Equipment containing PCBs is still used even now, after the production of PCBs itself has been forbidden. Especially the capacitor of fluorescent lights cannot be disregarded. Although there are just small amounts of PCBs in each capacitor, they are numerous, and exist in familiar places, such as in schools and in hospitals. Do PCBs leak from capacitors? Is it really safe to use them?

Structure of an internal capacitor



Photograph of an internal capacitor

In order to check whether PCBs volatilize from fluorescent lights, two experiments were conducted in collaboration with the Department of Engineering in the Tokyo University of Agriculture and Technology (Masaaki Hosomi's laboratory) (Funakawa et al., 2002).

• Investigation of ambient air pollution by PCBs in a room where a fluorescent light capacitor containing PCBs is used.
• One capacitor is removed and put into a sealed-container experiment system in order to measure the amount of PCBs that volatilize from the stabilizer.

According to the method for working-environment measurements, air was sampled in a room where capacitors containing PCBs were used (Fig. 1). Samples were taken continuously under the following situations: for 3 to 4 days, all usable fluorescent lights were turned on, air-conditioning was stopped, and doors and windows were closed, and air was sampled. Samplings were conducted twice, in September and in December 2001.

In addition, a sampling of the Department of Engineering in the Tokyo University of Agriculture and Technology was conducted as a control. Analysis was conducted by GC/MS.


(Fig. 1) Figure of the air sampling method

<The PCB concentrations were higher in the room where equipment containing PCBs was used>

PCBs were not detected in the control room. However, PCBs were detected in the room where the capacitors containing PCBs were used (Table 1), at levels of 110 ng/m3 (September) and 26 ng/m3 (December). It was then investigated whether PCBs leak from a fluorescent light capacitor.

(Table 1)Observed PCB concentrations in the indoor air(ng/m³)

PCB Control Site JOF's office   Sep. Dec. Mono PCB N.D. (<1.5) N.D. (<2.0) N.D. (<0.8) Di PCB N.D. (<1.5) 34 3.0 Tri PCB N.D. (<1.5) 62 20 Tetra PCB N.D. (<1.5) 17 3.3 Penta PCB N.D. (<1.5) N.D. (<2.0) N.D. (<0.8) Hexa PCB N.D. (<1.5) N.D. (<2.0) N.D. (<0.8) Hepta PCB N.D. (<1.5) N.D. (<2.0) N.D. (<0.8) Octa PCB N.D. (<1.5) N.D. (<2.0) N.D. (<0.8) Nona PCB N.D. (<1.5) N.D. (<2.0) N.D. (<0.8) Deca PCB N.D. (<1.5) N.D. (<2.0) N.D. (<0.8) Total PCB N.D. (<1.5) 110 26

Control Site: Tokyo University of Agriculture and Technology laboratory
JOF's Office: Using the PCB-containing Ballast
N.D.: Below Detection Limit

<Measurement of the amount of PCBs that volatilizes from a capacitor>

The stabilizer containing PCBs (Matsushita Electric Works, Ltd., made in 1970, product code: SNZ40211HB-7) was removed, and sealed in a glass container (Fig. 2), after which the amount of PCBs that volatilized in the air was measured (Fig. 3). Temperature conditions were changed during the experiments, 2.2, 15.5, 30 and 50 degrees centigrade, respectively.

<The fact that PCBs volatilized from a capacitor was checked.>

As the temperature became higher, more PCBs volatilized. Under the severest conditions of 50 degrees centigrade, 1 million/ng of PCBs volatilized from just one capacitor in a day. A capacitor gets hot while in use. It becomes about 50 degrees centigrade in midsummer.

Moreover, in all temperature conditions, the PCBs (di-penta chlorinated PCBs) with two to five chlorine molecules made up the highest percentage of total concentrations. And since this percentage mirrored the composition of the PCB product (KC-300), the possibility that the capacitor containing PCBs was the source of the indoor PCBs was further supported.


PCB volatilization rate from the PCB-containing ballast using the volatilization chamber (ng/day)

PCB Temperature 2.2 15.5 30 50 Mono PCB N.D. (<4.0) N.D. (<5.0) N.D. (<160) N.D. (<100) Di PCB 600 1100 8700 170000 Tri PCB 2000 3700 33000 680000 Tetra PCB 440 700 10000 180000 Penta PCB 14 16 230 5900 Hexa PCB N.D. (<4.0) N.D. (<5.0) N.D. (<160) N.D. (<100) Hepta PCB N.D. (<4.0) N.D. (<5.0) N.D. (<160) N.D. (<100) Octa PCB N.D. (<4.0) N.D. (<5.0) N.D. (<160) N.D. (<100) Nona PCB N.D. (<4.0) N.D. (<5.0) N.D. (<160) N.D. (<100) Deca PCB N.D. (<4.0) N.D. (<5.0) N.D. (<160) N.D. (<100) Total PCB 3000 5500 37000 1000000

N.D. : Below Detection Limit


Comparison of PCBs in the sample

The results of these experiments suggest that PCBs volatilize and spread when PCB containing capacitors that have deteriorated or exceeded their product life were used. Stabilizers in use are one source of PCB pollution, but since PCBs that have volatilized from capacitors diffuse, the concentration of PCBs detected in air is low. However, PCBs that escape into ambient air pollute foods we eat through biological accumulation, and these rebound upon us after all. This should not be disregarded.

Continuing use of PCBs contributes to the risk of accidents from exploding equipment, as well as other possibilities of further contamination. Equipment containing PCBs that is still in use should be collected immediately and treated.