東北医科薬科大学
医学部 英語
2024年度 解答・解説

[1] Priya Nandakumar still remembers the spring her street was torn up. Workers spent months replacing old water pipes outside her apartment, and drills roared from morning to evening. A university student at the time, Priya was preparing for her final exams. She tried studying at home with a pillow over her head, then in the library, then with music in her ears. Nothing seemed to help. She kept rereading the same page. "I felt like my head was full of static," she says.

[2] Priya passed her exams, but her marks were lower than she had hoped. Her roommate, who studied in a quiet town an hour away, did much better, though the two had worked equally hard. Priya wondered whether the noise had been partly to blame. At first she thought she was only making excuses. Her friends laughed and said everyone gets distracted. But the question stuck with her.

[3] Priya is not alone. As cities have grown, there have been more and more complaints about trouble with noise, not only near building sites but also in homes, schools and open offices. Some people say they still cannot concentrate in the weeks and months after a noisy project ends. But proving that sound is the cause is harder than it seems.

[4] Scientists have long suspected that noise harms learning. In the 1970s, researchers who studied children living beside a railway found that those pupils read more slowly than classmates from quieter streets. Since then, studies have shown that loud, unpredictable sounds can disturb memory and attention more than a steady hum does. Even so, for many years noise was seen mainly as a minor annoyance rather than a health issue.

[5] Henrik Vos directs the Listening Lab at Calder University in Denmark. When he asks volunteers to memorize word lists while recordings of street traffic play, they remember fewer words than people working in silence. The volunteers also give up sooner on the hardest puzzles, the ones that demand the most attention. Simple tasks, by contrast, take about the same time with or without the traffic noise.

[6] Stress hormones, chemicals that prepare the body to react to danger, appear to play a major role, Vos says. When volunteers hear sudden loud sounds, levels of the hormone cortisol rise, causing their attention to narrow. When scientists give volunteers a drug that lowers cortisol, the noise bothers them less — even when the sounds stay just as loud.

[7] It's harder to do the same kind of research in schools, and results are mixed about how noise changes real learning. But studies suggest that, at least to some extent, children react in ways comparable to adults. In studies from the 2000s, researcher Anita Roos and colleagues played recordings of classroom chatter to pupils and found that even moderate noise lowered reading scores and heightened tiredness.

[8] But once the noise went on for weeks, people showed patterns not typically seen in short experiments. "A short burst of noise makes people work harder for a while," Vos says. "But over time, that extra effort wears you down."

[9] To see how long-term noise affects students, Vos and colleagues recruited 120 first-year students who lived near a busy road. For one semester, the students kept a detailed study diary and wore a small sensor on their wrists that measured sleep. Thirty students withdrew before the end. Overall, the students who lived on the noisiest side of the building slept less and studied longer each week, the researchers reported in 2023.

[10] ( ① ) But the extra hours did not pay off. ( ② ) Students on the noisy side needed longer to finish the same tasks and made more errors on weekly quizzes. ( ③ ) Anecdotally, that matches what many students say about living near roadwork: long hours at a desk with little progress. ( ④ ) The effort of ignoring the sound seems to use up energy that would otherwise go to learning, Vos says.

[1] Walk past a gray concrete wall in a busy city and you might not give it a second look. But some walls wear a thin green coat of moss. Scientists have long known that moss traps bits of dust from the air. No one knew whether a moss wall could really clean the air beside a busy road — until now. A study has just given a first answer.

[2] Researchers in Portugal reported the results in the journal Urban Ecology Letters. The worry is fine dust. Technically, a particle is called "fine" if it is smaller than 2.5 micrometers. Such particles can slip deep into the lungs. And that's what makes city air hard to clean, says Tiago Ferreira, an engineer in Porto. Ordinary filters miss most of it. Amira Haddad is a public health specialist in Cairo, Egypt. She did not take part in the new study. Fine dust, she adds, "has been linked to asthma." Cities need cheap ways to cut it.

[3] Inês Carvalho and Tomás Rocha were part of a team at the University of Porto. As materials scientists, they test ways to clean the air. ( ① ) No one had tested moss walls on real streets before. ( ② ) Counting fine dust in open air isn't easy. You can't just watch the air and count. ( ③ ) They fixed moss panels to 30 walls along busy roads and placed a sensor beside each one. ( ④ ) Each sensor counted particles smaller than 2.5 micrometers (0.0001 inch) across. For perspective, a grain of table salt is about 100 times wider.

[4] After one year, the team compared dust beside the moss with dust at 30 bare walls nearby. Fewer particles were counted next to the moss at 24 of the 30 sites. That's four in every five. Half of those 24 sites had moss thicker than 5 centimeters. Where the moss had dried out in the hot summer, the walls did no better than bare concrete.

[5] The team also traced where the dust came from. Much of it was bits worn off tires. Smaller shares came from brake pads and from construction work. The team also looked for soot from diesel engines but found none. If it was present, they say, it was at levels too low to detect.

[6] "Cities are full of walls," says Kofi Mensah. He is an urban planner at the University of Lagos in Nigeria. He did not take part in the Porto study. But in a March review, he helped examine green walls in hot countries. The data are so limited that "we don't really know how well they work," he cautions. "It's hard to judge," he adds, partly because "moss stops growing in hot, dry weather, and every site is different."