Abstract

The construction industry is always ranked as one of the largest emission contributors of air pollutants including nitrogen oxides (NOx), carbon oxides (CO), volatile organic compounds (VOCs), and sulfur oxides (SOx), which accounts for approximate 23% of the global air pollutions each year. These pollutants are detrimental to the ambient air quality and the health and safety of construction practitioners. The high pollutant emission level has attracted the government’s interests to release regulations and initiatives to reduce the air pollutant emissions of construction projects. Also, construction practitioners and researchers are encouraged to mitigate the environmental impacts during the construction process. So far, most of the mitigation efforts have been placed on pre-assessing the environmental impacts of construction activities in the planning stage using emission estimation models. The emission estimation models were developed based on the emission rate analysis of the uninstalled engines in the laboratory environment. Therefore, the estimation models are not able to reflect the real-world emission rates, especially the emission rates of different working modes. In addition, the Portable Emissions Measurement System (PEMS) is employed to monitor the air pollutant emissions of the operating equipment in the construction stage. However, the costly expenses and the particular precautions when using the PEMS to monitor the air pollutant emissions significantly impede the utilization of PEMS. Also, it is impossible to install PEMS to each piece of construction equipment for the air pollutant emission monitoring of the whole construction projects.
The main objective of this research is to develop a set of tools to monitor and visualize the air pollutant emission on construction sites in the real-time and automatic manner. Towards this objective, an Internet of Things (IoT)-based system is created with the integration of microcontrollers, microsensors, and high-definition (HD) cameras. Specifically, the system can be employed to: 1) monitor the onsite air pollutant emissions during construction operations in an automatic and real-time manner; 2) dynamically and continuously visualize the air pollutant emission; 3) automatically trigger alarms when the air pollutant emissions violate the standards; and 4) quantitatively assess the potential impacts on ambient air quality and the health of workforces. The system has been tested on real construction sites. The results indicated that the system could assist construction practitioners in the monitoring and visualization of the air pollutants produced from construction operations. Also, the results are able to facilitate decision-making on reducing the air pollutant emissions and promote the sustainability of construction operations.