Northeast Oxidant and Particle Study (NE-OPS)

Northeast Oxidant and Particle Study (NE-OPS)
This project contributed to the understanding of how pollutant transport in the upper levels of the
atmosphere contribute to high levels of air pollution. Located in Philadelphia, the Northeast Oxidant and
Particle Study (NE-OPS) conducted intensive air quality measurements in the summers of 1999, 2001,
and 2002. Seven universities, three national laboratories, six agencies, and private industry collaborated
on the project.
Investigate the urban polluted environment to find the relationships among conditions leading to
concentrations of ozone and fine particles
Determine the contributions from local and distant pollution sources.
Examine the role that meteorological properties play in the build-up and distribution of pollutant
concentrations over urban and regional scales and interpret these results within the context of past
measurement programs to extend the knowledge gained to other applicable locations and atmospheric
Research Conclusions
Meteorology is the primary driver and leading factor controlling high ozone and particulate matter
episodes in the northern U.S.
Essentially all of the major air pollution events involve regional scale circulations and are associated
with transport from the Midwest.
Vertical mixing of pollutants and precursors from the storage/transport reservoir above the nocturnal
boundary layer provide major input to pollution episodes.
Vertical profiles of atmospheric properties are essential for understanding the processes and evolution
of air pollution episodes.
Successful application of simpler modeling options has been validated using the NE-OPS ground and
upper air data. The NE-OPS data base will provide opportunities for critical testing and evaluation
of models.
Funding for this project was provided by the U.S. EPA and the state of Pennsylvania. The principal
investigator was Russell Philbrick of the Pennsylvania State University.
For more information see: