Water Pollution Notes 3

Outdoor Air Pollution Subtitle

Sources Ambient air pollution is air borne waste from everyday activities Can be natural or man made Natural Sources Volcanic eruptions release particles as well as sulfur dioxide and other gas Fires from burning vegetation Winds can kick up dust in dry regions Man Made Sources Can be mobile or stationary and point source or non-point source Coal plant would be point source and stationary Cars would be a mobile non-point source Pollutants can either be harmful directly or cause chemical reactions that cause harmful compounds Primary pollutants include soot and carbon monoxide and can react to form harmful substances Secondary pollutants are made from reactions from primary pollution such as tropospheric ozone or sulfuric acid

Sources Residence time is how long a substance remains in the air Depends on how they react with air and how quickly they settle to the ground Brief residence times exert localized impacts Long residence times exert impacts regionally or globally – drive global climate change because they deplete ozone

Types of Pollution and Issues Posed Toxic air pollutants are known to cause cancer, reproductive defects, neurological developmental, immune system, or respiratory problems Monitor 188 different toxic air pollutants 300 monitoring sites that map the toxins and help with risk assessment for different diseases Smog is our most common air quality problem Industrial smog from coal or oil burning by-products such as soot and the chemicals found in coal and oil Photochemical smog formed when sunlight drives chemical reactions between primary pollutants and normal atmospheric compounds – Found predominantly in urban areas Synthetic chemical deplete stratospheric ozone Halocarbons – Hydrocarbons that halogens have replaced the hydrogens CFCs: chlorofluorocarbons which has been severely limited in use due to the extremely detrimental effects

Types of Pollution and Issues Posed Rural areas see air pollution as well Drift from cities Pesticides that enter the air A lot of rural pollution comes from feedlots Acid Deposition Also known as acid rain, when acid reaches the Earth’s surface from the atmosphere by some means whether through precipitation or particulates settling Acid deposition has many impacts Cumulative effects on the environment Leeches nutrients from the soil Mobilizes toxic metal ions such as zinc, mercury, and copper by making them soluble Acidifies bodies of water

Clean Air Act Subtitle

1989 2014 Legislation Starting in the 50s, the US began looking at improving air quality through research and laws Clean Air Act of 1970 created stricter standards, imposed emissions limits for new stationary and mobile sources of pollution 1995 Businesses were only allowed certain amounts of emissions and were able to sell and trade those allowances Saw a decrease in sulfur dioxide emissions Spawned similar cap-and-trade programs for other pollutants like greenhouse gasses EPA has national standards but its up to the states to monitor

EPA sets standards for “Criteria Pollutants” Criteria pollutants are pollutants judged to pose a threat to human health Carbon Monoxide Colorless, odorless gas produced by vehicles and engines – 78% Factories and burning materials release this gas as well Binds in an irreversible manner to hemoglobin blocking oxygen Sulfur Dioxide Colorless but pungent gas Most comes from burning coal Forms sulfur trioxide and sulfuric acid that settles back to Earth as acid deposition Nitrogen Dioxide Highly reactive, foul-smelling reddish brown gas that contributes to smog Made in combustion engines

EPA sets standards for “Criteria Pollutants” Tropospheric Ozone Human activity forms ozone in the lower portion of the troposphere that acts as a pollutant Secondary pollutant because it reacts with other components like sunlight, nitrogen oxides and volatile carbon-containing compounds O3 can react and lose an oxygen molecule. That free molecule can injure living tissue Particulate Matter Solid or liquid that can be suspended in the atmosphere Can damage respiratory tissue when inhaled EPA classifies them by size PM10 – 10 microns includes dust PM2.5 – 2.5 microns includes pollution from combustion

EPA sets standards for “Criteria Pollutants” Lead Enters as a particulate pollutant Tetraethyl lead and tetramethyl lead added to gasoline to improve engine performance but enters the atmosphere Can enter the food chain and accumulate in body tissue causing nervous system issues Lead has been phased out of gas in the US in the 80s EPA monitoring finds a large number of Americans live in areas that exceed the concentration of critical pollution or where they regularly reach unhealthy levels

Agencies monitor emissions Not only are the six criteria pollutants monitored, so are other pollutants that affect those criteria pollutants Look at volatile organic compounds (VOCs) Carbon-containing chemicals that are used in and emitted by vehicles and a wide variety of solvents, household chemicals, consumer items, and industrial processes Hydrocarbons such as methane (natural gas), butane (lighter fluid), propane and octane (component of gasoline) Human activity accounts for about half of VOC emissions while the rest is naturally occurring

Cleaning up and Preventing Pollution

Reducing Pollution Smog The Montreal Protocol Having catalytic converts on cars to reduce pollution Incentives for people to replace old cars or reduce amount of driving Maps and information boards are posted in smog ridden areas Expanded mass transportation The Montreal Protocol 1987 treaty to reduce CFCs Various additional agreements have been over the years for other pollutants and most have been phased out of products since then However, due to the long residence time of many halocarbons, effects to the environment can persist long after regulations have been put in place Also, there is no way to force countries to comply with global regulations but the Montreal Protocol has been considered a success in addressing global environmental problems for several reasons Research developed rapidly Engaged industries to help Testing many methods and implementing the best options