Noise & Health, November-December 2014, Volume 16:73, 368-373 368 Introduction The restaurant industry employs a large number of people worldwide. The US National Restaurant Association reported that the restaurant industry grows rapidly and employs around 13 million Americans in a million locations, about 10% of the US workforce. [1] It also estimated that the restaurant trade is expected to reach US$ 660.5 billion sales in 2013. In the UK, the number of caterers including restaurants, cafes, and canteens was 0.43 million, employed 1.6 million people, and contributed GBP 25.2 billion to national gross valued added in 2011. [2] In Hong Kong, the restaurant industry does not only serve 7.1 million local customers. The restaurant industry also plays an important role to support the tourism industry because Hong Kong attracts >42 million visitors each year. According to the statistics provided by the Hong Kong Census and Statistics Department, [3] sales and other receipts in the food services trade amounted to HK$ 101.4 million in 2010, increasing by 6.9% from 2009. In that year, there were 13,910 food services establishments. About 5080 of them were Chinese restaurants, 1143 were fast food restaurants, and 7687 were other food services establishments including a wide variety of western and exotic food restaurants. In total, these food services establishments employed 238,276 people; that is, 7.4% of the total number of employees in Hong Kong. A signifcant portion of restaurant employees needs to work for over 8 h a day. They are exposed to a wide range of occupational hazards such as cuts, burns, sprains and strains, slips and falls, [4-6] second-hand smoke, [7-9] and air pollutants including cleaning chemicals and emissions from cooking fume. [10-14] In addition, service employees are exposed to high noise levels during peak hours in the morning, during the lunch time, and in the evening hours that may affect psychological and physiological well-being. Unfortunately, the extant literature of noise primarily focused on industrial and environmental noise. [15-18] While in the indoor environment such as restaurants, researchers primarily focused on indoor air quality, ventilation, thermal comfort, and lighting. [10,19-23] In this paper, a mathematical model that describes the noise in restaurants is presented. Noise measurements, geometrical, and operational parameters were recorded in different types of restaurants during peak hours. In doing so, this study provides answers to the following research questions: Noise in restaurants: Levels and mathematical model Wai Ming To, Andy W. L. Chung 1 Macao Polytechnic Institute, School of Business, Rua de Luis Gonzaga Gomes, Macao SAR, 1 EDMS (Hong Kong) Ltd., Department of Environmental Science, Central, Hong Kong SAR, People’s Republic of China Abstract Noise affects the dining atmosphere and is an occupational hazard to restaurant service employees worldwide. This paper examines the levels of noise in dining areas during peak hours in different types of restaurants in Hong Kong SAR, China. A mathematical model that describes the noise level in a restaurant is presented. The 1-h equivalent continuous noise level (L eq,1-h ) was measured using a Type-1 precision integral sound level meter while the occupancy density, the foor area of the dining area, and the ceiling height of each of the surveyed restaurants were recorded. It was found that the measured noise levels using L eq,1-h ranged from 67.6 to 79.3 dBA in Chinese restaurants, from 69.1 to 79.1 dBA in fast food restaurants, and from 66.7 to 82.6 dBA in Western restaurants. Results of the analysis of variance show that there were no signifcant differences between means of the measured noise levels among different types of restaurants. A stepwise multiple regression analysis was employed to determine the relationships between geometrical and operational parameters and the measured noise levels. Results of the regression analysis show that the measured noise levels depended on the levels of occupancy density only. By reconciling the measured noise levels and the mathematical model, it was found that people in restaurants increased their voice levels when the occupancy density increased. Nevertheless, the maximum measured hourly noise level indicated that the noise exposure experienced by restaurant service employees was below the regulated daily noise exposure value level of 85 dBA. Keywords: Indoor noise levels, occupational exposure, restaurants Access this article online Quick Response Code: Website: www.noiseandhealth.org DOI: 10.4103/1463-1741.144412 PubMed ID: ***