electronics Article Public Needs for Wearable Particulate Matter Devices and Their Influencing Factors Haiying Wang 1 , Lin Wang 2, *, Heechan Kang 3 , Moon-Hyon Hwang 4 , Do Gyun Lee 5 and Da Young Ju 6, *   Citation: Wang, H.; Wang, L.; Kang, H.; Hwang, M.-H.; Lee, D.G.; Ju, D.Y. Public Needs for Wearable Particulate Matter Devices and Their Influencing Factors. Electronics 2021, 10, 3069. https://doi.org/10.3390/ electronics10243069 Academic Editors: Sharnil Pandya and Hemant Ghayvat Received: 4 November 2021 Accepted: 6 December 2021 Published: 9 December 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 School of Art Design, Zhejiang A&F University, Hangzhou 311300, China; why2019@zafu.edu.cn 2 Department of Library and Information Science, Incheon National University, Incheon 22012, Korea 3 Department of Economics, Incheon National University, Incheon 22012, Korea; henrykang@inu.ac.kr 4 Division of Health & Kinesiology, Incheon National University, Incheon 22012, Korea; mhwang@inu.ac.kr 5 Department of Environmental Engineering, Incheon National University, Incheon 22012, Korea; dlee31@inu.ac.kr 6 Department of Design Science, Kookmin University, Seoul 02707, Korea * Correspondence: wanglin@inu.ac.kr (L.W.); dyju@kookmin.ac.kr (D.Y.J.) Abstract: Recently, increasing numbers of people have realized the harm that particulate matter (PM) causes to health, especially those with a diameter less than 2.5 μm (PM2.5). With the increasing popularity of wearable devices in recent years, it is believed that wearable technology can contribute feasible solutions to prevent health hazards caused by PM2.5. In order to better understand the public’s needs regarding wearable devices, this study aimed to determine what kinds of PM2.5 wearable devices were needed by the public and the factors that may influence these needs. An online survey was conducted in the Beijing metropolitan area of China of a total of 894 subjects. The results showed that the public’s overall need for wearable PM2.5 purifiers was higher than for wearable PM2.5 trackers. The public’s needs for wearable breathing-zone PM2.5 devices were significantly higher than for any other type, indicating that people care about the quality of the air they actually breathe. It was also found that education, income level, and attitude toward PM2.5 positively affected their needs for wearable devices. In contrast, age had a negative influence on their needs. The results of this study are expected to serve as a valuable reference for related academic and industrial research. Keywords: ultrafine dust; PM2.5; wearable devices; needs; influencing factors 1. Introduction Particulate matter (PM) is a major air pollutant in both indoor and outdoor environ- ments [1]. PM10 is defined as a substance less than 10 μm in diameter, called fine dust. PM2.5 is defined as a substance with a diameter of less than 2.5 μm, called ultrafine dust [2]. Ultrafine dust is a fatal substance that causes respiratory system diseases and heart-related diseases because it cannot be filtered from the respiratory system [3,4]. PM is generally recognized by the public as small substances that are difficult to identify with the naked eye and are harmful to health. Some people may experience severe rhinitis or soreness of the eyes when fine dust concentration levels are high [5]. The level of PM affects many aspects of the public’s daily lives and behavior patterns. For example, when checking daily weather forecasts, people may also check the air quality. On days with a high PM2.5 concentration, people may reduce unnecessary outings, wear masks when going out, and use air purification systems. As the public’s awareness of PM2.5 deepens, more people realize that PM2.5 concentration is not only affected by the external natural environment. Many indoor pollution sources, including many human behaviors themselves, cause the concentration of indoor PM2.5 to increase [6,7]. Recently, wearable devices have been designed to help people reduce the possible harm caused by PM2.5 to health. Wearable technology is worn in various forms such as Electronics 2021, 10, 3069. https://doi.org/10.3390/electronics10243069 https://www.mdpi.com/journal/electronics