EMME observational campaigns to evaluate of carbon dioxide and methane emissions from urban ecosystem of St. Petersburg

Accurate Quantitative Assessment of Anthropogenic Greenhouse Gas Emissions, Primarily CO2 and CH4, is Necessary for the study of mechanisms and factors that determine the impact of atmospheric composition on climate, ecosystems, and human health, as well as for the development and control of international agreements and standards in environmental protection and climate. 

St. Petersburg - second most populous city (~5.6 million people) in the Russian Federation and fourth in Europe. To obtain experimental estimates of greenhouse gas emissions from the St. Petersburg agglomeration, the authors conducted the Emission Monitoring Mobile Experiment (EMME) campaigns in 2019, 2020, 2021, and 2024 [1,2, 3].

EMME Observational Campaigns in 2019 and 2020. The key equipment for the 2019 campaign was two portable FTIR spectrometers (Bruker EM27/SUN), which were used to measure CO2, CH4, and CO concentrations from both downwind and upwind sides of the city. The planning of field measurements was done in the evening before and included determining the optimal location for the FTIR spectrometers based on weather forecasts combined with numerical modeling of pollution transport in the city area.

The experiment continued in 2020, retaining its overall concept. The main difference between EMME-2020 and the 2019 campaign is that only one FTIR spectrometer was used. The apparatus was located in a car during spectral registration, significantly increasing the speed of measurements. The second half of the EMME-2020 campaign took place under COVID-19 pandemic-related restrictive measures introduced in St. Petersburg on March 28, 2020.

EMME Campaigns in 2021 and 2024. In 2021 and 2024, a new approach was tested based on in situ measurements of CO2 and CH4 concentrations performed while the car moved along a circular highway. The air intake was installed on the roof of a vehicle, and the measuring equipment was placed in the cabin. The campaign included both daytime/early evening and nighttime/early morning mobile measurements, with a total of 6 experiments in 2021 and 5 experiments in 2024. Los Gatos Research (LGR) gas analyzer was used to record CO2 and CH4 concentrations.

Methods for Quantitative Assessment of Integrated Emissions and Area Fluxes. Different modifications of the mass balance method [1,3] and inverse modeling methods [2] were used to evaluate integrated emissions and area fluxes of CO2 and CH4 from the St. Petersburg agglomeration based on observational campaigns conducted in 2019, 2020, 2021, and 2024.

Assessment of the Impact of Emissions. The report presents assessments of the impact of CO2 and CH4 emissions from St. Petersburg on concentrations of these gases in the atmosphere, as well as experimental ("top-down") estimates of CO2 and CH4 flows for the St. Petersburg agglomeration obtained based on mobile experiments conducted in 2019, 2020, 2021, and 2024, along with a comparison of results from EMME campaigns with literature data.

Funding and Acknowledgments. The study was supported by a grant from the Russian Science Foundation No. 24-27-00033 (https://rscf.ru/project/24-27-00033/). The research was carried out using equipment from the "Geomodel" Resource Center (Scientific Park of St. Petersburg State University).

References

1. Makarova M.V. et al. [https://doi.org/10.5194/amt-14-1047-2021].

2. Ionov D.V. et al. [https://doi.org/10.5194/acp-21-10939-2021].

3. Макарова М.В. и др. DOI: 10.15372/AOO20240805.