Respirable Crystalline Silica Dust Exposure during Concrete Breaking and Drilling in Hong Kong Construction Industry

Construction dust is one of the most concerned pollutants presenting risks to human health. Dust from construction activities, particularly true for silica dust, have an adverse effect on the local environment and on the health of local residents, as well as on those working on the site. There is a long-term concern about the over exposure of construction workers to respirable crystalline silica. The high exposure to silica, even over a short period, can lead to silicosis. No comprehensive study has been conducted in a holistic way to evaluate the effectiveness of current dust control practices in Hong Kong’s construction industry. Therefore, the authors proposed this research aims to evaluate the effectiveness of construction dust control practices in Hong Kong. The current dusty work processes and trades were firstly identified through a series of interviews and focus group meetings. Personal respirable samples were then collected and analysed based on NIOSH 7500 method. This paper presents the staged outcome of this research on the concrete breaking and drilling process. 48 samples have been collected and analysed. The results showed that the concentration of silica dust in more than half of the samples exceeded the current recommended threshold limit value of 0.05mg/m 3 . The main dust control measures during concrete breaking and drilling process are wet methods and fans, and the respiratory protection was also inadequate. Therefore, there is a strong need to devise methods for controlling workers' exposure to crystalline silica dust during concrete breaking and drilling activities in Hong Kong construction industry.