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December 27, 2023

Seasonal allergies and accidents

Opinion image

Although at least 400 million people suffer from seasonal allergies worldwide, the adverse effects of pollen on "non-health" outcomes are hardly studied. 

In the heart of spring, as flowers bloom and trees flourish, millions worldwide brace for the onset of "hay fever" symptoms. Medically termed as seasonal allergic rhinitis (SAR), this chronic condition, triggered by airborne allergens like pollen and dust, is more than just a seasonal nuisance. SAR affects a staggering 30% of individuals in developed countries, translating to around 400 million sufferers globally.

While most are aware of the sneezing, itching, and discomfort, few recognize the cognitive implications of this condition. Preliminary lab studies have hinted at pollen's potential to diminish attention spans and slow reaction times. However, the real-world ramifications of these findings, especially in field settings, remain largely uncharted territory.

To delve into the tangible effects of pollen exposure on daily life, particularly its influence on accident rate, we combine data on pollen counts with administrative ambulance records. The study, spanning from 2008 to 2019, was conducted in Japan—a nation with pollen monitoring stations 42 times denser than the US. By juxtaposing pollen counts with ambulance records, we aimed to discern any correlation between heightened pollen levels and increased accidents.

We find that elevated daily pollen counts correlated with a surge in various accidents, from traffic mishaps to work-related injuries and even sports and fire accidents. More concerning was the revelation that high pollen exposure did not just result in minor incidents; it also escalated accidents with fatal outcomes. These discoveries challenge the prevailing understanding of the societal costs of airborne allergens. Traditionally, these costs have been gauged by direct health outcomes, missed school days, and work absenteeism. However, the study suggests that this approach might grossly underestimate the true societal burden.

But with Japan's robust broadcasting of pollen levels through TV, newspapers, and mobile apps, surely its citizens are well-informed and prepared? The data paints a mixed picture. On the positive side, in-home scanner data reveal a spike in purchases of allergy-relief products during high pollen periods. Yet, when it comes to more proactive measures, like limiting outdoor activities, the responses are lukewarm at best. Geolocation data show only a marginal reduction in outdoor foot traffic in busy areas on weekends with high pollen counts.

These results underscore a potential disconnect. Despite the availability of information, many might be underestimating or simply unaware of the cognitive risks posed by pollen exposure. Relying solely on individual self-protection might be an inadequate strategy. Introducing initiatives like a "pollen alert," advising allergy sufferers to limit outdoor activities and avoid driving or operating machines on high pollen days, could be a game-changer. Such measures could instigate widespread behavioral shifts, minimizing pollen-induced accidents.

This finding is very likely to reflect the tip of the iceberg of the potentially extensive social cost. As pollen impairs cognitive function, it can subtly influence any daily activity demanding cognitive sharpness and decision-making. With global warming threatening to extend pollen seasons and amplify pollen production, understanding its full societal impact is more urgent than ever.

© Mika Akesaka and Hitoshi Shigeoka
Mika Akesaka is Assistant Professor at the Research Institute for Economics and Business Administration, Kobe University

Hitoshi Shigeoka is Professor at the Graduate School of Public Policy, University of Tokyo, and IZA Research Fellow

Please note:
We recognize that IZA World of Labor articles may prompt discussion and possibly controversy. Opinion pieces, such as the one above, capture ideas and debates concisely, and anchor them with real-world examples. Opinions stated here do not necessarily reflect those of the IZA.

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Photo by Towfiqu Barbhuiya on Unsplash