Jump to main content or area navigation.

Contact Us

Human Exposure and Atmospheric Sciences

Climate Research

EPA scientists are developing laboratory and computer modeling methods to determine the effects that emissions in ambient air have on humans and ecosystems. These tools will enhance scientific ability to forecast future atmospheric conditions, making it possible for EPA to take pro-active approaches for addressing the major atmospheric chemistry issues of the 21st century, including climate change.

Researchers are using sophisticated test chambers to simulate atmospheric conditions under highly controlled conditions. This allows scientists to observe the interactions of various chemicals and determine how they transform. The scientists are also developing an innovative computational chemistry-based method for predicting lifetimes and fates of atmospheric compounds. In other climate change research, EPA exposure scientists are developing and testing innovative technologies for estimating environmental air quality.

Computational atmospheric chemistry helps EPA scientists forecast future atmospheric conditions
EPA scientists have developed an innovative computational chemistry-based method called COMPCHEM that is used for predicting lifetimes and fates of atmospheric compounds. COMPCHEM consists of a set of well-established, state of the science, quantum chemistry and gas phase kinetic codes, all of which have been used in numerous studies reported in peer-reviewed literature. It is anticipated that COMPCHEM will be a cost effective tool for supplementing atmospheric chemistry data generated through laboratory studies.

Sophisticated test chambers used to simulate atmospheric conditions
EPA scientists are using experimental laboratory studies to gather and assess data on atmospheric gas phase and particulate phase chemistry in order to determine the effects that various source emissions have on humans and ecosystems. Researchers are also working on the construction and development of a new, mobile photochemical reaction chamber to be used to study the toxicity of combustion emission sources. Research results are anticipated improve understanding of how atmospheric reactions and transformations influence the toxicity of air pollutant mixtures.

Development of Federal Reference and Equivalent Methods for measuring key air pollutants
EPA researchers are continually evaluating potential new Federal Reference Methods and Federal Equivalent Methods to foster innovation and improved measurement of atmospheric pollutants. The methods are tested in the lab and field. The scientists keep up-to-date on current air pollution sensor technologies, including availability and commercialization of emerging technologies. Adopting new technologies improves EPA’s ability to measure air pollution in new ways and locations.

Air pollution near roadways
EPA researchers are partnering with the University of Michigan on a study of the impact of vehicle emissions on near-road air quality, human exposures, and potential health effects in asthmatic children. The Near-Road Exposures to Urban Air Pollutants Study (NEXUS) is being conducted as part of EPA’s larger research program on roadway air pollution and its potential health effects. The study design will help tease out the health effects of particulate matter from diesel-burning truck and car exhaust. Particulate matter and other pollutants are being measured immediately next to the roadways and at various distances from them, to study how pollutant concentrations change as distance from the roadway increases.

Apps & Sensors for use in Human Exposure & Community Monitoring Studies
Smart phone applications and hand-held monitoring devices, or Apps and Sensors, are being developed world-wide that have the capability of detecting various air pollutants. Through collaborations with outside developers, EPA exposure scientists are working on the development, improvement, and application of these newly emerging environmental Apps and Sensors. App and Sensor technology has the potential to advance the paradigm of how air quality measurements are gathered, while reducing the cost and expense of their collection.

Positive Matrix Factorization (PMF) Model
EPA’s Positive Matrix Factorization (PMF) Model is one of several receptor models developed by EPA scientists that provide scientific support for current ambient air quality standards and implementation of those standards by identifying and quantifying the relative contributions that various air pollution sources contribute to ambient air quality in a community or region. Users of EPA’s PMF model provide files of sample species concentrations and uncertainties which the model uses to calculate the number of sources types, profiles, relative contributions, and a time-series of contributions.

Unmix 6.0 Model
EPA’s Unmix 6.0 Model is one of several receptor models developed by EPA scientists that provide scientific support for current ambient air quality standards and implementation of those standards by identifying and quantifying the relative contributions that various air pollution sources contribute to ambient air quality in a community or region. Users of EPA’s PMF model provide files of sample species concentrations and uncertainties which the model uses to calculate the number of sources types, profiles, relative contributions, and a time-series of contributions.

Jump to main content.