Pollen and Exam Scores: The Grades May Depend on the Air That Week

Every spring, students sit the exams that shape their next decade — and every spring, those exams land in the middle of tree-pollen season. That overlap is usually treated as bad luck. Two large Scandinavian studies suggest it is something more specific: pollen and exam scores move against each other, measurably, in datasets covering nearly a hundred thousand students. The effects are small for any one student on any one day. But on exams where a point or two can decide a university place, small and unfair is exactly the combination worth paying attention to.

Key takeaways

• Finland's study analysed 92,280 students and 156,059 matriculation exam scores from 2006 to 2020: each 10-grain rise in alder pollen per cubic metre was linked to a 0.0034 standard-deviation fall in scores, and hazel's figure was 0.0144.
• The clearest Finnish signal was in mathematical subjects, where each additional 10-grain increase in alder pollen was associated with a statistically significant fall in scores.
• Norway's earlier study found that a one-standard-deviation rise in pollen — about 20 grains per cubic metre — cut the average grade by 2.5 per cent, and that roughly one in ten pupils with hay fever dropped a full grade.
• Scores in Finland dipped on low-pollen days as well as high ones compared with pollen-free days — a U-shaped pattern the authors flag rather than fully explain.
• Around one in five secondary students has allergic rhinitis, so the average effects across all students likely understate the effect on the allergic minority.

The Finnish Study: 156,059 Scores' Worth of Pollen and Exam Scores

The bigger dataset comes from Finland, where the national matriculation examination — taken at the end of secondary school — carries heavy weight in university admissions. Researchers Timo Hugg, Marko Korhonen, and colleagues analysed the results of 92,280 students in the Helsinki and Turku metropolitan areas who sat the exams between 2006 and 2020: 156,059 individual exam scores. Their study, "Pollen exposure and matriculation exam performance among students in Finland," was published in the Journal of Epidemiology & Community Health.

The timing made the analysis unusually clean. Finland's spring exams fall when only two pollen types are in the air: alder and hazel — the same early-season pair we profile in our alder pollen post. The team matched each exam day to the regional pollen counts and adjusted for temperature, air pollution (including fine particles and ozone), and rainfall during exam hours. The association survived all of it:

• An increase of 10 alder pollen grains per cubic metre of air was linked to a fall of 0.0034 standard deviations in the standardised score; for hazel, the figure was 0.0144 standard deviations.
• In raw points on the 0–66 exam scale, those increments correspond to reductions of roughly 0.04 and 0.17 points respectively — and the highest alder day in the data averaged 521 grains per cubic metre, many increments at once.
• Scores dipped on low-pollen days as well as high ones, compared with pollen-free days — a U-shaped pattern the authors flag rather than fully explain.
• The clearest signal was in mathematical subjects. Each additional 10-grain increase in alder pollen was associated with a statistically significant fall in maths scores, which the researchers suggest may reflect how much sustained accuracy and concentration maths exams demand.

The authors are careful about what this is: an observational study. They did not know which students were actually allergic — around one in five secondary students has allergic rhinitis, they note — so the average effect across all students likely understates the effect on the allergic minority. Their conclusion is about fairness and preparedness: exam success helps determine further education and working life, so awareness of pollen exposure on exam days, and access to accurate pollen information in advance, are part of levelling the field.

Norway Heard It First

Finland's study had a forerunner. Economist Simon Bensnes at the Norwegian University of Science and Technology (NTNU) linked written end-of-year exam results from 2008–2011 to the pollen count at each exam location on each exam day. His finding, reported in NTNU's university release, was starker: when the pollen count rose by one standard deviation — about 20 grains per cubic metre — the average pupil's grade fell by 2.5 per cent. Working from the reasonable assumption that non-allergic pupils are unaffected, Bensnes calculated that roughly one in ten pupils with hay fever dropped a full grade at that increase. The effect held after accounting for weather and air pollution, and it was stronger among boys than girls.

Two countries, two exam systems, two methods — same direction. That rhyme is what elevates pollen and exam scores from a curiosity to a pattern worth planning around.

Why Pollen and Exam Scores Might Move Together

Neither study can watch the mechanism directly, but the plausible pathways are mundane rather than exotic. Allergic rhinitis disrupts sleep in the nights before an exam; congestion, itchy eyes, and sneezing are poor companions for a three-hour paper; and the Finnish team's maths result hints that whatever pollen does, it taxes exactly the faculties — accuracy, concentration, stamina — that timed problem-solving burns fastest. The CDC's overview of pollen and health lists the symptom load plainly: sneezing, congestion, runny nose, itchy and watery eyes. Read that list as an exam-day handicap and the statistics stop being surprising.

