Air Pollution

• Air Pollution


  Any alteration of the physical, chemical and biological properties of the atmospheric air, or any discharge thereto of any liquid, gaseous or solid substances that will or is likely to create or to render the air resources of the country harmful, detrimental, or injurious to public health, safety or welfare or which will adversely affect their utilization for domestic, commercial, industrial, agricultural, recreational, or other legitimate purposes
• Smoke, haze, dust, odors, corrosive gases, noise, and toxic compounds are among our most widespread pollutants
• Globally, air pollution is estimated to contribute to over 3 million deaths per year
• Air Pollutant


  Any matter found in the atmosphere other than oxygen, nitrogen, water vapor, carbon dioxide, and the inert gases in their natural or normal concentrations, that is detrimental to health or the environment, which includes but not limited to smoke, dust, soot, cinders, fly ash, solid particles of any kind, gases, fumes, chemical mists, steam and radio-active substances

  
• Ambient air quality

  The general amount of pollution present in a broad area; and refers to the atmosphere's average purity as distinguished from discharge measurements taken at the source of pollution

  
• Ambient Air

  The air around us
• Primary Pollutants


  Released directly from the source into the air in a harmful form
• Secondary Pollutants

  Converted to a hazardous form after they enter the air or are formed by chemical reactions as components of the air mix and interact
• Fugitive Emissions

  Those that do not go through a smoke stack. The most massive example is dust from soil erosion, strip mining, rock crushing, and building construction (and destruction). Fugitive industrial emissions are hard to monitor, but they are extremely important sources of air pollution. Leaks around valves and pipe joints, and evaporation of volatile compounds from oil-processing facilities, contribute as much as 90% of the hydrocarbons and volatile organic chemicals emitted from oil refineries and chemical plants
• Six Conventional or Criteria Pollutants

  • Sulfur dioxide
  • Nitrogen oxides
  • Carbon monoxide
  • Ozone
  • Lead
  • Particulate Matter
• Sulfur Dioxide

  Colorless corrosive gas, directly damaging to both plants and animals. Once in the atmosphere, it can be further oxidized to sulfur trioxide (SO3), which reacts with water vapor or dissolves in water droplets to form sulfuric acid (H2SO4), a major component of acid rain. Some of the smelliest and most obnoxious air pollutants are sulfur compounds, such as hydrogen sulfide from pig manure lagoons or mercaptans (organo-sulfur thiols) from paper mills
• Nitrogen Oxides (NOx)


  Highly reactive gases formed when nitrogen in fuel or in air is heated (during combustion) to temperatures above 650°C in the presence of oxygen. Bacteria can also form NO as they oxidize nitrogen-containing compounds in soil or water. The initial product, nitric oxide (NO), oxidizes further in the atmosphere to nitrogen dioxide (NO2), a reddish-brown gas that gives photochemical smog its distinctive color. In addition, nitrous oxide (N2O) is an intermediate form that results from soil denitrification. Nitrogen oxides combine with water to make nitric acid (HNO3), a major component of acid rain
• Carbon Monoxide (CO)

  Colorless, odorless, nonirritating, but highly toxic gas. Produced mainly by incomplete combustion of fuel (coal, oil, charcoal, or gas), as in furnaces, incinerators, engines, or fires, as well as in decomposition of organic matter. CO blocks oxygen uptake in blood by binding irreversibly to hemoglobin (the protein that carries oxygen in our blood), making hemoglobin unable to hold oxygen and deliver it to cells. Catalytic converters on vehicles are one of the important methods to reduce CO production by ensuring complete oxidation of carbon to carbon dioxide (CO2)
• Ozone (O3) and Photochemical Oxidants


  Ground level O3 is a product of photochemical reactions (reactions initiated by sunlight) between other pollutants, such as NOx or volatile organic compounds. Hydrocarbons in the air contribute to the accumulation of ozone by combining with NO to form new compounds, leaving single O atoms free to form O3. A general term for organic chemicals that evaporate easily or exist as gases in the air is Volatile Organic Compounds (VOCs). Plants are the largest source of VOCs, releasing an estimated 350 million tons of isoprene (C5H8) and 450 million tons of terpenes (C10H15) each year. In addition to natural VOCs, a large number of other synthetic organic chemicals, such as benzene, toluene, formaldehyde, vinyl chloride, phenols, chloroform, and trichloroethylene, are released into the air by human activities. These chemicals play an important role in the formation of photochemical oxidants

