Based on the domestic conditions of Taiwan, this project aims to investigate and analyze the impacts of statutory nuisance from artificial light and related measurement factors, and then to propose the related tactics and recommendations. Through survey of the relevant regulations and scientific literatures and collection of pleader cases. This research focuses on both perception of glare and flicker for LED combo lamp light sources and LED multimedia light sources. The main tasks include: (1) made summary and translation of literatures related to light pollution, (2) study on the borderline between comfort and discomfort (BCD) of human perception and cognitions of LED combo light sources in laboratory, and LED billboard in outdoor environment, to perform subjective evaluation of glare and flicker at night condition, (3) case study of the background luminance and illumination level impacts on measuring resultants, and (4) proposal of prevention and management program of light pollution according to the international regulations and domestic status.
First, this study made summary and translation of 4 literatures. Second, this work conducted 159 measures of static luminance and 53 measures of time-varied illuminance for the selected 3 LED combo light sources and 2 LED multimedia light sources, through Fast Fourier Transform (FFT) of the time-varied illuminance of the light sources to analyze the frequency response. Third, the experiments have conducted for BCD of light pollution in laboratory. The questionnaire included the maximum glare and the maximum flicker. The independent variables included 3 luminance levels of LED, and 52 patterns and one video. There were 20 participants involved and total of 3,180 data were recorded. Results revealed that:
1) For the perceived maximum glare and perceived maximum flicker, four main effects of luminance of LED light sources, pattern/video type, age and gender were significant, respectively. The luminance level of LED light sources and pattern/video type were more important.
2) Due to the maximum luminance for single packaged of LED combo light sources are highly related to subjective glare score (R2=0.89), and the mean vertical illuminance for LED multimedia light source are highly related to subjective glare score (R2=0.93) as well. This study develops a glare prediction model and lists a luminance recommendation table of glare for LED combo light sources and LED multimedia light sources.
3) Comparing with the previous study, the cycle or frequency of playing patterns were significant for discomfort flicker evaluation (R2=0.62). To those frequency below 0.7 Hz, average scores of oveall paticipants are above the acceptable level. However, it is insufficient to develop a flicker prediction model due to the lack of feasible measurable frequency characteristics factors.
Meanwhile, the real-time luminance measures and BCDs of outdoor LED billboards have been conducted at four regions in Taichung city. The mean luminance of each LED billboard is 616.2 cd/m², 818.9 cd/m², 1,220.6 cd/m² and 145 cd/m², respectively. There are 461 participants to take part in this survey and totally 1,385 data to be collected. There are 686 males (50.5 %) and 672 females (49.5 %) that are counted for the evaluation of subjective comfortable rating. There are four groups of age distinctions to be considered in this study. The results indicated that the average de Bore scores of glare in 4 places are range from 3.68 to 4.36. In other words, the feelings of participants are tended to uncomfortable between disturbing and satisfactory categories. In addition, the average ratings of flicker scores in 4 places are falling in the range of 3.33 to 4.54. It indicates the similar results with the previous uncomfortable range of glare.
The 90th percentile per minute of flicker magnitude measurement of four each LED billboards showed that those values were less than the recommended value between 31 and 33 in previous study. In term of discomfort flicker, the perceived flicker of four LED billboards should are acceptable. However, the overall mean scores of flicker subjective evaluation of four LED billboards were fallen into disturbing and satisfactory ranks. Comprehensive comparisons of the LED billboards flicker magnitude measures and field survey data indicated that people’s response of flicker resulted from LED billboards were stronger than participants in a well controllable laboratory environment.
Meanwhile, this study conducted a total of 4 case studies of monitoring the luminance of LED billboards, vertical and horizontal illuminance in Taichung metropolitan area. In addition, this research collected a total of 560 petition cases from 14 cities and counties, there was none of case related to road accident. In accordance with the analysis of light pollution sources, 5 % (27 cases) related to sunlight reflection of glass or exterior wall, 41 % (228 cases) related to LED advertising category, 17 % (94 cases) related to non-LED advertising category, and 38 % (211 cases) accounted for other light sources(non-advertising category). In accordance with the analysis of human annoy perception, 67 % (374 cases) petitions denote the light source is too bright, 3 % (18 cases) petitions denote the light source is too flickering, 25 % (138 cases) petitions denote the light source is too bright and flickering, and 5 % (30 cases) petitions cannot be classified in category. In accordance with the public impact scenario analysis, 13 % (75 cases) petitions indicate the light source that may affect driving safety, 52 % (288 cases) indicate the light source affect lifestyle or home sleep, 35 % (197 cases) petitions cannot be classified in category. There are different ratios of four petition light source categories between Taipei city and Tainan city, this result shows difference of petition sources still exist between the cities.
This research proposed a draft of luminance measuring method, a draft of vertical illuminance measuring method for dynamic light sources. In addition, there were divided into different stages to practice the prevention strategies of light pollution in accordance with urgency, feasibility and technical completeness based on domestic status and results in this study. Final, one control plant was suggested for the prevent control and management of light pollution.