And finally, we’ve neared the end of 2019 which means we’re only a short couple weeks away from New Year’s Eve. We could talk about the fact that Times Square in New York City produces around 50 tons of trash, but we’re gonna take it a different route with one of the rowdiest holidays.

New Year’s Eve is just downright loud and that proved to be the best segue into noise pollution.

What is Noise Pollution?

It is unwanted noise, which can be pretty subjective. So when do noises become unwanted? If they’re interfering with normal activities – think sleep or a conversation – they’re deemed unwanted. But unwanted noises are also any noise that disrupts or diminishes someone’s quality of life. A helpful distinction is natural versus man-made noise.

It’s helpful when talking about noise pollution to have an understanding of what noise is.

When sounds occur, they have to travel through a medium. The medium is typically wherever the sounds are occurring (water versus air, for instance). Sound is generated and this source of sound creates vibrations in whatever medium. The sound continues to vibrate inside the medium as it moves away from the source at the speed of sound. How fast sound can move depends on the medium, but the temperature and the types of gas in the medium are also impactful! You can find a visual representation of sound here.

A useful quality in determining sound pollution stems from the fact that sound can be measured.

Sound is measured using a logarithmic formula in a unit called decibels (dB). Decibels are used to measure the intensity of sound and, as a function of logarithms, are measured in orders of magnitude.

Orders of what?

Magnitude! Near total silence is 0 dB on the decibel scale. A whisper, which is maybe 10x more powerful than almost silence, is 10 dB. When you have a sound that is 100x more powerful than near total silence, you hit 20 dB. Jet engines are 1,000,000,000,000x more powerful than our near total silence and they clock in at 120 dB. As a point of reference, any sound over 85 dB can cause damage to our hearing, potentially resulting in hearing loss.

Is all noise Noise Pollution?

Nope! This is where that aforementioned distinction comes in handy. Manmade noise is what constitutes noise pollution. The main source of noise pollution worldwide is caused by machines – cars, planes, propagation systems, etc. This could help to explain why poor urban planning is sometimes associated with a rise in noise pollution. Funny enough, urban environments and their correlation with noise pollution stem as far back as ancient Rome.

What’s the harm in some extra noise?

Noise pollution has been shown to affect human health and behavior. For children, attending school in a louder area can impact behavior so dramatically, it negatively impacts their exam performance. For adults, loud environments can add some annoyance but beyond that, noise pollution has been connected to hypertension, higher stress levels, tinnitus, hearing loss – especially premature loss, and sleep disturbances. After a review of existing scientific literature in 2019, noise pollution was associated generally with faster cognitive decline.

So why does noise affect us?

Scientists believe it has to do with our evolutionary processes. The idea is that we’ve been programmed over time to respond to noise because noise often translated directly to a threat. In modern times, noises don’t reflect potential threats, but scientists believe still naturally trigger our flight-or-fight response. Even if we’re sleeping, noise can trigger a release in stress hormones – thereby raising our heart rates and blood pressure. When we consistently have this sort of exposure, there can be long term consequences. These consequences can include high blood pressure, type 2 diabetes, cardiovascular disease, and lower birth weights.

Noise even affects animals!

And the effects on animals can also be detrimental.

When we introduce man-made noises into an animal’s natural environment, we’re essentially creating distractions. Animals need noises for a variety of activities – including hunting, navigation, and reproduction. When we introduce an influx of unnecessary noise, we’re messing with the delicate balance that makes up animal relations.

The issues with man-made noise don’t end on land either. On the ocean, ships, air guns, and general tanker traffic are creating a stressful environment for our aquatic life. There are even some scientists who believe these noises can cause the gradual, if not eventual, death of sea creatures. Water is much denser than air and that density allows sound to travel faster and farther. To be specific, sound travels 4x faster and much, much farther in water. Not only that, but the sound has a way of reverberating in water that makes it especially incessant.

A 2017 study researching aquatic life and sound found that a loud blast could eradicate nearly 2/3 of the available zooplankton in ¾ of a mile. Zooplankton might be small but the concerns are mighty. Because zooplankton are on the bottom of the food chain, they are a food source for so many different animals – including great whites and shrimp.

A notable study was completed after the September 11 attacks. There was a decline in the amount of ship traffic taking place and researchers caught that there was a significant drop in the level of stress hormones found in whale feces. This study was actually the first indication that ship noise can even cause stress in whales.

And maybe our plants?

Noise creates burdens for rodents that are necessary for a plant’s reproduction, but we don’t know for sure that noise pollution directly impacts plants. What we do know is that plants have been observed as extending their roots towards vibrations caused by running water. Fascinatingly, a recent study of garden peas showed that the peas could distinguish between real nature sounds and a recording. The vibrations associated with sound are still concerning, however. There are some animals that don’t technically “hear” but they still exhibit changes in behavior when confronted with human noises.

Sound is even in our National Parks

It’s become so hard to escape manmade noise, there are avid outdoors people who actively search for quiet areas in the wilderness. Those especially involved in the effort say it’s become increasingly difficult. At some point, they end up running into sounds of vehicles, industries, or even voices.

Map of existing sound conditions per the National Park Service

Map of natural conditions per the National Park Service

How noisy is it?

A Washington State acoustic ecologist believes that there are only about 12 places left in the continental United States where you can spend 15 minutes without hearing any man-made sounds. Based on previous studies, noise pollution in the parks and other conserved land areas has mostly doubled. In all protected areas across the US, we can expect that 63% of them will experience at least a 3 dB increase in sound as a result of noise pollution. There’s a 10 dB increase in ⅕ of conserved lands – which is a tenfold increase in sound!

How do they know that?

The National Park Service currently has policies requiring that park rangers measure “baseline acoustic conditions.” After this, they have to work to figure out which of these sounds might be having an adverse effect.

Before these policies were enacted, the Environmental Protection Agency had an office dedicated to noise. The Office of Noise Abatement and Control existed in the 1970s.

How do Park Rangers measure noise?

Noise is definitely a complicated pollution to measure. Noise can’t be detected by satellite in the same way that other methods of pollution can. In the park, scientists take hikes to set up special listening stations. These stations include a sound level meter and a recorder and the stations run for about 30 days. At the end of the 30 days, the scientists pick out the various sounds they hear and categorize it – based on natural and man-made. When they take out the natural sounds, they’re able to quantify the expected amount of noise pollution. Because of the geographical modeling that takes place during this research, these scientists can get to a point where they’re able to predict noise levels at any given location in the United States.

What are the Takeaways?

Quiet is a wonderful thing for humans to relish in. When we introduce excessive noise, especially in naturally quiet environments, we’re robbing ourselves of the full experience. According to some scientific studies, nature sounds provide us with reductions in stress alongside general improvements in our moods. Spend 2020 brightening your mood!

For some suggested potentially quiet hiking spots, check out here, here, here.

NOISE POLLUTION!