NanoWatch: A Real-Time IoT-Integrated Nanoparticle Pollution Monitoring System

Nanoparticles are widely used in industrial, pharmaceutical, and consumer applications, raising concerns about their environmental accumulation and associated health risks.Current detection methods, including electron microscopy and dynamic light scattering (DLS), are costly, laboratory-bound, and unable to perform real-time environmental monitoring. This study introduces NanoWatch, a portable, IoT-integrated static light scattering (SLS) device designed to monitor nanoparticle pollution in air and water in real-time. NanoWatch employs two distinct sampling methods. Airborne nanoparticles are captured by bubbling ambient air through a cuvette containing a 70:30 ethanol-water solution, effectively trapping nanoparticles within minutes. Water samples are directly analyzed using batch-based sampling. The device utilizes a 532 nm laser, photomultiplier tube (PMT), and an Arduino-controlled stepper motor to perform multi-angle scattering analysis. Real-time nanoparticle concentration data is transmitted via an ESP8266 IoT module to a cloud dashboard, enabling continuous remote monitoring and automated pollution alerts. Experimental results demonstrated successful detection of nanoparticles (10-100 ppm), with scattering intensity closely aligning with theoretical predictions. The system offers repeatable, near-instantaneous environmental analysis with minimal waste generation, making it scalable for largescale applications. This study confirms the effectiveness of a low-cost, field-deployable monitoring solution. Future enhancements will focus on automating the sampling process for fully continuous operation, improving sensitivity for ultrafine nanoparticles (<10 nm), and further extending its environmental applications.