The interactive atmospheric chemistry and climate model, which is part of MIT's Integrated Global System Model (IGSM), has been improved by incorporating a parameterized urban-scale atmospheric chemistry model (PUAC model). The parameterization of the urban air chemistry processes in the PUAC model, including those related to nonmethane hydrocarbons (NMHC), is derived by employing the probabilistic collocation method to simulate the predictions of the California Institute of Technology - Carnegie Mellon University (CIT) Urban Airshed Model. We are now for the first time able to study the impact of urban air pollution, which is an important subgrid scale chemistry process in the global model, on global atmospheric chemistry and hence on climate in the framework of an IGSM. Several sensitivity simulations for two different time periods - 50 and 100 years - have been carried out. The results are compared to our reference run which was obtained excluding the parameterized urban air chemistry processes. Two major tendencies in the tropospheric chemistry could be observed due to the implemen-tation of the parameterization: i) the tropospheric averaged concentrations of OH and O$_{3}$ decrease (about 10\% and about 4\% respectively) and ii) the tropospheric averaged concentrations of CO and CH$_{4}$ increase (about 10\% and about 8\% respectively). Additionally, we have compared the model results for CH$_{4}$ and CO with observational data for several stations and found reasonably good agreement for both species. The change of the annual-mean global surface temperature over the whole period from 1985 to 2100 was about the same for the reference run and the new model version.