The effects of covering materials on indoor Rn concentrations in offices in Hong Kong

The variation of Rn concentrations in 134 offices with different covering m aterials cladded on internal building surfaces, including walls, ceilings a nd floors, were measured. The three commonest combinations (87 sites of cov ering materials for the walls, ceilings and floors in Hong Kong are (A): wa ll paper, fibre board, carpet; (B): paint, paint and plastic tile and (C): paint, fibre board, plastic tile. The average Rn concentrations for combina tions (A) and (B) were about the same, while that for combination (C) was s ignificantly lower than those for (A) and (B). A person working in an offic e with combination (C) can receive an average annual tracheobronchial equiv alent dose smaller than one working in an office with combinations (A) and (B) by an amount as large as 0.8 mSv. (C) 1999 Elsevier Science Ltd. All ri ghts reserved.