Related Experiment Video
Updated: Oct 24, 2026

Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O
Published on: October 7, 2020
Observations show increased nitrate in coastal cloud droplet residuals from large-particle activation and N2O5
Abigail S Williams1, Lynn M Russell1, Sanghee Han1
1Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA.
Abstract:
Clouds change the chemical composition of aerosols, yet observations characterizing these processes are quite limited. Ground-based in-cloud measurements in coastal Southern California show that the highest nitrate to sulfate ratio (2.5 ± 1.7) in droplet residuals is near cloud base where cloud liquid water content and droplet number concentration are below the observed 20th percentile. The number size distribution of nitrate-rich particles peaks at a larger diameter than sulfate-rich particles, supporting growth to droplets of nitrate-rich particles at lower supersaturations than for sulfate-rich particles. Nitrate mass concentrations are up to three times higher in-cloud compared to pre-cloud and correlated with statistically significant reductions in ozone concentrations, consistent with contributions from in-cloud nitrate formation by N2O5 hydrolysis. This study provides quantitative relationships of cloud properties to nitrate production in droplet residuals and associated ozone reduction, illustrating the impacts of aqueous reactions in clouds.
Related Concept Videos
Precipitate Formation and Particle Size Control
The obtained precipitate should be either a pure substance of known composition or easily converted to one by a simple process, such as ignition or drying. In addition, the precipitate should be insoluble and easily filterable. In general, filterability...
2° Amines to N-Nitrosamines: Reaction with NaNO2
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Overview
The nitrous acid is unstable. Hence, it is formed in situ from a solution of sodium nitrite and cold aqueous acids such as hydrochloric or sulfuric acid. In an acidic solution, the –OH group of nitrous acid undergoes protonation to give oxonium ion, followed by water loss...
Nucleophilic Substitution Reactions
In 1896, the German chemist Paul Walden discovered that he could interconvert pure enantiomeric (+) and (-) malic acids through a series of reactions. This conversion suggested the involvement of optical inversion during the substitution reaction. Further, in 1930, Sir Christopher Ingold described for the first time two different forms of nucleophilic substitution reactions, which are known as SN1 (nucleophilic substitution unimolecular) and SN2 (nucleophilic substitution...
Types of Coprecipitation
Sometimes, ions in a crystal lattice can undergo isomorphous replacement by inclusions of similar charge and size. For...
Colloidal precipitates

