Years of technological advances have made our home and office a lot easier. Over the years, the only option for indoor lighting was the regular, power-hungry incandescent light bulbs. But today it is increasingly common for energy-saving light-emitting diodes, LEDs.

As LED lights become more and more popular, environmentalists warn that although they may consume less energy, their brightness increases the light pollution in cities.

In October, a new five-screen size LED screen opened in the heart of Hong Kong’s Causeway Bay shopping precinct, which has become notorious for the night’s light.

Installed on the front of Sogo, the screen is about 1,400 square meters and is one of the largest LED screens in Asia.

“The LED lights are not completely eco-friendly.” “If people think they consume less energy and therefore maintain a longer period of lighting, there is actually not much difference from using incandescent lamps,” said Dr. Pan Juncheng, lead lecturer in physics at the University of Hong Kong.

According to Hong Kong Electric, one of the city’s two major electricity suppliers, incandescent lamps used in most traditional household bulbs convert only 10% of their energy into light and the remaining 90% into heat. LED lights generate less heat and are therefore more energy efficient.
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Tan Yiu-wen, chief executive of Green Sense, an environmental group, said that while LEDs seem to be the way forward compared to short-lived and high-energy incandescent light bulbs or globes, the former is still less than ideal for the environment because of light pollution.

And Mr. Tan noticed that the intensity of light required by LED or other signs is not the same as the intensity of light outdoors and the intensity of comfort that most people have at home.

Using a light meter, he found that the light level in Mongkok under a huge neon light was at least 2000 lux (lux is a measure of light intensity). This is as low as 300 lux compared to the readings in the apartment.

He said: “High-intensity lighting should pose a problem to the government.” The closure of these LED light bulbs (such as the big Causeway Bay screen) at night will not only save energy but also reduce the disruption caused to nearby residents. This is a win-win situation.