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Seasonal Allergy Air Quality & Weather

How Weather and Pollen Work Together to Make Us Sick

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By Dr Amir Paster on February, 5 2020
weather and pollen

Dry weather and rain alike can potentially raise pollen counts, but precise, timely data can help ward off allergy symptoms.

Each spring, warm weather and brand-new blooms bring with them an unwelcome friend: pollen. Dusting every outdoor surface with a light yellow tinge, pollen is an annoyance for most consumers — but for others, it can be debilitating or even downright dangerous.

Seasonal allergies are the immune system's response to pollen, which not only triggers an inflammatory response, but can also leave people more prone to other harmful triggers like dust or air pollution. For many people — 30% of US adults and 40 percent of US children, to be exact — this results in aggravating sniffles and sneezing. However, exposure to high pollen levels can also contribute to increased hospital admissions for asthma patients or increase the risk of early asthma in unborn children. It can even trigger fatal allergy attacks.

The risks associated with pollen are real, but they don’t have to drive your customers or patients to spend all spring indoors. Instead, it’s important to understand how and why weather affects pollen counts so you can help people make informed decisions about when they want to spend their time outside, or when they need to stay inside with the windows shut.  

Why is it so Hard to Predict Pollen Season?

Pollen’s Ideal Weather Conditions

Pollen is the male fertilizing agent of plants, for example trees, grasses, and weeds. For successful reproduction, the pollen grains need to reach female flowers. Some plants rely on wind to transfer their pollen, and since this process is non-targeted, these plants need to release billions of grains to ensure that some of them reach female flowers.  Different strains of pollen arise during slightly different times of year, which are determined by the species of plant they come from as well as the local climate. Other factors — like a particular tree’s emission period or plant density — can also affect the concentration and make-up of pollen in a specific location at any given moment.

In addition, pollen counts vary depending on the weather. For example, dry and windy weather provides the ideal conditions for pollen to be released from the plant. Incredibly small and light, pollen can easily become airborne in windy conditions and travel long distances.

That’s part of what makes pollen so hard to monitor; it can encroach on a lovely spring day and cause allergy attacks even when no flowering trees are in sight. That’s also why people with allergic asthma will find that cold or dry air can increase their symptoms, especially when they exercise outside.

Pollen Can Also Thrive in Rain

If pollen thrives in dry weather, it stands to reason that rain could neutralize it — but that’s not entirely the case. While the popular idea that rain washes away pollen isn't entirely wrong, it doesn’t paint the full picture, either. While rain could wash away pollen, it stands as good of a chance of breaking up clumps of pollen into smaller particles, and even breaking pollen grains to small pieces in a process called “osmotic shock.” Such small fragments of the pollen grain can be transported to larger distances and increase allergic symptoms in patients.

What’s more, rain can also lead to a seasonal rise in mold spores, another common allergen; mold spore counts can double during rain.

The Relationship Between Air Pollution and Pollen

In recent decades, pollen allergies have become more common; many people who have never experienced them before are now suffering severe attacks each spring. This is especially true in urban areas. Though there aren’t as many plants or trees in population-dense cities, the increased air pollution in these areas can exacerbate pollen’s effects and cause more people to become sensitive to the allergen. In fact, hay fever prevalence in urban areas increased 50 percent from 2014 to 2015, largely due to increased CO₂.

Not only are pollen allergies uncomfortable and dangerous, they’re also incredibly expensive. The US spends $18 billion a year on pollen medications, even though many of these medications don’t offer patients complete relief. Fortunately, patients with allergies don’t necessarily have to rely on expensive medication to enjoy the spring; accurate, timely pollen data can help them make informed action when needed.

Because pollen is dynamic — counts vary on a street-to-street level, minute by minute — patients need pollen counts delivered in real time in order to take informed action to improve their symptoms. With better data, it’s not necessary to spend spring shut inside with the windows closed; it’s possible to enjoy lovely spring weather when it’s safest to do so.

Pollen is both a public health issue and an economic issue; consumers, healthcare companies, and governing bodies are all stakeholders in the pollen problem. Investments in better environmental data from all of these parties is the solution.

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