Air Pollution - Chapter 16 PDF

Air Pollution Major Pollutants In Our Air  Major Pollutants In Our Air Most of us don’t realize how bad air pollution used to be here in N. America. Developing countries still face terrible air quality Aesthetic Degradation Changes in environmental quality that offe...

Air Pollution Major Pollutants In Our Air  Major Pollutants In Our Air Most of us don’t realize how bad air pollution used to be here in N. America. Developing countries still face terrible air quality Aesthetic Degradation Changes in environmental quality that offend our aesthetic senses. Pollution can be natural also but humans have caused the most pollution 3 million lives are lost a year in China and India alone  Major Pollutants In Our Air The Clean Air Act of 1970 established new standards country wide and addressed six Conventional Pollutants The seven major pollutants (sulfur dioxide, carbon monoxide, particulates, hydrocarbons, nitrogen oxides, photochemical oxidants, and lead) identified and regulated by the U.S. Clean Air Act. Unconventional Pollutants Compounds and that are produced in less volume than conventional pollutants but that are especially toxic. Primary Pollutants Chemicals released directly into the air in a harmful form. Secondary Pollutants Chemicals that acquire a hazardous form after entering the air or that are formed by chemical reactions as components of the air interact. Fugitive Pollutants Substances that enter the air without going through a smokestack. Dust from soil erosion, strip mining, rock crushing, construction, and building demolition, etc  Major Pollutants In Our Air Conventional Pollutants Sulfur Dioxide A colorless, corrosive gas directly damaging to both plants and animals. SO2 does come from natural sources (hot springs, volcanoes, etc) but 2/3rds come from human sources mostly from coal and smelting Forms sulfuric acid in the atmosphere and can become acid rain  Major Pollutants In Our Air Conventional Pollutants Nitrogen Oxides Highly reactive gases formed when nitrogen in fuel or combustion air is heated to over 650°C (1,200°F) in the presence of oxygen, or when bacteria in soil or water oxidize nitrogen-containing compounds. Responsible for yellowish color of smog, acid rain, and is a greenhouse gas Excess nitrogen can also cause eutrophication  Major Pollutants In Our Air Carbon Monoxide A colorless, odorless, non-irritating, but highly toxic gas produced by incomplete combustion of fuel, incineration of biomass or solid waste, or partially anaerobic decomposition of organic material. CO blocks oxygen uptake in the blood 90% of CO turns to CO2  Major Pollutants In Our Air Conventional Pollutants Ozone (O3) and Photochemical Oxidants Products of secondary atmospheric reactions Also includes Volatile Organic Compounds (VOCs) Plants emit most of these but conc. are low.  Major Pollutants In Our Air Conventional Pollutants Lead The most abundantly produced metal air pollutant Toxic to our nervous systems and has made IQ levels lower Sources are mining, burning coal, smelting, and leaded gas.  Major Pollutants In Our Air Conventional Pollutants Particulate Matter Atmospheric aerosols, such as dust, ash, soot, lint, smoke, pollen, spores, algal cells, and other suspended materials. Aerosols Minute particles or liquid droplets suspended in the air. Not only from humans but can be from dust storms  Major Pollutants In Our Air Mercury, from coal, is particularly dangerous Mercury is released by coal and oil burning, smelting, and mining. It is a powerful neurotoxin, and most humans get it from eating fish Mercury can travel via global air circulation  Major Pollutants In Our Air Hazardous Air Pollutants (HAPs) can cause cancer and nerve damage Especially dangerous air pollutants, including carcinogens, neurotoxins, mutagens, teratogens, endocrine system disrupters, and other highly toxic compounds. They are dangerous because they can bioaccumulate and persist in ecosystems The EPA has cut back 70% of these emissions and must be registered Toxic Release Inventory (TRI) A program created by the Superfund Amendments and Reauthorization Act of 1984 that requires manufacturing facilities and waste-handling and disposal sites to report annually on releases of more than 300 toxic materials.  Major Pollutants In Our Air Indoor air can also be hazardous Chemicals can be 70 times higher in our homes than what is outside Many people in developing countries cook over an open fire  Atmospheric Processes Temperature Inversions can trap pollutants A stable layer of warm air overlying cooler air, trapping pollutants near ground level. Los Angeles is a classic example  Atmospheric Processes Wind currents carry pollutants worldwide  Atmospheric Processes Chlorine destroys ozone in the stratosphere Stratospheric Ozone The ozone (O3) occurring in the stratosphere 10 to 50 km above the earth’s surface. Chlorofluorocarbons damage the ozone layer Chemical compounds with a carbon skeleton and one or more attached chlorine and fluorine atoms. Commonly used as refrigerants, solvents, fire retardants, and blowing agents.  Atmospheric Processes The Montreal Protocol was a resounding success The first international response to phasing out CFCs. The ozone hole should be gone by 2050 It also slowed climate change because CFCs are a powerful greenhouse gas.  Effects of Air Pollution How does pollution make people sick? WHO estimates that 5-6 million people die every year for air pollution CO and lead bind to hemoglobin Bronchitis, emphysema, and chronic obstructive lung disease (COPD)  Effects of Air Pollution Sulfur and nitrogen emissions produce acid rain Acid Deposition Acidic rain, snow, fog, or dry particulates deposited from the air due to an increased release of acids by anthropogenic or natural resources. This can cause soils to become acidic and reduce fertility. Regulations have been made to stop the burning of high sulfur coal  Effects of Air Pollution Acid deposition damages ecosystems and infrastructure Lakes can become too acidic for fish to survive Forests can become weaken and die or attacked by insects. Buildings and structures can dissolve and rust  Pollution Control “Dilution is the solution to pollution” didn’t work out for us. Pollutants can be captured after combustion Filters, precipitator, sulfur removal, catalytic converters, complete combustion of hydrocarbons are a few  Pollution Control Clean air legislation is controversial but effective Pollution is seen by some as the cost of progress This is not supported by evidence! Enforcing the law could save 6,000 lives a year in the US.  Pollution Control Clean air protections help the public’s health and save money  Pollution Control Rapid growth is outpacing pollution controls in the developing countries. Even if there are laws, enforcement is often weak Examples: Mexico City and Norilsk, Russia  Pollution Control Air quality does improve when controls are put in place! Sweden and West Germany cut sulfur dioxide emissions to end acid rain Cubatao, Brazil has cleaned up. Particulate pollution down 75% and sulfur dioxide down 84%. Fish are returning to the river!