Determination of deposition rates of organic nitrate compounds to soil and plant leaves using the dynamic chamber method

Abstract

Organic nitrates, including peroxy nitrates (RO2NO2) and alkyl nitrates (RONO2), are formed in the atmosphere by the reaction of NOx with oxidation products of volatile organic compounds (VOCs). They comprise up to 20% of all oxidized forms of nitrogen (NOz) and, once formed, can be transported by the winds, undergo chemistry, be incorporated into aerosol or be deposited to the Earth's surface. Deposition rates and foliar uptake of inorganic nitrogen (NO2, NH3), and more recently, nitrous acid (HONO) and peroxyacetyl nitrate (PAN) to soil and plants has been reported. However, so far, information is lacking regarding deposition of organic nitrates. The deposition through foliar uptake of atmospheric nitrogen compounds by plants could represent a major contribution of global atmospheric inputs of nitrogen into the ecosystems, once it consists in a direct addition of nitrogen to plant metabolism and could potentially more readily influence plant growth compared to soil deposited nitrogen. In this way, this project proposes to investigate the deposition and foliar uptake of organic nitrates compounds to different types of soil and plants, using a dynamic chamber method, under controlled environment conditions. The chambers were developed at the Max-Planck Institute for Chemistry and their performance was described in previous works of the Institute. This work is essential to i. improve the understanding about the impact of agriculture on air quality (ozone formation influence and N gases losses) ii. determining atmospheric radical budgets; iii. estimate the nitrogen input in remote environments; iv. improving regional and global models of transport v. contributing to more effective strategies for improving air quality. (AU)