<p>Wet deposition is a component of the global cycle of different elements through which dissolved and suspended pollutants from the atmosphere can enter terrestrial and aquatic ecosystems. Moreover, with water scarcity and environmental pollution increasing, the need to protect rainwater quality is becoming increasingly of concern. This paper presents the results of an investigation into the concentrations of some nutrients (nitrogen, phosphorus, and silica) in 240 rainwater samples collected in 27 inner and suburban districts of Hanoi city in both the rainy and dry seasons during the period 2023 to 2025. The results showed very high variations of nitrate, nitrite, ammonium, total nitrogen, phosphate, total phosphorus, and dissolved silica (DSi) concentrations in rainwater samples in Hanoi city. Higher values in the dry season than in the rainy season were observed for nitrogen and DSi at most sites. The results show that rainwater quality in Hanoi city has been strongly affected by increasing population and urbanisation, notably from fossil fuel combustion from high vehicule densities, especially in inner-city districts in the dry and early rainy season. Regarding environmental factors, rainfall intensity has played an important role in reducing nutrient levels in rainwater in Hanoi city. The results are of significance and provide a scientific basis for policies that concern the protection of air quality in Hanoi city, as well as in other large cities in the Asian developing countries.</p>