Indoor air contamination after the breakage of mercury-containing compact fluorescent lamps (CFLs)

Abstract

As energy-saving replacement for conventional incandescent light bulbs compact fluorescent lamps (CFLs) are increasingly used for many purposes. Elementary mercury (Hg) is set free and evaporates into the air when these lamps are inadvertantly broken in indoor spaces. An exposure of room users to concentration levels that may be harmful to health has to be considered. In a pilot study indoor air levels were analyzed after breakage of Hg-containing CFLs and one amalgam-containing CFL as well as one fluorescent tube. The study was conducted applying different ventilation and room temperature scenarios and cold and hot lamps that had been turned on before breakage. Background concentrations in the building were measured over a period of approximate-ly 8 hours in 11 offices and laboratory areas. The levels ranged from 5 to 50 ng/m 3 (average value: 15 ng/m 3 ). In a further unventilated room of the laboratory, an average value of 120 ng/m 3 was detectable. In 10 four-hour trials with 6 different elemental Hg-containing CFLs and poor ventilation maximum room concentrations of 380 to 910 ng/m 3 (room temperature: 14 to 18°C) and of 680 to 10,300 ng/m 3 (temperature: 21 to 22°C) were quantified. As expected, the levels were lower with a higher air exchange rate. With a hot CFL that had been turned on for one hour prior to the experiment, air concentrations of up to 5,500 ng/m 3 were observed (cold CFL: 500 ng/m 3 ). In a long-term trial over 4 days the concentrations decline in a poorly ventilated room even though the source was present. After airing and removal of the source only a small increase of the concentration was observed. In our study only one amalgam-containing CFL could be tested. Compared to the CFLs with elementary mercury the maximum room concentration of 140 ng/m 3 was clearly lower. Using a hot amalgam-containing CFL the maximum air level rose after breakage to 580 ng/m 3 . The highest room concentrations with a maximum of 31,900 ng/m 3 were observed after breaking an approximately 2 year old fluorescent tube. Health effects are not probable after the breakage of a CFL if the room is immediately ventilated and the mercury and glass fragments of the lamp are carefully removed from the room.