AP Environmental Science Unit Nine
Pollution: Air & Water
AIR POLLUTION
Air Pollution
Overview Atmosphere as a Resource Types and Sources of Air Pollution Effects of Air Pollution Controlling Air Pollution in the US Ozone Depletion in the Stratosphere Acid Deposition Air Pollution Around the World Indoor Air Pollution
Atmosphere as a Resource
Atmosphere as a Resource Atmospheric Composition Nitrogen: 78.08% Oxygen: 20.95% Argon: 0.93% Carbon dioxide: 0.04% Ecosystem services Blocks UV radiation Moderates the climate Redistributes water in the hydrologic cycle
Types & Sources of Air Pollution
Air Pollution Chemicals added to the atmosphere by natural events or human activities in high enough concentrations to be harmful Two categories Primary Air Pollutant Harmful substance that is emitted directly into the atmosphere Secondary Air Pollutant Harmful substance formed in the atmosphere when a primary air pollutant reacts with substances normally
Major Air Pollutants
Major Classes of Air Pollutants Particulate Material Nitrogen Oxides Sulfur Oxides Carbon Oxides Hydrocarbons Ozone
Particulate Material Thousands of different solid or liquid particles suspended in air (aerosols) Includes: soil particles, soot, lead, asbestos, sea salt, and sulfuric acid droplets (aerosols) Dangerous May contain materials with toxic/carcinogenic effects Small particles can become lodged in lungs
Particulate Material Thousands of different solid or liquid particles suspended in air (aerosols) Lead most common metallic air pollutant acts as a neurotoxin (disrupts cognitive ability) Asbestos mineral with long, thin fibrous crystals used as a building material because of some unique properties been linked to cancer and other health related issues European Union has banned its extraction and use
Nitrogen and Sulfur Oxides Nitrogen Oxides Gases produced by the chemical interactions between atmospheric nitrogen and oxygen at high temperature Greenhouse gases that cause difficulty breathing Sulfur Oxides Gases produced by the chemical interactions between sulfur and oxygen Causes acid precipitation
Carbon Oxides and Hydrocarbons Carbon Oxides Gases carbon monoxide (CO) and carbon dioxide (CO 2 ) Greenhouse gases Hydrocarbons Diverse group of organic compounds that contain only hydrogen and carbon (ex: CH 4 - methane) Some are related to photochemical smog and greenhouse gases
Ozone Tropospheric Ozone Man- made pollutant in the lower atmosphere Secondary air pollutant Component of photochemical smog Stratospheric Ozone Essential component that screens out UV radiation in the upper atmosphere Man-made pollutants (ex: CFCs) can destroy it
Sources of Outdoor Air Pollution Two main sources Transportation Industry Intentional forest fires is also high Anthropogenic sources of carbon dioxide increasing at a rate of 0.5% per year
Urban Air Pollution Photochemical Smog (ex: Los Angeles below) Brownish-orange haze formed by chemical reactions involving sunlight, nitrogen oxide, and hydrocarbons
Formation of Photochemical Smog
Formation of Photochemical Photochemical Smog (includes ozone) VOC s (volatile organic compounds) contribute to smog production a major source of VOC s is the incomplete burning of fossil fuels other sources include paints, dry cleaners, cleaning products and even bakeries
Temperature Inversions can lead to pollution such as smog, violent thunderstorms and even freezing rain in cold climates normally troposhpere is warmer than air above it but here stable warm air overlays cold air air becomes still and murky because dust and pollutants are no longer lifted from the surface
Sources of Smog in Los Angeles
Effects of Air Pollution
Effects of Air Pollution Low level exposure Irritates eyes, causes inflammation of respiratory tract Can develop into chronic respiratory diseases Most common human health response to air pollution is inflammation in sensitive tissues
Effects of Air Pollution
Children and Air Pollution Greater health threat to children than adults Air pollution can restrict lung development Children breath more often than adults Children who live in high ozone areas are more likely to develop asthma
Controlling Air Pollution (U.S.)
