A new study from the University of Gothenburg has shown that residents’ health was considerably improved after a hybrid bus line was switched to all-electric.
A bus route in Gothenburg, Sweden, was replaced with an all-electric mass transit line and the health benefits achieved by the residents in the area were evident in terms reduced fatigue, day-time sleepiness and overall noise levels.
Before the switch to all-electric buses along the bus route in Gothenburg, noise levels were perceived as disturbing, especially on uphill stretches. Noise-level measurements indicated that disturbance from low-frequency noise in indoor environments was present in the residential area. The low-frequency noise has a high disturbance potential and facades or noise barriers do not effectively block this noise.
“We can be disturbed by different noises, but the issue with low-frequency noise is that it’s attenuated less well by facades or windows and therefore intrudes into people’s homes more easily,” said Kerstin Persson Waye, professor of environmental medicine at the University of Gothenburg. “Even small increases in its level are perceived as very noticeable.”
The University of Gothenburg study involved residents in two phases: before and after the switch to electric buses. Half of the residents lived in homes that lined the bus route in two districts: Masthugget and Lunden. The other half lived further away from the bus line.
Noise measurements were performed in several homes—including indoors—and this measurement required special rigging with 10-12 microphones in each dwelling unit to provide correct data of the low-frequency noise.
Researchers found the changes between the phases were significant and the amount of noise the residents experienced was noticeable. About 75% of respondents noticed noise from buses before the switch to electric, a number that fell to 39% after the switch. The proportion of those respondents that were noise-annoyed to a very high degree decreased from 26% to 5%.
University of Gothenburg researchers found a clear reduction of perceived health effects. Those that felt exhausted once or twice a week declined from 49% to 39% and those with low mood decreased from 22% to 17% after the switch.
Additionally, fewer respondents said they were very sleepy in the daytime after the switch.
“So, there was an improvement: People felt significantly better,” Persson Waye said. “Although we can’t say with certainty that the results reflect the whole population and how lasting the positive health changes are, we think they may be generalizable in residential settings where bus transportation makes up a large share of the exposure. Given, too, that other forms of transportation in the urban environment are getting more silent, this could influence public health.”
Learn more about the full research from the University of Gothenburg.