Free Webinar - The pandemic’s impact on outdoor and indoor air quality

Posted by Monica Mellinger on

Host: AIChE Environmental Division

Date: Aug 23rd, 2021

Time: 5:30 - 6:30 PM EST

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Speaker: Lea Hildebrandt Ruiz, Assistant Professor, The University of Texas at Austin


Worldwide, air pollution in indoor and outdoor environments results in approximately 8 million human deaths every year. Reducing air pollution requires a detailed understanding of its sources and atmospheric fate. Restrictions in cities around the world aimed to control the COVID-19 pandemic have provided a novel opportunity to study how changes in human activities and their associated emissions affect atmospheric chemistry and air quality. We assessed impacts of the 2020 COVID-19 lockdown on ambient air quality in Delhi, India. The primary pollutants NOx, CO and BC were most reduced, primarily due to lower transportation emissions. Concentrations of submicron particulate matter (PM1) changed only moderately compared to prior years. The lockdown restrictions led to rather small perturbations in the primary fraction ofPM1, with secondary aerosol (formed from photochemical production) continuing to dominate. Overall, our results demonstrate the impact of secondary and primary pollution on Delhi’s air quality and show that large changes in emissions within Delhi alone are insufficient to bring about needed improvements in air quality.

While lockdown restrictions have decreased emissions, widespread disinfection to curb the spread ofCOVID-19 has increased emissions of disinfectants and their byproducts, increasing human exposure to these compounds, especially in indoor environments. We simulated a classroom and measured exposure to disinfectants and disinfection byproducts. Masks decrease inhalation exposure to some disinfection byproducts and increase exposure to others via adsorption of vapors to the mask. In addition, adsorbed chemicals, mask materials and water vapor (from exhalation) react to produce additional chemical products which are potentially more harmful than the primary vapors. Results from this work can be used to evaluate which disinfectants to use and which masks to wear, and how often to change them, during and after disinfection.

Speaker Bio:

Dr. Lea Hildebrandt Ruiz is Associate Professor in the McKetta Department of Chemical Engineering and at the Center for Energy and Environmental Resources at the University of Texas at Austin. Dr. Hildebrandt Ruiz holds a B.S. with Honors in Chemical Engineering from the California Institute of Technology (Environmental Track) and a Ph.D. in the Department of Chemical Engineering and the Department of Engineering and Public Policy from Carnegie Mellon University. She was a postdoctoral fellow at that National Center for Atmospheric Research. Her research focuses on air quality engineering and the effects of physical and chemical processing of pollutants on human exposure in indoor and outdoor environments. Current specific research interests include tropospheric chlorine chemistry, air quality impacts of unconventional oil and gas development, air quality in New Delhi, India and indoor air quality impacts of disinfection. Dr. Hildebrandt Ruiz received an NSF CAREER award, the James J. Morgan Early Career Award from the ACS Environmental Division, and the Early Career Award from the AIChE Environmental Division.