2000 Progress Report: Investigations of Factors Determining the Occurrence of Ozone and Fine Particles in Northeastern USA

EPA Grant Number: R826373
Title: Investigations of Factors Determining the Occurrence of Ozone and Fine Particles in Northeastern USA
Investigators: Philbrick, C. Russell , Allen, George , Clark, Richard , Daum, Peter , Dickerson, Russell R. , Doddridge, Bruce , Georgopoulos, Panos G. , Hatch, Victoria , Koutrakis, Petros , Lawrence, Joy , Lazaridis, M. , Lysak, Dan , Mohnen, Volker , Munger, J. W. , Newman, Leonard , Porter, Steve , Rao, S. Trivikrama , Wofsy, Steven C. , Wolfson, Jack M. , Zurbenko, Igor
Current Investigators: Philbrick, C. Russell , Allen, George , Clark, Richard , Daum, Peter , Dickerson, Russell R. , Doddridge, Bruce , Georgopoulos, Panos G. , Hatch, Victoria , Hogrefe, Christian , Kleinman, Larry , Koutrakis, Petros , Lawrence, Joy , Lazaridis, M. , Mohnen, Volker , Munger, J. W. , Porter, Steve , Rao, S. Trivikrama , Ryan, William , Wofsy, Steven C. , Wolfson, Jack M. , Zurbenko, Igor
Institution: Pennsylvania State University , Brookhaven National Laboratory , Harvard University , Millersville University of Pennsylvania , Rutgers University - New Brunswick , The State University of New York at Albany , University of Idaho , University of Maryland
Current Institution: Pennsylvania State University , Brookhaven National Laboratory , Harvard University , Millersville University of Pennsylvania , Rutgers, The State University of New Jersey , The State University of New York at Albany , University of Idaho , University of Maryland
EPA Project Officer: Shapiro, Paul
Project Period: April 15, 1998 through April 14, 2003 (Extended to April 14, 2004)
Project Period Covered by this Report: April 15, 2000 through April 14, 2001
Project Amount: $3,000,000
RFA: Special Opportunity in Tropospheric Ozone (1997) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Air


The objectives of this research project are to investigate the urban polluted environment to find the relationships and conditions leading to high ozone concentrations and increased levels of fine particles, determine the contributions from local and distant sources, examine the role of that meteorological properties play in concentrating and distributing pollutant concentrations, and interpret these results within the context of past measurement programs to extend the knowledge gained to other applicable locations and atmospheric conditions.

Progress Summary:

A field site in northeast Philadelphia was established, and the initial field measurements program was conducted on August 1-22, 1998. The field measurements program was given the name NE-OPS (Northeast - Oxidant and Particle Study) and was associated with the NARSTO program to adopt the NARSTO data archiving convention for the project. The primary objective of the measurement program during summer 1998 was to develop the facilities for operation of the field site and to compare several instruments to be employed during the measurements program. However, the major air pollution episode of the summer occurred at the end of the measuring program, August 21-22, 1998, and provided an excellent data set for analysis. The measurements from the August 21-22 event clearly show the importance of transported aged materials in development of a significant pollution event. The unique set of vertical profiles obtained with lidar, tethersondes, and aircraft spirals clearly show the incursion of processed precursor materials from an aloft layer, transported into the region, and then mixed downward to the surface by the rising daytime convective boundary layer. The initiation of an ozone and particulate matter pollution event on August 21, 1998, was captured in vertical profiles of the ozone, aerosol extinction, water vapor, and other meteorological parameters. The measurements clearly show the value of time sequences of ozone and aerosol (PM) profiles in understanding the evolution of air pollution episodes. Results reveal the importance of the surface layer dynamics in determining the actual pollution hazard for the surface dwelling population. During the 2-week period of the pilot study, hazardous levels of ozone were frequently observed existing above the surface layer. The vertical transport intensity and the composition of surface layer gases that can destroy ozone cause surface exposures to differ.

