The main tasks of this project include, the flicker evaluations of light pollution sources, the monitoring methods of light pollution source and the petition case counselings, and the international regulations on light pollution and the proposed study of light pollution management.
The following conclusions and recommendations can be drawn upon the completion of above-mentioned tasks.
A total of 8 light sources in 3 areas, which located in Taipei City and New Taipei City were included in the outdoor human perception experiment. were completed, A total of 160 people were evaluated and 320 data entries (glare/flicker) were compiled.
For the flicker evaluations, a negative linear correlation was found between the flicker frequency intensity and the average subjective flicker evaluation for the locations where vertical illuminance were over 25 lx, i.e., it means the higher measured flicker frequency intensity , but no correlation was found for the location where vertical illuminance is less than 25 lx. However, for the management of flicker in the LED combined lights in practice, the recommendation is to select the glare luminance as the reference for the petition of light pollution, and to manage with the maximum luminance exposure in the Guide for the light pollution management (draft).
For the light pollution monitorings, three routes near the light pollution sources in Taipei City and in New Taipei City were evaluated. More than 18,000 measurements for the horizontal illuminance, frontal vertical illuminance, left-side vertical illuminance, right-side vertical illuminance, respectively. More than 17,000 measurements were performed for frontal image the average luminance. For the three routes after 10 pm, the overall average vertical illuminance shows a declining trend. In other words, there is a conspicuous declining trend for the illumination.
For the differentiation analysis of the petition cases, a total of 1,256 petition cases in 22 counties/cities from 2016 to June 2019 were tabulated. Most petitions occurred in metropolitan areas, i.e., the 6 municipalities, Keelung City, Hsinchu County, Hsinchu City, Chiayi City. The sources of light pollution can be categorized as advertisements, non-advertisements, and reflections. The advertisements accounted for the largest share of petitions(70 %).
For the petitions and counsellings of light pollution, the counselling and improvement recommendations in the categories of reflection, LED billboard, and slideshow LED lights were completed. With regard to the improvements in the reflection category, the recommendation was to use matte and dark materials on the reflection area. For the improvements of LED light source category, the recommendation was to reduce the maximum luminance of the light source as well as to adjust the irradiation duration.
For the status of the international regulations on light pollution, four abstracts, one for the American NCSL, one for the recommended standard of China, one for European EMPIR, and one for European JRC, were completed. With regard to the light source management policy, the ‘Guide for light pollution management (draft)’ is recommended to set regulations suitable for each location in countries/cities. It is recommended to manage the glare impacts of artificial light source with luminance management, and to manage the light pollution from street lamps with the vertical illumination. For the improvements of light source, the ‘Guide for light pollution management (draft)’ is recommended for the protection and improvement. With regard to the related administrative works of ‘Guide for light pollution management (draft)’, 3 seminars were completed.