Hygroscopic properties of particulate matter and effects of their interactions with weather on visibility

Wan-Sik Won; Rosy Oh; Woojoo Lee; Sungkwan Ku; Pei-Chen Su; Yong-Jin Yoon

doi:10.1038/s41598-021-95834-6

Hygroscopic properties of particulate matter and effects of their interactions with weather on visibility

Sci Rep. 2021 Aug 12;11(1):16401. doi: 10.1038/s41598-021-95834-6.

Authors

Wan-Sik Won¹, Rosy Oh², Woojoo Lee³, Sungkwan Ku⁴, Pei-Chen Su⁵, Yong-Jin Yoon^{6

7}

Affiliations

¹ School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, 639798, Singapore.
² Department of Industrial and Systems Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Korea.
³ Department of Public Health Sciences, Graduate School of Public Health, Seoul National University, Seoul, 08826, Korea.
⁴ Department of Aviation Industrial and System Engineering, Hanseo University, Seosan-si, Chungcheongnam-do, 32158, Korea.
⁵ School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, 639798, Singapore. peichensu@ntu.edu.sg.
⁶ School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, 639798, Singapore. yongjiny@kaist.ac.kr.
⁷ Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Korea. yongjiny@kaist.ac.kr.

Abstract

The hygroscopic property of particulate matter (PM) influencing light scattering and absorption is vital for determining visibility and accurate sensing of PM using a low-cost sensor. In this study, we examined the hygroscopic properties of coarse PM (CPM) and fine PM (FPM; PM_2.5) and the effects of their interactions with weather factors on visibility. A censored regression model was built to investigate the relationships between CPM and PM_2.5 concentrations and weather observations. Based on the observed and modeled visibility, we computed the optical hygroscopic growth factor, [Formula: see text], and the hygroscopic mass growth, [Formula: see text], which were applied to PM_2.5 field measurement using a low-cost PM sensor in two different regions. The results revealed that the CPM and PM_2.5 concentrations negatively affect visibility according to the weather type, with substantial modulation of the interaction between the relative humidity (RH) and PM_2.5. The modeled [Formula: see text] agreed well with the observed [Formula: see text] in the RH range of the haze and mist. Finally, the RH-adjusted PM_2.5 concentrations based on the visibility-derived hygroscopic mass growth showed the accuracy of the low-cost PM sensor improved. These findings demonstrate that in addition to visibility prediction, relationships between PMs and meteorological variables influence light scattering PM sensing.

Publication types

Research Support, Non-U.S. Gov't