The 1999 summer intensive measurements included those techniques used in the initial field program during summer of 1998, with several additional research groups and instruments. Several groups, who were not funded under the original consortium, have joined in this effort to provide additional measurements for characterization of air quality. Investigators from Brigham Young University brought instruments to measure the volatile organic contribution to the particulate matter. The activity of Pacific Northwest National Laboratory (PNNL) and Argonne National Laboratory (ANL) brought several additional measurements (sondes, sounders, chemistry laboratory) into the program and added two temporary field sites that have added significant value to the activity. The efforts of Professors Steve McDow of Drexel University, Hans Hallen of NC State University, Derrek Dunn of North Carolina A&T State University, Bill Ryan (now of Penn State University), and Delbert Eataugh of Brigham Young University are highlighted here because of their contribution to the activity during 1999 by joining into the measurement and analysis efforts.

The intensive phase of the investigation began on June 28, and ended on August 18, 1999. The primary activity was conducted at our field site at the Baxter Water Treatment Plant of the City of Philadelphia located about 14 km north-northeast of city-center Philadelphia. Measurements were added by PNNL and ANL at Centerton, NJ, and West Chester, PA (south and west of Philadelphia) during the period of July 23-August 11, 1999. The summer period produced eight periods of special interest that were associated with ozone and/or PM events, which are listed in Table 1. The large range of conditions for the PM and ozone events that occurred during the 1999 summer provide a rich database for investigations of the factors effecting the evolution of air pollution events. It is worthy to note that the largest ozone event (>180 ppb) during the past 10 years was captured during one of the intensives.

During the year 2000, the valuable data obtained during summer 1999 have been used to test many of the ideas concerning the factors that are most important in controlling the evolution of air pollution episodes. Most of the episodes are associated with the transport of pollutant or precursors for pollutant formation into the region. Even though local sources are present, the periods of high pollution levels appear to be dominated by material transported into the region. The dynamics of horizontal and vertical transport are the key parameters for describing the evolution of air pollution episodes. The quickest recovery from a period of high air pollution occurs, not unexpectedly, when a frontal passage with rain moves through the region, as evidenced in two episodes. However, the period of time before a frontal passage appears more likely to exhibit pollution enhancement. This phenomena may be associated with the accumulation and push of polluted air and precursors ahead of the front. Several activities during the past year have centered on testing modeling properties.

Table 1. Intensive periods identified as special interest during 1999 summer

Intensive Periods of Observation - 1999 (June 28–August 20, 1999)
# Dates Comments
1 July 3-5 PM (>65 g/m3) and Ozone (>120 ppb) Event - UMD aircraft
2 July 8-10 PM and Ozone Event ahead of front passage
3 July 16-21 Several days of ozone end with large PM (>75 g/m3) UMD aircraft
4 July 23-24 2-day Ozone and large PM (with sondes and sounder at added sites)
5 July 27/ August 1 Several days of moderate ozone lead into largest ozone event in 10 years, 162 ppb surface-180 ppb aloft - BNL and UMD aircraft
6 August 7-8 PM event with little ozone response
7 August 11-13 PM and ozone (125 ppb on August 12) followed by storm on night of August 13
8 August 15-17 Moderate PM and ozone event - new UMD Aztec aircraft


Several high ozone and PM events occurred during the 1999 NEOPS field intensive that were largely affected by horizontal transport and vertical mixing. An understanding of these events can only be elucidated by aloft measurements that include a characterization of the thermodynamic structure and evolution of the PBL. The advantage of the Philadelphia site is that it can provide a detailed measurement of variations in PM and trace gases at the surface as they relate to changes in the thermodynamic and dynamic fields aloft. Regional and local scale circulations can drastically alter the surface concentrations of gases and fine particles. For instance, sea breeze fronts and thunderstorm outflow boundaries are extremely shallow features that can, literally within minutes, generate a three-fold increase in PM concentration and two-fold decrease in ozone concentration. Currently, these features are poorly simulated by high resolution (3 km grid spacing) numerical models, and the state-of-the-science will not improve without validation through observation and measurements aloft.

The results obtained during 1998-2000 from the NEOPS intensives have highlighted the importance of the boundary layer transition period in determining the resulting height of the daytime PBL and the concentrations of gases and fine particles. Maximum daytime concentrations were affected by the time required for the transition from a stable nocturnal PBL to a fully developed daytime mixed layer. In some cases, this transition was extremely rapid, with the PBL becoming convective within 30-60 minutes after the onset of surface heating, and leading to better fumigation and lower afternoon concentration maxima. In other cases, the transition was much slower, occurring over several hours while allowing concentrations of gases and particles to accumulate, and often leading to large exceedances by afternoon. Such assessments can only be documented using a combination of high frequency surface and aloft measurements, which the Philadelphia site can provide.

