pollutants

Carbon Monoxide 

  1. Colorless Odorless Gas 

  2. Sources: Motor vehicle exhaust,- indoor include kerosene or wood burning stoves

    1. Anywhere you have INCOMPLETE combustion you can have CO

  3. Health Effects: Asphyxiant (interferes with uptake of oxygen), 

    1.  fetal development and death. 

Lead 

  1. Source: Metal Refineries, lead smelters, battery Manufacturers, iron/steel producers. 

  2. Before CAA, lead was a common gasoline additive; EPA began phaseout of lead from gasoline in 1974

  3. Vehicles made after 1974 are required to have catalytic converters to reduce NOx, CO and hydrocarbon emissions (lead damages catalytic converters)

  4. Health Effects: known neurotoxicant, Brain and Kidney damage, Lowered IQ, Anemia. 

(7.4) PM10 vs. PM 2.5  Particulate Matter: solid or liquid particles suspended in air (also referred to as “particulates)

  1. PM10  ( <10 micrometers)

    1. Particles or droplets like dust, pollen, ash, or mold

    2. Too small to be filtered out by nose hairs and trachea cilia; can irritate respiratory tract & cause inflammation

  2. PM2.5  ( <2.5 micrometers)

  3. Particles from combustion (especially vehicles) smaller dust particles

  4. More likely to travel deep into the lungs due to smaller size

  5. Associated with chronic bronchitis and increased risk of lung cancer

Nitrogen Oxides (NOx)

  1. Reddish Brown Gas, which is highly reactive

  2. Source: Released by combustion of anything, especially FFs & biomass

  3. NOx refers to nitrogen oxides (both NO, and NO2) 

    1. NO forms when N2 combines with O2 (esp. during combustion) 

    2. NO can become NO2 by reacting with O3 or O2

    3. sunlight converts NO2 back into NO

  4. Human Health Impacts: Resp. irritant (cough, chest pain, difficulty breathing)

  5. Environmental Impacts: Leads to tropospheric ozone (O3) formation, which leads to photochemical smog; Combines with water & O2 in atm. to form nitric acid → acid precipitation

Photochemical Smog (7.2) 

  1. Formation 

  1. Sunlight breaks NO2 into NO + O 

  2. O bonds with O2 to form O3

  3. VOCs bond with NO to form photochemical oxidants 

  4. Without NO to react with O3 builds up instead of returning to O2 & NO2 overnight. 

  5. O3 combines with photochemical oxidants (NO+VOCs) to form photochemical smog. 

2. Factors that Increase Smog Formation 

  1. Increased vehicle traffic; increases NO2 emissions & therefore O3 formation

  2. Higher VOCs emissions (gas stations, laundromats, petrochem. & plastic factories)

  3. Warmer temperature, speedes evap. of VOCs and rxn that lead to O3

  4. More sunlight (summer, afternoon) = more O3

  5. Urban areas have more smog due to all of these factors

Ozone (7.2) 

  1. Sources: Gaseous secondary pollutant when formed in the Troposphere. Vehicle exhaust and VOC fumes (gasoline, conifer trees, formaldehyde) reaction in the presence of sunlight. 

  2. Health Effects: Eye and throat irritation, inflames airways, coughing, asthma and lung damage

  3. Environmental Effects: Plant and ecosystem damage; Interferes with plants ability to produce and store food and makes them more susceptible to weather, disease and pest.;  Increases global temperatures. 

  4. Ways to Reduce Impact: Reduce the need for fossil Fuels. How? 

Sulfur Dioxide (SO2)

  1. Colorless gas that comes from coal fired power plants, petroleum refineries, burning diesel fuels, manufacture of sulfuric acid and smelting ores containing sulfur. 

  2. Health Effects: Respiratory irritant (inflammation of bronchioles, lungs), worsens asthma & bronchitis, Eye irritation

  3. Environmental Impacts: Sulfur aerosols (suspended sulfate particles) block incoming sun, reducing visibility & photosynthesis; Forms sulfurous (grey) smog; Combines with water & O2 in the atmosphere to form sulfuric acid → acid precip.

Acid Rain (7.7) 

  1. Formation of Acid Rain

    1. NOx and SO2 react with O2 and H2O in the atmosphere, forming nitric and sulfuric acid

    2. Sulfuric acid and nitric acid dissociate in the presence of water into sulfate and nitrate ions, and hydrogen ions (H+)

Effects of Acid Rain 

  1. Aquatic species have diff. pH tolerances

  2. As pH decreases (more acidic) outside optimal range for a species, pop. declines

    1. When pH leaves range of tolerance, they cannot survive at all, due to:

  • Aluminum toxicity

  • Disrupted blood osmolarity (Na+/Cl- balance disrupted at low pH)