Characterization of IMPROVE data quality

Each year the Air Quality Research Center delivers nearly one million new measurement values for the IMPROVE network. A large community of researchers and analysts use these data to address a wide range of scientific and regulatory issues. All data pass through multiple layers of review and quality assurance before publication, but all carry some uncertainty from the irreducible error that is present in any measurement.

An ongoing program of research works to:

Image: Air Quality stations on a rooftop surrounded by equipment.
One method that AQRC researchers use to identify sources of uncertainty in the data measurement process is by studying and comparing output from IMPROVE aerosol samplers located side by side. These samplers are located on the roof of Gausi Hallat UC Davis. Credit: Liese Greensfelder
  • characterize various dimensions of this uncertainty; 
  • supply clear guidance on the strengths and limitations of IMPROVE data in the diverse analyses to which they are subjected;
  • identify the sources of uncertainty in the measurement process, and
  • reduce the uncertainty in the measurement through new quality assurance measures.

Contact—Nicole Hyslop (530-754-8979) and Warren White (530-752-1213)

Miscellaneous on-line advisories on specific data issues are collected at