An electromagnetic interference (EMI)-free wide-range indoor dust monitoring system that employs the optical orthogonal frequency-division multiplexing (OFDM)-based visible-light communication (VLC) is proposed. For the long-term transmission of dust information, VLC can be utilized even in EMI-restricted areas, such as medical centers, emergency rooms, and nursing homes. Discrete cosine transform-based optical OFDM is adopted to transmit a large amount of dust information. For robust light detection from eliminate ambient light and low-frequency noise, an average voltage-tracking technique is utilized and as a result LED illumination is detected over 18 m distance with reliable error rate. Wide-range dust information from multiple dust sensors are clearly displayed through the designed user interface. Users can then monitor the air quality in real-time, improving the environmental awareness of individuals.