Environmental Issues

Transcription

1 Environmental Issues

2 Environmental health: the area of health concerns that focuses on the interactions of humans with all aspects of their environment Ø Diseases associated with contaminated water, food, waste, and other pollutants Ø Pollutants that result from human and industrial activities and that cause chronic diseases and global environmental damage Ø Climate change, the depletion of resources, and world overpopulation

3 Water and Water Quality Water cycle: natural process by which the earth s supply of water is continuously collected, purified, and distributed Ø Surface water: precipitation stored in lakes, reservoirs, and wetlands on the surface of the earth Ø Groundwater: precipitation that sinks into the ground and makes up 95% of the world s supply of freshwater Deep aquifers: giant underground reservoirs

4 Water Supplies and Shortages US and Canada: Abundant water supply but water is contaminated by agricultural and industrial wastes EPA: 36 states will face water shortage by 2025 Ø Drought Ø Wasteful use of water/ artificially low cost of water Ø Increase in earth surface temperatures

5 Water Supplies and Shortages Ø Consumers and businesses need to use water-saving technologies Ø Farmers and the agricultural industry need to develop ways to irrigate crops more efficiently Ø Failure to address our water-related problems will lead to economic and health problems, increased environmental degradation, and loss of biodiversity

6 Virtual Water Virtual water: water used to produce foods, consumer products, and other services

7 Water Footprint for Food Production The amount of water needed to produce a given amount of a product is its water footprint

8 Water Pollution Any chemical, biological, or physical change in water quality that harms living organisms or makes water unsuitable for desired use Most surface-water reservoirs are contaminated by pollutants at specific locations through sewers, pipes, or ditches

9 Main sources of groundwater contamination: Ø Septic tanks Ø Landfills and hazardous waste dumps Ø Underground storage tanks filled with gasoline, oil, solvents, and hazardous waste

10 Safe Drinking Water The Safe Drinking Water Act (1974) established many health standards for drinking water EPA sets the standards for tap water 98% of Americans have plumbing where lead can leach into tap water as pipes and fixtures deteriorate over time Ø Cold water from the tap is less likely to contain lead from supply pipes Many benefits to water fluoridation, but excessive fluoride consumption can lead to fluorosis

11 Conserving Water Americans use three times the water per capita of the average worldwide 70% used for washing and carrying away waste There are many ways to use less water: Bathroom: shorter showers, turn off faucet when brushing teeth; low-flow toilet; water-saving showerheads Laundry: wash only when full load; buy only Energy Star appliances Kitchen: run dishwasher only with full load; do not run water continuously when doing dishes by hand

12 Air Pollution

13 Earth s Atmosphere Troposphere: lower atmosphere, containing about 80% of the earth s air Stratosphere: upper atmosphere, 11 to 30 miles above the earth s surface Greenhouse effect: warming of the earth s surface by heat trapped by gases in the lower atmosphere Greenhouse gases: carbon dioxide, water vapor Ozone in the upper atmosphere shields us from about 95% of the sun s UV rays Protective in upper atmosphere, but at ground level it is a main source of air pollution

14 Air Pollution Air pollution: the presence of one or more chemicals in the atmosphere in sufficient quality and quantity to cause harm to life Air Quality Index (AQI): measure of air pollution issued daily by the EPA (ozone, particle pollution, carbon monoxide, and sulfur dioxide) 100 or higher, air is considered unhealthy for sensitive groups, such as people with asthma 300 or higher, air is considered hazardous

15 Air Quality Index

16 Ozone and Particulate Matter Ground-level ozone is poisonous to most living organisms Causes respiratory irritation, aggravates respiratory and heart disease, and damages the lungs, especially in those with respiratory problems Particulate matter consists of particles or droplets of dust, soot, oil, metals, or other compounds suspended in the air

17 Smog Mixture of pollutants in the lower atmosphere that makes the air hazy Industrial smog: air pollution that forms mostly in cold weather Coal and oil burning Photochemical smog: sits as a thick haze over cities in the summer Vehicle exhaust, industry, and other sources combine, producing large amounts of ozone and more than 100 other chemicals

