Size spectra and source apportionment of fine particulates in tropical urban environment during southwest monsoon season
In this study, we carried out high time-resolution measurements of particle number concentration and size distribution (5–1000 nm) in Singapore, which represents a tropical urban environment. The measurements were taken during the southwest monsoon season in 2017 using a fast-response differential m...
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| Main Authors: | , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | English |
| Published: |
2020
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| Subjects: | |
| Online Access: | https://hdl.handle.net/10356/143062 |
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| Institution: | Nanyang Technological University |
| Language: | English |
| Summary: | In this study, we carried out high time-resolution measurements of particle number concentration and size distribution (5–1000 nm) in Singapore, which represents a tropical urban environment. The measurements were taken during the southwest monsoon season in 2017 using a fast-response differential mobility spectrometer at a sampling rate of 1 Hz. In the measurement, short-lived nucleation events were found prominent at early afternoon because of the abundant incoming radiation that enhances the photochemical reactions in atmosphere. For the first time in the region, a five-factor positive matrix factorization approach was applied to the size spectra data. Based on particle number concentration, two sources within nucleation mode (30 nm) were resolved and account for 43% of total number concentration, which is higher than the available monitoring data in other big cities. Among the sources, O3-related atmospheric photochemical reactions with peak size at 10–12 nm is a unique factor and prominent in early afternoon nucleation events. The findings of this work can serve as a baseline for assessing influence of local and cross-border airborne emissions during various seasons in the future. |
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