Principal Investigator: Ferro
Resuspension, the lift off and reentrainment of settled particles into the air, is an important source of human exposure to particle bound pollutants, both indoors and outdoors. However, resuspension has not been well characterized and existing fundamental models have thus far been limited to ideal cases that do not accurately predict resuspension in real environments. To address this research gap, this CAREER project will investigate the resuspension of pollutants using an integrated research and teaching approach. The objectives of the career development plan are: (1) to develop well prepared scientists and engineers who can apply their knowledge in the area of pollutant fate and transport; (2) to increase the numbers of underrepresented students in science and engineering undergraduate and graduate study; (3) to characterize the behavior of resuspended particles through a combination of theoretical and experimental work; (4) to improve and validate a fundamental resuspension model to predict particle behavior in the built environment; and (5) to transform the way people view human exposure to harmful substances by advancing and communicating the role the resupension/deposition cycle in exposure pathways. The PI will conduct integrated experimental and theoretical research to characterize and model the behavior of resuspended particles from human walking. She will employ chamber and wind tunnel studies to quantify resuspension factors and modeling studies to develop and validate a theoretical resuspension model.
By providing the tools to incorporate resuspension in human exposure and pollutant cycling models and through a targeted educational and outreach plan, the proposed research could result in: 1) changes in the selection of materials used in the built environment; 2) guidance for emergency response to chemical and biological agents; and 3) human behavior modification and policy changes to reduce exposure to resuspended pollutants. This project will train graduate, undergraduate, and K-12 teachers and students in the fate and transport of environmental pollutants, and increase the presence of underrepresented groups in science and engineering research through active recruitment and mentorship.
Resuspension, the stirring up of settled particles into the air, is an important source of human exposure to pollutants, both indoors and outdoors. Resuspended particles are of health concern due to their size (many are small enough to be breathed into the lungs) and their composition. Indoor dust is not limited to pet allergens, dust mites, and chemicals introduced to indoor environments by occupants. It also contains a large contribution from outdoor sources such as soil, pollen, road dust, and airborne particles from automobile emissions. House dust can contain high concentrations of bacteria, pesticides, heavy metals including lead and mercury, and other toxins, and these contaminants persist indoors for long time periods, even decades. The resuspension of pollutants is not well understood and often ignored. For this project, Dr. Andrea Ferro’s research group at Clarkson University quantified the amount of particles that are resuspended during normal human activity. They developed a standard method for estimating resuspension from human walking by using a mechanical foot, and, using this method, they investigated the factors that affect particle resuspension. These factors include particle size, flooring type, relative humidity, and dust loading level. They found that dust is more easily resuspended from carpets than from hard flooring and also more easily resuspended from low-density carpet than high-density carpet. They developed emission rate estimates (amount of particles resuspended per unit of time) which can be used to directly predict human exposures. Dr. Ferro’s group also conducted experiments in a wind tunnel and developed a mathematical model for resuspension of real particles. Their innovative model, which includes bumps and roughness on particle surfaces, predicts experimental data better than previous models. In the process of conducting this research, Dr. Ferro trained 10 undergraduate student researchers and five graduate student researchers in pollutant fate and transport. She worked with a high school teacher to develop a curriculum that includes air pollution for environmental science and biology classes. She also conducted a number of seminars and workshops for the general public geared toward understanding the science behind air pollution and creating healthy living environments. To help people understand the effect human activities have on indoor air quality, Dr. Ferro developed a new intervention program. The participants of the program are provided with an audit in their home to evaluate sources of indoor pollutants as well as tailored intervention strategies to improve indoor air quality. Indoor air pollutant levels are measured with an indoor air quality monitor, and participants receive direct feedback of the indoor pollutants levels via a web-based dashboard application. Thus, participants are able to determine in real-time the impact of their activities and make changes that improved the quality of the air they breathe. The overall goal of Dr. Ferro’s work is to improve human health by improving the quality of the air we breathe through source control, ventilation and purification strategies, education, and regulatory policy. Through this project, Dr. Ferro has provided scientific evidence to support the preference for hard flooring for persons with sensitivities to house dust (e.g., allergies or allergy-induced asthma). The methods she developed and study findings are also applicable to other important areas, such as guidance for emergency response to chemical and biological agents that can be resuspended from outdoor and indoor surfaces. This study demonstrates how exposure to pollutants via resuspension can be mitigated by better product selection and minor changes in human behavior.