18 Acid Deposition and Precipitation Acid deposition: the depositing of acidic pollutants from the atmosphere on the earth s surface, in either dry or wet form Acid precipitation: mixing of acidic pollutants in the atmosphere with moisture and their precipitation in the form of rain, snow, sleet, hail, or fog

19 Reducing Outdoor Air Pollution Clean Air Act (1990) empowered the EPA to set emission standards Improved air quality Clear Skies Initiative (2002) set mandatory caps to reduce emissions of sulfur dioxide, nitrogen oxide, and mercury A new car today emits 75% less pollution than cars built in % of Americans still live in areas where the air is considered unhealthy at some time of the year

20 Global Warming and Climate Change Climate change is the long-term changes in average daily weather that occurs over many years Substantial evidence of earth s warming; debate over whether it s natural or human-caused Human activities have increased the amount of greenhouse gases in our atmosphere As a result, global temperatures have risen Melting glaciers and polar ice caps; rising sea levels Intensification of greenhouse effect has led to global warming

21 The Greenhouse Effect

22 Your Carbon Footprint Every time you use fossil fuels you contribute to carbon dioxide emissions Driving a car, turning on a light, running a dishwasher/ Walk more; drive less; consume less electricity; recycle; eat less or no meat The more CO 2 you generate, the larger your carbon footprint index.htm

23 Indoor Air Pollution Indoor air pollution can be higher and more hazardous than outdoor air pollution; yet we spend 80 90% of our time indoors Environmental tobacco smoke, carbon monoxide, mold Also dust mites, animal dander, mildew Reduce many pollutants by keeping the house, pets, and bedding clean; maintaining 30 50% humidity; and removing shoes

24 Solid Waste Any unwanted or discarded material that is not a liquid or gas; garbage 1,600 pounds per person per year in U.S. E-waste is the fastest growing problem; the U.S. sends most to Afghanistan and Haiti for disposal and recycling Hazardous waste: any discarded solid or liquid material that meets one or more of four criteria: Carcinogens, toxins, irritants Flammable Highly reactive, could explode or release toxic fumes Corrosive

25 Approaches to Waste Management Sanitary landfills are carefully selected sites where waste is buried in plastic-lined pits Incinerators burn waste and sometimes sell the energy generated by the burning Recycling: circle, or loop, program; materials collected, sorted, cleaned, and processed into raw materials to make new products

26 Ecosystems and Biodiversity Ecosystem: an interconnected community of organisms living together as a balanced, mutually supportive system Biodiversity: variety of different animal and plant species on earth and the genetic variation in their gene pools Human activities significantly disrupt these ecosystems and have caused a decline in biodiversity through: Deforestation Desertification Loss of freshwater resources

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29 Protecting Ecosystems Stringent federal and state protection of animal and plant habitats in forest, deserts, and wetlands is a component of sustainable land management programs Protecting endangered species; controlling climate change Individuals can help: Reusing and recycling paper products Refusing the buy products or materials made from endangered or threatened species Purchasing wood with the Good Wood Seal Stopping junk mail

30 Population Growth Ø For most of history, the human population grew very slowly Ø Growth rate began to increase about 10,000 years ago, then soared during the past two centuries

31 US Census Bureau (2013) Rank Country or Area Population 1 China 1,349,585,838 2 India 1,220,800,359 3 United States 316,668,567 4 Indonesia 251,160,124 5 Brazil 201,009,622 6 Pakistan 193,238,868 7 Nigeria 174,507,539 8 Bangladesh 163,654,860 9 Russia 142,500, Japan 127,253,075

32 Age structure: The age distribution of individuals

33 Future Growth Ø World population is expected to reach 8.9 billion by 2050, and possibly to decline as the century ends Ø China and India each hold more than one billion people (together, 38% percent of the world population); the United States is third, with 317 million

34 A Sustainable Planet An ecological footprint compares human consumption of resources with the planet s capacity to regenerate them The ecological footprint of the United States is the largest in the world Consume more resources, generate more pollution, and discard more waste Each of us can take actions today to reduce that footprint