Nitrate radical formation rates in scandinavia

Seasonal mean production rates, monthly doses, and distribution of formation rates of N03 radicals were calculated using measured 03 and NO2 data from five sites in southern and central Scandinavia. The variation in average production rate between rural and urban sites for a particular season was found to be less than a factor of 3.2. Typical mean monthly doses fall between 1 and 4 × 1012 molecules cm−3 month−1, regardless of site and season. Urban N03 loss is expected to be dominated by reaction with NO. Using measured N03 life times from the literature it is shown that turnover of N03 in rural southern and central Scandinavia may well be controlled by reactive hydrocarbons during the dark hours. A comparison between doses and limited deposition data suggests that a significant part of the nighttime nitric acid formation takes place via N03 radicals.