Constraints on observational timeframes of heterogeneous chemistry within emission plumes

Few studies investigate the link between gases and particles in point source emission plumes, particularly those in a marine environment where emissions are dominated by oceangoing vessels. One key reason for this is the heterogeneity of interactions and reaction pathways. Thus, we aim to contextualize this understudied relationship in support of future air quality, satellite, and related modeling activities. In this study, we present an ensemble of ground-based, airborne, and satellite observations collected during the 2017 Ozone Water-Land Environmental Transition Study (OWLETS 2017) with focus on three specific events where ship emission plumes were advected directly over the monitoring site. Previously, we have shown observations of induced boundary layer NO_x enhancement and O₃ depletion on short timescales following these emission events, but heterogeneous interactions with aerosol were not considered. Expanding on these analyses, we investigate the spatiotemporal alignment of trace gas particle interactions during emission events within the marine boundary layer. It is often observed and reported that freshly emitted plumes are well-mixed, resulting in expected alignment of trace gas and particle chemistry. However, during one presented emission event from 01 August 2017, chemical effects trailed the observed aerosol plume by approximately 15 minutes, suggesting that plumes are not always spatially homogeneous and that many factors contribute to observational timeframes. To test this hypothesis, we constrain these events by local and mesoscale meteorology as well as dominant pathways and interactions to show influences on transported species and timing. Providing a more complete picture of these emission events and conditions contributing to their observation will allow for advanced understanding of gas particle interactions in a marine setting, helping pilot future air quality and modeling studies.