Air and Noise Pollution

Air Pollution Problem Air is a mixture of gases – 78% nitrogen, 21% oxygen, and small amounts of argon, CO 2, and water vapor Air pollution – harmful materials that enter the environment and released into the atmosphere Pollutants can be from natural sources (sandstorms, volcanic eruptions), or from human activity Human caused air pollution Air pollution became a big problem during the industrial revolution during the 1700’s Huge amounts of coal and wood were burned and human health effects were devastating

Outdoor Pollutants Air Pollutants can be gases or particulates Air particulates – tiny solids suspended in the atmosphere (ash, dust, soot, liquid droplets, trace metals, pesticides, fertilizer dust, etc) Particulates are dangerous because they are so small and are easily inhaled and get trapped in people’s lungs Gaseous Pollutants – most are oxides (compounds of oxygen and another element like carbon, sulfur, or nitrogen) released when fossil fuels are burned

Outdoor Pollutants Photochemical Smog – a yellow-brown haze formed when sunlight reacts with pollutants produced by cars Develops in cities with heavy automobile traffic (L.A. New York) Contains: Ozone – (O 3 ) very corrosive and breaks down rubber and synthetic fibers. High concentrations are poisonous to plants and animals Nitrogen Dioxide - (NO 2 ) brown gas that gives smog its color

Outdoor Pollutants Hydrocarbons – made of hydrogen and carbon Methane – most common – produced by certain bacteria, livestock, and by rotting plant and animal matter Chlorofluorocarbons – (CFC’s) compounds of carbon, chlorine, and fluorine once used in refrigerators, air conditioners, aerosol cans, and in the production of Styrofoam

Indoor Pollutants Air inside of buildings can often contain high levels of pollutants Home products such as plastics, insulation, and cleaners can give off harmful fumes Air circulation in buildings is poor – especially in winter Most people spend hours/day inside Indoor air can contain: Cigarette smoke – dangerous to smokers and nonsmokers Microorganisms – bacteria and fungus Radon –colorless, odorless, radioactive gas from natural breakdown of radium. Radon gas enters the soil and then your basement. Can cause lung cancer.

Air Pollution and Living Things…

Health Effects Carbon Monoxide – dangerous because it takes the place of oxygen on your red blood cells. High concentrations can stress the heart, cause headaches and dizziness, and even cause death Ozone and Oxides of Sulfur and Nitrogen – irritate the eyes and respiratory tract, trigger asthma and allergy attacks, cause bronchitis and emphysema Emphysema – disease in which tiny air sacs in the lungs break down Particulates – can cause cancer – a disease in which cells grow abnormally and without restraint.

Plants and Animals Plants : Affected by ozone and sulfur oxides Causes stems to be brittle and leaves to develop spots Affected millions of Ponderosa Pines in L.A. Also damages agricultural crops Animals: Loss of plants – no food for animals Eye and lung irritation, bronchitis, and cancer Industrial air pollutants (lead and zinc) can contaminate rangeland and make grazing animals sick

Global Effects of Air Pollution

Pollution Pollution can threaten ecosystems and even the entire planet Three major air pollution problems threatening the global environment: Acid precipitation Ozone depletion Global warming

Acid Precipitation Rain or snow that is more acidic than normal precipitation Normal precipitation has a pH of 5.6 Carbon dioxide mixes with water in the air and forms carbonic acid Burning fossil fuels releases: sulfur into the air which mixes with water to form sulfuric acid nitrogen into the air which mixes with water to form nitric acid Acid rain: falls in forests and hurts the trees falls into lakes and hurts the fish Falls on buildings/statues and deteriorate them

Ozone Layer At earth’s surface, ozone is a poisonous gas At km above earth, it forms a protective layer around earth The ozone layer absorbs almost all of the ultraviolet (UV) radiation given off by the sun This prevents the UV rays from reaching earth and harming living things.

Hole in the Sky 1980’s – scientists discovered a hole in the ozone layer over both the South Pole and the North Pole Damage to the ozone layer could greatly increase the amount of UV radiation that reaches earth In humans this can cause: Sunburn Blindness Skin cancer Can also cause severe crop damage

Causes of Ozone Depletion CFC’s – main cause of ozone depletion – used in refrigerators, air conditioners, and aerosol sprays CFC’s are OK in the lower atmosphere, but when they reach the stratosphere they are exposed to UV radiation UV radiation causes CFC’s to break down and release chlorine and fluorine atoms Chlorine and fluorine atoms destroy ozone

Global Warming Greenhouse Effect – the trapping of radiated heat by gases in the atmosphere Light energy from the sun enters the atmosphere and is absorbed by earth’s surface Once absorbed, light energy is changed to heat Earth radiates this heat back into space in the form of infrared radiation Some of the infrared radiation gets trapped and warms the air in the lower atmosphere Without the greenhouse effect, life on earth would not be possible!

Greenhouse Gases Atmospheric gases that trap heat: Carbon dioxide (CO 2 ) Methane Sulfur and nitrogen oxides CFC’s Water vapor Amounts of greenhouse gases are increasing because of pollution caused by human activities Burning fossil fuels releases CO 2 into the air Ice cores are used to determine the levels from many years ago

Global Warming An increase in earth’s average surface temperature caused by an increase in greenhouse gases Another large increase in atmospheric carbon dioxide occurred at the end of the last ice age (14,000 years ago) Scientists think there is the same link between increased carbon dioxide and temperature now As the temperature rises, water in the oceans will expand, polar ice caps will begin to melt and flooding will occur

Controlling Air Pollution

Natural Air Pollution Control Precipitation is the most effective natural method of removing particulates and aerosols from the air But, removing pollutants from the air means putting them somewhere else – land, water Carbon dioxide is removed from the air 2 ways: Biological activity – plants remove CO 2 to make sugars (photosynthesis) – it plants get buried, we get fossil fuels Ocean water – depends on temperature. If temperatures rise due to global warming, the ocean will begin to release CO 2

Human Air Pollution Control Automobiles – major source of air pollution States have set strict emission control standards Cars equipped with catalytic converters Cars designed for better gas mileage Look for other means of fueling cars (electricity) Power Plants – major source of pollution Design ways of cleaning the emissions – scrubbers Can be very expensive

Noise Pollution Can cause annoyance, stress, and hearing damage Sources are airplanes, machines, and concerts Sound intensity is measured in decibels (dB) Softest sounds are around 0 dB Annoying sounds are around dB Damaging sounds are around dB 1972 – Congress passed the Noise Control Act – set standards for maximum noise levels Industries have also tried to reduce sources and levels of noise pollution in the workplace Don’t listen to very loud music and wear earplugs if you will be in a noisy area!!