Controlling Air Pollution Smokestacks with electrostatic precipitator (right) Without Electrostatic precipitator With Electrostatic precipitator
Controlling Air Pollution Smokestacks with electrostatic precipitator (right) With Electrostatic precipitator
Controlling Air Pollution Smokestacks with scrubbers (right) Particulate material can also be controlled by proper excavating techniques
Controlling Air Pollution Phase I Vapor Recovery System for gasoline
The Clean Air Act Authorizes EPA to set limits on amount of specific air pollutants permitted Focuses on 6 pollutants: lead, particulate matter, sulfur dioxide, carbon monoxide, nitrogen oxides, and ozone Act has led to decreases
The Clean Air Act
Urban Air Quality
Other Ways to Improve Air Quality Reduce sulfur content in gasoline from its current average of 330 ppm to 30 ppm Sulfur clogs catalytic converters Require federal emission standards for all passenger vehicles Including SUVs, trucks and minivans Require emission testing for all vehicles Including diesel
Other Ways to Improve Air Quality Catalytic Converters- device used to reduce the toxicity of emissions from an internal combustion engine mainly reduces nitrogen oxides also can reduce carbon monoxide and other hydrocarbons Catalytic Converters first introduced into the auto market in 1975 with tightening EPA regulations, still commonly used today and in a variety of transportation
Ozone Depletion
Ozone Depletion in Stratosphere Ozone Protects earth from UV radiation
Ozone Depletion in Stratosphere Ozone thinning/hole First identified in 1985 over Antarctica Caused by human-produced bromine and chlorine containing chemicals Ex: CFCs
Ozone Depletion in Stratosphere Hole over Antarctica requires two conditions: Sunlight just returning to polar region Circumpolar vortex - a mass of cold air that circulates around the southern polar region Polar stratospheric clouds form Enables Cl and Br to destroy ozone
Effects of Ozone Depletion Higher levels of UVradiation hitting the earth Eye cataracts Skin cancer (right) Weakened immunity May disrupt ecosystems May damage crops and forests
Recovery of Ozone Layer Montreal Protocol (1987) Reduction of CFCs Started using HCFCs (greenhouse gas) Phase out of all ozone destroying chemicals is underway globally Satellite pictures in 2000 indicated that ozone layer was recovering Full recovery will not occur until 2050
Tropospheric Ozone Layer High levels of ozone in the troposphere are pollutants can have negative effects on health Ozone in the stratosphere screens out harmful UV radiation
Acid Deposition
Acid Deposition Sulfur dioxide and nitrogen dioxide emissions react with water vapor in the atmosphere and form acids that return to the surface as either dry or wet deposition ph scale
How Acid Deposition Develops
Effects of Acid Deposition Declining Aquatic Animal Populations fish eggs die & population suffers Thin-shelled eggs prevent bird reproduction Calcium is unavailable in acidic soil Forest decline
Acid Deposition and Forest Decline
Global Air Pollution
Air Pollution Around the World Air quality is deteriorating rapidly in developing countries Developing countries have older cars Shenyang, China Residents only see sunlight a few weeks each year 5 worst cities in world Beijing, China; Mexico City, Mexico; Shanghai, China; Tehran, Iran; and Calcutta, India
Case-In-Point Air Pollution in Beijing and Mexico City Beijing (left) Mexico City (above)
Long Distance Transport Air Pollutants Global Distillation Effect
Indoor Air Pollution
Indoor Air Pollution Pollutants can be 5-100X greater than outdoors Radon, cigarette smoke, carbon monoxide, nitrogen dioxide, formaldehyde pesticides, lead, cleaning solvents, ozone, and
Indoor Air Pollution - Radon Comes from radioactive decay in the earth below the house has been linked to lung cancer 6% of US homes warrant corrective measures
Indoor Air Pollution-Formaldehyde especially problematic because it is used in so many household products most significant source is particleboard, pressed wood, plywood panels health issues from allergic reactions to respiratory issues to cancer
WATER POLLUTION
Water Pollution
Overview Types of Water Pollution Water Quality Today Improving Water Quality Laws Controlling Water Pollution
Types of Water Pollution
Types of Water Pollution Water pollution Any physical or chemical change in water that adversely affects the health of humans and other organisms Eight categories Sewage, disease-causing agents, sediment pollution, inorganic plant and algal nutrients, organic compounds, inorganic chemicals, radioactive substances, and thermal pollution
Sewage The release of wastewater from drains or sewers Causes 2 serious environmental problems: Enrichment Fertilization of a body of water by high levels nitrogen and phosphorus Increase in Biological Oxygen Demand (BOD) A way to measure sewage and organic waste Amount of oxygen needed by microorganisms to decompose biological wastes As BOD increases Dissolve Oxygen (DO) decreases
Sewage
Sewage: Eutrophication Oligotrophic Unenriched, clear water that supports small populations of aquatic organisms
Sewage: Eutrophication Eutrophic Slow-flowing stream, lake or estuary enriched by inorganic plant and algal nutrients such as phosphorus and nitrogen ions cultural eutrophication is a result of human activity
Disease-causing Agents Infectious organisms that cause diseases Originate in the wastes of infected individuals biggest threat to human health Common bacterial or viral diseases: Typhoid, cholera, bacterial dysentery, polio, and infectious hepatitis
Disease-causing Agents Monitored by testing for presence of E. coli in the water via a fecal coliform test Indicates the presence of pathogenic organisms
