7.5

• Developed vs Developing countries:

  • Developing nations use more subsistence fuels (wood, manure, charcoal)
  • These biomass fuels release CO, PM, NOx, VOCs
  • Often combusted indoors with poor ventilation
  • Developed nations use more commercial fuels (coal, oil, natural gas) supplied by utilities
  • Typically burned in closed, well ventilated furnaces/stoves
  • Major indoor pollutants in developed countries come from chemicals in products (adhesives in furniture, cleaning supplies, insulation, lead paints)
• PM:

  • PM are a common indoor pollutant (smoke from indoor biomass combustion/cigarettes), dust, and asbestos
• Asbestos is a long silicate particle previously used in insulation (stopped after being linked to lung cancer and asbestosis)
• Carbon monoxide:

  • CO is produced by incomplete combustion of any fuel
  • not all fuel Is combusted due to low O2 or temperature
  • CO is an asphyxiant; causes suffocation due to CO binding to hemoglobin in blood, displacing O2
  • Lethal to humans in high concentrations, especially with poor ventilation
  • Developed nations: CO released into home by malfunctioning natural gas furnace ventilation
  • Developing nations: CO emitted from indoor biomass combustion for heating and cooking
• VOCs (volatile organic compounds):

  • Chemicals used in variety of home products that easily evaporate, enter air, and irritates eyes/lungs/bronchioles
  • Adhesives/sealants: chemicals used to glue carpet down, hold furniture together, seal panels
  • Formaldehyde is a common adhesive in particle board and carpet glues
  • Common household cleaners and deodorizers (febreeze)
  • Plastics and fabrics: both can release VOCs themselves or from adhesives used in production
• Radon gas:

  • Radioactive gas released by decay of uranium naturally found in rocks underground (granite especially)
  • Usually enters homes through cracks in the foundation and then disperses up from basement/foundation of the house
  • 2nd leading cause of lung cancer
  • Prevented by testing with airborne radon detector, sealing cracks in foundation, increasing ventilation in homes
• Dust and Mold:

  • Natural indoor pollutants that can worsen asthma, bronchitis, COPD, emphysema
  • Dust settles in homes, disrupted by movement, entering air/respiratory tract
  • Mold develops in areas that are dark and damp and aren't well ventilated (under sinks/showers, behind panels in walls and ceiling)
  • Black mold is a class of mold that releases spores into air; especially harmful to the respiratory system
• Lead:

  • found in paint in old homes (EPA banned lead paint in 78')
  • Paint chips off walls/windows or inhaled as dust
  • Lead water pipes can also releases lead into drinking water sources, less common than lead paint
  • Damages CNS of children
  • Can be removed from home by stripping paint and replacing with non-lead based paint
  • Lead water pipes can be replaced by cities with copper pipes