Indoor Air Pollution

1. Indoor Air Pollution Ch 17

2. Indoor airpollution Indoor air contains higher concentrations of pollutants than outdoor air (up to 70x) Synthetic materials not comprehensively tested To reduce heat loss & improve energy efficiency: ventilation systems are sealed off & recirculate air windows do not open This traps pollutants inside. Indoor air pollution usually is a greater threat to human health than outdoor air pollution. Avg. U.S. citizen spends 90% of time indoors 6,000 people die per day from indoor air pollution Pollution levels inside cars in traffic clogged urban areas can be up to 18 times higher.

3. Indoor Air Pollution--Developing World • From burning wood, charcoal, dung, crop waste • With little to no ventilation • Soot and carbon monoxide • Causes pneumonia, bronchitis, allergies, cataracts, asthma, heart disease, cancer & death • ~1.6 million deaths/year

4. Indoor Air Pollution--Developed World • According to the EPA, the 4 most dangerous indoor air pollutants in developed countries are: • Tobacco smoke • Formaldehyde • Radioactive radon-222 gas • Very small fine & ultrafine particles

5. Other Important Indoor Air pollutants Nitrogen dioxide Carbon monoxide Volatile Organic Compounds (VOCs) House dust mites (& other allergens… from pets) Chlorinated organic compounds (ex. pesticides) Asbestos & man-made mineral fibers Sources Building materials Furnishings & fabrics Glues Cleaning products Combustion appliances (cooking & heating) Open fires Smoking Living organisms Outdoor air

6. Tobacco Smoke • The most dangerous indoor pollutants in the developed world • Secondhand smoke from cigarettes is especially dangerous • Containing over 4000 dangerous chemicals • Causes eye, nose, and throat irritation • Smoking has declined in developed nations

7. Volatile Organic Compounds (VOCs) • The most diverse group of indoor air pollutants • Released by everything from plastics and oils to perfumes and paints • Ex. formaldehyde, which leaks from pressed wood and insulation, irritates mucous membranes and induces skin allergies • Ex. pesticides, which are found indoors more often than outdoors due to seepage • Most VOCs are released in very small amounts • Unclear health effects due to low concentrations

8. Radon-222 • colorless, tasteless, odorless, radioactive gas from decay of U-238 found in some soils & rocks • can seep into some houses • Most homes are now radon resistant • 55% of our exposure to radiation comes from radon • May harm lungs from long term exposure. • increases the risk of lung cancer • Chance increase more if a smoker (synergistic effect) • causes 20,000 deaths a year in the U.S. • Reducing the risk • Sealing cracks in floors and walls • Simple systems using pipes and fans

9. Sources & paths of entry for indoor radon-222 gas

10. Radon risk across the U.S.

11. Living organisms can pollute indoors • Dust mites • feed on human skin & dust • live in materials such as bedding & furniture fabrics • can cause asthma attacks & allergic reactions • Fungi, mold, mildew, airborne bacteria • cause severe allergies, asthma, & other respiratory ailments • Animal dander • worsen asthma

13. Major Indoor Pollutants Pollutant Source Health Effects http://www.metricmind.com/ac_honda/main.htm

14. http://www.metricmind.com/ac_honda/main.htm

15. http://www.metricmind.com/ac_honda/main.htm

16. Sick Building Syndrome • A sickness produced by indoor pollution w/ general & nonspecific symptoms • Ex. dizziness, headaches, coughing, sneezing, nausea, burning eyes, chronic fatigue, irritability, eye/nose/throat irritation, dry skin, nasal congestion, difficulty breathing, nose bleeds, flu-like symptoms • persistent set of symptoms in >20% population • complaints/Symptoms relieved after exiting building • causes(s) not known or recognizable • New buildings are more commonly “sick” than old ones because of reduced air exchange. • Can be solved with low-toxicity building materials & good ventilation

17. Building Related Illness • Also due to exposure to indoor air pollutants • Recognizable Causes • Clinically Recognized Disease • Examples • Pontiac Fever – Legionella spp. • Legionnaire's Disease • Hypersensitivity Pneumonitis • Humidifier Fever • Asthma • Allergy • Respiratory Disease • Chronic Obstructive Pulmonary Disease

18. Reducing Indoor Air Pollution • Little effort has been devoted to reducing indoor air pollution even though it is more harmful to human health than outdoor air pollution • Environmental & health scientists call for us to focus on preventing air pollution (especially indoor) in developing countries.

19. Solutions Indoor Air Pollution Cleanup or Dilution Prevention Use adjustable fresh air vents for work spaces Cover ceiling tiles & lining of AC ducts to prevent release of mineral fibers Increase intake of outside air Ban smoking or limit it to well ventilated areas Change air more frequently Set stricter formaldehyde emissions standards for carpet, furniture, and building materials Circulate a building’s air through rooftop green houses Prevent radon infiltration Use exhaust hoods for stoves and appliances burning natural gas Use office machines in well ventilated areas Use less polluting substitutes for harmful cleaning agents, paints, and other products Install efficient chimneys for wood-burning stoves Fig. 19-20, p. 461

20. We can reduce indoor air pollution • In developed countries: • Use low-toxicity material • Monitor air quality • Keep rooms clean • Limit exposure to chemicals • Allow for better mixing of indoor & outdoor air • In developing countries: • Dry wood before burning • Cook outside • Use less-polluting fuels (natural gas)

21. We can reduce indoor air pollution • The amount of air available (for mixing of indoor & outdoor air) to dilute pollutants is an important indicator of the likely contaminant concentration • Indoor air can mix with outside air by 3 mechanisms • infiltration • natural ventilation • forced ventilation

22. Mixing of Indoor & Outdoor Air • Infiltration • natural air exchange that occurs between a building & its environment when doors & windows are closed • leakage through holes or openings in the building • Influenced by: • pressure differentials inside & outside the building • temperature differentials inside & outside of bldg ~in winter, warm air inside wants to rise  exits through cracks in ceiling & draws in outside air • how fast wind is blowing

23. Mixing of Indoor & Outdoor Air • Natural ventilation • air exchange that occurs when windows or doors are opened to increase air circulation • Forced ventilation • mechanical air handling systems used to induce air exchange using fans & blowers

24. What Can You Do? Indoor Air Pollution • Test for radon and formaldehyde inside your home and take corrective measures as needed. • Do not buy furniture and other products containing formaldehyde. • Remove your shoes before entering your house to reduce inputs of dust, lead, and pesticides. • Test your house or workplace for asbestos fiber levels and for any crumbling asbestos materials if it was built before 1980. • Don't live in a pre-1980 house without having its indoor air tested for asbestos and lead. • Do not store gasoline, solvents, or other volatile hazardous chemicals inside a home or attached garage. • If you smoke, do it outside or in a closed room vented to the outside. • Make sure that wood-burning stoves, fireplaces, and kerosene- and gas-burning heaters are properly installed, vented, and maintained. • Install carbon monoxide detectors in all sleeping areas. Fig. 19-21, p. 461