Air and Noise Pollution

Air Pollution ProblemAir is a mixture of gases – 78% nitrogen,

21% oxygen, and small amounts of argon, CO2, 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 pollutionAir pollution became a big problem during the

industrial revolution during the 1700’sHuge amounts of coal and wood were burned

and human health effects were devastating

Outdoor PollutantsAir Pollutants can be gases or

particulatesAir 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 – (O3) very corrosive and breaks down rubber and

synthetic fibers. High concentrations are poisonous to plants and animals

Nitrogen Dioxide - (NO2) brown gas that gives smog its color

Outdoor Pollutants

Hydrocarbons – made of hydrogen and carbonMethane – 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 PollutantsAir inside of buildings can often contain high levels

of pollutantsHome products such as plastics, insulation, and

cleaners can give off harmful fumesAir circulation in buildings is poor – especially in

winterMost people spend 16-18 hours/day insideIndoor air can contain:

Cigarette smoke – dangerous to smokers and nonsmokers

Microorganisms – bacteria and fungusRadon –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 EffectsCarbon 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 emphysemaEmphysema – disease in which tiny air

sacs in the lungs break downParticulates – can cause cancer – a

disease in which cells grow abnormally and without restraint.

Plants and AnimalsPlants :

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 animalsEye and lung irritation, bronchitis, and cancerIndustrial air pollutants (lead and zinc) can

contaminate rangelandand make grazing animals sick

GlobalEffects of Air Pollution

PollutionPollution can

threaten ecosystems and even the entire planet

Three major air pollution problems threatening the global environment:Acid precipitationOzone depletionGlobal warming

Acid PrecipitationRain or snow that is more acidic than normal

precipitationNormal 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 acidnitrogen into the air which mixes with water to

form nitric acidAcid rain:

falls in forests and hurts the treesfalls into lakes and hurts the fishFalls on buildings/statues and deteriorate them

Ozone Layer

At earth’s surface, ozone is a poisonous gas

At 20-50 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 Sky1980’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:SunburnBlindnessSkin 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 atmosphereLight energy from the sun enters the

atmosphere and is absorbed by earth’s surfaceOnce absorbed, light energy is changed to heatEarth radiates this heat back into space in the

form of infrared radiationSome of the infrared radiation gets trapped

and warms the air in the lower atmosphereWithout the greenhouse effect, life on earth

would not be possible!

Greenhouse Gases

Atmospheric gases that trap heat:Carbon dioxide (CO2)MethaneSulfur and nitrogen oxidesCFC’sWater vapor

Amounts of greenhouse gases are increasing because of pollution caused by human activities

Burning fossil fuels releases CO2 into the airIce 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 ofthe 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 airBut, removing pollutants from the air

means putting them somewhere else – land, waterCarbon dioxide is removed from the air 2 ways:

Biological activity – plants remove CO2 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 CO2

Human Air Pollution Control

Automobiles – major source of air pollutionStates have set strict emission control

standardsCars equipped with catalytic convertersCars designed for better gas mileageLook for other means of fueling cars

(electricity)Power Plants – major source of

pollutionDesign ways of cleaning the emissions

– scrubbersCan be very expensive

Noise PollutionCan cause annoyance, stress, and hearing damage

Sources are airplanes, machines, and concerts

Sound intensity is measured in decibels (dB)Softest sounds are around 0 dBAnnoying sounds are around 70-80 dBDamaging sounds are around 120-130 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!!