Motivation
Respiratory infections and ambient air pollution are two of the leading causes of death globally. Combined, they account for more than 10 million deaths every year worldwide and pose a severe threat to human health. Infections and air pollution-induced diseases are triggered by inhaling air containing pathogens and/or pollutants. Due to their small sizes, pathogen-laden particles and particulate matter can easily penetrate to the lower respiratory tracts to infect susceptible individuals, damage healthy tissues, and cause adverse health effects. Thus, there is an urgent need to explore the environmental behaviors of pathogen-laden particles and particular matter, and the inhalation risks associated with them.
Research Interests
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Bioaerosol emission, transport, and decay
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Environmental monitoring on airborne microorganisms
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Indoor air quality and human exposure
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Particle lung deposition
Current Projects
1. Emission, Transport, and Survival of Airborne Microorganisms.
Inhalation of viable pathogens, including bacteria and viruses, can cause severe respiratory infections. For example, the current global pandemic is caused by the inhalation of the airborne SARS-CoV-2 virus. Various pathogens can be released into the environment from different sources, including patients, wastewater treatment plants, natural sources etc. Once emitted into the environment, they are able to maintain their viability for a long period of time, during which they may transport to other locations and later cause human infection via inhalation. Thus, It is very important to identify the emission sources, the survival, and the transport of airborne pathogens in order to avoid disease transmission.
In this study, we collect samples in both indoor and outdoor environments. To understand people's daily exposure to airborne pathogens, we use traditional culture-based, molecular, and next-generation sequencing techniques to identify and quantify microorganisms in the collected samples. To explore inactivation mechanisms, we investigate the effects of different factors, including particle chemical composition and air composition, on the survival of airborne pathogens using a customized rotating drum under controlled conditions.
2. Detecting Airborne Pathogens Captured on Air Filters in HAVC systems.
Each year, a large number of people get infected, hospitalized, and die from respiratory diseases such as seasonal influenza and COVID-19. Thus, close and accurate monitoring of airborne pathogens in the environment, especially in the indoor environment is extremely important. Monitoring data can not only profile airborne pathogens, but also allow us to estimate human exposure and perform quantitatively assessment on human risks, which will be beneficial for public health.
In this project, we are working with IPF at MSU to collect MERV-13 filters from HVAC systems. By analyzing the samples, we will be able to understand the amount of airborne pathogens might exist in classrooms in different buildings, and thus estimate the health risks by inhalation.
Previous Projects
1. Deposition and Clearance of Little Cigar Smoke Particle in Rat Lungs.
Little cigars are emerging tobacco products that are very popular among the young generation. But its health effects are understudied. Knowledge of the exact locations of particle deposition and the clearance pattern after smoke exposure is critical because it greatly affects the dose and thus health effects on smokers and others. However, this is a complicated question to answer since many factors can affect the deposition locations, including particle size and breathing pattern of smokers. In this study, we use novel techniques, i.e., inductively coupled plasma mass spectrometry and a hyperspectral microscope Cytoviva, to explore the lobe-by-lobe particle deposition as well as high-resolution spatial mapping of deposited particles. Results from the animal study will be used to improve the performance of a mathematical model so it can better predict particle deposition in human lungs.
Use this link to access the peer-reviewed open access journal article from this study.
2. Aerosolization and Dispersion of Bacteria By Hand Dryers
Hand dryers are widely used in public space as an alternative to paper towels, yet their potential to release and disperse microorganisms in such space remain a public health concern. This study investigates the aerosolization and dispersion of bacteria on hands from two commercial hand dryers commonly used in public restrooms. A test chamber was built to simulate restroom conditions, and E. coli K12 was used as a representative microorganism. Bacteria deposition on surfaces were assessed using agar plates in the test chamber. The release of airborne E.coli was quantified by collecting air samples in a confined space made by an Atmosbag. While the potential for hand dryers to aerosolize bacteria from washed hands is low, the results highlight that hand dryers can disperse microorganisms to a considerable distance in the space. This study provides insight into the impact of hand dryers on indoor air quality and the spread of bacteria.
A manuscript from this project is currently in revision in Aerosol Science and Technology.
