###### Abstract
All the acquired data of TVOC, IAQ index and IAQ level, as well as ambient temperature and humidity, were sent to the IoT-cloud system through a WeMoS D1 Mini Wi-Fi module and Wi-Fi network. Recently, some commercialized environment-monitoring devices have become available online. For example, [PERSON] adopted a commercially available PIM485 with Enviro+ for Raspberry Pi to implement a citizen-centric environment-monitoring IoT system [17]. A BME280 (temperature, pressure, humidity) sensor, LTR-559 (light and proximity) sensor, MICS6814 analog gas sensor, and MEMS microphone were well built in the Enviro+ for Raspberry Pi and a connector for a PM sensor and an SCL/SDA interface to connect additional sensors with the standard I\({}^{2}\)C protocol were designed as well. In addition, the SV11 environmental sensor device in Verkada was commercialized and connected to the cloud-based Command platform through a power over Ethernet (PoE) protocol [18]. However, the Enviro+ for the Raspberry Pi platform and Verkada's SV11 environmental sensor module aggregating the VOC sensor, PM sensor, motion detection sensor, temperature/humidity sensor, and noise sensor were not cost-effective in a large-scale implementation. To our best knowledge, heterogeneous integration for diverse sensors for monitoring environmental conditions on a campus, especially in classrooms, can be cost-effectively designed using a commercially available Wi-Fi module and existing Wi-Fi communication network. This motivates us to develop a DYU Air Box to monitor the learning environment conditions in classrooms at Da-Yeh University, Taiwan using the public ThingSpeak IoT platform. Da-Yeh University was ranked 55 out of 1183 entries by the UI GreenMetric World University Ranking which is a ranking of green campuses and environmental sustainability [19]. The proposed DYU Air Box integrates heterogeneous environmental sensors for learning environments including indoor air quality (IAQ) with AQI value/level, PM\({}_{1.0}\)/PM\({}_{2.5}\) and CO\({}_{2}\) concentration, as well as illumination, ambient temperature and relative humidity (RH), in order to reach the goals of environmental, social, and corporate governance (ESG) for all stakeholders including the students, faculty, and staff on campus as well as other stakeholders such as the alumni and students' parents. The features are compared with the above publications and tabulated in Table 1. Therefore, the research aims of this work are to simply implement the proposed DYU Air Box on the DYU campus, cooperating with the existing DYU-802.1X campus network and openly provide the environmental information of the DYU campus on the public ThingSpeak IoT platform for all stakeholders. Table 1 reveals that only the proposed wireless environment-monitoring IoT system includes the accessibility of the public ThingSpeak IoT platform through the existing DYU-802.1X Wi-Fi communication network with Wi-Fi Protected Access 2 (WPA2) Enterprise security. The work is aimed to facilitate the environment-monitoring IoT system of the proposed DYU Air Box and the DYU-802.1X campus Wi-Fi network on the DYU campus to publicly share the environmental information on the ThingSpeak IoT platform for all stakeholders according to their interests. This will positively promote the international ESG impression of DYU. The main contributions of this paper include two aspects: (1) to address the wireless DYU Air Box with multiple environment-monitoring sensors using an ESP32 Wi-Fi device, which is more cost-effective than the two commercially available ones above; (2) to send the acquired data to the public ThingSpeak IoT platform through the DYU-802.1X communication network with WPA2 Enterprise security. The remainder of this paper is organized as follows. First, the system design and the related theory are described in Section 2. Section 3 illustrates the implementation of the wireless DYU Air Box and the visualization of the multi-sensor EMIoT system on the public Thing5 peak IoT platform.