Case Study of Mixing Height Measurement from Commercially Available Ceilometers.

The EPA requires non-attainment air districts to install update PAMS monitoring sites. In addition to the EPA criteria pollutant measurements, volatile organic compounds are being added to the required measurements. Boundary layer wind profilers are optionally instruments which removes the potential for the measurement of the local mixing height. To address the mixing height measurements, the EPA has selected the commercially available ceilometer instrument which first gained traction for their ability to measure the local cloud height. By altering the application, several ceilometers have been modified to measure the local mixing height based on the vertical distribution of particulate matter. This paper presents the results of a summer 2019 field program to compare ceilometer mixing height measurements with several independent measurements such as radiosondes, radiometers, wind profilers and Doppler sodar systems. The intent of this effort is to provide guidance and standard operation procedures to air districts as they consider the purchase of a ceilometer. In addition the authors will discuss quality assurance guidance for the ceilometers.