RELATIONSHIPS BETWEEN NITROUS-ACID AND OTHER NITROGEN-OXIDES IN URBANAIR

Nitrous acid (HNO2), nitric acid (HNO3), nitric oxide (NO) and nitroge n dioxide (NO2) were measured over a four day period in Clairmont, CA. Concentrations of each nitrogen oxide (NOx) compound varied diurnally during the study period. HNO3, NO2 and NO generally reached maxima du ring daylight hours. Conversely, HNO2 concentrations were highest at n ight. HNO3 and HNO2 concentrations increased with increasing NO and NO 2. HNO3 dependance became limited at high NO2 and NO. HNO2 concentrati ons declined when high NO and NO2 concentrations were present. The dec line in HNO2 is postulated to result from direct photolysis during the time periods of NO and NO2 maxima or from reactions to form HNO3.