400 million people worldwide live with hay fever. That's 10–30% of all adults globally, around 1 in 4 people across Europe, and over 16 million in the UK alone. And every year, the season starts earlier and lasts longer — climate change is already the dominant driver of longer pollen seasons, with seasons starting up to 20 days earlier than in the 1990s.

Why is air pollution key in pollen?

It’s not just about how much pollen is in the air, it’s about what else is in the air with it. Pollen and air pollution don't just coexist, they interact. And the combination is significantly more damaging than either alone.

How do Pollutants and Pollen react when they are together?

• Particulate matter (PM2.5) amplifies the allergic response to pollen, on high PM2.5 days, pollen triggers significantly more allergic reactions than on cleaner days. 
• Pollution fragments pollen into smaller particles that penetrate deeper into the lungs reaching parts of the respiratory system larger grains typically can't. 
• Nitrogen dioxide (NO₂) and ozone worsen airway inflammation and impair your airways' natural ability to clear allergens, extending symptoms well beyond high pollen days.

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Urban vs Rural

• A 2023 University of Manchester study found that urban dwellers reported worse hay fever symptoms than people in rural areas, even when rural pollen counts were higher. Runny nose, sore eyes, and wheezy breathing were roughly twice as severe in urban areas than rural ones. 
• Cities are starting to act. 
• Japan has committed to reducing cedar forests by 20% within a decade, with a goal of halving pollen levels within 30 years. ‍
• Islamabad is removing 80,000–100,000 paper mulberry trees and replacing them with native, low-allergen species.