An Investigation Into HONO Formation Mechanisms in the Troposphere

EPA Grant Number: R826182
Title: An Investigation Into HONO Formation Mechanisms in the Troposphere
Investigators: Zhou, Xianliang
Institution: Wadsworth Center: New York State Department of Health
EPA Project Officer: Shapiro, Paul
Project Period: December 1, 1997 through November 30, 1999 (Extended to November 30, 2000)
Project Amount: $162,728
RFA: Exploratory Research - Environmental Chemistry (1997) RFA Text |  Recipients Lists
Research Category: Water , Land and Waste Management , Air , Engineering and Environmental Chemistry


The proposed research is to investigate reactions leading to nitrous acid formation, and thus to provide insight into the mechanisms for HONO formation in the troposphere under both NOx -rich and NOx -limiting conditions.


A series of laboratory experiments will be designed and conducted to study the following two types of reactions: Kinetics of NO/NO2 reactions with water vapor on various surfaces using a flow tube reactor and with liquid water using a gas-liquid reactor; Reaction kinetics of HNO3 with soluble reducing agents, such as SO2, HCHO and Br-, in acidic solutions, again using a flow tube reactor and a gas-liquid reactor; The reaction product, nitrous acid, will be monitored throughout each experiment, using a DNPH derivatization/HPLC-UV analysis method in the liquid phase, and a coil sampling/DNPH/HPLC-UV method in the gas phase.

Expected Results:

This proposed research is to provide insights into atmospheric HONO formation mechanisms in both urban and clean environments, and thus advance our understanding of HONO chemistry in the troposphere, such as its role in reactive nitrogen cycling. This knowledge, when incorporated into models along with other information such as its temporal and spatial distributions, will improve our ability to predict the photoformation of oxidants, such as OH radicals and ozone, and photodegradation of pollutants on a regional or global scale.

Publications and Presentations:

Publications have been submitted on this project: View all 3 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 2 journal articles for this project

Supplemental Keywords:

HONO, nitrogen oxides, nitric acid, tropospheric, atmosphere, formation mechanisms, laboratory investigation, surface reactions, HNO3 reduction, OH radicals, ozone, photooxidants., Scientific Discipline, Air, Environmental Chemistry, Chemistry, Engineering, Chemistry, & Physics, nitrous acid formation, ozone, chemical composition, photooxidants, HONO, chemical kinetics, gas-liquid reactor, troposphere, flow tube reactor

Progress and Final Reports:

  • 1998 Progress Report
  • 1999
  • Final Report