Daily drinking of 10 cups of water helps remove fine dust residues from body

"Lung cancer, asthma, cardiac arrest, stroke, diabetes and bladder cancer…." These are diseases that are known to be caused by fine dust according to studies in Korea and overseas. The Korean government announced comprehensive measures to control fine dust on Friday, but citizens remain concerned, because they have no choice but to continue breathing toxic polluted air until practical effect is generated.

People have the option of avoiding using humidifier disinfectant (which caused many deaths in Korea), but they cannot help but breath fine dust circulating everywhere. The Dong-A Ilbo sought to answer questions through advice from Professor Kim Shin-do of department of environmental engineering at University of Seoul, Professor Kim Young-wook of the environmental pollution institute at Yonsei University), and Professor Heo Yang-im of family medicine at Seoul Paik Hospital.

Q. Do we get more fine dust on days when skies look foggy?

A. Ultrafine dust with particulates measuring 2.5 μm (one μm equals 1/1 millionth of a meter), disperses a large amount of sunlight and makes the skies look foggy. This does not mean that the fine dust level is necessarily lower on fine day. Because particulates are relatively large, a large amount of such fine dust reaches deeper into the lung, even though such dust is not dispersed with a significant amount of sunlight. For this reason, fine dust warnings are issued even on a fine day with visibility of 10 km or more.

Q. Are there any foods that are beneficial to health against fine dust?

A. It is water. If you drink eight to 10 cups of water a day, it will help remove fine dust from your body. Pear juice helps discharge fine dust through phlegm. However, coffee is not helpful because it helps dry up your bronchial tubes. Sea weeds including laver and sea mustard containing lots of dietary fiber also stimulate intestinal operation and thus helps discharge harmful substances from the body. However, excessive intake of such food could cause constipation.

Q. How can we reduce emission of fine dust when grilling mackerel?

A. When the fine dust level is very high, outdoor fine dust density amounts to about 200 μg per cubic meters. If you grill mackerel or operate the vacuum cleaner indoors with doors closed, the level could reach up to 2000 μg. Hence, in order to reduce fine dust levels, you should habitually operate the kitchen ventilator and ventilate indoor air.

You should keep the kitchen ventilator operating for about five minutes even after the end of cooking, to ensure that fine dust can be adequately removed from indoor air. It is good to use a wet mop to swipe window frames or shelves that could be covered with dust after cooking or cleaning. If fine dust is combined with water particles, it gets heavier and blows less. If you set the flame of the gas stove at the intermediate level when grilling mackerel or samgyepsal (pork belly) and thus prevent the fish and meat from being burnt, you can also significantly reduce the volume of fine dust generated.

Q. Are air cleaners effective?

A. The answer to this question is whether the air cleaner can filter out ultrafine dust (PM2.5) or not. Common electronic air cleaner at households can filter out more than 90 percent of ultrafine dust. However, if the filter is overused and aged, the filtering capability declines. Plants such as flowerpots help increase indoor humidity, but it have limited effect in reducing the fine dust level. Even in Gangwon Province where there are thick forests, the fine dust level is not so low.

Q. Is it effective if you apply tissue or handkerchief on your ordinary facial mask?

A.There is no efficacy. A mask filters dust because of fine structure of its material. Rather, not because of its thickness. Dust and other harmful substances from the tissue applied on top of the mask could be more detrimental to your health. Once you have used a yellow dust mask or a facial mask for fine dust marked as "KF80"," or "KF94," which filters out which filters out more than 80 percent of fine dust measuring 0.6μm on average, and more than 94 percent of fine dust measuring 0.4μm on average, you are advised not to reuse it. People with respiratory diseases should avoid outing even the next day after the day of a high fine dust level. This is because fine dust, which settled down the previous date, could blow away anew.

조건희기자 becom@donga.com