A model investigation of the impact of increases in anthropogenic NO x emissions between 1967 and 1980 on tropospheric ozone

Abstract

Recent observations suggest that the abundance of ozone between 2 and 8 km in the Northern Hemisphere mid-latitudes has increased by about 12% during the period from 1970 to 1981. Earlier estimates were somewhat more conservative suggesting increases at the rate of ~ 7 % per decade since the start of regular observations in 1967. Previous photochemical model studies have indicated that tropospheric ozone concentrations would increase with increases in emissions of CO, CH 4 and NO x. This paper presents an analysis of tropospheric ozone which suggests that a significant portion of its increase may be attributed to the increase in global anthropogenic NO x emissions during this period while the contribution ofCH 4 to the increase is quite small. Two statistical models are presented for estimating annual global anthropogenic emissions of NOx and are used to derive the trend in the emissions for the years 1966-1980. These show steady increase in the emissions during this interval except for brief periods of leveling off after 1973 and 1978. The impact of this increase in emissions on ozone is estimated by calculations with a onedimensional (latitudinal) model which includes coupled tropospheric photochemistry and diffusive meridional transport. Steady-state photochemical calculations with prescribed NO x emissions appropriate for 1966 and 1980 indicate an ozone increase of 8-11% in the Northern Hemisphere, a result which is compatible with the rise in ozone suggested by the observations.

Estimating product yields of carbon-containing products from the atmospheric photooxidation of ambient air alkenes

“…Latitudinal distributions of anthropogenic VOC's, including alkenes, do not appear available; however, latitudinal distributions of CO (Khalil and Rasmussen, 1990) and of NO x (Dignon and Hameed, 1985) are available. Both CO and NOx emissions peak at midlatitudes in the Northern Hemisphere, with most of the emissions probably coming from anthropogenic sources in this latitude zone.…”

“…Both CO and NOx emissions peak at midlatitudes in the Northern Hemisphere, with most of the emissions probably coming from anthropogenic sources in this latitude zone. Approximately 80% of the anthropogenic NO x emissions are estimated to occur between 31" and 63* north latitude (Dignon and Hameed, 1985). Anthropogenic emissions of alkenes from vehicular emissions, gasoline distribution losses, and stationary combustion sources should have about the same latitudinal distribution.…”

Estimation of the Natural Background of Ozone Present at Surface Rural Locations

“…In this latter study 41 the effect of doubling the biogenic NO* emissions on the average Northern Hemisphere tropospheric O3 layer based on the three scenarios above were as follows: scenario (1) an increase in O3 concentration from 22.6 to 28.9 ppb, scenario (2) an increase in O3 concentration from 36.6 to 40.9 and scenario (3) an increase in O3 concentration from 40.7 to 44.5 ppb. Therefore, the effect of the doubling in the biogenic NO* emissions on the predicted O3 concentrations decreases on both an absolute and percent basis as the anthropogenic emissions of NO* increase.…”

“…41 Scenario (1) in this study includes (a) a stratospheric source of reactive N of 0.5 TgN/yr, (b) a source of NO* from lightning discharges of 2.1 TgN/yr and (c) a global biogenic NO* source of 10 TgN/yr. Scenario (2) includes these NO* sources plus an anthropogenic source of NO* which was estimated for the Northern Hemisphere in 1966 to be 14.5 TgN/yr.…”

“…439 Several tropospheric photochemical modeling studies include scenarios involving various sources of nitrogen oxides. 35 ' 38 ' 40 ' 41 A number of such scenarios were applied to July conditions in the application of a two-dimensional tropospheric model. 35 A condensed version of the scenarios used and the O3 concentrations predicted at lower altitudes in the Northern Hemisphere are given in Table II.…”