Sediment Pollution Excessive amounts of suspended soil particles Originates from erosion of agricultural lands, forest soils exposed by logging, degraded stream banks, overgrazed rangelands, strip mines, and construction Problems Limits light penetration Covers aquatic animals and plants Brings insoluble toxins into waterways
Inorganic Plant and Algal Nutrients Nitrogen and phosphorus that stimulate the growth of plants and algae Harmful in large concentrations Sources: Human and animal wastes, plant residues, atmospheric deposition, and fertilizer runoff Causes: Enrichment, bad odors, and a high BOD
Inorganic Plant and Algal
Organic Compounds Chemicals that contain carbon atoms Natural examples: sugars, amino acids, and oils Human-made examples: pesticides, solvents, industrial chemicals, and plastics
Volatile Organic Compounds in
Inorganic Chemicals Contaminants that contain elements other than carbon Do not degrade easily Lead Found in old paint, industrial pollutants, leaded gasoline Mercury Mercury bioaccumulates in the muscles of top predators of the open ocean
Radioactive Substances Contain atoms of unstable isotopes that spontaneously emit radiation Sources Mining Processing radioactive materials Nuclear power plants Natural sources
Thermal Pollution Occurs when heated water produced during industrial processes is released into waterways Organisms affected Temperature affects reproductive cycles, digestion rates, and respiration rates Warm water holds less DO than cold water
Water Quality Today
Two Types of Water Pollution Point Source Pollution Water pollution that can be traced to a specific origin Relatively easy to monitor and regulate Non-point Source Pollution Pollutants that enter bodies of water over large areas rather than being concentrated at a single point of entry Diffuse, but its cumulative effect is very large Difficult to monitor, regulate and clean up
Two Types of Water Pollution Point Source Pollution enters environment through pipes, sewers or ditches examples: a factory, sewage treatment plant Non-point Source Pollution land pollutants that enter bodies of water over large areas examples: agricultural run off, mining waste, municipal waste, construction sediment,
Water Pollution from Agriculture Agriculture is leading source of water pollution in US Animal wastes and plants residues have high BOD Chemical pesticides can leach into groundwater Almost all streams and rivers are polluted with agricultural pesticides
Municipal Water Pollution
Industrial Wastes in Water Different industries generate different pollutants Food processing plants- high BOD Paper mills- High BOD and toxic compounds Many industries recover toxins before they go into the waste stream
Case-In-Point Green Chemistry
Groundwater Pollution
Water Pollution in Other Countries Lake Maracaibo, Venezuela 10,000 oil wells tap lake bottom Leak oil into lake Agricultural wastes from local fields Unit recently raw human waste polluted the lake
Water Pollution in Other Countries Po River, Italy Similar to Mississippi River Pollutants: Sewage, industrial wastes, sediment >16 million Italians depend on the river for drinking water Cleanup will require a national management plan and may take decades
Water Pollution in Other Countries Ganges River, India Used for bathing and washing clothing Sewage and industrial waste discharged into river Ganga Action Plan initiated by government Construction of 29 sewage treatment plants
Improving Water Quality
Purification of Drinking Water In US most municipal water supplies are treated Collected from water or reservoir Treated
Purification of Drinking Water Treated water distributed to customers Sewer lines bring sewage to treatment plant Sewage treated at sewage treatment plant
Purification of Drinking Water Chlorine Dilemma Chlorine byproducts are linked to numerous cancers, miscarriages and birth defects Peru stopped using chlorine 1991: huge cholera epidemic that infected 300,000 people Fluoridation Prevents tooth decay Linked to cancer, kidney disease
Municipal Sewage Treatment Primary treatment Removing suspended and floating particles by mechanical processes (removes solids) Secondary treatment Treating wastewater biologically to decompose suspended organic material; reduces BOD
Municipal Sewage Treatment Sewage Sludge Solids remaining after primary and secondary sewage treatment has been completed Tertiary treatment Advanced wastewater treatment methods that are sometimes employed after primary and secondary treatments Reduce phosphorus and nitrogen Municipal sewage can be a excellent source of useful metals
Municipal Sewage Treatment
Municipal Sewage Treatment
Individual Septic System:
Individual Septic System: Used in primarily private residences in rural areas Requires care and maintenance to operate properly Requires a well aerated drain field Uses bacteria to break down waste should never pore bleach, drain cleaners or other chemicals that kill bacteria down the drain Sludge must be removed every 2-5 years Can pollute groundwater and waterways if not maintained properly
Individual Septic System:
Side Note: Management of Waste Biological Treatment of Wastes & Chemicals Bioremediation - use of bacteria and other microorganisms to break down hazardous waste into relatively harmless products Ex: Duckweed to treat in lagoons to treat sewage Time consuming Phytoremediation - use of plants to absorb and accumulate hazardous materials in the soil Ex: Indian mustard removed heavy metals
Laws Controlling Water Pollution
Laws Controlling Water Pollution Citizen Watchdogs to Monitor Pollution Safe Drinking Water Act (1974) Set uniform federal standards for drinking water including maximum contaminant level Clean Water Act (1972) EPA sets up and monitors National Emissions Limitations Effectively improved water quality from point sources
Laws that Protect Groundwater Safe Drinking Water Act National Pollutant Discharge Elimination System (NPDES) Resource, Conservation and Recovery Act