Air Quality Monitoring System ER diagram models a multi-table relational schema for tracking pollution and weather data across distributed monitoring stations. Users table links to Stations, which connect to Pollution Data, Weather Data, Model Predictions, and Alerts tables through foreign key relationships. The schema captures real-time sensor readings, meteorological conditions, predictive model outputs, and threshold-based alert triggers for air quality exceedances. Fork this diagram on Diagrams.so to customize station hierarchies, add alert escalation rules, or extend with data quality metrics. This normalized structure supports both operational dashboards and historical analysis for environmental compliance and public health monitoring.