Of the main routes of exposure to environmental contaminants (dermal contact, ingestion, inhalation), inhalation is of the most concern to human health because we cannot control what we breathe as well as what we touch or eat. In fact, we are still discovering ways in which the inhalation of air pollutants (especially aerosols) affects health. We now know that air pollution kills 7 million people per year. Beyond that, we are curious about chronic, low-dose exposure levels that may be linked to conditions that we are still discovering. For example, exposure to PM2.5 (particulate matter < 2.5 micrometers) has been recently tied to mental health issues, such as brain aging and anxiety.
We are interested in using engineering concepts to characterize emissions of aerosols (small particle or droplets suspended in air) from everyday sources and their subsequent transformations indoors and outdoors. These measurements can aid in developing tools and strategies to control emissions and minimize exposures, especially to vulnerable populations—such as children and the elderly, and incidentally exposed populations (i.e., bystanders of a certain activity). Applications of our research include evaluating physical and chemical transformations of aerosols indoors and outdoors and assessing emissions to inform "safer by design" consumer products. Our mission is to perform research that will lead to positive impact in human health and the environment.
Main research topics:
- Formation, transport, and fate of aerosols, ranging from ultrafine (<100 nm), fine (< 2.5 µm), to coarse (>2.5 µm).
- Physical and chemical characterization of particulate matter using single-particle techniques, such as electron microscopy.
- Evaluation and use of low-cost sensors for air pollution measurements indoors and outdoors.
- Assessment and minimization of people's exposure to environmental contaminants.
- Ambient and source aerosol sampling and characterization.
- Assessment of the release of nanomaterials or aerosols from consumer products.
- Development nanotechnology applications for environmental sustainability.
Current and past projects:
- Aerosol filtration testing of novel and homemade masks and respirators (2020 - present)
- CASA: Chemical Assessment of Surfaces and Air (2020 - present)
- Home sensors: Evaluating the use of low-cost particulate matter sensors in home applications (2018 - present)
- HOMEChem: A collaborative indoor air chemistry field study (2017 - present)
- Emissions of particulate matter from cooking oils (2017 - present)
- IndoorChem: A community of researchers in the chemistry of indoor environments (2017 - present)
- Investigating the impacts of air pollution and weathering on the efficiency of photovoltaic systems (2017 - present)
- Emissions of ultrafine aerosols from 3D printers (2015 - present)
- NanoEarth: The Virginia Tech National Center for Earth and Environmental Nanotechnology Infrastructure (project ongoing, my participation ended in 2016)
- Characterization of nanoscale components of dust and aerosols in the city of Shanghai, China (2014 - 2016)
- Keeping track of nanotechnology in the real world: Redeveloping the Wilson Center’s Nanotechnology Consumer Products Inventory (2013 - 2015)
- Children's exposure to silver nanoparticles in nanotechnology-enabled consumer products (2010 - 2012)
- Consumer exposure to silver nanoparticles in spray products (2008 - 2012)
- Cal-Mex: Atmospheric Studies in the US-Mexico Border Region (2010)
- Indoor air quality in a Brazilian hospital (2007 - 2008)
- Development of methods for sampling and characterizing odorous air samples (2003 - 2008)
- Olfactometry and impact assessment of odors and VOCs in the vicinity of industrial sites (2003 - 2008)
Some of our Laboratory Instrumentation
- TSI scanning mobility particle sizer (SMPS) systems, including a 1-nm SMPS, nano DMA, and long DMA.
- TSI Nanoscan portable SMPS system + optical particle sizer for size distributions 12 - 10,000 nm
- Aethlabs 5-wavelength aethalometers
- Thermodenuder, atomizer
- 1 cubic meter teflon chamber and smaller, table-top 0.5 cubic meter chambers
- A 38 cubic meter aerosol emissions evaluation room, separate from the building's HVAC system, with a independent 30 ACH flushing system.
- Access to GC-MS, ICP-MS, transmission and scanning electron microscopy