Chapter 25: Indoor Air Pollution

1. Chapter 25: Indoor Air Pollution

3. Sources of Indoor Air Pollution • Secondhand smoke • Most hazardous common indoor air pollutant • Legionella pneumophila • Bacterium that causes a type of pneumonia called Legionnaires’ disease when inhaled. • Some molds (fungal growths) in buildings release toxic spores. • Cause chronic inflammation and scarring of lungs

4. Sources of Indoor Air Pollution • Radon gas • seeps up naturally from soils and rocks below buildings • Thought to be the second most common cause of lung cancer. • Pesticides • Deliberately or inadvertently applied in buildings to control pest • Are toxic to people as well

5. Sources of Indoor Air Pollution • Some varieties of asbestos • Known to cause a particular type of lung cancer • Formaldehyde • A VOC, used in many materials found in homes and offices. • Emit formaldehyde as a gas into buildings. • Dust mites and pollen • irritate the respiratory system, nose, eyes, and skin of people who are sensitive to them.

7. Dust mite

8. Pollen grains

11. Sources of Indoor Air Pollution • Common indoor air pollutants are often highly concentrated compared with outdoor levels. • Why? • There are so many potential indoor sources of pollutants. (Furniture, beds, carpet, plastics) • The effectiveness of the steps we have taken to conserve energy in buildings (ie, weather stripping) has led to the trapping of pollutants inside.

13. Heating, Ventilation, and Air-Conditioning Systems • Systems are designed to provide a comfortable indoor environment for people. • Design depends on a number of variables • Including the activity of people in the building, air temperature and humidity, and air quality. • Done correctly it will • Provide thermal comfort for people inhabiting the building. • Provide the necessary ventilation (utilizing outdoor air) • Remove common air pollutants via exhaust fans and filters

14. Pathways, Processes, and Driving Forces • Many air pollutants originate within buildings and may be concentrated there because of lack of proper ventilation. • Other air pollutants may enter by infiltration, • Through cracks and other openings in the foundations and walls (Radon, VOC’s) • Or by way of ventilation systems. (proximity to roads)

15. Pathways, Processes, and Driving Forces • A chimney effect (or stack effect) • Occurs when there is a temperature differential between the indoor and outdoor environments. • Warmer air rises in the building to the upper levels, it is replaced in the lower portion of the building by outdoor air. • Secondhand smoke, may also be drawn into a building by the chimney effect.

16. Building Occupants • People living or working in particular indoor environments react to pollutants in different ways: • Some groups of people are particularly susceptible to indoor air pollution problems. • The symptoms reported by people in a particular environment vary. • In some cases, the symptoms reported result from factors other than air pollution.

17. Particularly Susceptible People • A person’s susceptibility to a particular air pollutant also depends on genetic factors, lifestyle, and age. • Sometimes a matter of concentration rather than susceptibility. • Older people and children are generally more sensitive. • People suffering from chronic lung or respiratory diseases are more susceptible. • Individuals who have suppressed immune systems. • Some people, when exposed to chemicals, develop multiple chemical sensitivity (MCS).

18. Symptoms of Indoor Air Pollution • A great variety of symptoms can result from exposure to indoor air pollutants. • Nosebleeds, chronic sinus infections, headaches, and irritation of the skin or eyes, nose, and throat. • More serious problems include loss of balance and memory, chronic fatigue, difficulty in speaking, and allergic reactions, including asthma. • Other pollutants cause dizziness or nausea. • Radon, asbestos, and chemicals such as benzene, may have long-term chronic health effects (cancer).

19. Sick Buildings • There are two types of sick buildings: • Buildings w/ identifiable problems • Occurrences of toxic molds or bacteria known to cause disease. • Diseases are known as building-related illnesses (BRI). • Buildings w/ sick building syndrome (SBS) • Symptoms people report cannot be traced to any one known cause.

