APCG meets on a monthly basis, to discuss on state-of-the-art research issues of interest to its members. Today, another fruitful meeting was held at IERSD premises, where Dr. Stelios Myriokefalitakis introduced the importance of multiphase processes on the formation of secondary organic aerosol (SOA) in the atmosphere and on atmospheric nutrient cycles. Also, his modeling results on the impacts of bioaerosols on the global scale set the basis for a long discussion on the health aspects of atmospheric pollution, as well as on the bridging spatial model scales.