Photolysis of nitrogen dioxide is a major reaction resulting in the formation of ozone in the troposphere. The rate constant, k1, for the photodissociation of NO2 is, under ambient conditions, a function of latitude, solar zenith angle, and cloud cover; therefore, k1 is highly variable. Nitrogen dioxide photolysis data for calculating k1, and radiometric and selected meteorological data, all under a variety of meteorological conditions, were collected during the spring and fall, 1975. Data from this study can be used to aid the modeling of tropospheric photochemical air quality and smog chamber results.

Project Officer: Joseph J. Bufalini. Project Officer: Bruce W. Gay, Jr. Research Triangle Institute "March 1978." "EPA-600/7-78-053."

Photolysis of nitrogen dioxide is the major reaction resulting in the formation of ozone in the troposphere. Under ambient conditions, k1, the rate constant for the photodissociation of NO2, is a function of solar altitude and cloud cover, and therefore, is highly variable. The objective of this study was to collect k1, radiometric, and selected meteorological data over periods of several days under a variety of meteorological conditions. Data were collected during the spring and fall of 1975. Eight days of data were collected between 21 April and 30 April. The time resolution of these data was 10 minuted for 6 days and 5 minutes for the remaining 2 days. Between 3 October and 31 October, 13 days of data were collected with 1-minute time resolution. Data from this study are needed to aid the modeling of troposheric photocemical air quality and smog chamber results.