Establish new capabilities to provide long-term measurements and vertical profiles of reactive compounds and PM that will allow meaningful examination of long-range transport and trends in background concentrations.
These two recommendations will require providing support to:
develop uniform and traceable standards, on a global basis, for calibration of both gas-phase and aerosol measurements;
improve measurement technologies for use in current observational platforms (such as ground-based air quality monitoring networks, commercial aircraft, and balloons/sondes), and in new potential platforms such as “supersites” for measuring a comprehensive suite of compounds in remote locations and unmanned aerial vehicles for long-duration sampling of the atmosphere over a wide range of altitudes;
integrate measurements obtained from different observational programs and platforms, with a particular focus on integrating remotely-sensed satellite observations with in situ aircraft and ground-based observations;
promote observational programs specifically designed to address chemical and meteorological data requirements for the development and evaluation of models.
Responsibility for carrying out this work should be clearly assigned to a U.S. federal agency (or interagency) research program, and the United States should play a leadership role in fostering international cooperative research and observational activities to enhance our understanding of global air quality changes.