20. Sick Buildings • When the cause is not detected. A number of things may be happening: • The complaints result from the combined effects of a number of contaminants present in the building. • Environmental stress from another source is responsible. • Employment-related stress may be leading to the symptoms reported. • Pollutants or toxins may be present but not identified.

21. Environmental Tobacco Smoke • Environmental tobacco smoke (ETS) • Secondhand smoke • Comes from two sources: • smoke exhaled by smokers • smoke emitted from burning tobacco in cigarettes, cigars, or pipes. • People who are exposed to ETS are referred to as passive smokers.

22. Environmental Tobacco Smoke • It is hazardous for the following reasons: • Tobacco smoke contains several thousand chemicals, many of which are irritants. • Studies of nonsmoking workers exposed to ETS found that they have reduced airway functions, suffer more illnesses, and lose more work time than those not exposed to ETS. • In the US, about 3,000 deaths from lung cancer and 40,000 deaths from heart disease a year are thought to be associated with ETS.

23. Radon Gas • Radon is a naturally occurring radioactive gas that is colorless, odorless, and tasteless. • Radioactive decay chain from radiogenic uranium to stable lead • Radon-222 has a half-life of 3.8 days, is the product of radioactive decay of radium-226. • Radon decays with emission of an alpha particle to polonium-218, which has a half-life of ~ 3 minutes

25. Geology and Radon Gas • The concentration of radon gas that reaches the surface of the Earth and thus can enter our dwellings is • Related to the concentration of radon in the rocks (generally granitic rock) and soil. • Some regions in the United States contain bedrock with an above-average natural concentration of uranium.

26. How Does Radon Gas Enter Building? • Radon gas enters homes and other buildings in three main ways: • 1. It migrates up from soil and rock into basements and lower floors. • 2. Dissolved in groundwater, it is pumped into wells and then into homes. • 3. Radon-contaminated materials, such as building blocks that are used in construction.

28. Radon Resistant Techniques for Homes and Other Building • Protection is straightforward and relatively inexpensive. • Techniques are variable depending on the type of foundation a particular home has, • The basic strategy is to prevent radon from entering • And to safely ensure that radon is removed from the home site.

29. A. Gas Permeable Layer: Allow the soil gas to move freely underneath the house. B. Plastic Sheeting: Help prevent the soil gas from entering the home. C. Sealing and Caulking: Openings in the concrete foundation floor are sealed to reduce soil gas entry into the home.

30. D. Vent Pipe: A PVC pipe runs from the gas-permeable layer through the house to the roof to safely vent radon above the house. E. Junction Box: An electrical junction box is installed if an electric venting fan is needed.

31. Indoor Air Pollution and Green Buildings • Building green. • The processes involves using building designs that result in less pollution and better use of resources. • Providing for a good indoor environmental quality is a significant part. • Designing, constructing, and maintaining buildings that minimize indoor air pollutants. • Ensuring that fresh air is supplied and circulated, and managing moisture content to remove the threat of moisture-related problems such as mold.

32. Control of Indoor Air Pollution • There are strong financial incentives to provide workers w/ a clean air environment. • A good starting point would be passing environmental legislation requiring minimum indoor air quality standards. • Including increases in the inflow of fresh air through ventilation. This concept is at odds with the principles of Energy Efficiency….

34. Control of Indoor Air Pollution • One of the principal means for controlling quality is by dilution • Fresh outdoor air mixed via a ventilating air-conditioning system and windows that can be opened. • Various types of air-cleaning systems reduce potential pollutants • Such as particles, vapors, and gases. • Can be installed as part of the heating, ventilation, and AC system or as stand-alone appliances.

35. Control of Indoor Air Pollution • Education also plays an important role • May involve deciding not to install unvented or poorly vented appliances. • Educated people are more aware of their legal rights with respect to product liability and safety. • Education provides people with the information necessary to make decisions concerning exposure and strategies to avoid potentially hazardous conditions in the home and workplace.