This research investigates the impact of major pollutants (CO, NO2, and SO2) on acid rain production and their relationship with intense precipitation events in the Metropolitan District of Quito (DMQ). Air quality parameters, including pH, temperature, conductivity, and total dissolved solids, were analyzed through bi-daily (7 am and 7 pm) samplings conducted between October 2022 and March 2023. Samples were collected in southern Quito and Los Chillos Valley, locations selected for their proximity to local meteorological and air quality REMMAQ stations. Using data of rainfall events and pollutant levels, quality control and statistical analysis were performed to establish correlations between acid rain and the identified pollutants and rainfall. The results indicate a negative correlation between pH and temperature, as well as between pH and pollutant levels, and intense rainfall. Additionally, the highest pH values (indicating alkalinity) were attributed to volcanic ash emissions in October 2022. The most acidic pH values recorded were 4.53 in the southern zone and 4.77 in the valley region, while the most alkaline values reached 8.11 and 8.56, respectively. These measurements confirm the occasional occurrence of both acidic and basic rain events in the southern areas of Quito.