<p>An effective method of investigating air quality, which is an important factor for human health, is monitoring rainwater quality. Consequently, it is of vital importance to compile a rainwater quality database, preferably with wet and dry depositions separately, which can then be used for future predictions as well. Changes in the composition of wet and dry depositions would lead to an understanding of the fluctuations in air quality, although such studies are limited. In this context, the study reported herein provides a trend analysis of wet and dry depositions, ion concentrations and trace metal concentrations determined through frequent sampling events at Peradeniya, Kandy District, in Sri Lanka, leading to many air quality issues. Determination of the volume-weighted average (VWA) values of 48 samples including 28 rain episodes were analyzed and VWA pH of 5.8 and VWA conductivity of 6.84 µS cm^− 1 were determined for wet depositions. The lowest recorded pH in a single rain episode was 4.77 within this period. Major ionic species present in wet precipitation samples were in the order of Na⁺ &gt; NH₄⁺ &gt; Cl⁻ &gt; SO₄²⁻ &gt; Ca²⁺ &gt; NO₃⁻ &gt; K⁺ &gt; Mg²⁺, while the order for dry deposition is Na⁺ &gt; Cl⁻ &gt; K⁺ &gt; Ca²⁺ &gt; SO₄²⁻ &gt; NH₄⁺ &gt; NO₃⁻ &gt; Mg²⁺. The neutralization of acidity of dry deposition is much more related to CaCO₃ than to NH₃. Moreover, Zn, Al and Fe were the predominant trace metals in both wet and dry depositions. Differences in air quality determined through the separate determination of wet and dry depositions would be important in determining the extent of transboundary pollution.</p> Graphical Abstract <p></p>