Project 1-228 Lebanon

Partnerships for enhanced engagement in research (PEER) SCIENCE
Cycle 1 (2011 Deadline)

Assessment of the tropospheric HONO budget: instrumental development and field measurements

PI: Charbel Afif, Université Saint Joseph de Beyrouth

U.S. Partner: Sebastian Dusanter, University of Indiana

Project Dates: May 2012 - May 2014

Project Overview

Climate change is one of the most important environmental concerns of the 21^st century, and there are concerns regarding atmospheric warming due to increases of greenhouse gas emissions. Reliable climate projections will depend on how well models of atmospheric chemistry can forecast concentrations of greenhouse gases, whose lifetimes depend on the global concentration of the hydroxyl (OH) radical. However, there are still large uncertainties related to the atmospheric OH budget. Recent studies focusing on the chemistry of nitrous acid (HONO), an important source of the OH radical, indicate that model-predicted concentrations of HONO do not agree with field measurements performed in various environments (urban, rural, forests, etc.). These results suggest that our understanding of HONO chemistry is incomplete and call into question our ability to model the atmospheric oxidative capacity and therefore our ability to predict future changes in the atmosphere.

This project supported construction of a reliable instrument (NitroMAC) at the Université Saint Joseph de Beyrouth to measure atmospheric HONO concentrations. The principal investigator and the U.S. partner gathered data during field campaigns in both countries. Furthermore, the project initiated air quality studies in Lebanon and will help promote the development of efficient strategies for pollution control.

Final Summary of Project Activities

In the first phase of the project, the PI and team built and customized their NitroMAC system, designing it specifically for portability and shorter sampling time for field campaigns. The researchers and team met with the U.S. partners in Indiana to share knowledge and prepare for their respective field samplings. The PI undertook a field campaign with the U.S. partner, measuring HONO, NOx and ozone for several days near the Indiana University Golf course.

The team purchased NOx and CO₂ analyzers and shipped the NitroMAC back to Lebanon to analyze the data collected in Indiana. The raw data collected using these instruments during the August 2013 Indiana field sampling campaign were analyzed. The project team tested the instruments for several days in the lab before launching the ambient air field campaign at the suburban site at the Science and Technology Campus at Saint Joseph University. They were also granted a permit to drive a mobile unit equipped with air quality analyzers both in and outside the Salim Slam tunnel, a 500-meter tunnel that constitutes the south entry to Beirut and the main road to Beirut International Airport. The methodology consisted of alternating measurements of the different pollutants for around 30 minutes inside and outside the tunnel in order to be able to determine HONO emission factor in respect to NOx and to the quantity of fuel burned. The field campaign was successful and was also used as input data for the modeling study of the ambient field campaign.

The PI gave two seminars on the PEER project—one for faculty members at University of Indiana and one at the USJ-Faculty of Sciences—covering HONO chemistry and its link to climate change, as well as gaps in our understanding and knowledge of HONO. A meeting was also held with the Ministry of Environment concerning the outcomes of the project. Part of the results will be implemented in an on-going government project regarding air quality.

Publication

C. Abdallah, C. Afif, S. Sauvage, A. Borbon, T. Salameh, A. Kfoury, T. Leonardis, C. Karam, P. Formenti, J.F. Doussin, N. Locoge, K. Sartelet. 2020. Determination of gaseous and particulate emission factors from road transport in a Middle Eastern capital. Transportation Research Part D: Transport and Environment, Volume 83, 102361, ISSN 1361-9209, https://doi.org/10.1016/j.trd.2020.102361.

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