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The abundance of bright artificial lights is making Hong Kong one of the most light polluted cities in the world and depriving people of the natural wonder of a starlit night sky, say experts.迷利倉 Hazel Knowles writes. It was a fantastic display: the biggest firework and pyrotechnic show in the history of Hong Kong’s New Year countdown celebrations. The thousands who had gathered to enjoy the spectacle on Tuesday evening “ooohed” and “aahed” as the fireworks burst into life above the city’s iconic night skyline and a huge LED screen on top of the Hong Kong Convention and Exhibition Centre counted down the seconds to the New Year. No one could deny it was an impressive sight. However, for astronomers in the city, something was missing: the backdrop of a natural starlit night sky. According to Dr Jason Pun Chun-shing, of the University of Hong Kong’s (HKU) Department of Physics, this seeming lack of stars was the result of light pollution caused by artificial lights in the city which now had one of the most light polluted urban skies in the world. “It is quite obvious now that the extent of light pollution in Hong Kong is so severe that a lot of young kids probably never see a star in the sky as they grow up,” said Pun. “They might see the moon or a planet, such as Venus which has been very bright recently, but they don’t see the stars.” Pun is the principal investigator of Hong Kong Night Sky Brightness Monitoring Network (NSN), a project set up in May 2010 by HKU to monitor the light pollution condition in the city. Since then, Pun and his colleagues have collected more than five million night sky brightness measurements — all of which paint a dark picture of how manmade light is polluting the night skies. The data, collected from 18 stations around Hong Kong, show that between 8.30pm and 11.30pm, the urban night sky is between 100 and 1,000 times than the international dark sky standard — a level established by the International Astronomical Union which refers to the brightness of the sky when it is lit only by stars and not reflected light from cities. Areas rich in illuminated signboards and floodlights such as Tsim Sha Tsui emerged as the most light polluted. However, Pun said even Sai Kung Astropark, the darkest station in the study and the best place to observe the stars, had a night sky at least 20 times brighter than international dark sky standard before 11pm, showing that light pollution is swiftly destroying the few remaining star-grazing locations in Hong Kong. The team found the night sky dims progressively at times when public and commercial lightings are turned off during the evening, proving that human lighting is the source of the light pollution. Light nuisance According to Pun, this light pollution is not only affecting the brightness of the night sky and causing light nuisance but also affecting the life cycle of wildlife. Light nuisance and energy wastage are two of the major concerns expressed by Friends of the Earth (Hong Kong) which in 2008 launched its Dim It campaign to raise awareness of light pollution. Director of General Affairs Edwin Lau Che-feng said the worst offenders were the big neon signs, flashing LED screens and advertisements with spotlights. “We are not opposed to neon signs that are switched on during operating hours to attract people. That is normal business. What we really disagree with is excessive lighting that is too bright and which stays on outside business hours,” he said. The Environmental Protection Department (EPD) says it has received about 200 complaints about external lighting every year since 2009.Of these, almost half involved shop signs and advertisements boards which were causing light nuisance rather than energy wastage. In a statement to China Daily, the EPD said as light pollution was a relatively new issue, there was not a universally accepted definition of and regulatory framework for “light pollution” which meant different places may define it in different ways. It stressed, despite the lack of a universal definition, the government attached great importance to the possible light nuisance and energy wastage that may be caused by external lighting, and had taken measures to identity the problems and possible solutions. These included commissioning a study looking at the experiences of other cities, and creating guidelines a迷你倉med at encouraging the public and stakeholders to minimize light nuisance and energy wastage The Environment Bureau has also set up a task force which is currently drawing up recommendations for the government on the issue following a report and recently conducted public consultation exercise. The statement pointed out that while the work of the Night Sky Brightness Monitoring Network dealt with the amount of light in thenight sky, the task force focused on tackling light nuisance and energy wastage problems caused by external lighting to residents. It said notwithstanding these different focuses, the task force and NSN had made similar observations about how switching off decorative and commercial lights at a set time reduced light nuisance and darkened the night sky. “This observation is consistent with the recommendation of the Task Force…that the requirement to switch off external lighting of decorative, promotional or advertising purposes after the preset time is the appropriate way forward for Hong Kong,” it said. Toothless guideline Friends of the Earth’s Edwin Lau called the current guidelines on external lighting “toothless” and said the only way of tackling light pollution was for the government to introduce legislation setting out the specifics to control the intensity of lights and the hours they could be illuminated. “The(current) guideless are so weak and so general. They talk about lights not being so bright but there are no real specifics on things like maximum intensity for the industry to follow,” he said “We should be looking at ways to let our city in a more equal and sustainable manner,” said Lau. “The government is responsible for providing people with the environment for them to have a good sleep. That is why the government has the noise control ordinance that limits noise after 11pm. I see no reason why it shouldn’t be the same with lighting.” Pun believes in addition to regulations, society also needs to make a commitment to stop abusing the use of outdoor lightings and to limit its adverse effects to the environment. “There is a belief that brighter is safer, brighter is better, and brighter means prosperity. But I believe this kind of thinking will soon be regarded as outdated,” said Pun. “There is all kinds of research showing brighter is not safer. For old people, bright lighting can create glare which is damaging to their sight. “I see public estates lit up with really bright lights and I cringe. Humans operate very well in a much darker settings and have been doing so perfectly well for millions of years. “I do think we can do a lot better with smarter designs and more appropriate usage of outdoor lighting so we can keep the whole city at a more reasonable night light level. “It is not a difficult thing to do.Lighting should be designed to be prudent, so it serves its purpose and is not excessive. “I hope our research will open a public dialogue about whether we need so much light.” Ironically the display on New Year’s Eve invited observers to make a wish on shooting stars fireworks which were blasted across the starless sky every 15 minutes in the hour leading up to midnight. For astronomers like Pun the wish most probably would be for less artificial light so Hong Kong could enjoy some starry starry nights. “I know we will not do any serious astronomical research in Hong Kong, because it is not the ideal place for it,” he said. “But, on the other hand, I still want the future generations to be able to appreciate the night sky. This is one of part of nature which really is available to everyone. “We appreciate all this artificial beauty but the natural beauty is there every day and we just do everything to destroy it.” The government is responsible for providing people with the environment for them to have a good sleep. That is why the government has the noise control ordinance that limits noise after 11pm. I see no reason why it shouldn’t be the same with lighting.” edwin lau director, friends of the earth I know we will not do any serious astronomical research in Hong Kong, because it is not the ideal place for it. But, on the other hand, I still want the future generations to be able to appreciate the night sky. This is one of part of nature which really is available to everyone.” dr jason pun department of physics, university of hong kong 自存倉