The Puzzle in the Data: Why Low-Pollen Days Dipped Too

The strangest result in the Finnish study is not the high-pollen dip — it is the low-pollen one. Scores were lower on days with low pollen (1–10 grains per cubic metre) than on days with none at all, producing the U-shaped curve. The researchers treat this carefully, as an association in need of interpretation rather than a settled mechanism, but the readings they discuss are instructive. A low-pollen day in March is often the first pollen day of the year — the season's opening move, arriving before students have adjusted to it or even recognised it. Symptoms can also precede the counts people notice: a sensitised student may react to the season's first grains at levels a monitor records as trivial. And the moderate middle may benefit from simple adaptation — by the time moderate days arrive, the allergic students know the season has started and are managing it. None of this is proven; the authors offer it as the kind of question the data raises. But it carries a practical moral that needs no proof: the risk window opens with the season's first grains, not with its peak, so the forecast matters from day one of the season, not just on the dramatic days.

What the Researchers Suggest Doing With This

Both teams resist turning their findings into panic, and both land in the same place: information and scheduling. The Finnish authors argue that because matriculation scores carry real weight in further education and working life, creating more equal performance conditions means reducing exposure where possible and — in their words' spirit — improving preparedness, including more accurate and accessible pollen information for students. The Norwegian context sharpens why this matters: Norway's asthma and allergy federation estimates that between 25 and 30 per cent of Norwegian young people experience pollen allergy symptoms, so the exposed group in any exam hall is not a handful of students but a substantial minority, most of them sitting the same paper, in the same room, on the same fixed morning as everyone else. Bensnes' framing was never that allergic students lack ability — it was that a grade can silently absorb the weather. A grade dropped on a high-pollen day looks identical in the record to a grade dropped for any other reason, which is precisely the fairness problem: the handicap is real, invisible, and randomly assigned by the exam timetable.

What This Means Outside Scandinavia

American students meet the same collision. AP exams and spring finals fall in May, squarely inside the spring allergy season — tree pollen cresting, grass season opening — in northern cities like those on our Minneapolis pollen count, Milwaukee pollen count, and Detroit pollen count pages. Exam dates are fixed years ahead; pollen is not. What a student, parent, or school can control is information: knowing the forecast for exam week the way you'd know the weather for a field trip. A quick scan of the pollen heatmap shows whether a high-pollen spell is building toward the days that matter.

One honest caveat, because the studies themselves insist on it: this research links pollen exposure to lower scores on average. It does not prove that pollen caused any individual student's result, and it offers no excuses industry — most students, allergic or not, perform fine on most days. It simply shows that the air is one of the silent variables in the room.

Frequently Asked Questions

Does pollen actually lower exam scores?

Two large Scandinavian studies found a measurable association. In Finland, higher alder and hazel counts on exam days were linked to lower scores even after adjusting for temperature, air pollution, and rainfall — but it is an observational study, so it links pollen exposure to lower scores on average without proving pollen caused any individual student's result.

How big was the effect in the Norwegian study?

When the pollen count rose by one standard deviation — about 20 grains per cubic metre — the average pupil's grade fell by 2.5 per cent. Working from the assumption that non-allergic pupils are unaffected, Bensnes calculated that roughly one in ten pupils with hay fever dropped a full grade, and the effect was stronger among boys than girls.

Why did Finnish scores dip on low-pollen days too?

The Finnish data showed a U-shape: scores were lower on low-pollen days (1–10 grains per cubic metre) than on pollen-free days. The authors discuss possible readings — a low-pollen day is often the season's first, arriving before students have adjusted, and a sensitised student may react at levels a monitor records as trivial — but they offer these as interpretation, not proof.

Which subjects were most affected?

Mathematical subjects showed the clearest signal in Finland: each additional 10-grain increase in alder pollen was associated with a statistically significant fall in maths scores. The researchers suggest this may reflect how much sustained accuracy and concentration maths exams demand.

If spring symptoms reliably ambush a student every exam season, that's worth raising with a specialist well before May — you can find an allergist through the Pollen Atlas directory. This article is general information only and is not medical advice. And when exam week approaches, treat pollen and exam scores as a pair: check the free counts and 5-day forecasts for your city at PollenAtlas.com, so at least the air holds no surprises.