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2. Noise Pollution  Noise pollution is excessive, displeasing, human, animal or machine-created environmental noise that disrupts the activity or balance of human or animal life.  Most outdoor noise worldwide is mainly construction, transportation systems, airplanes buses, motorcycles, car alarms, emergency sirens, fireworks, barking dogs, audio entertainment and people  This type of pollution affects human health, the environment, and animals.  Affects the lives of millions of people daily!

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4. Human Health.  Noise pollution plays an important part in human health  Certain loud and unwanted noise can damage physiological health  Such things like annoyance, aggression, hypertension, high stress levels, hearing loss, sleep disturbances, speech interference, lost productivity etc. occur  Interferes with sleeping, conversation, and diminishes the quality of ones life

5. NIHL   NIHL is a haring health disorder (Noise Induced Hearing Loss)  This is one of the most common and often discussed health effects  You can protect yourself by using earplugs, or earmuffs  Happens when we are exposed to harmful noise— sounds that are too loud or loud sounds that last a long time— sensitive structures in our inner ear can be damaged, causing noise- induced hearing loss (NIHL).  Explosions  Once damaged, your hearing loss can be permanent

6. Environmental Health  Noise Pollution has a detrimental effect on animals, increasing the risk of death by changing the balance of predator and prey  Animals use sounds for communication, reproduction, and navigation  Certain species of whales died due to the loud sound of military sonar  Lombard Vocal Response- makes species communicate louder

7. Legal Status  In the U.S, there are certain standards for highway and aircraft noise  Up until the 1970’s, governments considered noise a “nuisance” rather than an environmental problem  Noise laws vary widely, and are not in every city  Noise is only allowed for certain times and certain activities during certain times of the day  Most city ordinances prohibit sound above a threshold intensity from trespassing over property line at night between 10pm and 6am  There are specific laws on building codes, urban planning, and roadway development  Engines of planes can only be so loud

8. Decibel  Decibels = dB  A unit to measure the intensity of a sound  Measures sound based on human hearing, which makes it one of the most unusual scientific measurements.  Expressed as the base of 10 on the logarithmic scale  Noise intensity is measured in decibel units  Distance diminishes the decibel level  Ex) To a driver with a car window open or a pedestrian on the sidewalk, the same traffic rates about 70 decibels  Ex) The noise of a jet takeoff reaches about 110 decibels— approximately the same as an automobile horn only 3 ft (1 m) away

9. Intensity  Intensity is the power of the sound. This is measured in watts/meters^2 or watts/cm^2.

10. Threshold of Hearing  The absolute threshold of hearing (ATH) is the minimum sound level of a pure tone that an average ear with normal hearing can hear with no other sound present.

11. Threshold of Pain  The threshold of pain is the point at which pain begins to be felt.  In hearing, the pressure at which sound becomes too painful for the ears  Depending on age, determines your threshold of pain. Threshold of Pain Sound pressure levelSound pressure 120 dBSPL20 Pa 130 dBSPL63 Pa 134 dBSPL100 Pa 137.5 dBSPL150 Pa 140 dBSPL200 Pa