Journal of the Air & Waste Management Association最新文献

The EPA proposed regulations for municipal waste combustors (MWCs) on December 20, 1989. The regulations include (1) performance standards under Section 111(b) of the Clean Air Act (CAA) for new, modified, or reconstructed MWCs and (2) draft emission guidelines and compliance schedules for the states to use to develop control requirements from existing MWCs under Section 111(d). This paper will outline the proposed air emission standards and guidelines, as well as the basis for the prescribed emission limits. The schedule for the remainder of the regulations development will also be discussed.

A new field sampler has been developed for measuring the particulate matter (PM) and carbon monoxide emissions of woodburning stoves. Particulate matter is determined by carbon balance and the workup of a sample train which is similar to a room-temperature EPA Method 5G train. A steel tank, initially evacuated, serves as the motive force for sampling and also accumulates a gas sample for post-test analysis of time-averaged stack CO and CO2 concentrations. Workup procedures can be completed within 72 hours of sampler retrieval. The system has been compared to reference methods in two laboratory test series involving six different woodburning appliances and two independent laboratories. The correlation of field sampler emission rates and reference method rates is strong.

The CF Systems Organic Extraction Process was used to remove PCBs from contaminated sediment dredged from the New Bedford Harbor. This work was done as part of a field demonstration under EPA's Superfund Innovative Technology Evaluation (SITE) program. The purpose of the SITE program is to provide an independent and objective evaluation of innovative waste remediation processes. The purpose of this paper is to present the results of the SITE demonstration of this technology. Results of the demonstration tests show that the system, which uses liquefied propane, successfully removed PCBs from contaminated sediments in New Bedford Harbor. Removal efficiencies for all test runs exceeded 70 percent. Some operational problems occurred during the demonstration which may have affected the efficiency with which PCBs were removed from the dredged sediment. Large amounts of residues were generated from this demonstration project. Costs for using this process are estimated to be between $150/ton and $450/ton.

The objective of this critical review is to address soil remediation techniques at uncontrolled hazardous waste sites with regard to the following areas: 1) important regulatory and technical issues and information needs concerning soil remediation at uncontrolled hazardous waste sites; 2) approaches for selection of remediation techniques; and 3) the current state of knowledge regarding soil remediation techniques, including applications and limitations. The areas identified above are addressed with regard to current information, selected milestone publications, and specific applications of technologies to provide a synthesis of the topic. The information concerning current issues, approaches, and soil remediation techniques presented was critically reviewed in order to: 1) identify deficiencies in current approaches; 2) develop a conceptual framework for remediation; and 3) recommend improved approaches for selection of remediation technologies.

Those responsible for state and local radon programs often express frustration about the small share of homes that have been tested for radon, and the small share of those with high readings that have been mitigated. There are now a number of completed studies that have examined how well alternative ways of communicating about radon risk have accomplished the goals of motivating appropriate testing and mitigation. This paper summarizes the research results that are most crucial for planning and implementing effective radon risk communication programs. We identify six reasons why people do not respond to radon as a serious threat and provide some remedies suggested by radon studies.

Fourteen single-family detached houses in Spokane, Washington, and Coeur D'Alene, Idaho, were monitored for two years after high concentrations of indoor radon had been mitigated. Each house was monitored quarterly using mailed alpha-track radon detectors deployed in each zone of the structure. To assess performance of mitigation systems during the second heating season after mitigation, radon concentrations in seven houses were monitored continuously for several weeks, mitigation systems in all houses were inspected, and selected other measurements were taken. In addition, occupants were also interviewed regarding their maintenance, operation, and subjective evaluation of the radon mitigation systems. Quarterly alpha-track measurements showed that radon levels had increased in most of the homes during many follow-up measurement periods when compared with concentrations measured immediately after mitigation. Mitigation-system performance was adversely affected by (1) accumulated outdoor debris blocking the outlets of subsurface pressurization pipes; (2) fans being turned off (e.g., because of excessive noise or vibration); (3) air-to-air heat exchanger, basement pressurization, and subsurface ventilation fans being turned off and fan speeds reduced; and (4) crawl-space vents being closed or sealed.

