Night-sky brightness monitoring in Hong Kong
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Results of the first comprehensive light pollution survey in Hong Kong are presented. The night-sky brightness was measured and monitored around the city using a portable light-sensing device called the Sky Quality Meter over a 15-month period beginning in March 2008. A total of 1,957 data sets were taken at 199 distinct locations, including urban and rural sites covering all 18 Administrative Districts of Hong Kong. The survey shows that the environmental light pollution problem in Hong Kong is severe—the urban night skies (sky brightness at 15.0 mag arcsec − 2) are on average ~ 100 times brighter than at the darkest rural sites (20.1 mag arcsec − 2), indicating that the high lighting densities in the densely populated residential and commercial areas lead to light pollution. In the worst polluted urban location studied, the night-sky at 13.2 mag arcsec − 2 can be over 500 times brighter than the darkest sites in Hong Kong. The observed night-sky brightness is found to be affected by human factors such as land utilization and population density of the observation sites, together with meteorological and/or environmental factors. Moreover, earlier night skies (at 9:30 p.m. local time) are generally brighter than later time (at 11:30 p.m.), which can be attributed to some public and commercial lightings being turned off later at night. On the other hand, no concrete relationship between the observed sky brightness and air pollutant concentrations could be established with the limited survey sampling. Results from this survey will serve as an important database for the public to assess whether new rules and regulations are necessary to control the use of outdoor lightings in Hong Kong.
KeywordsAir pollutant concentration Environmental assessment Environmental monitoring Light pollution Night-sky brightness Pollution risk
- Blask, D. E., Brainard, G. C., Dauchy, R. T., Hanifin, J. P., Davidson, L. K., Krause, J. A., et al. (2005). Melatonin-depleted blood from premenopausal women exposed to light at night stimulates growth of human breast cancer xenografts in nude rats. Cancer Research, 65, 11,174–11,184.CrossRefGoogle Scholar
- Cinzano, P. (2005) Night Sky Photometry with Sky Quality Meter. Available at: http://www.lightpollution.it/download/sqmreport.pdf. Accessed 29 August 2010.
- Garstang, R. H. (2004). Mount Wilson observatory: The sad story of light pollution. The Observatory, 124, 14–21.Google Scholar
- IDA (1994). Terminology and Units in Lighting and Astronomy. Available at: http://data.nextrionet.com/site/idsa/Archive%20IS099.pdf. Accessed 29 August 2010.
- IDA (2010). International Dark-Sky Association. http://www.darksky.org. Accessed 29 August 2010.
- Marín, C., Jafari, J. (eds) (2007). Starlight: A Common Heritage, Proceedings of the International Conference in Defence of the Quality of the Night Sky and the Right to Observe the Stars. International Initiative in Defence of the Quality of the Night Sky and the Right to Observe the Stars, Starlight Initiative Instituto De Astrofisica De Canarias (IAC).Google Scholar
- Massey, P., & Foltz, C. B. (2000). The spectrum of the night sky over Mount Hopkins and Kitt Peak: Changes after a decade. Publications of the Astronomical Society of the Pacific, 112, 556–573.Google Scholar
- McKinney, M. L., Schoch, R. M., & Yonavjak, L. (2007). Environmental science: Systems and solutions. Sudbury: Jones & Bartlett Publishers.Google Scholar
- Ogden, L. J. E. (1996). Collision Course: The Hazards of Lighted Structures and Windows to Migrating Birds. World Wildlife Fund Canada and the Fatal Light Awareness Program.Google Scholar
- Paulin, D. (2001) Full Cutoff Lighting: The Benefits. http://www.iesna.org/PDF/FullCutoffLighting.pdf. Accessed 29 August 2010.
- Roach, F. E., & Gordon, J. L. (1973). The light of the night sky. Dordrecht, Boston: Reidel.Google Scholar
- Smith, F. (1979). Report and Recommendations of IAU commission 50. Reports on Astronomy, Transactions of the International Astronomical Union, 17A, 22.Google Scholar
- Stalin, C. S., Hegde, M., Sahu, D. K., Parihar, P. S., Anupama, G. C., Bhatt, B. C., et al. (2008). Night sky at the Indian Astronomical Observatory during 2000–2008. Bulletin of the Astronomical Society of India, 36, 111–127.Google Scholar
- Unihedron (2007). Sky Quality Meter - L. http://www.unihedron.com/projects/sqm-l/. Accessed 29 August 2010.
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