Abstract—Air quality is getting worse worldwide, especially in cities with high population density and many industrial parks. Raising community awareness and applying science and technology are effective ways to mitigate the negative impacts of industrialization and pollution on the natural environment as well as public health. This work presents the design and deployment of an IoT-based air quality monitoring system, named the Environmental Monitoring System (EnMoS). LoRa (Long-Range) wireless communication technology and innovation sensors being used aim to facilitate the development of data communication network over a large area, improving sensing reliability, extending battery life as well as reducing total system costs. The air quality factors such as particulate matter (PM2.5 and PM10), carbon dioxide (CO 2 ), air temperature and humidity, after being read from the sensors were uploaded to a real-time database server for Air Quality Index (AQI) calculation. In addition, for indicating conveniently obtained AQI values a web page is also developed to provide an interactive map along with corresponding charts. A case study on an actual LoRa network consisting of three sensing nodes and a gateway were conducted for validating the feasibility of the system. Index Terms—Air quality monitoring, EnMoS, internet of things, LoRa technology. I. INTRODUCTION Climate change has been causing significant impacts on people’s living conditions, stability, and socio-economic development status in the Lower Mekong River Basin day by day. Besides, due to population growth, the rapid increase of industrialization, as well as indiscriminate use of chemical fertilizers and pesticides in agriculture, are causing serious impacts on the environment, climate, and public health. Air quality is getting worse noticeably, especially in urban areas where high population density and many industrial parks. World Health Organization (WHO) announced that there are approximately 4.2 million premature deaths globally are linked to ambient air pollution [1]. Air Quality Index is a metric to assess how polluted the air is. Recently, air pollution levels in Hanoi and Ho Chi Minh City have reached alarming levels [2]. According to Vietnam's AQI ranking (see Table I), the index reaches a threshold of over 150 Manuscript received June 17, 2020; revised February 5, 2021. This work was supported in part by the Can Tho University, Vietnam, and the Undergrad Research Initiative (URI) Research Symposium, BUILD-IT project. Tuyen Phong Truong, Duy Thanh Nguyen, and Phong Vu Truong are with the Department of Electronics and Telecommunication Engineering, College of Engineering Technology, Can Tho University, Can Tho, 900000, Vietnam (e-mail: tptuyen@ctu.edu.vn, duyb1609696@student.ctu.edu.vn, phongb1609733@student.ctu.edu.vn). indicating that air quality is harmful to health. In order to mitigate the negative impacts of industrialization and pollution on both the environment and public health, growing community consciousness and applying science and technology is one of the sustainable solutions. Many environmental monitoring applications based on the Internet of Things (IoT) have been applied successfully in many countries. These projects were employed short-range communications, for example, Zigbee, Wi-Fi, for implementing real-time air quality, both indoor and outdoor, monitoring systems [3][7]. With the rapid development of integrated electronic devices and communication technologies (such as low power long-distance wireless communication technology) which allows deploying the distributed sensing systems on a wide-area and reducing maintenance costs as well [8]. Consequently, the objective of this research is to develop large-scale environmental monitoring by adopting IoT-based systems with the advantages of long-distance wireless communication and innovative sensor technology. A lot of research on air quality has been conducted to reflect the current state of air quality in Vietnam. The scientists used high-resolution satellite images in combination with ground-based meters to calibrate the values in order to observe a large area [9]. The research also focuses on analyzing the factors that affect air pollution and their harm to public health, particularly vulnerable groups due to environmental change [10], [11]. Apart from monitoring AQI values recognized by governments, the research directions seek to identify areas with a high risk of air pollution or other pollutant compounds [12], [13]. Nevertheless, most of the researchers worked on the existing data collection systems instead of developing air quality index monitoring systems themselves. In Vietnam, most air quality monitoring systems were located in major cities with a high cost of implementation and operation [14]. For example, until now only Hanoi has an automatic air quality monitoring system managed by the Vietnamese government [15], [16]. The implementation of air quality monitoring systems is essential for areas that are at high risk of air pollution, directly affecting human health such as industrial parks, production complexes, university laboratory complexes, and so on. The goal of this study is to design and implement an affordable air quality monitoring systems in areas with several kilometers radius. The monitoring AQI values are reported on a public website for the purposes of early warning and preventive action. In Fig. 1, on the right, it is a LoRa star network consisting of a gateway and three sensing nodes. LoRa SX1276 modules manufactured by Modtronix were used in order to Design and Deployment of an IoT-Based Air Quality Monitoring System Tuyen Phong Truong, Duy Thanh Nguyen, and Phong Vu Truong International Journal of Environmental Science and Development, Vol. 12, No. 5, May 2021 139 doi: 10.18178/ijesd.2021.12.5.1331