A compact air purification technology capable of maintaining its performance for extended periods, even on trains operating in highly polluted regions such as India, is currently being developed. The technology is designed to mitigate the rapid clogging of conventional filters and can be installed in existing train HVAC systems without requiring structural modifications.
A research team at the Korea Institute of Machinery and Materials (KIMM) – including Principal Researchers Dr. Sang Bok Kim and Dr. Inyong Park and Senior Researcher Dr. Younghun Kim of the Department of Urban Environment Research, Eco-friendly Energy & Environment Research Division – has begun developing a compact electrostatic precipitator-based air purification module for use in Indian trains. The project is a collaborative effort with THN Co., Ltd., a KIMM Family Company (partner firm), as part of KIMM’s flagship air purification brand, Air Five.
The electrostatic precipitator-based air purification module under development electrically charges fine particles in the air and collects them on oppositely charged plates. Conventional filtration systems tend to become clogged more quickly as fine-dust concentrations increase, shortening filter life and increasing airflow resistance. In contrast, the electrostatic precipitation method maintains an open airflow path, enabling stable treatment of large volumes of air even under high-concentration fine-dust conditions.
Specifically, the module is designed to be compact and can be installed without modifying the structure of existing train HVAC systems. The research team aims to achieve fine-dust reduction performance equivalent to MERV 15, comparable to that of conventional high-performance filter-based air purification systems. Considering the severe fine-dust conditions encountered by trains in India, the team plans to ensure high particulate removal efficiency and verify the technology’s performance and stability under actual operating conditions through field demonstrations on local trains.
* MERV (Minimum Efficiency Reporting Value): A rating that indicates how effectively an air filter removes fine particles. A higher number represents greater particle-removal efficiency.
The research project was initiated in response to a request from an Indian railway company to develop air purification technology for train cabins. Given India’s high ambient fine-dust concentrations, the key objective is to effectively remove fine particles entering from outside and maintain a comfortable indoor air environment inside train cabins.
The research team plans to install the developed air purification modules on trains in India and evaluate their fine-dust removal performance, durability, and energy efficiency. In particular, the team will verify the long-term stability of the air purification performance and analyze potential issues arising from high fine-dust concentrations and local climatic and environmental conditions. Based on the results, the technology will be further optimized for India’s railway environment.
The team also plans to collaborate with Chonnam National University to integrate a function for inactivating airborne infectious agents into the electrostatic precipitator. Through this effort, the researchers aim to develop and verify a comprehensive indoor air quality management system for public transportation that can control not only fine dust but also airborne infectious agents.
The technology is expected to be applicable not only to trains but also to HVAC systems in various public-use facilities, including airports, hospitals, government offices, and public institutions. The research team is currently pursuing pilot deployments at Indian government agencies, public institutions, and major hospitals and plans to expand the scope of deployment after validating performance and reliability through local demonstrations.
If the field demonstrations in India are successfully completed, the technology’s application is expected to be expanded into railway and public infrastructure markets in Southeast Asian countries with high fine-dust concentrations, including Thailand and Vietnam. Through these efforts, KIMM plans to broaden the application of Air Five, its flagship air purification technology brand, to overseas transportation and public infrastructure sectors and pave the way for Korean air purification technologies to enter the global market.
Dr. Sang Bok Kim stated, “This research is significant in that it will directly apply Korean-developed air purification technology to trains operating in India, which suffer from severe fine-dust pollution, and verify its performance and reliability under real-world conditions. We plan to successfully complete the field demonstrations and expand the technology’s application across a wide range of HVAC markets, including not only railways but also hospitals, airports, and public facilities, thereby contributing to the overseas expansion of Korean air purification technologies.”
This research is supported by the “Industry Demand-Based 1% MVP Project” of the Ministry of Trade, Industry and Energy and the Korea Institute for Advancement of Technology (KIAT), running from May 2026 to December 2027.
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The Korea Institute of Machinery and Materials (KIMM) is a non-profit government-funded research institute under the Ministry of Science and ICT. Since its foundation in 1976, KIMM is contributing to economic growth of the nation by performing R&D on key technologies in machinery and materials, conducting reliability test evaluation, and commercializing the developed products and technologies.