Future Activities:

The move of the field site to an improved nearby location is to be completed by May 2001 with help from the Philadelphia Air Services Management Office. A major summer intensive is planned for the Philadelphia site during July 2001, to correspond with the Northeast Supersites in New York, Pittsburgh, and Baltimore. We expect that our central location and our measurements of the meteorological properties will prove valuable in interpretation of the summer results. Because of funding limitations, the measurement program will be shortened to 4 weeks, the priority of the efforts will be shifted slightly, and the brief winter campaign will not be conducted. The BNL aircraft will not be available for summer of 2001, but they will send an air chemistry laboratory to obtain measurements at the Philadelphia site. Additional groups joining the summer 2001 program include Clarkson University, Texas Tech University (supporting the EPA Laboratories), and additional optical sensors from the University of Maryland and Pennsylvania State University to describe airborne particulate matter. Several new sensors will be operated by Millersville University. Results from the program are planned for presentations at the NYSERDA Symposium and the American Meteorological Society Symposium on Air Chemistry, and articles are to be prepared for a Journal of Geophysical Research issue.

Journal Articles on this Report : 4 Displayed | Download in RIS Format

Other project views: All 194 publications 26 publications in selected types All 20 journal articles
Type Citation Project Document Sources
Journal Article Eatough DJ, Obeidi F, Pang YB, Ding Y, Eatough NL, Wilson WE. Integrated and real-time diffusion denuder sampler for PM2.5. Atmospheric Environment 1999;33(17):2835-2844. R826373 (1998)
R826373 (2000)
R826373 (2002)
R825367 (Final)
  • Full-text: ScienceDirect-Full Text PDF
  • Abstract: ScienceDirect-Abstract
  • Journal Article Ku J-Y, Mao H, Zhang K, Civerolo K, Rao ST, Philbrick CR, Doddridge B, Clark R. Numerical investigation of the effects of boundary-layer evolution on the predictions of ozone and the efficacy of emission control options in the Northeastern United States. Environmental Fluid Mechanics 2001;1(2):209-233. R826373 (2000)
    R826373 (2002)
  • Full-text: ResearchGate-Abstract & Full Text-PDF
  • Abstract: Springer-Abstract
  • Other: UMD-Full Text-PDF
  • Journal Article Lin C-YC, Jacob DJ, Munger JW, Fiore AM. Increasing background ozone in surface air over the United States. Geophysical Research Letters 2000;27(21):3465-3468. R826373 (2000)
    R826373 (2002)
  • Full-text: ResearchGate-Abstract & Full Text PDF
  • Abstract: Wiley-Abstract
  • Other: NOAA-Full Text PDF
  • Journal Article Zhang KS, Mao HT, Civerolo K, Berman S, Ku J-Y, Rao ST, Doddridge B, Philbrick CR, Clark R. Numerical investigation of boundary-layer evolution and nocturnal low-level jets:local versus non-local PBL schemes. Environmental Fluid Mechanics 2001;1(2):171-208. R826373 (2000)
    R826373 (2002)
  • Full-text: University of Maryland-Full Text PDF
  • Abstract: Springer-Abstract
  • Other: ResearchGate-Abstract & Full Text PDF
  • Supplemental Keywords:

    ambient air, atmosphere, ozone, tropospheric species, particulates, VOC, oxidants, nitrogen oxides, sulfates, organics, modeling, monitoring, measurement methods, environmental chemistry, general circulation models, remote sensing, northeast, Atlantic coast, mid-Atlantic region, EPA Region 3., RFA, Scientific Discipline, Air, Geographic Area, Environmental Chemistry, State, Environmental Monitoring, tropospheric ozone, Atmospheric Sciences, remote sensing, urban air, emission sources, ozone occurrence, Pennsylvania, ambient ozone data, ambient air, air pollution models, diurnal cycle of polluted air masses, fine particle sources, atmospheric chemical reservoirs, meteorological fluctuations, PA

    Relevant Websites:

    http://www.ee.psu.edu Exit

    Progress and Final Reports:

    Original Abstract
  • 1998 Progress Report
  • 1999 Progress Report
  • 2001
  • 2002 Progress Report
  • Final