Illumining Hong Kong’s light pollution

Thanks for putting up with us as while our blog has been on hiatus these past two months! Char and I were settling into a new environment and we’re now writing from Hong Kong. We’re living in a relatively suburban area in New Territories, Hong Kong and one of the biggest differences from suburban Toronto is the darkness level at night. Although we overlook a small city park, we still see quite a bit of light from the neighbouring apartments. This isn’t all that surprising given the population density here (Hong Kong is one of the most densely populated countries in the world).

But aside from residential lighting, retail lighting makes up a significant huge portion of lighting sources. Even in a suburban area like the Tseung Kwan O district in New Territories, Hong Kong, retails signs for grocery stores and shopping malls are brightly lit. The signage lights combined with other artificial lighting sources like street lamps, contribute to Hong Kong’s “light pollution”.


Photo of Tseung Kwan O Olympic Stadium (Photo credit: Wikipedia user Anthony Leung-Mercutiostwin)

Light pollution

“Light pollution” refers to excessive artificial outdoor lightning which includes everything from street lights to neon signs and billboards. This light can have negative effects on humans and wildlife, whether affecting sleeping patterns or disorienting nocturnally migrating birds. The additional light brightens the night sky and making it tough for astronomers and astronomy enthusiasts to see stars and other cosmic objects.

Recently, researchers from Hong Kong Night Sky Brightness Monitoring Network (NSN) reported that the night sky between 8:30 to 11:00 pm over the Hong Kong Space Museum in Tsim Sha Tsui was on average 1000 times brighter than the international standard of dark sky (i.e. the night sky brightness level when not influenced by human made light pollution). The large number of billboards and floodlights nearby contribute to the extreme brightness of the area. Surprisingly even the Wetland Park in the remote area of Yuen Long is over 100 times brighter than the standard dark sky.

Also, the NSN team found that the 12 urban stations were on average about 10 times brighter than the other 6 rural sites. “This conclusively shows that manmade outdoor lightings is the dominant factor in determining the extent of light pollution,” said NSN’s principle investigator Dr Jason Chun Shing Pun in a recent media release.

light pollution

As you can see Hong Kong has one of the world’s most brightly lit night skies. The map was put together by researchers from the Kitamoto Asanobu/National Institute of Infomatics and represents light pollution data collected from 2010. Take a look at this interactive map to get an idea of light pollution worldwide:

Currently Hong Kong does not have any legislation to address light pollution, according to the WSJ. But the NSN believes that the light pollution data they have collected can serve as a database for HK authorities to use when assessing the need for new rules and regulations to control outdoor lighting. “In addition  to  regulations, we as a society have to make a commitment  to  stop  abusing  the  use  of  outdoor lightings, and to limit its adverse effects to the environment,” said Pun.

Canadian connection to Hong Kong’s light pollution research

The NSN uses portable Sky Quality Meters (SQM)that are imported from Canada to measure the night sky brightness. This instrument is only about the size of a deck of playing cards and can give sky brightness values instantly. The Network uses 17 SQMs at the 18 observations sites, collecting data every minute. The stations are fully automated and real time data is sent back to HKU over the city’s mobile phone network.

Canadian imported Sky Quality Meters (SQM) used by the NSN (Photo credit: HKU)

Public awareness of light pollution

There’s is increasing public awareness for the need to reduce light pollution resulting from the growing number of campaigns and outreach events. Coinciding with WWF’s Earth Hour on Saturday, The University of Hong Kong  (HKU) is hosting a Light Pollution Science Roadshow in the Avenue of Stars in Tsim Sha Tsui, on Saturday. Participants will be able to use Real-time sky brightness measurement equipment to have first hand look at Hong Kong’s light pollution. So if you happen to be in the area tomorrow, be sure to check out this event!


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