Transport and Fate of Contaminants in the Atmosphere
The following is a list of currently active externally funded research projects:

Studying the Mixing State of Aerosols and Its Impact on Global Climate - Jacobson, M. Z. (NSF)
The goal of this project is to analyze the effect of the mixing state of aerosols on global and regional direct forcing and temperatures. One scientific question to be addressed is, what is the global- and regional-scale mixing state of aerosol-particles and what is the resulting direct radiative forcing? A second question is, which feedbacks of aerosol-particles to climate are important and which ones are not? A third question is, what are the climate effects of (a) fossil-fuel soot and organic matter, (b) biomass burning gases and particles, (c) sulfur dioxide and resulting sulfate, and how do the effects of these components compare with the effects of CO2 and CH4?

Studying the Effects of Aerosols and Clouds on Climate - Jacobson, M. J. (NSF)
This is a project to study the effects of aerosols and clouds on climate. The goals of the project are to quantify the overall effects of aerosols on regional and global temperatures, to study the variations of aerosol composition and size on temperatures, to study the effects of aerosols on vertical temperature profiles, to study the day- and nighttime effects of aerosols on temperatures and to study the direct effects of clouds on temperature.

Building Ventilation Design and Indoor Air Quality- Hildemann, L. M. (UPS Endowment)
Individuals spend ~90% of their time indoors, where the concentrations of airborne particles like molds, fungi and pathogens can be much higher than outdoor levels. It has been hypotehsized that ventilation systems may play an important role in propagating and disseminating these "bioaerosols". This study will measure bioaerosols within and eminating from indoor ventilation systems, to investigate what factors influence the types and concentration levels of molds and fungi present.

Measurement of Dilution Characteristics for Motor Vehicle Emissions - Hildemann, L. M. (Ford Research Foundation)
The sizes of particulate matter (PM) in motor vehicle emissions are greatly influenced by the rate at which motor vehicle emissions undergo dilution. This study will use a wind tunnel to experimentally measure dilution rates downstream of different vehicle shapes, and will assess how factors like vehicle speed, tailpipe location, and tailpipe emission velocity influence the dilution process. The results may prove useful for determining what vehicle design parameters and/or operating conditions will minimize the formation of "ultrafine" PM, which may be of substantial health concern.

Resuspension of Biological Particles from Carpeting - Hildemann, L. M. (Clorox Company)
The sources causing elevated personal exposure to airborne particles in the indoor environment are not well understood. However, resuspension of dust from carpeting due to human activities is believed to be a substantial contributor. This project will focus on biological particles ("bioaerosols"), such as fungi and bacteria, which are of health concern because they can cause allergies and asthma attacks. Field experiments will assess the relationship between the bioaerosol sizes and levels found in the air of typical homes and those present in carpet dust. 

Studying the Effects of Ca, Mg, and K on Aerosol Size and Composition, NOy, and Radiative Transfer - Jacobson, M. Z. (NASA).
This is a project to study the effects of calcium, magnesium, and potassium on aerosol size and composition. These chemicals, present in soil dust and/or sea spray, have been found to have an important effect on aerosol size distributions in polluted and relatively clean air, shifting nitrate from the coarse mode to the accumulation mode. For this study, the feedback between these chemicals on radiative parameters, such as UV, total solar, and infrared irradiance and top-of-the-atmosphere radiative forcing will be examined. The calculations will also be coupled with gas-phase chemistry to estimate the effects of Ca, Mg, K, and total aerosols on gas-phase NOy concentrations. The purpose of this exercise is to estimate the extent to which aerosols as a whole and individual aerosol components affect the NOy:NOx ratio, which is typically overpredicted in many models.

Return to top of page

Return to Environmental and Water Studies Research