Session Presentations

Athena G. Progiou a,b*, Ioannis Sempos b, Aikaterini-Maria Zarogianni c

Lockdown restrictions due to the COVID-19 pandemic led to economic shudtdown and traffic limitations  causing thus considerable reductions of air pollutant emissions and air quality levels. This work aims at studying the impact of traffic restrictions, due to pandemic, on air pollutant emissions and on atmospheric pollutant concentrations in the Greater Area of Athens, Greece. Data from the most representative air quality monitoring stations were collected and analysed for the period March to May 2017-2020 and were compared to the corresponding emission levels and emission reductions due to COVID-19 containment measures. Findings showed that road traffic emissions exhibit reductions, ranging for NOx, from 20 to 40% in March and April 2020, respectively. Likewise, PM10 emissions decreased by 25 and 40%. In the urban/traffic stations, significant reductions of NO2 (38-71%) and PM10 (30%) concentrations were determined in April 2020 compared to previous years. Reduction of C6H6 concentrations (50-80%) reflect emission decreases from petrol vehicles. In the analysis conducted, the relation between air pollutant levels and the corresponding emissions was identified. The conclusions drawn on air quality levels might provide policy makers with useful insights in order to plan and apply more efficient measures to reduce air pollution and comply with air quality standards and European Directives.This research was funded by the Natural Environment and Climate Change Agency (NECCA) of the Hellenic Ministry of Environment and Energy, under the framework of the project “Impact of restriction measures due to COVID-19 pandemic in terms of air pollution and climate change in the Greater Area of Athens (Greece)”. 

Victor Almanza¹ and Agustín García¹

¹Centro de Ciencias de la Atmósfera, UNAM, CU, Mexico City, 04510.

Despite the many challenges derived from the COVID19 pandemic, the current worldwide lockdown measures still represent a unique opportunity for the development and evaluation of mitigation measures aimed to abate air pollution. In Mexico, the lockdown coincided with periods of high temperature and intense solar radiation, which can result in ozone episodes and biomass burning emissions. In addition, given the highly nonlinear dynamics of ozone formation, the effects on air quality might be different among regions according to the magnitude and spatial distribution of emissions. In this work, the impact of emissions reductions will be presented for the Megalopolis area, which consists of the Mexico Megacity and the 5 surrounding states in Central Mexico. The variation in local emissions was estimated mainly on both official mobility data and on the adjustment factors developed as part of the CONFORM (COvid adjustmeNt Factor fOR eMissions) global emissions dataset [1]. The biomass burning emissions were included using the FINN inventory. The variations in surface ozone, fine particles and secondary organic aerosols obtained with the WRF-Chem model will be discussed for both the 3 main stages of the lockdown period and the first weeks of the so-called “new normal”, when some of the main economic activities began to re-open.

References

1. Doumbia, T., Granier, C., Elguindi, N., Bouarar, I., Darras, S., Brasseur, G., Gaubert, B., Liu, Y., Shi, X., Stavrakou, T., Tilmes, S., Lacey, F., Deroubaix, A., and Wang, T.: Changes in global air pollutant emissions during the COVID-19 pandemic: a dataset for atmospheric chemistry modeling, Earth Syst. Sci. Data Discuss. [preprint], https://doi.org/10.5194/essd-2020-348, in review, 2021.

Munshi Md Rasel^1*, Kevin L. Chen², Rachel C. Nethery², and Lucas R.F. Henneman¹

¹Department of Civil, Environmental, and Infrastructure Engineering, George Mason University, Fairfax, VA, USA

²Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, USA *Corresponding Author: mrasel@gmu.edu

Public health interventions implemented to reduce the spread of the Coronavirus Disease 2019 (COVID-19) impacted air quality globally due to change in emissions from transportations, industries, and energy sectors. Subsequent research has identified reduced on-road vehicle emissions as a reason for improved air quality in U.S. cities in early 2020, but the extent that emissions changes from large stationary sources influenced regional air quality has yet to be investigated in full. This study assesses emissions from 977 electric facilities across the United States using a generalized synthetic control (GSYNTH) causal inference model trained on daily facility emissions from January to April 2010-2019. Using historic emissions trends and meteorological covariates, the GSYNTH model estimates the counterfactual emissions at each facility, i.e., the emissions expected during the lockdown period in the absence of lockdown, and uses these to estimate changes in emissions due to lockdown. We apply GSYNTH to estimate lockdown effects on NOx and SO2 emissions at each facility. Overall, we find average increases of 254 (confidence interval will be presented at the poster presentation) tons of SO2 and 121 (confidence interval will be presented at the poster presentation) tons of NOx emissions per day during the COVID-19 lockdown period relative to expected emissions in the absence of lockdown. While some facilities emitted less than expected, other facilities emitted more—in Texas, Louisiana, and Pennsylvania, for instance, we find increases of 22, 15, and 18 tons of NOx per day. Conversely, Ohio, Tennessee, and Nebraska saw emissions reductions of 15, 4, and 3 tons of NOx per day. Louisiana, Arizona, and Indiana emitted 47, 38, and 29 more tons of SO2 per day than expected. We find that facilities in Ohio emitted, on average, reduced NOx and SO2 emissions more than facilities in other states relative to their expected emissions. Ongoing work will identify the location, fuel type, and other features related to facility-specific emissions changes across the lockdown period, and we will identify long-term effects. These findings provide a post-hoc assessment of the impacts of the lockdowns on electric utility emissions, and they serve as a blueprint for future studies of emission responses to large-scale interventions.