Work

Evaluating the Applicability of a Real-Time Highly Oxygenated Organic Molecule (HOM)-Based Indicator for Ozone Formation Sensitivity at a Boreal Forest Station

Year: 2024

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide Ground-level ozone (O 3 ), formed via complex photochemistry involving nitrogen oxides (NO x ) and volatile organic compounds (VOCs), is a critical secondary pollutant and oxidant. Therefore, understanding whether the formation of O 3 is NO x - or VOC-limited is essential for effective air quality management. Recently, we demonstrated that the distribution of highly oxygenated organic molecules (HOMs) can be used as a real-time indicator to determine the sensitivity of the O 3 formation regime in monoterpene oxidation chamber studies. The key reactions between peroxy radicals and NO that form O 3 also determine the branching between nitrate-containing and non-nitrate HOM species. However, validation outside laboratory conditions is lacking. This study evaluates the HOM-based indicator’s applicability at a boreal forest station in Hyytiälä, Finland. Using model scenarios with doubled NO x or VOC emissions as references, we find that the monoterpene HOM-based indicator can determine O 3 formation sensitivity regimes at this site. Our results indicate that this rural background station is primarily NO x -limited, especially during elevated temperatures with high VOC concentrations but is often in a transition region between the two limit regions. Future studies are needed to assess the applicability of this HOM-based indicator at other sites and times, especially where monoterpenes are not the dominant VOC species.

Source: Environmental Science & Technology Letters

DOI: 10.1021/acs.estlett.4c00733

Authors: Jiangyi Zhang, Jian Zhao, Robin Wollesen de Jonge, Nina Sarnela, Pontus Roldin, Mikael Ehn

Institutions: University of Helsinki, Lund University, IVL Swedish Environmental Research Institute

Language: English

Topic: Atmospheric chemistry and aerosols

Subfield: Atmospheric Science

Field: Earth and Planetary Sciences

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,500