Technology to Reduce Scattering Dust in City Roadworks
▲ Senior Researcher Baek Cheol-min, Department of Infrastructure Safety Research
▲ Senior Researcher Yang Seong-rin, Department of Infrastructure Safety Research
▲ Postdoctoral Researcher Lee Jong-won, Department of Infrastructure Safety Research
▲ Student Researcher Han Su-hyeon, Department of Infrastructure Safety Research
Dust is an airborne particulate matter. Dust released directly into the atmosphere is called "scattering dust." Main sources of scattering dust include construction sites and plants where cement, coal, earth/sand, or aggregates are handled. As with general dust, scattering dust can be divided based on particle size (diameter) into total suspended particles (TSP) under 50 μm, fine dust under 10 μm, ultrafine dust under 2.5 μm, and extremely fine dust under 1 μm. Environmental issues related to scattering dust include the dust dome effect, impaired visibility, respiratory disorders such as pneumoconiosis, and deterioration of facilities. Exposure to fine dust (PM10) harms the human body. A 10 μg/m³ increase in fine dust concentration increases the likelihood of death by stroke by 10%, and worsens asthmatic symptoms by 29%.
Since 1987, the World Health Organization has been providing guidelines related to fine dust. In 2013, the International Agency for Research on Cancer, a subsidiary of the World Health Organization, classified fine dust as a "Group 1" carcinogen. The Ministry of Environment of Korea attributes 30% to 50% of fine dust production to foreign countries, i.e. China. With regard to domestic production of fine dust, in the Seoul area, it attributes 29% to diesel vehicles. Nationwide, it attributes 41% to business operations such as manufacturing plants. A notable finding is that in cities such as Seoul, the concentration of roadside fine dust is 4 to 11 μg/㎥ higher than the concentration of fine dust measured in the atmosphere. This has been found to be caused by vehicle emissions and roads. The National Institute of Environmental Research defined fine dust as an atmospheric pollutant in 2015, and has since been setting limits on fine dust emission in its regular reports on national air pollutants emission. Figure 1 is an overview of scattering dust production in 2017, the National Institute of Environmental Research's latest finding, and it can be seen that over 60% of scattering dust is attributed to construction and roads. As such, there is an increasing need for research on the means and technologies for monitoring and reducing scattering dust created by construction and roads.
Development of Technology to Reduce Scattering Dust in Roadworks
Since 2013, the Korean government has been executing progressively strengthened control of scattering dust through policies and manuals on scattering dust (Figure 2). In 2019, the cold months of December to March were designated as a "high-concentration fine dust" period, and intensive control of fine and scattering dust has been implemented.
Reduction of scattering dust requires a technology that can continuously reduce the precursors of scattering dust, NOx, SOx, and fine dust (PM10, PM2.5). Roadworks are primarily taking place in cities such as Seoul where a concentration of population, traffic, and industry is present. As most such roadworks involve the maintenance of existing roads rather than the construction of new ones, scattering dust is generated at a high rate during production and installation processes. Scattering dust from roadworks makes up a large proportion of the scattering dust generated by paved roads.
The research and development of technology to reduce scattering dust in all stages of road pavement have been set as a component of the "Development and Verification of Technology for Reducing Road-generated Fine Dust," a national research and development project of the Korea Agency for Infrastructure Technology Advancement to be executed over five years from 2019 to 2023, and are being carried out by 14 organizations including the KICT. This research group is developing technology to reduce the generation of scattering dust throughout all stages of road pavement, as shown in Figure 3, with the goal of reducing scattering dust generation in production phases by more than 30% (reduction of precursors such as NOx included) and at installation and operation phases by more than 10%. So far, in-plant facilities (combustion chambers, dust collection systems, etc.), eco-friendly scattering dust suppressants, sidewalk-driven scattering dust removal vehicles, and equipment to measure volumes of scattering dust generated by road pavement have been developed. Detailed plans for the practical application of developed technologies are being formed through field trials, systemization, and cooperation with related agencies (see Figure 4).
Some notable achievements of the research group include the following. POSCO Engineering & Construction developed an eco-friendly scattering dust suppressant with improved mechanical and environmental function achieved through a newly developed technique of mixing silicate hybrid polymers with palm oil. This product, compared to the world's best-rated product, is 80% more economical and reduces loss of scattering dust by 2.54 times. A sidewalk-driven scattering dust removal vehicle developed by DaeilTec, which has a compact size and features water blasting and remote control, is currently being field-trialed in partnership with the Seoul Metropolitan Government. The Korea Expressway Corporation Research Institute developed a tester for measuring volumes of scattering dust generated by road pavement. This equipment measures scattering dust directly generated by the abrasion of tires and pavement materials, and plays a crucial role in the development of technology for reducing tire wear (see Figure 5).
With regard to the production phases involved in road pavement, laws on reducing scattering dust production by road pavement material production facilities will be enacted with the aim of establishing national standards and systems for reducing scattering dust and its precursors (NOx), to be implemented in the domestic market. In terms of the installation phases, elementary technology, products, and guidelines for reducing scattering dust production in road pavement works will be developed. For the operation phases, products and their operating methods for reducing scattering dust production by sidewalks and road surfaces will be developed. The research group's goal is to develop technology for reducing scattering dust production in all stages of road pavement works, from production to installation to operation, and to develop a system that can measure volumes of scattering dust production.
The Seoul Metropolitan Government recently designated six self-governing districts (Seocho-gu, Eunpyeong-gu, Jung-gu, Geumcheon-gu, Dongjak-gu, Yeongdeungpo-gu) as "focused fine dust control zones," and is providing their residents with a wide range of effective means for reducing fine dust, as well as for protection from fine dust. The fine dust generated by roads in cities has become a serious environmental issue that directly affects the health of pedestrians and drivers. By identifying and developing means to reduce scattering dust production throughout all stages of road pavement (production, installation, operation), this research is expected to improve the roadside atmosphere and minimize the risks to which pedestrians are exposed.