AIR POLLUTIONChapter 22

INTRODUCTION

• Pure air does NOT exist! Air impure to the degree we call polluted is an increasingly serious problem.

• Air pollution has many different manifestations, depending on who offends and who is offended.

• To the average home owner it means eye irritation, added costs due to excess laundry and cleaning bills, excessive house painting , and car-finish deterioration.

Cont.

• To the farmer it means damaged crops and live-stock. To the airline pilot it means increased hazards in taking off and landing due to poor visibility.

• To industry it means rejects of precision materials, process control problems, and poor public relations.

• To everyone it means serious health problems from ingesting pollutants such as sulfur dioxide, carbon monoxide, oxides of nitrogen, dust, soot, pollen and other contaminants.

Pollutants

• Pollutants are harmful substances that enter the environment.

• Air pollution may be made up of particulates or gases, usually OXIDES.

• Pollutants can be present outdoors or indoors

Outdoor Pollutants

• Particulates-tiny solids suspended in the atmosphere-ash, dust, soot from burning organic matter; metals like lead, iron, copper;these are dangerous because they easily can become trapped in lungs

• Gaseous- oxides are cmpds of 02 + another element-burning of fossil fuels releases these gases

Photochemical Smog

• Photochemical Smog- yellow-brown haze formed when sunlight reacts with pollutants produced by car emissions- Ozone is one of the chemicals; highly corrosive in large amounts can also be poisonous to living things. NO2 gives PS its distinct brown color.

Hydrocarbons

• Hydrocarbons- Methane most common pollutants- decaying organic matter or as a by product or burning organic matter.

CFSs

• CFCs- cmpds of chlorine, carbon, and fluorine once used in refrigerators, air conditioners, and aerosol cans.

Indoor Pollutants

• Home products- such as plastic, insulation, and cleaners give off harmful fumes.

• Cigarette smoke- extremely harmful to both smokers and nonsmokers

• Microorganisms- ventilation ducts contain bacteria and fungi

• Radon- a colorless odorless radioactive gas. Radon forms when radium, a radioactive element in soil breaks down. Radon from soil is drawn into a home through the basement.

Air pollution and its effects on living things

• Air pollution can affect human health and the health of plants and animals.

• Humans health problems can range from eye and respiratory tract irritation to emphysema and lung cancer.

• Air pollution can also damage crops and be passed from contaminated food and water to grazing animals

Human diseases

emphysemaLung cancer

Crop damage by air pollution

Global effects of air pollution

• Air pollution can have global as well as local effects.

• Acid precipitations is rain or snow with a very low pH, resulting from oxides combining with water in the air.

Normal rain pH=5.6

Acid rain=3-4.5 Vlemon=2 HCL=1.5

Cont.

• Sulfuric and nitric acid falls on the earth in the form of acidic precipitation destroying entire ecosystems

• Sweden- 20,000 lakes are too acidic to allow fish to survive

• Thousands of other lakes in Norway, Canada and the Northeastern US are so acidic that they contain no fish or plant life.

Ozone depletion

• At the surface of Earth, Ozone is a corrosive, poisonous gas.

• 20-50 Km above the earth’s surface it is vital for life as we know it! Ozone absorbs most of the UV radiations given off by the sun, before they reach the earth’s surface. UV radiations are damaging to living things

Ozone holes over North and South Poles

Continue

• Ozone depletion results from the breakdown of O3 molecules in the stratosphere by CFSs. (Cl and Fl)

• Experiments have proven that natural sources contribute very little chlorine to the stratosphere; we are the major producers of fluorine and chlorine in the stratosphere.

Global Warming

• The greenhouse effect-caused by gases such as CO2 in the atmosphere, could lead to global warming.

Global Warming: cont.

• Deforestation at an increase speed also causes this warming trend.

• Every second, a rainforest the size of

a football field disappears.

Amazon rain forest

Controlling Air Pollution

• Some air pollutants are removed by natural processes such as precipitation and biological activities.(CO2 removal)

• Local state and federal government agencies have been trying to reduce the quantities of polluting materials discharged into the atmosphere. Significant reduction for adequately clean air will require many years and ENFORCED laws.