Using Compact Fluorescent Light (CFL) bulbs is touted as a big way to reduce energy consumption. After all, these bulbs use but 25% of the energy used by an incandescent lamps and produce the same amount of light. However, scientists have now found structural defects in these bulbs which makes them radiate UV light, meaning that we are no safer from UV exposure in our homes than outside in the sun.
A previous survey had found that CFL bulbs, which are claimed to emit light only in the visible spectrum, also radiate UV A and C light. The amount of UV light exposure exceeds the recommended threshold after only 5 hours of exposure at a typical working distance of 35cm from a desk lamp. What was particularly alarming was that the amount of UV C light was more than that in ambient sunlight on a mountain.
‘White Holes’ on the Surface Emit UV
CFL bulbs consist of narrow glass tubes which are coiled. The outer surface of the glass is coated with a layer of phosphorus which absorbs the UV emissions from inside the bulb and emits visible light instead. This twisted structure puts pressure on the phosphorus coating, which often chips or gets cracked, leaving behind uncoated ‘bald’ areas on the bulb. Researchers at Stony Brook University in New York have found that these chips or cracks on the surface are found across all common brands of these bulbs in the United States. They then studied the effects of these bulbs on healthy skin cells and found effects similar to UV radiation from the sun. There was a significant increase in the amount of toxic substances called ‘Reactive Oxygen Species’ found in these cells—these are indicators of damage. Exposure to incandescent lamps did not show any of these features.
Shortcomings in the manufacturing process of CFL bulbs have led to a discovery of disquieting proportions. “Despite their large energy savings, consumers should be careful when using compact fluorescent light bulbs,” said Professor Miriam Rafailovich, who headed this research. “Our research shows that it is best to avoid using them at close distances and that they are safest when placed behind an additional glass cover.”
Rafailovich also said it’s incredible that this situation has arisen. “You should not need suntan lotion to protect you from indoor lighting,” she said.
You can read about this work here.