Pollution

Fatal Little Things

By Aries Poon

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Photo by Helena Chui


    Though smoking is considered the main cause of lung cancer, the number of people who die of lung cancer has tripled since the ’60s while fewer people smoke.
     Dr. Linda Koo is a lecturer in the Department of Community Medicine at the University of Hong Kong, and a researcher at the Cancer Research Laboratory of the Hong Kong Anti-Cancer Society.
     “We’ve found a higher rate of respiratory diseases among children and women in southern China and Hong Kong who had never smoked,” said Dr. Koo.
     “Indoor pollution and problematic dietary pattern can be the cause of it,” she concluded.
     Dr. Koo said this factor should be taken seriously, especially when the person is not involved in a history of active smoking.
     Indoor pollution is a problem which is often overlooked. Sometimes people don’t even realize its danger.
     An example is the traditional Chinese practice of burning incense at homes and workplaces for religious purposes.
     Dr. Koo said, “This is the most obvious source of indoor pollution following cigarette smoke, though not the worst to one’s health.”
     As the time and intensity of incense burning increase, the nitrogen dioxide levels increases significantly.
     However, this will not cause direct harm to humans.
     “This distinct smell is perceived as pollutants,” said she. “People respond by increasing ventilation naturally.”
     Dr. Koo called this kind of response “compensation behaviour”.
     “So, it turns out the concentration of nitrogen dioxide in air is actually reduced with more pollutants emitted,” said she.
     The same theory applies to the oily gases produced during stir-frying and other forms of cooking.
     “If this distinct smoke is ignored, it will cause irritation and promote respiratory diseases, including lung cancer,” said she.
     However, when pollutants are circulated under a central air-conditioning system, the effect on health can be increased.
     “The system is characterized by its rigid ventilation. Air is being recycled,” said Dr. Koo. “Little fresh air is added to lower the concentration of pollutants.”      Most offices in Hong Kong adopt a central air-conditioning system, and many are suffering from its defects.      “It may cause cross-infection,” said she. “Some common but highly contagious sicknesses, like influenza, may spread all over one’s workplace.
     But changing the whole air-conditioning system is very costly. Employers may consider having regular clean-up of the system an effective and less expensive way of getting rid of the accumulated pollutants.
     There are other processes carry pollutants dangerous to health.
     Dr. Koo pointed out that the chemicals added during dry-cleaning and in hair spray are actually pollutants.
     Some may suggest to stop using these goods. But it is not as easy as one thinks.
     “Glue, a necessity in children’s art lessons, is also a pollutant-carrying product,” said Dr. Koo.
     “Furthermore, the raw materials for construction contains many pollutants. Formaldehyde released from pressed wood, radon from cement and granite of a building are materials which are not smelly but harmful,” said she.
     Food may be a source of lung cancer.
     “It is found that cancer can be caused by the N-nitroso compounds found in salted fish, cured meats like Chinese sausage, pressed duck, and preserved food,” Dr. Koo said.
     “Having vegetables which contain vitamin C may helps to prevent it,” said she. “Therefore it is better to stick to fresh food.”
     Miss Ruby Lo Bik Yu, a practising student nurse, explained the correlation between food nutrition and cancer.
     “A human body needs vitamins and minerals for normal functioning, or our body undergoes changes which cause lung cancer and many others diseases,” she said.
     Miss Lo said that there was only one kind of food our body did not need.
    She said preservatives and artificial colourings have no nutritional value. These substances are expelled through metabolism to maintain physical equilibrium.
     “If the accumulated unwanted substances exceed the rate of metabolism, problems emerge,” said she.
     She also said that if tuberculosis, or TB, was not properly treated, it would slowly develop into lung cancer.
     Miss Lo also attributed lung cancer to genetic factors.
     “Although the correlation is not significant and direct, it is still positive,” said she. “After all, no one dares to say there is absolutely no correlation between the two.”
     Dr. Koo recommended some tips to hedge against the tripling lung cancer mortality rate.
     “Maintain good ventilation, have a well-balanced diet and avoid breathing in pollutants are some main points that one must remember,” said Dr. Koo.
     “Of course, doing more exercises and keeping oneself relaxed are also essential,” she said. “They promote better metabolism altogether.”