Online measurements of ambient fluorescent aerosol particles by WIBS at a polluted regional site in the North China Plain: potential impact of burning activities

Abstract:

Online measurements of ambient fluorescent aerosol particles by WIBS at a polluted regional site in the North China Plain: potential impact of burning activities

Zhibin Wang¹, Xiawei Yu^1,3, Simonas Kecorius², Zhouqing Xie³, Gavin McMeeking⁴, Christopher Pöhlker¹, Minghui, Zhang¹, Alfred Wiedensohler², Uwe Kuhn¹, Yafang Cheng¹, Ulrich Pöschl¹, Hang Su^1,*

¹Multiphase Chemistry and Biogeochemistry Departments, Max Planck Institute for Chemistry, Mainz 55128, Germany

²Leibniz-Institute for Tropospheric Research, Leipzig 04318, Germany

³School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China

⁴Droplet Measurement Technologies, Boulder 80301, USA

 

ABSTRACT

Bioaerosols are the main subset of super-micron particles, and significantly influence the evolution of cloud and precipitation, as well as the public health. Currently, the detection of ambient biological materials in real-time is mainly based on the presence of fluorophores in the particles. In this study, we present the wideband integrated bioaerosol spectrometer (WIBS) measurement results to characterize the fluorescent aerosol particles (FAP) at a polluted regional site (Xianghe, 39.80 °N, 116.96 °E) in the North China Plain. We observed substantially much higher number concentration of FAP as compared with those of previous studies in clean environments. We found the good agreement between the FAP number fraction in coarse mode particles (> 1 mm) and BC mass fraction in fine particles (< 1 mm), possibly indicating a majority of the observed FAP is to a certain extent related to the anthropogenic burning activities nearby. This interference and uncertainty should be especially noticed when performing fluorescence measurements in the polluted area, where the certain non-biological compounds (such as SOA, PAH and soot) may significantly lead to a positive fluorescence measurement artifacts and an overestimation of actual fluorescent biological aerosol particles. We also suggested to introduce the classification analysis of fluorescence spectral patterns from single FAP into the data analysis, which aims to reduce the potential misattribution and provide extra dimensions in the differentiation and identification of fluorescent aerosol particle.