Volatile organic compounds (VOCs) form ozone (O3) and secondary organic aerosols (SOAs) in the atmosphere under favourable conditions. Biogenic VOC levels in the marine atmosphere are significantly lower compared with levels in the atmosphere above terrestrial ecosystems. However, much less is known about the marine biogenic VOC sea-to-air flux, specifically at the sea surface level. Therefore, here we describe a newly developed and cost-effective floating chamber system that has the capacity to measure the VOC sea-to-air flux near the sea surface (< 1 m). The floating chamber is coupled with adsorbent cartridges, and samples were analysed in the laboratory using commercial thermal desorption and gas chromatography mass spectrometry (TD-GC-MS). The structural performance of the floating flux chamber was evaluated, and it was shown to have the capacity to stay continuously afloat for up to 72 h in various conditions (e.g., rainy, windy) and with wave heights up to approximately 1 m in coastal waters. Preliminary measurements of isoprene (3-Methyl-1,2-butadiene) (C5H8) sea-to-air flux using the floating flux chamber in the coastal waters off the east coast of Peninsular Malaysia found values in the region of 107 molecules/cm2/s, comparable with most published values based on various flux measurement techniques. We suggest the proposed floating chamber system could serve as a cost-effective VOC flux technique that allows measurements near the sea surface.
Keywords: Adsorption cartridge; Air-sea interface; Isoprene; Sea surface microlayer; TD-GC–MS; Volatile organic compounds.
© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.