- Research Article
- 10.1021/acsestair.5c00240
Biogenic VolatileOrganic Compounds from PennsylvanianLakes Sampled during the 2024 Algal Bloom Season
- Nov 04, 2025
- ACS Es&t Air
- Christine Troller + 5 more +5
Biogenic volatileorganic compounds (BVOCs) emitted fromaquaticsystems are increasingly recognized for their influence on atmosphericchemistry. However, emissions from freshwater environments, specificallyduring harmful algal bloom (HAB) events, remain poorly quantified.These HAB events are increasing globally in frequency and intensity,driven by climate change, nutrient runoff, and land-use changes. Thisstudy investigates the water-to-air gas exchange rates of BVOCs fromsouthwestern Pennsylvanian freshwater lakes during peak HAB conditions,with a focus on nitrogen-containing compounds that are typically underrepresentedin atmospheric measurements. Using atmospheric pressure, hydroniumchemical ionization mass spectrometry (CIMS), we measured BVOC emissionsfrom 18 lake samples in the laboratory, capturing real-time fluxesof 900 unique masses. Ammonia, pyrroline, and pyridine consistentlyexhibited the highest emission fluxes across samples. Alkylamineswere less abundant, although they remain atmospherically importantdue to their role in new particle formation. These results representthe first reported real-time freshwater flux measurements of alkylamines,pyrroline, and pyridine, offering new insight into the atmosphericimplications of HABs. Notably, no clear correlation was observed betweenBVOC fluxes and chlorophyll a and phycocyanin concentrations,which were taken to represent the cyanobacterial concentrations inthe samples. This suggests that emissions are influenced by otherbiological or chemical factors not captured in this study. Principalcomponent analysis identified two significant outlier water samples,driven by elevated ammonia, pyrroline, and an unknown compound at124.101 amu, though the underlying cause of these deviations remainsunresolved. The remaining lake emissions were similar. These findingsprovide foundational observations to better understand the role offreshwater system emissions in regional air quality and atmosphericprocesses.
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