Chloe Choi, a Korean-British living in London, says she fears visiting her native South Korea because of something she cannot bear: odor from the sewers.



The 29-year-old, who lived in Seoul from 2009-2010, said the distinctive smell on the streets often made her sick.



“I would cover my nose and run away from (the smell) as far as possible. I would literally run,” she told The Korea Herald.



“Being constantly exposed to it was definitely not right. I was shocked that this was the reaction I was getting -- feeling physically sick -- and yet people were just living with it.”



A street sewer in Huam-dong, Seoul. (Claire Lee/ The Korea Herald)



Choi, however, is not alone in finding the particular problem to be almost unbearable. Odor pollution is increasingly becoming a public concern in South Korea, where, in spite of a 2005 law, the number of malodor-related complaints surged 21-fold from 2005-2016.



Some 25,000 Koreans filed such complaints to the government in 2016 alone, with the largest proportion concerning unpleasant smells from food waste or smoke outside restaurants, as well as sewage.



“First, we have to acknowledge odor as a serious environmental pollution issue,” Kim Myung-ja, president of the Korean Federation of Science and Technology Societies, said in a recent public debate.



“If we do not actively tackle this issue, the quality of life of the general public may be severely jeopardized.”





Septic tank problem





According to a study by Ryu Hee-wook, a Soongsil University professor, almost 30 percent of people who filed odor-related complaints in 2016 complained about sewage odors.



The particular malodor has been linked to the country’s sewage system. As of 2016, more than 80 percent of all properties in Seoul -- including residential buildings -- use septic tanks, or small-scale sewage systems that treat and dispose household wastewater on site.



This makes almost all Korean streets with sewers, kitchens and bathrooms vulnerable to the sewage odor that smells like rotten eggs and ammonia, among other things. The malodor worsens in summer months when wastewater odors rise with the temperature.



In North America, only about 25 percent of the population relies on septic tanks, mostly in rural areas lacking connection to public sewage pipes.



Experts say hydrogen sulfide, an odor-causing gas that results naturally from septic conditions during the collection and treatment of wastewater, is only slightly soluble and therefore easily released into the atmosphere.



“This summer has been especially brutal,” said Kim So-hye, a mother of two in western Seoul.



“The weather itself was already almost unbearable. The worst days were when food waste was out on the street for collection. Combined with the sewer odor and the scorching heat, it often made me want to throw up.”



According to the Korean Federation of Science and Technology Societies, exposure to hydrogen sulfide, even at a low concentration in the air, can cause a number of health conditions, including headaches, eye irritation and fatigue.





Trash is piled up in the street near an outdoor market in Seoul on Sept. 26, the last day of the Chuseok holidays. (Yonhap)