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Environmental Education. Indoor Air Pollution. Contents. Introduction Sources and impacts of common indoor air pollutants Sick Building Syndrome (SBS) Legionnaires ’ disease Control measures. Introduction. “ Acceptable Indoor air quality ” :
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Environmental Education Indoor Air Pollution
Contents • Introduction • Sources and impacts of common indoor air pollutants • Sick Building Syndrome (SBS) • Legionnaires’ disease • Control measures
Introduction • “Acceptable Indoor air quality”: • Air in an occupied space towards which a substantial majority of occupants express no dissatisfaction, and in which there are not likely to be known contaminants at concentrations leading to exposures that pose a significant health risk Sources of information: web site of ASHARE (http://www.ashrae.org/ )
Common indoor air pollutants [1] • Biological contaminants • Carbon dioxide • Carbon monoxide • Nitrogen oxides • Environmental tobacco smoke • Formaldehyde • Volatile organic compounds (VOCs) • Ozone • Radon
Common indoor air pollutants [2] • Biological contaminants • Bacteria, fungi and viruses • Breed in humid environment • Spread through ventilation systems • Sources: • Naturally exist in air, humid and poor ventilated area • Effects: • Vary with types • e.g. Sick Building Syndrome, Legionnaires’ disease, Colds and Influenza
Common indoor air pollutants [3] • Carbon dioxide • No color, smell and taste • Accumulate in poorly ventilated areas • Non-toxic but makes ones uncomfortable in high concentrations • Sources: • Exhalation by living organisms during respiration • Combustion • Effects: • Feel sleepy and sensitive individuals may feel dizzy
Common indoor air pollutants [4] • Carbon monoxide • No color, smell and taste • Inhibits oxygen transport in blood • Irreversibly binds to hemoglobin • Very toxic • Sources: • Incomplete combustion • Effects: • Low concentration: • Flu-like symptoms, such as nausea, fatigue, rapid breathing, chest tightness and impaired judgement, cardiovascular diseases • High concentration: • death Carbon dioxide and carbon monoxide are released during combustion. (Sources: http://hkcg.com)
Common indoor air pollutants [5] • Nitrogen oxides • e.g. NO and NO2 • Gas generated from combustions • Sources: • Burning of cigarette • Vehicles exhaust fumes • Effects: • Irritate eye and respiratory tract
Common indoor air pollutants [6] • Environmental tobacco smoke (ETS) • Mixture: • smoke from the burning cigarette or cigar • exhaled smoke from smokers • At least 4,500 compounds found in tobacco smoke • 60 of the 4,500 compounds are known as carcinogens • Some components such as hydrogen cyanide, nicotine and nitrogen oxides are toxic and irritative • Effects • Especially harmful to children • Increase the incidence of respiratory tract infections, lung cancers and heart Environmental tobacco smoke includes the smoke from burning cigarette and exhaled smoke from smoker. (Sources: http://www.corbis.com)
Common indoor air pollutants [7] • Volatile organic compounds (VOCs) • A range of organic compounds • Examples: benzene, chloroform and xylene • Evaporate at room temperature • Some are carcinogens, e.g. benzene and formaldehyde • Sources: • Solvents, cleaning agents, wood, paints, plastic, dyes, office machines (fax machines,computers, printers, etc), insecticides, and etc. • Effects: • eye, nose, throat and respiratory tract irritation, headaches, poor concentration, dizziness and tiredness • damages of central nervous system, liver and kidney
Cleaning agents are also a source of indoor VOCs. (Sources: http://www.wellcome.hk.com) Some home appliance such as personal computer can release VOCs too. (Sources: http://www.fortress.com.hk) Common indoor air pollutants [8] • Volatile organic compounds (VOCs) (con’t)
Oil-based paints are a source of indoor VOCs. (Sources: http://www.corbis.com) Common indoor air pollutants [9] • Formaldehyde • One of Volatile organic compounds (VOC) • Chemical smell in high concentration • Sources: • Paints, plastics, pressed-wood products, plywood and urea-formaldehyde foam insulation, etc. • Effects: • Irritate and sensitize eye, nose and respiratory tract • Carcinogen
Common indoor air pollutants [10] • Ozone • Odorless and colorless • Highly reactive • Sources: • photocopier, laser printers and ionisers • Effects: • Damage lung seriously • Irritate eye and respiratory tract Photocopiers also release ozone. (Sources: http://www.fortress.com)
Common indoor air pollutants [11] • Radon • No color, smell and taste • radioactive. • Sources: • Release from granite in the concrete building. • Effects: • Prolonged intake: • increase the incidence of lung cancer • The mixture of radon and tobacco smoke is much more harmful to human • Smokers have high probability of having lung cancers than non-smokers under the same level of radon.
Sick Building Syndrome (SBS) • A range of symptoms • including eyes, nose and throat irritation, flu-like symptoms, chest tightness, headaches, lethargy, poor concentration and itchy skin with rash • Not life-threatening • Commonly occur in air-conditioned buildings • The syndrome causes • poor work performance, • higher rate of absenteeism and sick leaves • Poor indoor air quality is believed to be a major contributing factor
Legionnaires’ disease • Caused by bacteria, Legionnella pneumophila • Symptoms: • Pneumonia, high-fever, chills, headache and muscle pain
Control measures • Eliminate the sources of pollutant • Increase ventilation • Keep the ventilation system clean Covering the wall with wallpaper can eliminate the release of radon from concrete. (Sources: http://www.corbis.com) Upgrade, clean and sterilize the air conditioner is one way to keep the indoor air in good quality. (Sources: http://www.fortress.com.hk)
Discussion • Have you ever felt uncomfortable in an indoor environment with flu-like symptoms, but they all disappear once you move out to outdoor environment? Where? How do you explain? • What kind of indoor air pollutants could be found in the classroom? • How do the problems associated with indoor air quality affect the social and economic development in Hong Kong? • How do the government and you help to improve the indoor air quality?
Relevant Websites • Hong Kong Council on Smoking and Health (http://www.info.gov.hk/hkcosh/) • Indoor Air Quality Association (http://www.iaqa.org) • Indoor Air Quality Information Centre (http://www.iaq.gov.hk/) • World Health Organisation (WHO) (http://www.who.int/home-page/) • Environmental Protection Department (http://www.info.gov.hk/epd/index.htm)