Evaluation of continuous ceilometer-based mixing layer heights and correlations with PM2.5 concentrations in Beijing

Beijing air quality suffers from frequently occurring inversion layers. These inversion layers can last for several days and below these layers, pollution is accumulated. In the absence of inversions an urban boundary layer still exists delimiting the urban atmosphere from the free atmosphere. The height of this layer can potentially influence the urban atmospheric pollution. In both cases, particle concentration might change with height. A measurement campaign was performed to study those meteorological conditions, which are one of the causes for intensive air pollution in the region of Beijing during spring 2009. The mixing layer height (MLH) was studied by a ceilometer continuously. It was used to analyse the actual development of the height of inversion and boundary layers and the distribution of particles. Additionally, meteorological data from a radiosonde station are available. The measurements to study the vertical distribution of atmospheric layers in combination with particulate concentrations for specific times will be presented. The results of that campaign will be discussed.