Re ECF Project: 2007-01

Project Title: A Survey of Light Pollution in Hong Kong

Applicant: The University of Hong Kong (Dr. Chun-shing Jason PUN)

Total Approved Grant: $132,886.66 (ECF & WWGF: 50/50)

Duration: 01/11/2007 to 30/04/2009

Project Status/Remarks: Completed

Scope:
This project consists of three components:

1. night sky brightness data will be taken across Hong Kong over a one-year period using a simple and portable device called the Sky Quality Meter (SQM), around 30 groups of contributors pledged to participate in the data collection campaign;
2. a public webpage will be set up to serves both as a data input and reporting interface, and an educational resource for the general public about the issue of light pollution; and
3. the data reported by all observers will be analyzed to generate a map of the night sky brightness level in Hong Kong. The results will be released to the public through the webpage.

Summary of the Findings/Outcomes:
The survey shows that the light pollution in Hong Kong is severe - urban night skies are on average 100 times brighter than at the darkest rural sites, indicating that high population and thus high lighting densities in dense urban areas can cause severe light pollution. In the worst polluted urban areas such as Wan Chai and Mong Kok, the night sky is at least 500 times brighter than the darkest sites in Hong Kong such as eastern Sai Kung and southern Lantau Island. Moreover, later night skies (at 11:30pm) are generally darker than at earlier time (at 9:30pm), which can be attributed to some public and commercial lightings being turned off late at night. The study failed to establish any conclusive correlation of night sky brightness with different meteorological and air quality factors due to insufficient data coverage. 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.