Given the huge toll the flu takes on schools, it’s always a relief for staff when winter fades into spring and the elm trees start blooming. Except for this: the end of flu season means the beginning of allergy season.

Fever and chills may be over, but runny noses, itchy eyes, and sneezes are in store for millions who walk the K-12 hallways or join circle time at preschool.

“Allergen levels in schools can be significantly higher than in the home environment,” note researchers at the National Institutes of Environmental Health Sciences, in a studyof indoor allergens at school and daycare environments.

In the United States alone, allergies and asthma account for more than 10 millionmissed school days per year, enough to compromise academic performancein those with sensitivity. Asthma is the most prevalent chronic illness in children, affecting about 10% of school-age kids, and that number is on the risefor unknown reasons. Asthma is also a known occupational health problem among teachers and teacher’s aides.

Among school-aged children, asthma is the top cause of absenteeism, and these absences are often triggered by the proliferation of springtime allergens in the school environment, such as grass and tree pollens floating about, along with some surprising perennial sources.

Interestingly, while influenza and allergies have entirely different causes and strike in different seasons, these conditions have an important commonality: they are often transmitted through airborne particles.

This means allergies, like the influenza virus, can be contained by purifying indoor air — a highly effective and cost-effective mitigation strategy that is often overlooked.

Children in daycare and elementary school classrooms are at particularly high risk of exposure to airborne allergens. Not only are these classrooms loaded with potential “allergen reservoirs” — such as upholstered furniture, pillows, toys, books, and stuffed animals — but younger kids are constantly on the move. When these kids plop on the beanbags, shake out blankets, flip through books, or toss soft toys about, they launch allergens into the air.

As a research team of Texas immunologistsput it, younger kids are “typically more physically active in schoolrooms thus increasing air turbulence.”


Schools Must Step Up to Clear the Air

It’s long been known that exposure to allergens at home triggers watery eyes, runny nose, fatigue, and other allergy symptoms in children. Parents of sensitive kids are urged to take all the usual precautions: keep pets super clean, have kids bathe nightly, zealously vacuum and dust, replace carpeting with hardwood or linoleum, dump houseplants with moldy soil, and keep the kitchen crumb-free, so as to fend off allergy-triggering cockroaches.

It’s not easy to keep a household free of allergens — but it’s also not enough. After all, kids spend 8 hours a day, 5 days a week at school, where the top allergen sources may be entirely different. For example, mice.

The School Inner-City Asthma Study, which tracked tracked students at 37 American public schools, found mice allergen in 99.5 percent of samples taken from classroom floors, desks, and chairs. The mice allergen levels detected at school were significantly higher than mouse allergens detected in the students’ homes.

The more exposure to school mouse allergens, the greater the children’s asthma symptoms, the researchers found. In fact, children with mouse allergen exposure at the 75^thpercentile experienced asthma symptoms on 12 additional days over the school year compared to kids at the 25^thpercentile of exposure, according to the authors.

Numerous other studies suggest that students are exposed to cat and dog allergens at school — allergens that hitch a ride to the classroom via the clothing and hairof pet-owning students and staff, then find their way onto surfaces and into the air. Dust mite and cockroach allergens also have also been detected in surface and airborne samples from daycares and schools, research shows.

The bottom line, according to the National Institutes of Healthresearchers: “Indoor air quality in schools and daycare environments can affect millions of people including students and staff.

Allergen exposures at schools may be so high, according to the researchers, that all the zealous cleaning parents do at home may be for naught.

“It is essential,” they conclude, “to establish cost-effective approaches to reduce allergen levels in these indoor environments.”

So what can schools do to help alleviate all the runny noses and itchy eyes?

Well, in one study, a Swedish school had tremendous success lowering cat allergen levels — except that “rigorous,” the term used by researchers, doesn’t even begin to describe the study’s intervention measures. Children from pet-free households were taught separately and used a separate school entrance, school clothes were worn and laundered only at the school, and teachers changed clothes before entering the classroom.

Not exactly a realistic model!

And school custodians can only do so much to keep school floors, cafeteria tables, and desks free from allergens. Schools are active, busy, lively places, and allergens inevitably get launched into the air. While improved ventilation systems may help some schools, a far more cost-effective approach is to use today’s technologyto clean the air.