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Science & Policy Update October 2014: The Built Environment

Keep It Down! How Noise Pollution Affects Public Health
By: Monika Shankar, Health and Environment Associate

Many years back, I lived in a small one-bedroom apartment at the intersection of a moderately traveled residential street, and a more frequently traveled commercial street. The intersection was not very well built, and at its center rose a small ridge of cement that interrupted the relatively smooth surface of the rest of the road. Intermittently, a commercial truck would speed down the corridor and hit the ridge at about 40 mph, producing a deep rumbling noise that traveled through my window and into my bedroom. I eventually became accustomed to the rumblings that occurred every 15 to 30 minutes, night and day. Apart from being an annoyance, I never regarded the situation as something that could impact my health.

A growing body of research indicates that noise can adversely affect a range of health conditions. This year, professors Dr. Eoin King and Dr. Enda Murphy published Environmental Noise Pollution: Noise Mapping, Public Health, and Policy, a book that synthesizes decades of central debates surrounding environmental noise pollution, including primary stressors. But perhaps most compelling of their research is the range and degree to which environmental noise pollution impacts public health. The effects of environmental noise has been extensively studied. Over the decades, we have learned that noise pollution adversely affects millions of people across the world, leading to a myriad of health impacts including sleep disturbance and annoyance, cognitive impairment in children, and Tinnitus.

“Many people become habituated to noise over time… The biological effects are imperceptible, so that even as you become accustomed to the noise, adverse physiological changes are nevertheless taking place, with potentially serious consequences to human health.”
– Deepak Prasher, University College of London (taken from EHP article “The Sound Behind Heart Effects”)

The causal relationship between noise and cardiovascular disease, especially hypertension and heart disease, is an area of research that has especially taken off in recent years. Here’s how it works: noise is a psychosocial stressor that activates the sympathetic and endocrine system. As your body receives signals from the environment (let’s say traffic noise from a nearby freeway), the hypothalamus alerts the pituitary gland, which then releases stress hormones into the blood stream, such as cortisol, adrenaline and noradrenaline. Chronic high levels of stress hormones can lead to hypertension, stroke, heart failure, and immune problems. Specifically addressing the noise factor, these studies support the strong association between noise, stress hormones and cardiovascular risk. So what does this look like in real life? Most case studies have been conducted primarily in Europe, and reveal some hard facts on noise pollution. For example, 2% of Europeans suffer severely disturbed sleep, while 15% suffer severe annoyance due to environmental noise. New figures suggest that around 3% of deaths from coronary heart disease are due to long term exposure to traffic noise. Furthermore, another study showed an 80% increased risk of cardiovascular mortality for women who judged themselves as sensitive to noise.

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In the context of Los Angeles, the reality is that noise pollution (primarily from transportation) is just another layer of pollution burdening our communities. Noise, poor air quality and land contamination contribute to the cumulative impact burden that residents feel in their environment. The California Environmental Protection Agency recently released a tool, the CalEnviroScreen2.0, which measures this cumulative impact and identifies the communities most burdened by social and environmental pollutants. 54% of census tracks in Los Angeles County are in the top 20% most burdened in California. And noise pollution wasn’t even a factor considered in this equation. The need to reduce pollution of all kinds – including noise – is urgent, especially in the most impacted communities.

Pollution Burden Map of Los Angeles, CalEnviroScreen 2.0

Pollution Burden Map of Los Angeles, CalEnviroScreen 2.0

PSR-LA is working with the United Neighbors In Defense Against Displacement (UNIDAD) to incorporate environmental health policy solutions into the South and Southeast Community Plans, one of which is identifying and enforcing designated truck routes through heavily residential neighborhoods. In addition to mitigating a harmful pollution source in communities, an additional co-benefit of this strategy is reducing noise pollution. The Community Plans will be finalized in 2015. PSR-LA and our allies will continue to advocate for strong environmental health protection that take into account all types of pollutions that impact health. If you are interested in getting involved in any of these efforts, contact Monika Shankar at mshankar@psr-la.org.

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