Odor complaints have increased in volume as citizens are becoming increasingly aware and sensitive about a pleasant living environment. To meet the ever-growing expectations of its citizens, Seoul is implementing a serious of policies targeting every source of odor. The aim is an annual 10% reduction of odor complaints in the city.
 

Odor Affecting Lives of Citizens
Malodor complaints arising from residential settings have gradually increased in volume from 292 in 2008 to 430 in 2012, a 68% jump in just a few years. It is worth noting that 75% of the total complaints, or 359 cases, were submitted from May to October 2012. Sewage is a big cause of odor problem in Seoul, too. Complaint associated with sewer jumped from 595 in 2009 to 3,135 in 2012, a 6-fold increase. In particular, 78% of complaints (2,443) were about the disagreeable sewage odor coming from drainage pipes in streets.
 
Difficulties Fighting Odor
In Korea, most drainage pipes take a combined sewage system, and 87% of Seoul’s drainage pipes have a combined system which requires installation of a separate septic tank to prevent odor. Replacing the combined system with a separate sewer system would indeed be very effective in fighting odor; however, it costs a whopping KRW 100 trillion and more than 300 years to install, making the replacement near impossible.
Another challenge is the lack of legal ground to enforce odor control in restaurants and laundry shops. The owners tend to dodge from investing in odor control facilities that cost a substantial amount. Also, those living in low-income residential areas face more serious odor problem because of obsolete drainage pipes, malfunctioning bathroom and illegally dumped trash around home.
 
Policies to Counter Odor
A survey conducted by the city government in 2012 on odor issue found that 52% of respondents experienced some sort of discomfort due to unpleasant smell, but 76% of those did not respond with counter-measures. Also 66% of the respondents said that the city government should strengthen administrative measures and upgrade the current odor map. Taking the valuable input of its citizens into consideration, SMG developed policies accordingly.

Seoul aims to reduce 30% of odor complaints by 2018 to make Seoul a pleasant environment for all Seoulites to live free from unpleasant odor.
 
Systematic, Tailored Odor Control System
The Seoul government is targeting large buildings for its odor-free imitative for the private sector. When effluent water is discharged from septic tanks of buildings in inner city area to drain pipes, the water passes or stays in manholes and street inlets which cause serious foul smell. To eliminate odor made in this process, buildings in downtown area are required to install air feeders at septic tanks. By 2018, 7000 air feeders for all septic tanks in large buildings will be equipped with air feeders. In addition, drain pipes repair and maintenance works will continue in order to curb sewer odor coming from decomposition organic matters. Seoul will also open up to enlist creative ideas about best solutions to sewer odor, some of which can be applied to demonstration projects.
Seoul is applying stricter standards for the public sector. Currently, there are 54 public sites under radar, including waste transfer station, food waste treatment facilities, agriculture and fisheries markets, water reuse centers, all of which will be subject to more stringent standard than the average odor permissible level. Other projects include installing smell sensors at septic tanks to alleviate the stink of sewage.
More research should also help Seoul fight odor. For instance, the Seoul odor map will be upgraded using up-to-date data on odor sources and current status. Such data will be the basis for anti-odor measures. Seoul plans to make a manual with case studies to be distributed to odor-causing businesses such as restaurants to help them understand what they can do to reduce foul smell.
 
Legal Ground for Enforcement
Large-scale businesses such as Tancheon Water Reuse Center, Songpa Food Waste Recirculation Facility are legally required to install odor-control devices in accordance with the Offensive Odor Control Act. The law, however, excludes smaller-sized businesses. Seoul is currently working to enact an ordinance that would lay legal foundation for the city to provide financial support to businesses that are not bound by law and are willing to install odor prevention facilities. Meanwhile, there is a mobile odor metering vehicle that is equipped with odor sequestration system. Seoul is driven to expand the number of this vehicle to 4 by 2018 so that they can collect samples of air in odor-affected areas. The system introduced in 2012 will help resolve complaints by operating the system from 10pm to 8am to collect samples, analyze it and identify sources of odor in problematic areas.
 
Public Engagement for Fragrant Seoul
Seoul engages its citizens for the success of its odor-free initiative. For example, ‘Fragrant Seoul’ is a contest in which citizens propose creative ideas about planting trees or flowers as means of absorbing odor in traditional markets and small alleys. Another example of civic engagement has to do with gingko trees. Ginkgo trees have been a source of smell around Seoul due to the raw stench of fallen seeds. The city government plans to replace the fruit-bearing female gingko trees with their male counterparts while operating several nuts-collecting teams, as part of a larger plan to help reduce unpleasant aromas in the city.
 
Measure for Residential Area
In order to help alleviate odor in many underprivileged neighborhoods that seem to be more affected by malodor more often than not, food trash recirculation facilities will be placed in those communities. The facilities automatically sort the food trash when it dumped as pulverized. For other residential areas, Seoul will supply devices that reduce the volume of food waste while expanding the number of garbage collecting centers from 61 in 2014 to 141 by 2018.