Scientific Objectives. ACROSS (Atmospheric ChemistRy Of the Suburban foreSt) is an integrative, innovative, multi-scale project, developed under the “Make Our Planet Great Again” (MOPGA) initiative. ACROSS is designed to improve knowledge of the chemical evolution of mid-latitude urban plumes when they mix with biogenic emissions from surrounding forested areas. One of the hypotheses of ACROSS is that the mixing of anthropogenic-biogenic air masses leads to changes in the production of oxygenated volatile organic compounds (OVOCs) whose properties modify their importance in incorporation into secondary organic aerosols (AOS) and their roles in the production of ozone and other relevant secondary species. A likely important factor is the transport of NOx to suburban biogenic environments and the consequent modification of key chemical processes.

Measurement plan. The key feature of the ACROSS project is an intensive, multi-platform measurement campaign that will take place during the summer of 2022. The campaign will include a super-site in the suburban forest of Rambouillet in the south-west of Paris equipped with a 40-meter tower and supplemented with ground measurements, the French ATR-42 environmental research aircraft of Safire instrumented for airborne regional observations across Paris and suburban forest areas, and several multi-instrumented ground sites located in urban, peri-urban and rural environments in the Paris region.

Labs and institutes. Researchers from LISA (coordinator of the project), CNRM, EPOC, Harvey Mudd College, ICARE, IMT Nord Europe, INERIS, INRAE Grignon, IRCELYON, John Hopkins University, LAMP, LATMOS, LCE, LPC2E, LSCE, MPIC, PC2A, UNICH, University of Cambridge, University of San Diego

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