LED lights: Not only do the damage your retina and create dirty electricity, they emit radiofrequency radiation. Read more at EMCrules.
"Although today’s LEDs are capable of long life, and delivering high
light output levels with very little power consumption, most need to be
paired with a drive circuit to provide constant current sourcing to
operate in our homes and offices, and that’s where the problem comes in.
These switching drive circuits operate at increasingly higher
frequencies, and in order to maintain the highest efficiency, and
highest LED longevity possible, they also need to maintain very high slew rates [dirty electricity, or voltage changes].
These factors contribute to the overall unwanted emissions from each
individual lighting element, increasing the Electromagnetic background
noise. Most of the interference may be caused by very high frequency emissions,
typically in the 30 – 300 MHz range, and possibly higher."
or EMI mitigation inevitably increases the overall cost of products by
adding additional components to a design, or requiring a more
complicated and expensive design and layout, and for low price consumer
electronics, with very small profit margins, every penny counts. As EMI
mitigation is considered by some as an unnecessary expense, it is often
overlooked or simply disregarded."