makes them more easily inhalable. This phenomenon is known as ‘Thunderstorm asthma’.

Pollen Allergy & Thunderstorm Asthma – Learn More

Different Plants & Their Role in Pollen Count

The precise timing of when a specific plant starts to produce pollen depends on the climatic conditions at the location of the plant, and varies from one year to the next. Other factors — like plant density or the spread of invasive plants  — can also affect the concentration and make-up of pollen in a specific location at any given moment.

Why Does Climate Change Make It Harder to Predict a Pollen Season Like We Used To?

Most types of allergenic pollen are produced by a number of different types of trees, weeds and grass, all of which pollinate at different times of the year. 
However, our traditional understanding of pollen season is changing due to the impact of climate change and generally unpredictable weather conditions, which have the knock-on effect of impacting pollen production schedules on a global level – in terms of start and end dates, and amounts of pollen emitted.

  • One study looked back at approximately three decades and found that North American pollen concentrations increased by about 21% during this period. This research states these changes in pollen allergy season are in part driven by elevated temperatures and CO2 concentrations, both of which have been found to increase pollen production in greenhouses and other experimental studies. The largest and most consistent increases were observed in Texas and the midwestern United States. 
  • The changing climate and weather-pollen connection has been observed further by researchers who analyzed over two decades of data in the Northern Hemisphere and found 71% of the analyzed locations experienced an increase in total pollen production amounts while 65% saw pollen season extend by an average of 0.9 days per year.

Research into public health-related climate impacts is becoming an increasingly urgent area for exploration, as individuals and healthcare systems start to feel the impact of changing pollen and allergy seasons.

In this article, Dr. Anjeni Keswani, the Director of the Allergy and Sinus Center at The George Washington Medical Faculty Associates, describes how she’s seen a shift in ragweed pollen symptoms in her patients, as symptoms start earlier in the year and last longer, making allergy season a longer, more costly annual affair.

The Need for Smarter Pollen Forecasting

Traditionally, prior years’ patterns formed the basis for predicting when a pollen allergy patient might start to feel symptoms, but modern pollen season unpredictability makes it harder for patients and allergy management solution providers to rely on traditional methods alone today. The increasing difficulty of accounting for climate change-induced weather variations, and the impact on pollen production in different regions, necessitates a new approach.

Leveraging Big Data & AI to Create Pollen Intelligence

To deliver accurate and timely pollen forecasts and insights personalized to the individual allergy sufferer, BreezoMeter moves beyond traditional pollen reporting methods (station data and regional models) and leverages multiple environmental data layers (land cover maps, weather data, satellite imagery, and more) along with sophisticated AI-driven data analysis and prediction to forecast pollen dispersion and report risks at a hyperlocal level.

This approach enables:

  • The calculation of pollen production schedules and total annual production for any given location.
  • Forecasts for local pollen emissions for multiple consecutive days at a 1km resolution.
  • Daily results that reflect dynamic weather changes and the reality of ground-level pollen data.
  • AI-driven pollen dispersion models that estimate pollen load, which is then converted to BreezoMeter’s Pollen Index – a 5-level threat severity assessment based on scientific literature and continuous research.

Read BreezoMeter’s Guide to Pollen Forecasting

Start Delivering Personalized Allergy Management 

As allergy sufferers seek tailored solutions that address their specific sensitivities in the face of a changing climate, BreezoMeter’s pollen intelligence helps connect pollen allergy symptom risk to dynamically changing weather patterns.

Businesses can integrate data via our Pollen API and provide users with daily risk alerts, personalized and actionable recommendations, deliver color-coded pollen heatmaps that visualize allergy risk at particular locations, and more.

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Dr Yvonne Boose
Dr Yvonne Boose

Data and Accuracy Lead Scientist @BreezoMeter. I hold a PhD in Atmospheric Physics and formerly worked as a Postdoc at the German Aerospace Center. I love translating science to real-life improvements at BreezoMeter.