Grantee Research Project Results
2004 Progress Report: FDP - Center for Environmental Science
EPA Grant Number: CR830890Subproject: this is subproject number R830890 , established and managed by the Center Director under a main grant
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: Solutions for Energy, AiR, Climate and Health Center (SEARCH)
Center Director: Bell, Michelle L.
Title: FDP - Center for Environmental Science
Investigators: Frederick, John
Institution: University of Chicago
EPA Project Officer: Chung, Serena
Project Period: July 1, 2003 through June 30, 2004 (Extended to June 30, 2006)
Project Period Covered by this Report: July 1, 2003 through June 30, 2004
Project Amount: $487,500
RFA: Targeted Research Center (2003) Recipients Lists
Research Category: Targeted Research
Objective:
The broad mission of the Center for Environmental Science (CES) is to enhance understanding of ways in which human activity, particularly urbanization, alters the chemical and physical environments to which large populations are exposed, with emphasis on local and regional atmospheric and surface conditions. Specific scientific objectives are to: (1) develop empirical descriptions of the radiative, chemical, and thermal environments of the Chicago area and (2) identify and evaluate the physical mechanisms responsible for altered air chemistry and regional climatic conditions.
Progress Summary:
This report summarizes the activities of the CES, a joint effort of the University of Chicago and Argonne National Laboratory, from its inception through June 30, 2004. Research carried out within CES focuses on the effects of urbanization on the physical and chemical environments to which large populations are exposed. Specifically, the focus is on conditions in Chicago, IL, with a metropolitan area population in excess of 9 million people.
CES supports two projects, the Urban Measurements Project (R830890C001) and the Urban Data Analysis and Modeling Project (R830890C002). The prime objective of the first project is to provide empirical inputs to the second project. See the individual 2003 Annual Report summaries for R830890C001 and R830890C002 for more details on these projects. The following paragraphs provide brief summaries of each activity.
R830890C001: The Urban Measurements Project
Activity to date in this project has centered on establishing the Urban Atmosphere Observatory (UAO), a facility composed of instruments to monitor various aspects of the urban environment. The following sensors now operate at UAO: (1) a Brewer Spectrophotometer which measures solar spectral irradiance over the wavelength range 290-363 nm (responsible for driving urban air chemistry); (2) a Robertson-Berger meter which records broadband ultraviolet sunlight with a spectral response similar to the biological weighting function for sunburn in Caucasian skin; (3) chemiluminescent sensors for monitoring ground-level ozone, nitric oxide and total odd nitrogen; (4) a nephelometer for measuring the total extinction coefficient of atmospheric particulate matter; (5) a seven-channel aethalometer which records the black carbon content of particulate matter; and (6) a Multifilter Rotating Shadowband Radiometer (MFRSR) for monitoring the direct and diffuse components of visible sunlight in selected wavelength bands. In addition to these items, CES purchased a Kipp and Zonen Net Radiometer to measure both solar and thermal infrared radiation. The last of these instruments is portable and will operate from several locations in the Chicago area during the coming year.
R830890C002: The Urban Data Analysis and Modeling Project
Thus far, effort has focused on interpretation of meteorological, radiative, and air quality datasets acquired in Chicago prior to establishment of the complete set of sensors at UAO. A study of archived weather data defined the character of Chicago’s urban heat island during different seasons, including its dependence on local time and meteorological conditions. Maximum daytime temperatures reached in the afternoon are very similar at urban (Chicago Midway Airport) and distant suburban (Dupage County Airport, Illinois) locations. Measurements, however, reveal a slower rate of overnight cooling at the urban site, leading to warmer temperatures in the pre-dawn hours. The urban-rural temperature contrast depends on wind speed, being as low as 1°C during extremely windy periods and near 4°C when the air remained nearly calm. Results of this work will be extended and published in the coming year.
Next, an analysis of solar ultraviolet spectral irradiances measured by the Brewer Spectrophotometer during a summer season revealed a link between tropospheric ozone levels and the optical characteristics of cloudy skies at wavelengths that drive urban air chemistry. The measured irradiances showed that cloudy skies provide a larger percentage attenuation at a wavelength of 305 nm than at 345 nm, where the difference between transmissions at the two wavelengths increases as the scattering optical thickness of the clouds increases. Absorption by ozone is strong at the shorter wavelength and negligible at the longer. Model-based radiative transfer calculations produce results consistent with the observations only when they explicitly account for absorption by ozone located in the interstitial air of a cloud. The results demonstrate that a given amount of tropospheric ozone placed inside a cloud provides a much greater absorption (at 305 nm) than the same quantity of ozone in clear air. A paper describing this work is under review by the Journal of Geophysical Research–Atmospheres.
Difficulties Encountered
Problems associated with instrumentation intended for use at UAO delayed the start of the measurements effort into the summer of 2004. Software difficulties involving communication between the data logger and sensors that measure trace gases and broadband ultraviolet radiation were eventually solved. The long-path laser system intended for ammonia measurements has not yet functioned properly. Several months before being placed at UAO, the apparatus operated successfully in Mexico City. It appears that an optical misalignment occurred, possibly when the instrument was shipped back to Chicago. Because the laser light lies in the near infrared, a simple manual realignment based on visual inspection is not possible. To solve this problem, the Center has ordered a Fault Locator, which uses a visible beam at a wavelength of 670 nm to check the continuity of the filter optics and telescope alignment. When this device arrives, work will proceed on the laser system.
