Each spring brings itchy eyes, frequent sneezing, and a familiar yellow dust that settles on cars across the United States. For millions of Americans, allergy symptoms become part of everyday life.
A large research project shows how daily pollen experiences shape public understanding of environmental change.
Social media posts, especially on Twitter, reveal strong links between lived pollen exposure, political views, and climate communication .
Pollen seasons are changing
Climate warming changes biological timing, also called phenology. Plants now release pollen earlier, for longer periods, and in larger amounts across many regions.
Rising temperatures increase plant growth and extend flowering periods. Longer pollen exposure raises risks for asthma, allergic rhinitis, and hospital visits.
Economic costs also rise due to medical care, lost workdays, and reduced quality of life.
Pollen stands out among climate signals because pollen affects breathing, comfort, and daily routines. Warm days feel forgettable, but pollen-covered cars and constant sneezing stay memorable.
Annual repetition also helps memory. Spring pollen arrives every year, making comparisons across years easier for many people.
Researchers collected over 190,000 pollen related Twitter posts from 2012 to 2022 across America.
Daily post numbers rose and fell alongside measured airborne pollen levels from national allergy monitoring stations.
Seasonal peaks also followed geographic patterns. Southern states experienced earlier peaks, while northern states saw later peaks.
Such alignment shows online users notice pollen changes accurately. Social media activity reflects real biological patterns over time and space.
Posts mentioned allergies, weather forecasts, outdoor cleaning, and nature observations. The public’s reaction tracked real pollen conditions without specialized tools or training.
Political views shape explanations
While pollen detection showed broad agreement, explanations differed. Researchers grouped users based on political orientation using followed accounts.
Conservative-leaning users often linked pollen increases to warmer weather. Liberal-leaning users more often connected pollen shifts to climate change.
Study lead author Yiluan Song is a postdoctoral fellow at the Michigan Institute for Data and AI in Society (MIDAS) and the School for Environment and Sustainability.
“There is a partisan gap in how we perceive the pollen seasons that are very relevant to our day-to-day life and even our health,” said Song.
Professor Kai Zhu noted that when people feel the impact of pollen in their own lives – sneezing more or cleaning pollen off their cars – it becomes personal.
“That experience can help connect the dots to climate change, which can feel abstract or distant,” said Professor Zhu.
Health impacts of climate change
Biological changes offer a powerful way to explain climate impacts. Pollen affects lungs, eyes, and daily comfort. Such direct exposure reduces psychological distance.
Public health framing makes environmental change easier to grasp compared with global averages or long-term graphs.
Research shows that pollen exposure is linked to asthma attacks, allergy medication use, and mental health risks.
Personal discomfort often leads people to talk online. Such conversations repeat yearly, reinforcing awareness.
Information flow and public voices
The scientists also studied how information spreads online. Media outlets and scientific experts played growing roles when posts discussed climate drivers behind pollen changes.
Technical explanations mostly came from journalists and researchers. Everyday users dominated general pollen complaints.
“When we look at the more technical discussions about how climate change drives pollen season change, a lot of it’s dominated by scientific experts and the media. There are pros and cons to this,” noted Song.
Communication led by experts improves accuracy, but it can limit personal storytelling. More grassroots sharing could help build understanding and trust across groups.
Pollen issues and climate talks
Pollen offers a shared experience across communities. Warm weather links resonate across political lines, creating possible common ground.
Framing climate messaging around pollen shifts attention away from abstract numbers and toward breathing, comfort, and health.
Annual pollen cycles help people notice long-term shifts. Social media records preserve memory beyond individual recall.
Together, biology and communication create opportunities for clearer climate understanding that’s rooted in everyday life.
The research was funded by the U.S. National Science Foundation (NSF), Schmidt Sciences, and the University of California Santa Cruz Building Belonging Program.
The study is published in the journal PNAS Nexus.
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