Atmospheric science and chemistry measurement network (ascent): operation, management, and scientific studies

The National Science Foundation Division of Atmospheric and Geospace Sciences awarded California Institute of Technology (Caltech) a $4.780 million cooperative agreement on March 1, 2026, to operate and manage the Atmospheric Science and Chemistry Measurement Network (ASCENT) through August 31, 2030, under the Geosciences program (CFDA 47.050).

ASCENT operates 12 monitoring sites in urban, rural, and remote areas across the United States equipped with advanced aerosol instrumentation for real-time, high time-resolution measurements of fine mode aerosol chemical composition and properties. The award funds continued acquisition of long-term state-of-the-art aerosol chemical and physical property measurements at the established sites; development of a database infrastructure for automated quality assurance and control, data upload and download, data discovery, visualization, and long-term data preservation; enhancement of training for students and current professionals in atmospheric air quality research; fundamental research into urban air quality, biomass burning aerosols, and biogenic aerosol sources and processing leveraging the uniform network of comparable observations; and catalyzing future development of an integrated, long-term atmospheric observation research infrastructure for aerosols and trace gases in the United States. Work is performed in Pasadena, California. The network provides the first comprehensive, high time-resolution, long-term aerosol dataset across the United States, supporting science-based policy decisions on air quality, human health, and environmental issues.

Abstract

This project supports the continued operation and management of the atmospheric science and chemistry measurement network (ascent). The ascent network was developed with support from the NSF mid-scale research infrastructure program and is providing the first, comprehensive, high time resolution, long-term aerosol data across the united states. IT consists of 12 sites in urban, rural, and remote areas that are equipped with a suite of advanced aerosol instrumentation for real-time measurements of fine mode aerosol chemical composition and properties. The ascent network fulfills the critical need for long-term, high time-resolution atmospheric aerosol chemistry measurements in the US. For informing science-based policy decisions on air quality related human health and environmental issues. The specific objectives of this project are to: (1) continue to acquire high time-resolution, high-quality, long-term state-of-the-art measurements of aerosol chemical and physical properties at the 12 established ascent sites that are essential to advancing research in air quality, atmospheric science, environmental change, and public health; (2) develop a database infrastructure for automated quality assurance/control, data upload and download, data discovery and visualization, and long-term data preservation; (3) enhance training of students and current professionals engaged in science and engineering related to atmospheric air quality research; (4) conduct research to advance fundamental understanding of urban air quality, biomass burning aerosols, and biogenic aerosol sources and processing which leverages the uniform network of comparable observations; and (5) catalyze and support future development of an integrated, world-leading, long-term, atmospheric observation research infrastructure for aerosols and trace gases in the U.S. And strengthen collaborations with international atmospheric observation networks. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the foundation's intellectual merit and broader impacts review criteria.- subawards are planned for this award.