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 ( )

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:

Common indoor air pollutants [5] Nitrogen oxides e.g. NO and NO 2 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:

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

Common indoor air pollutants [8] Cleaning agents are also a source of indoor VOCs. (Sources: Some home appliance such as personal computer can release VOCs too. (Sources: Volatile organic compounds (VOCs) (con’t)

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 Oil-based paints are a source of indoor VOCs. (Sources:

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:

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 Upgrade, clean and sterilize the air conditioner is one way to keep the indoor air in good quality. (Sources: Covering the wall with wallpaper can eliminate the release of radon from concrete. (Sources:

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 ( Indoor Air Quality Association ( Indoor Air Quality Information Centre ( World Health Organisation (WHO) ( Environmental Protection Department (