Daily Variations In Wet Deposition And Washout Rates Of Potentially Toxic Elements In Moscow During Spring Season

Dmitry V Vlasov,Irina D Eremina,Nikolay S Kasimov,Galina L Shinkareva,Natalia E Chubarova

doi:10.24057/2071-9388-2020-162

Dmitry V Vlasov, Irina D Eremina + Show 3 more

Open Access

https://doi.org/10.24057/2071-9388-2020-162

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Abstract

For the first time, the wet deposition and washout rates of soluble forms of potentially toxic elements (PTEs) were estimated in rains during the spring AeroRadCity experiment in Moscow. Rains are an important factor in reducing atmospheric pollution with PTEs in Moscow. Due to the resuspension of contaminated particles of road dust and urban soils, industrial and traffic impact, waste and biomass burning, rainwater is highly enriched in Sb, Pb, Se, Cd, and S, and less enriched in P, Ba, As, W, Mn, Sn, Na, Co, Ni, and Be. Significant wet deposition (μg/m2 per event) and washout rates (μg/m2 per hour) of PTEs were revealed during the public holidays in May which corresponded to the elevated aerosol content due to predominant air advection from southern and south-western regions in this period. During continuous rains, the level of PTEs wet deposition sharply decreases on the second and subsequent days due to the active below-cloud washout of aerosols during the initial precipitation events. We show that the length of the dry period and aerosol content before the onset of rain determines the amount of solid particles in rainwater, which leads to an increase in rainwater pH, and strongly affects wet deposition and washout rates of PTEs of mainly anthropogenic origin (W, Zn, Bi, Cd, Sb, Ni, B, S, K, and Cu). At the same time rainfall intensity contributes to an increase in wet deposition and washout rates of Se, As, B, Cu, Sb, S, Cd, Ba, Rb, and K. The obtained results provide a better understanding of atmospheric deposition processes and can be useful in assessing the urban environmental quality.

Highlights

The study of the chemical composition of atmospheric precipitation makes it possible to assess the washout rates of potentially toxic elements (PTEs), particulate matter, organic pollutants and ions from the atmosphere and to evaluate wet deposition fluxes on the Earth’s surface (Al-Momani 2008; Cizmecioglu and Muezzinoglu 2008; Bayramoğlu Karşı et al 2018; Talovskaya et al 2018, 2019; Ma et al 2019; Tian et al 2020; Cherednichenko et al 2020; Park et al 2020; LoyaGonzález et al 2020; McHale et al 2021)
The elemental composition of atmospheric precipitation has been studied in detail in many cities around the world
The duration of precipitation varied from short-term rains on April 6–7 and 21, May 2, 4 and 5–6 to 17 hours on May 18–19, and even 25 hours on April 17–18, the rain intensity varied from 0.2 L/m2 per hour to 2.9 L/m2 per hour depending on the event (Fig. 2)

Summary

Introduction

The study of the chemical composition of atmospheric precipitation makes it possible to assess the washout rates of potentially toxic elements (PTEs), particulate matter, organic pollutants and ions (such as sulfates, nitrates, ammonium, etc.) from the atmosphere and to evaluate wet deposition fluxes on the Earth’s surface (Al-Momani 2008; Cizmecioglu and Muezzinoglu 2008; Bayramoğlu Karşı et al 2018; Talovskaya et al 2018, 2019; Ma et al 2019; Tian et al 2020; Cherednichenko et al 2020; Park et al 2020; LoyaGonzález et al 2020; McHale et al 2021). Wet deposition compared to dry one is more efficient in removing PTEs from the atmosphere and causes higher pollutants input into terrestrial or aquatic systems (Ouyang et al 2015). In Moscow – the largest megacity in Europe – complex meteorological observations are being carried out since the mid-1950s (Chubarova et al 2014)

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