We present the results of synchronous observations of the ozone and gaseous impurity concentrations, chemical composition of the aerosol and meteorological parameters with a high temporal resolution (of minutes) at the background site Mondy, which is located in the highland area of East Siberia. We also analyzed the seasonal dynamics exhibited by the ozone, gaseous impurities of sulfur and nitrogen, and ionic composition of the aerosol over the long term (1998–2016). Ozone variability in the boundary layer depended on complicated relief and dynamic processes occurring in the atmosphere. The concentration of ions in the aerosol decreased by 2 times for the period of 2010–2015 compared to the beginning of the new millennium. Furthermore, sulfate, nitrate, chloride, potassium and sodium became the dominant ions in the aerosol. Due to the remote location of the site, the absence of anthropogenic pollution sources and the large series of data with different parameters obtained via on-line monitoring, this site may be regarded as a representative global background site for the vast region of Central Asia.