How Does Less Traffic Create More Pollution?

As the world went into lockdown last year to limit the spread of Covid-19, one of the more pleasant environmental consequences of coronavirus was enhanced air quality. Almost all across the globe, emissions diminished and air quality improved due to fewer passenger cars on the roads, less industrial activity and closed businesses.

However, a new study from the USA has suggested that while air pollution levels may have fallen, other forms of contamination actually increased. In particular, the findings demonstrate that noise pollution intensified in rural areas adjacent to major thoroughfares, since a lack of traffic allowed cars to drive more quickly and more noisily.

The sound of lockdown

While it might seem like lockdown measures would have resulted in lower levels of air and noise pollution – especially at locations notorious for both, such as construction sites, demolitions and other industrial areas – the research from Boston University found that the opposite was the case in some parts of the city.

The scientists used a sophisticated iPhone app known as SPLnFFT, which was capable of collecting noise samples at high sensitivity. They took their equipment to three different nature conservation locations around Boston and gathered the samples, then compared the decibel levels to the pre-existing library in the University lab. What they found surprised them.

While the first two locations did show reduced noise levels, the third demonstrated significantly higher levels of noise pollution at all locations of the park. The team quickly ascertained that the spike was due to motorists driving more recklessly on the highways which intersect the park – and that the increase in speed was likely due to the reduced amount of traffic on the road.

Adverse effects

While a few more decibels in a relatively remote part of town might not sound like the worst side-effect of improved air quality, several studies have shown that noise pollution can have debilitating impacts on animal life. For starters, it can inhibit their ability to communicate with one another or detect the presence of a predator approaching, while it can also interfere with migratory and hibernation patterns.

“There's an increasing volume of studies that say wildlife is very sensitive to noise pollution," explained Richard Primack, lead author on the study. “Animals rely strongly on their hearing for detecting predators and social interactions. The big impact [of noise pollution] is the filtering out of which species can live in an area, because if you have a species you need to conserve, you can't conserve them if they won't be able to survive in a loud area, or if the conservation area is right by a road.”

Meanwhile, noise pollution can also have negative implications for human health. Among other undesirable symptoms, it has been demonstrated to prompt higher blood pressure, increased irritability, an inability to sleep, mood swings, panic attacks and even a heightened risk of heart attacks. In a park that is specifically designed to provide a place for people to relax, that’s a most unwanted outcome.