APEL  - Pilot Study on Assessment of atmospheric optical properties during biomass burning events and long-range transport of desert dust main objective  is to foster the exchange of expertise between EARLINET and LALINET and to increase the capability of joint research, and thus setting the groundwork for the future Cal/Val of ESA’s atmospheric satellite missions. Beyond its short-term targets (presented below), the APEL project fosters research excellence in the field and supports international partnerships in applied space research. An integration between LALINET and EARLINET is a must, as a global measurement and data analysis protocol should be followed. Nowadays LALINET is developing its expertise on these issues and in this context supervision by a well-established network is desirable. Also, quality assurance and quality checks (QA/QC) standards should be followed in order to harmonize the different instruments available in LALINET and bring them down to a set of tests and procedures which are already acceptable among other networks.