Based on measurements at the Beijing 325-m Meteorological Tower, this study reports an analysis of atmospheric stability conditions and turbulent exchange during consecutive episodes of particle air pollution in Beijing (China), primarily due to haze and dust events (15–30 April 2012). Of particular interest were relevant vertical variations within the lower urban boundary layer (UBL). First, the haze and dust events were characterized by different atmospheric conditions, as quite low wind speed and high humidity are typically observed during haze events. In addition, for the description of stability conditions, the bulk Richardson number (RiB) was calculated for three different height intervals: 8–47, 47–140, and 140–280 m. The values of RiB indicated an apparent increase in the occurrence frequency of stably-stratified air layers in the upper height interval—for the 140–280-m height interval, positive values of RiB occurred for about 85% of the time. The downward turbulent exchange of sensible heat was observed at 280 m for the full diurnal cycle, which, by contrast, was rarely seen at 140 m during daytime. These results reinforce the importance of implementing high-resolution UBL profile observations and to address issues related to stably-stratified flows.