In general, summer is the most important season during which to conduct measurements. The original schedule for funding the Center did not allow for comprehensive data collection during the summer of 2003. To allow time for the Center’s personnel to generate substantial results, the initial meeting of the Science Advisory Committee was postponed until early 2005.
Future Activities:
Particulate Matter and Black Carbon
Measurements of the total extinction coefficient and the black carbon content of urban particulate matter have been ongoing since early summer of 2004. An analysis and comparison of these growing datasets will provide information on the contribution of absorption to the total attenuation provided by particulate matter over Chicago. Variability in the particulate black carbon abundance by day of the week (weekdays versus weekends) and its behavior over extended holiday weekends (Independence Day, Labor Day, and Thanksgiving Day 2004) will provide information on inputs associated with diesel soot from trucks and nearby construction activity.
Ongoing operation of the MFRSR provides data on extinction of visible sunlight by particulate matter in the total overhead column of the atmosphere. Optical thicknesses derived from the MFRSR will be compared with ground-level measurements from the nephelometer and aethalometer to assess the importance of particulate matter near the ground on total light extinction in the urban atmosphere.
Ammonia in the Urban Atmosphere
Efforts are underway to place the long-path laser system into regular use, and this should be possible after receipt of the Fault Locator required to fix the alignment problem noted previously. The laser will provide the first measurements of atmospheric ammonia available in the Chicago area. Ammonia, produced in the decay of organic matter, is a precursor to the ammonium ion that comprises a component of atmospheric aerosols. Because such data have not existed previously in the area of UAO, we seek to address very basic questions. Specifically, what is the abundance of ammonia in the urban atmosphere, and how does it vary over time?
Urban Microclimates and the Local Radiative Energy Budget
The Ph.D. research of graduate student Timothy Barzyk will examine factors that influence the temperature of specific locations in an urban area, leading to formation of the “urban heat island” under some meteorological conditions. The primary instrument to be used is the Kipp and Zonen CNR1 Net Radiometer, which consists of four separate sensors mounted on a portable tripod. These measure the upward and downward total solar irradiance and the upward and downward thermal infrared irradiance, where the latter is a measure of surface temperature. The CNR1 has been operating successfully at the UAO site, and in the coming months it will be deployed at various locations in Chicago. These sites include the bottom and top of a downtown "urban canyon" consisting of high-rise buildings plus a rural site at Argonne National Laboratory surrounded by a forest preserve. Data acquired by the CNR1 will be supplemented by information on atmospheric optical depth provided by the UAO-based MFRSR. A goal of this effort is to determine how the optical properties of the urban atmosphere and the thermal and optical properties of the lower boundary (concrete, grass, etc.) influence the daily cycle in local temperatures. A topic of special interest involves the influence of high-rise urban development on the magnitude of daytime heating by sunlight and of overnight cooling by infrared thermal emission. Downtown Chicago provides an ideal location for this study.
Journal Articles: 1 Displayed | Download in RIS Format
Other center views: | All 9 publications | 2 publications in selected types | All 1 journal articles |
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Winiecki S, Frederick JE. Ultraviolet radiation and clouds:couplings to tropospheric air quality. Journal of Geophysical Research 2005;110, D22202, doi:10.1029/2005JD006199. |
CR830890 (Final) CR830890C003 (Final) |
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Supplemental Keywords:
urbanization, particulate matter, air quality, solar radiation, thermal radiation, carbon, atmospheric energetics, air, atmosphere, modeling, monitoring, Chicago, Illinois,, RFA, Scientific Discipline, Health, Air, particulate matter, Environmental Chemistry, Health Risk Assessment, air toxics, Air Pollution Effects, Risk Assessments, Environmental Monitoring, Biochemistry, ambient aerosol, asthma, particulates, ambient air quality, health effects, biostatistics, cardiopulmonary responses, human health effects, morbidity, toxicology, air pollutants, exposure and effects, exposure, hazardous air pollutants, animal model, air pollution, children, particle exposure, atmospheric aerosols, ambient particle health effects, inhalation, mortality studies, human exposure, allergens, mortality, aerosols, particle transport, atmospheric chemistry, exposure assessment, cardiovascular diseaseRelevant Websites:
http://www.atmos.anl.gov/CES/ Exit
Progress and Final Reports:
Original Abstract Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
CR830890C001 The Urban Measurements Project—The Urban Atmosphere Observatory
CR830890C002 The Urban Data Analysis and Modeling Project
CR830890C003 Attenuation of Ultraviolet Solar Radiation by Cloudy Skies: Links to Urban Air Quality
CR830890C004 Measurements of Black Carbon in Chicago: Implications for Controls on Diesel Emissions
CR830890C005 Attenuation of Visible Sunlight by Limited Visibility and Cloudiness
CR830890C006 The Energy Balance of Urban Microclimates
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.