Precipitation Influence on Air Quality: Unraveling the Air Quality Index-Rainfall Dynamics

Air pollution remains an environmental challenge in Baghdad, driven by rapid urbanization, industrial emissions, and vehicular exhaust, resulting in persistently poor air quality. Although it has been globally demonstrated that precipitation enhances air quality through wet deposition, the dynamics of the role of rainfall in the Air Quality Index (AQI) of Baghdad in its arid climate are not thoroughly researched. This study examines precipitation properties and AQI variations in Baghdad between ۲۰۱۹ and ۲۰۲۴, using historical AQI data from the U.S. Embassy monitoring station and meteorological data from NASA. The research method combines statistical data analysis of pollutant levels (PM۲.۵, PM۱۰, SO۲, NO۲, O۳) and correlation analysis of rainfall levels and changes in AQI. Findings indicate that when rainfall exceeds ۱۰ mm, it can lower the AQI by ۱۰-۳۰% due to the removal of PM۲.۵ and PM۱۰ through wet deposition. Light precipitation (<۵ mm) temporarily raises PM۱۰ levels because particles are mobilized, followed by a subsequent improvement. Seasonal analysis indicates that winter rainfall with higher wind speeds is more effective in improving AQI compared with summer dust storms, which sustain hazardous AQI levels (>۱۵۰). These results can be empirically used to support the inclusion of rainfall patterns in pollution reduction measures in Baghdad. Air quality in dry cities should be managed in a manner specific to their climate.

کلیدواژه ها:

Air Quality Index (AQI) ، PM۲.۵ ، Precipitation ، Rainfall ، Seasonal air quality variation