Significant environmental and climatic challenges are being faced worldwide due to increasing urbanization, extensive traffic and industrial development. The rising levels of vehicular emissions and industrial waste have led to concerning levels of air pollution, which significantly impact public health including respiratory conditions. Given that air pollutants are often imperceptible to the naked eye, there is a critical need for an efficient and reliable monitoring system to assess air quality in real-time. To contribute to the efforts being performed for mitigating pollution drastic consequences, the current paper focuses on the following primary objectives. First, design and implement a cost-effective IoT-enabled air quality monitoring system. Second, establish a reliable wireless sensor network using Long-Range (LoRa) technology for extended coverage. Third, develop an interface for data visualization in real time, and finally, validate the system’s effectiveness in both indoor and outdoor environments over crowded areas. This research presents several novel contributions, including the integration of low-cost sensors with LoRa technology for enhanced range and reliability, the development of an energy-efficient monitoring solution, and the implementation of a scalable architecture suitable for dense urban environments. The system comprises multiple sensor nodes, each equipped with a microcontroller, LoRa communication module, and an array of environmental sensors that measure key parameters including temperature, humidity, air quality index, particulate matter, and harmful gas concentrations. These smart nodes transmit data to an IoT platform (ThingSpeak), which processes and shows them through an intuitive, user-friendly dashboard featuring real-time visualization of air quality metrics. Although this study is an early-stage investigation of the feasibility of the expected monitoring system, its initial deployment in a crowded city (Jeddah, Saudi Arabia) results indicate reliable performance in various environmental conditions, making it a promising solution for urban air quality monitoring. This research contributes to the development of sustainable smart city infrastructure and public health management systems in Jeddah and may be extended to larger urban environments, while offering a cost-effective alternative to existing expensive monitoring solutions. The system’s adaptability and scalability make it especially valuable for developing regions seeking to implement comprehensive environmental monitoring systems.