Unique nitrogenous organics in aloft atmospheric particles across the United States

Nitrogenous organic aerosol comprises up to 50% of the organic mass in atmospheric particles, but its broader impact remains poorly understood due to limited knowledge of its vertical distribution and molecular composition in the atmosphere. Here, via tethered balloon system flights in urban, agricultural, and mountainous ecosystem atmospheres across the United States, we show a vertical dependence for nitrogenous organic aerosol speciation; up to 30% of total aloft nitrogenous organic aerosol abundance is comprised of uniquely aloft nitrogenous organic aerosol species. We leverage a comprehensive in situ instrumentation (mainly high-resolution mass spectrometry) and modeling suite to explore causative factors, highlighting the particular importance of increased gas to particle phase partitioning of nitrogenous organic aerosol at aloft conditions. These insights are critical for refining atmospheric models, as neglecting the vertical distribution of nitrogenous organic aerosol can result in strong biases in the total organic aerosol budget.