Many kids are returning to schools without air conditioning. Should parents be concerned?

High temperatures can impact children’s health and educational performance.

Elementary students at the Paul Revere Innovation School in Revere arrived on their first day of school.David L. Ryan/Globe Staff

As the summer heat continues to hover around 90 degrees, many Boston students are returning to schools without air conditioning. Public schools in Springfield, Chicopee, and Westfield that lack A/C, have already announced they will close early Wednesday and Thursday, with many others warning students and families to be careful in the heat.

Exposure to high temperatures can have lasting impacts on children’s health and learning. As climate change is expected to drive more extreme weather, here’s what you need to know about the effects of non-air-conditioned schools on students.

My child goes to a school that lacks air conditioning. Should I be worried?

Exposure to heat can lead to a myriad of physical health issues ranging from dehydration and heat exhaustion to breathing difficulty and headaches. Children are more vulnerable to the effects of extreme heat than adults, according to the United States Environmental Protection Agency.

“We really worry about the physical health of children when the temperature gets above 90 degrees,” said Dr. Scott Hadland, chief of adolescent and young adult medicine at Massachusetts General Hospital for Children. “We will see more of these days even in September as the climate changes and the effects in many US classrooms, especially in Massachusetts, which often don’t have air conditioning.”

The main concern for pediatricians like Dr. Howard Kay, president of Boston Pediatrics, is dehydration. “In a warm classroom where kids are perspiring and not drinking enough, you will start to see kids faint,” he said.

Hotter temperatures also affect children’s academic performance. A 2021 study published in Nature found students who experience hotter temperatures both in classrooms and outdoors during the school year exhibited “reduced learning,” with kids showing poorer academic performance for each additional day over 80 degrees Fahrenheit.

Researchers found that younger students, who are more sensitive to temperature changes, were more strongly impacted.

What about kids with asthma? Are they at greater risk?

Yes. Hotter weather and humidity can both increase the risk of asthma attacks. A 2016 study published in Environmental Health found that extreme heat, particularly during the summer, increased risks of asthma-related hospitalizations. Heat and humidity can constrict and narrow airways, making it harder for asthmatic people to breathe, according to the Asthma and Allergy Network.

People with asthma are already more vulnerable to health-related issues during the month of September, when the presence of ragweed pollen and other triggers increases, according to Kay. “On top of that, kids are exposed to more illnesses once they’re back in school, so we tend to see more kids with severe asthma problems in general,” he said.

Asthma prevalence in Massachusetts is among the highest reported across US states, according to the state Department of Public Health, and Boston bears a disproportionate amount of that burden.

During the 2011-2012 school year, nearly 16 percent of K-8 students in Boston had asthma, higher than the statewide average of 11.9 percent, according to a report from the Massachusetts Department of Public Health. The report also found that children in Boston have higher rates of hospitalizations and emergency department visits due to asthma than in the rest of the state.

Rates are higher among Black and Hispanic children. According to the state health department, Black children are more than 5 times as likely as white children to have asthma, and Hispanic children are more than 3.7 times more likely.

How can I help my child deal with the heat?

Make sure students are staying hydrated and drinking plenty of fluids throughout the day, especially before playing sports or other physical activity.

The clothes they wear can make a difference, too. Kay recommends picking light-colored fabrics that deflect heat and loose-fitting clothes on hot days. Breathable fabrics such as cotton are also helpful as they allow sweat to evaporate, cooling down the child’s body, according to the EPA.

Is there a way to check how hot my child’s school is?

Boston Public Schools operates an online air quality dashboard to help identify and respond to air quality and temperature issues. The dashboard allows anyone to check the temperature, relative humidity, carbon monoxide, and other air quality metrics for all BPS schools.

Globe correspondent Maggie Scales contributed reporting.