Visualizing distribution of naturally discharged asbestos fibers in Korea through analysis of thickness changes in asbestos cement slates

Asbestos slates are harmful when asbestos fibers are lost and emitted into the surrounding areas through years of weathering. This study quantified the amount of asbestos discharged naturally from slates and visualized the amount of asbestos discharged naturally from slates in administrative districts in Korea. First, the researchers measured the thickness of slates and calculated the age of 193 slate-roofed buildings in three similar regions with average weather conditions in Korea. Then a regression analysis was conducted with SPSS 2.0 based on the results of the field survey, and this showed that the level of eroded slate by age is (-0.015 + 0.034 × n) mm/year. When applying the deduced formula for change in thickness, to slates with different specifications, the amount of asbestos discharged naturally per unit area of slate would be (-2.5 + 5.67 × n) g/m². The map visualized with the 'Natural Break' option of the ArcGIS program shows the amount of asbestos discharged naturally is relatively less in Gangwon-do (6903.36 kg/year), but greater in Gyeonggi-do (165,436.03 kg/year), Gyeongsangnam-do (108,375.41 kg/year) and Jeollanam-do (162,280.53 kg/year). The map visualized using the 'Equal Interval' option shows that the amount of asbestos discharged naturally from slates is overwhelmingly greater in Ulsan (64,704.24 kg/year) than in any other region. This study provides data that the government can utilize to establish a plan to remove and dispose of slates, and to select priority regions for slate removal to benefit public health and the environment. The results of this study also suggest methods that can be used to estimate the amount of asbestos discharged naturally from slates with different specifications in other countries.