AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
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Laboratory Studies of the Photolysis of Particulate Nitrate
QING YE, Qianwen Shi, Jennifer G. Murphy, Jesse Kroll, Massachusetts Institute of Technology
Abstract Number: 617 Working Group: Aerosol Chemistry
Abstract Recent studies have suggested that the photolysis of particulate nitrate can recycle NOx rapidly enough to significantly affect the NOx budget in areas far from NOx sources. However, reported nitrate photolysis rates differ by orders of magnitude, and experimental measurements of nitrate photolysis have mostly been conducted using indirect methods (e.g. collecting particles on substrates). In this work, we perform controlled laboratory experiments to better constrain the photolysis rate and products of suspended submicron nitrate-containing particles under various atmospherically-relevant wavelengths and relative humidities. A suite of instruments that measure particle-phase nitrates and gas-phase NOx and NOy species in real time are used to understand the atmospheric fate of N-containing species following photolysis. The systems studied include inorganic nitrates (NaNO3, NH4NO3) as well as organic nitrates derived from terpene oxidation under high-NOx conditions. Results can be used to inform global models of nitrate chemistry, and are aimed at improving our understanding of the lifecycles of reactive nitrogen species and their implications for global climate and air quality.