  
• Lead


  Most abundantly produced metal air pollutant. Lead is toxic to our nervous systems and other critical functions. Lead binds to enzymes and to components of our cell, such as brain cells, which then cannot function normally. Airborne lead is produced by a wide range of industrial and mining processes. The main sources are smelting of metal ores, mining, and burning of coal and municipal waste, in which lead is a trace element and burning of gasoline to which lead has been added
• Particulate Matter


  Includes solid particles or liquid droplets suspended in a gaseous medium. Very fine solid or liquid particulates suspended in the atmosphere are aerosols. These include dust, ash, soot, lint, smoke, pollen, spores, algal cells, and many other suspended materials. Particulates are often the most obvious form of air pollution, because they reduce visibility and leave dirty deposits on windows, painted surfaces and textiles. Particles smaller than 2.5 micrometers in diameter, such as those found in smoke and haze, and produced by fires, power plants, or vehicle exh
• Banning leaded gasoline in the US was one of the most successful pollution-control measures in American history
• Worldwide atmospheric lead emissions amount to about 2 million metric tons per year, or 2/3 of all metallic air pollution
• Globally, most of this lead is still from leaded gasoline, as well as metal ore smelting and coal burning
• Particulate Matter


  Includes solid particles or liquid droplets suspended in a gaseous medium
• Aerosols


  Very fine solid or liquid particulates suspended in the atmosphere, including dust, ash, soot, lint, smoke, pollen, spores, algal cells, and many other suspended materials
• Particulates

  • They reduce visibility and leave dirty deposits on windows, painted surfaces and textiles
• PM2.5

  Particles smaller than 2.5 micrometers in diameter, such as those found in smoke and haze, and produced by fires, power plants, or vehicle exhaust, are among the most dangerous particulates because they can be drawn into the lungs, where they damage respiratory tissues
• PM10

  Coarse inhalable particles larger than 2.5 micrometers but less than 10 micrometers in diameter, typically found near roads or other visible dust sources
• Epidemiological studies have shown that cities with chronically high levels of particulates have higher death rates, mostly from heart and lung disease
• The dust also carries pollen, bacteria, viruses, fungi, herbicides, acids, radioactive isotopes, and heavy metals between continents
• Airborne dust is considered the primary source of allergies worldwide
• Saharan dust storms are suspected of raising asthma rates in Trinidad and Barbados, where cases have increased 17-fold in 30 years
• Aspergillus sydowii, a soil fungus from Africa, has been shown to be causing death of corals and sea fans in remote reefs in the Caribbean
• Outbreaks of foot-and-mouth disease in Britain have been traced to dust storms from North Africa
• In the Philippines, traffic is the main contributor to PM2.5 at all sites in Metro Manila while biomass burning appeared to be the highest contributor in the areas outside NCR
• Other Pollutants

  • Mercury
  • Carbon dioxide
  • Halogens
  • Hazardous air pollutants(HAPs)
• Mercury


  Many toxic metals are released into the air by burning coal and oil, mining, smelting of metal ores, or manufacturing. Lead, mercury, cadmium, nickel, arsenic (highly toxic metalloid), and others are released in the form of metal fumes or suspended particulates by fuel combustion, ore smelting, and disposal of wastes. Among these, lead and mercury are the most abundantly produced toxic metals.
• Mercury has become regulated relatively recently (in Philippines, DAO 1997-38)
• Mercury toxicity


  Like Lead, toxic in minute doses, causing nerve damage and other impairments, especially in young children and developing fetuses
• 70% of airborne mercury derives from coal-burning power plants, metal processing (smelting), waste incineration, and other industrial combustion
• About 75% of human exposure to mercury comes from eating fish. This is because aquatic bacteria are mainly responsible for converting airborne mercury into methyl mercury, a form that accumulates in living animal tissues
• Swordfish, shrimp, and other seafood are also significant sources of mercury in our diet
• Half or more of the mercury that falls on North America may come from abroad, much of it from Asian coal-burning power plants
• Increased burning coal burning in China, which for years built new coal-burning power plants at the rate of one or two per week, is understood to be the main cause of growing mercury emissions in the Pacific