"As soon as I had escape the heavy air of Rome and the stench of its smoky chimneys, which when stirred poured forth whatever pestilent vapours and soot they held enclosed, i felt a change in my disposition."

Good air quality is essential to our health. Unfortunately, with human activities and development, many air pollutants are being released into the environment, which can be harmful to our health. At an individual level, we have very little power in changing our outdoor air quality, since it will require the collective efforts of government policy, industrial regulations and human efforts. In comparison, we have much greater control to the immediate environment that we are living in, especially with the indoor air quality of our home and workplace. A major characteristic of our modern lifestyle is that we spend a lot more time in indoor environments than outdoors. As a result, our health can be greatly affected by the indoor air pollutants. According to the Environmental Protection Agency (EPA) in the United States, indoor air pollution is worst environmental health problem in the states, and magnitude of the problem is estimated to be 2 to 10 times worse than outdoor air pollution. The top indoor air pollutants are: combustion byproducts, fungi, dust and volatile organic compounds

Combustion byproducts: The combustion of biomass fuels can release carbon monoxides, nitrogen dioxides, particulate matters or any chemicals found in the chemicals.  These compounds can have detrimental health effect on us in high concentration. For example, carbon monoxide has a much high affinity to hemoglobin, the oxygen carrier particle of our red blood cell, than oxygen. When exposed in high concentration, the carbon dioxide can displace the oxygen in our red blood cells and cause carbon monoxide poisoning, which can be fatal if not treated immediately. Particulate matters released from the combustion process can also cause respiratory cardiovascular problems, and some of them are carcinogenic. Natural gas is commonly used as a fuel for heating and cooking. The fuel itself contains impurities and contaminants such as benzene, toluene, xylene, radon, methyl mercury, organoarsenic and organolead, which are poisonous and that some people may develop sensitivity to these chemicals. Gas stoves or badly installed wood burning units with poor ventilation and maintenance can greatly increase the amount of combustion byproducts in the indoor environment. Dr. William J. Rea, MD, the founder and director of the Environmental Health Center in Dallas, states that the most important sources of indoor air pollution responsible for generating illness are the gas stoves, hot water heaters, and furnaces. Therefore, it is crucial to ensure that these appliances are probably installed and maintained in order to minimize the level of combustion byproducts in your home.  


Fungi (Mold): Molds are microscopic fungi that can virtually grow on the surface of any building materials when given the right moisture level. Indoor space that has high humidity or/and condensation, such as bathroom and basement, are especially prone to mold growth. Indoor mold can produce spores and toxins, which can cause respiratory symptoms, allergic reactions and immune dysfunction.  The best method to prevent mold growth is to keep any building surface dry. Any sort of water damage in the house should always be promptly repaired. Small mold patches on building surface can be safely removed by using unscented detergent and water, and the masks and gloves should be use when cleaning the mold patches. However, when there is more than three mold patches and each patch is greater than one square meter, you will need to recruit trained inspector and contractor to help mediate the mold in the house safely. The Canadian Mortgage and Housing Corporation (CMHC) has published a lot of info regarding cleaning up molds in your home; these information can be found in their website:


Dust: Dust is composed of organic and inorganic matters such as soil, pollens, minerals, mold, dust mites, dead skin cells and fibres from our textile and furniture. It is a well-known trigger for allergies and asthma. Dust mites are the most common cause of dust allergies; they are microscopic insects that feed on dead skin cells and they can be commonly found in bedding, mattress, and box spring. House dust has also been found to contain higher concentration of toxic metals such as lead, cadmium, antimony and mercury than outdoor dust samples, potentially due to their presence in home furniture and appliances. Dust is everywhere in our surrounding, while we are not able to completely get rid of it from our indoor environments, there are many strategies that we can undertake to reduce the amount of dust at home. For example, replaces any carpet flooring with hardwood floor, choose wood and leather furniture and vacuum weekly with vacuum cleaner containing HEPA filter. For protection against dust mites, beddings and pillows should be washed once a week in hot water and a de-humidifier can be used to keep indoor air dry to deter the growth of the dust mites.

Volatile Organic Compounds: VOCs are organic chemicals that can be emitted into the surroundings at room temperature. It can be released from different sources at home, such as paints, glues, resins, polishing materials, perfumes, spray propellants and cleaning agents. Different VOCs vary greatly in their health effect, with some being highly toxic while some no known health effect. Their health effects depend on the level and duration of exposure. The most common symptoms of VOCs exposure include eyes and respiratory tract irritation, headaches, loss of coordination, nausea, dizziness, visual disorders and memory problems. Formaldehyde is one of the most common VOCs emitted by household furniture and appliance. It is a colourless gas with a pungent smell, and people can develop sensitivity symptoms to it. The rate at which formaldehyde is released can be increased by heat and humidity. Therefore, it is essential to maintain a moderate temperature and humidity at home to reduce formaldehyde emissions.