Week 8 -9

• Climate change


  The long-term alteration of temperature and typical weather patterns in a place
• Climate change could refer to a particular location or the planet as a whole
• Climate change may cause weather patterns to be less predictable
• Effects of warming global temperatures associated with climate change

  1. Ice sheets and glaciers are melting at an accelerated rate from season to season

  2. Sea levels rising in different regions of the planet

  3. Expanding ocean waters due to rising temperatures, resulting in increased flooding and erosion of coastlines
• Causes of current climate change

  Largely human activity, like burning fossil fuels such as natural gas, oil, and coal, which releases greenhouse gases into Earth's atmosphere, trapping heat from the sun's rays inside the atmosphere causing Earth's average temperature to rise
• Global warming


  The rise in the planet's temperature
• Throughout Earth's history, climate has continually changed, and when occurring naturally, this is a slow process that has taken place over hundreds and thousands of years
• Natural variations in global climate


  • Internal fluctuations that exchange energy, water and carbon between the atmosphere, oceans, land and ice
  • External influences on the climate system, including variations in the energy received from the sun and the effects of volcanic eruptions
• Air pollution is generally the most widespread and obvious kind of environmental damage. While developed countries have been making progress, air quality in the developing world has been getting much worse.
• Sources of air quality degradation

  • Natural sources
  • Human-related sources
• Volcanoes spew out ash, acid mists, hydrogen sulfide, and other toxic gases.
• In many cases, the chemical compositions of pollutants from natural and human-related sources are identical, and their effects are inseparable can occur.
• While the natural sources of suspended particulate material in the air outweigh human sources at least tenfold worldwide, in many cities, more than 90 percent of the airborne particulate matter is anthropogenic (human-caused).
• Major categories of pollution sources

  • Stationary sources
  • Mobile sources
• Stationary sources


  • Have relatively fixed locations and include point sources, fugitive sources, and area sources
• Point Sources


  Emit pollutants from one or more controllable sites such as power plant smokestacks
• Fugitive Sources


  Generate air pollutants from an open area exposed to wind. It includes burning for agricultural purposes and dirt roads, construction sites, farmlands, storage piles, surface mines, and other exposed areas.
• Area Source


  A well-defined area within which several sources of air pollutants. It includes small urban communities, areas of intense industrialization within urban complexes, and agricultural areas sprayed with herbicides and pesticides.
• Mobile sources

  Include trucks and buses
• Categories of Pollution


  • Primary
  • Secondary
• Primary Pollutants


  Are those released directly from the source into the air in a harmful form? These pollutants are emitted directly into the air. They include particulates, sulfur dioxide, carbon monoxide, nitrogen oxides, and hydrocarbons.
• Secondary Pollutants


  They are modified to a hazardous form after they enter the air or are formed by chemical reactions as components of the air mix and interact. Solar radiation often provides the energy for these reactions. Photochemical oxidants and atmospheric acids created by these mechanisms are probably the most important secondary pollutants in human health and ecosystem damage.
• Criteria Pollutants


  • Sulfur Dioxide
  • Nitrogen Oxides
  • Carbon Monoxide
  • Ozone and Other Photochemical Oxidants
  • Particulate Matter
  • Lead
• Sulfur Dioxide


  A colorless and odorless gas usually present at Earth's surface in low concentrations. A significant feature of sulfur dioxide is that once it is emitted into the atmosphere, it can be converted into fine particulate sulfate and removed from the atmosphere by wet or dry deposition. The primary anthropogenic source of sulfur dioxide is the burning of fossil fuels.
• Nitrogen Oxides


  Highly reactive gases formed when nitrogen in fuel or combustion air is heated to temperatures above 650°C (1,200°F) in the presence of oxygen, or when bacteria in soil or water oxidize nitrogen-containing compounds.
• Carbon Monoxide


  Is a colorless, odorless gas that even at very low concentrations is extremely toxic to humans and other animals. The high toxicity results from a physiological effect. CO inhibits respiration in animals by binding irreversibly to hemoglobin.
• Ozone and Other Photochemical Oxidants


  A form of oxygen in which three atoms of oxygen occur together rather than the usual two. Photochemical oxidants are secondary pollution arising from atmospheric interactions of nitrogen dioxide and sunlight.
• Particulate Matter


  It is made of tiny particles. The term particulate matter is used for varying mixtures of suspended in the air we breathe, but in regulations, these are divided into three categories.
• Lead


  Is an important constituent of automobile batteries and many industrial products. Leaded gasoline helps protect engines and promotes more effective fuel consumption.
• Air Toxics


  • Gases
  • Metals
  • Organic chemicals
• Air Toxics


  Toxic air pollutants or air toxics are among those pollutants known or suspected to cause cancer and other serious health problems, either long-term or short-term exposure. Although most air contaminants are regulated because of their potential adverse effects on human health or environmental quality, a particular category of toxins is monitored by the U.S. EPA because they are particularly dangerous. Called hazardous air pollutants (HAPs), these chemicals include carcinogens, neurotoxins, mutagens, teratogens, endocrine system disrupters, and other highly toxic compounds.
• Water


  A marvelous substance that flows, ripples, and swirls around obstacles, seeping, dripping, and trickling, continually moving from sea to land and back again
• The total amount of water on our planet is more than 1,404 million km3 (370 billion gals)
• Water supply


  • Rain falls unevenly over the planet, some places get almost no precipitation while others receive heavy rain almost daily
• Factors controlling global water deficits and surpluses

  1. Global atmospheric circulation

  2. Proximity to water sources

  3. Topography
• Water compartments


  Interacting compartments in which water resides, sometimes briefly and sometimes for eons
• Residence time


  The length of time a water molecule stays in a compartment before it evaporates and starts through the hydrologic cycle again
• Oceans hold 97 percent of all water on Earth and contain more than 97 percent of all the liquid water in the world
• Oceans are too salty for most human uses, but they contain 90 percent of the world's living biomass
• Freshwater reservoirs


  • Glaciers, ice, and snow
  • Groundwater
  • Rivers, lakes, and wetlands
  • Atmosphere