A number of policies adopted by the federal government and the state have been designed to promote waste reduction or influence the choice of waste disposal technologies employed by generators of hazardous waste. Graphic analysis of smoothed time series data for hazardous wastes manifested in New York State for the period between June 1982 and February 1987 suggests that some of these policies have had the intended effects. Significant shifts in manifested waste volumes are evident that coincide with the following policy interventions: (1) increased state waste-end tax rates; (2) state and federal landfill bans; (3) federal restrictions on burning hazardous wastes and waste oils for energy recovery; and (4) changes in the federal regulatory definition of hazardous waste. Other changes in waste generation and management appear to be attributable to such factors as state and regional economic conditions and changes in instate treatment and disposal facility capacity. Analysis of the management of specific waste types supports evidence from the graphic analysis that waste generators changed from land disposal to "higher" waste handling technologies in response to several policy interventions.

This article analyzes numerical variability in ozone air quality data to understand how this variability affects the number of violations seen each year in metropolitan statistical areas (MSAs). Three commonly cited violation indices are used: 1) the annual number of expected exceedances averaged over 3 years is greater than 1; 2) the n+ 1th hourly value in n years of data is greater than 0.12 ppm; and 3) the annual number of expected exceedances is greater than 1. Only the first index is consistent with applicable regulations. The analyses indicate that about 23 percent of all MSAs with valid data had one or more change in their ozone violation status between 1979 and 1987. This change in status occurred for approximately 7 percent of all MSA-years of available data. This statistic was about one-third of the value usually obtained when the two incorrect, but commonly used, criteria of ozone violations are used.

A compilation of data from earlier studies of 172 homes in the Pacific Northwest indicated that approximately 65 percent of the 46 homes tested in the Spokane River Valley/Rathdrum Prairie region of eastern Washington/northern Idaho had heating season indoor radon (222Rn) concentrations above the U. S. EPA guideline of 148 Bq m-3 (4 pCi L-1). A subset of 35 homes was selected for additional study. The primary source of indoor radon in the Spokane River Valley/Rathdrum Prairie was pressure-driven flow of soil gas containing moderate radon concentrations (geometric mean concentration of 16,000 Bq m-3) from the highly permeable soils (geometric mean permeability of 5 x 10(-11) m2) surrounding the house substructures. Estimated soil gas entry rates ranged from 0.4 to 39 m3h-1 and 1 percent to 21 percent of total building air infiltration. Radon from other sources, including domestic water supplies and building materials was negligible. In high radon homes, winter indoor levels averaged 13 times higher than summer concentrations, while in low radon homes winter levels averaged only 2.5 times higher. Short-term variations in indoor radon were observed to be dependent upon indoor-outdoor temperature differences, wind speed, and operation of forced-air furnace fans. Forced-air furnace operation, along with leaky return ducts and plenums, and openings between the substructure and upper floors enhanced mixing of radon-laden substructure air throughout the rest of the building.

Evaluation of indoor air pollution problems requires an understanding of the relationship between sources, air movement, and outdoor air exchange. Research is underway to investigate these relationships. A three-phase program is being implemented: 1) Environmental chambers are used to provide source emission factors for specific indoor pollutants; 2) An IAQ (Indoor Air Quality) model has been developed to calculate indoor pollutant concentrations based on chamber emissions data and the air exchange and air movement within the indoor environment; and 3) An IAQ test house is used to conduct experiments to evaluate the model results. Examples are provided to show how this coordinated approach can be used to evaluate specific sources of indoor air pollution. Two sources are examined: 1) para-dichlorobenzene emissions from solid moth repellant; and 2) particle emissions from unvented kerosene heaters. The evaluation process for both sources followed the three-phase approach discussed above. Para-dichlorobenzene emission factors were determined by small chamber testing at EPA's Air and Energy Engineering Research Laboratory. Particle emission factors for the kerosene heaters were developed in large chambers at the J. B. Pierce Foundation Laboratory. Both sources were subsequently evaluated in EPA's IAQ test house. The IAQ model predictions showed good agreement with the test house measurements when appropriate values were provided for source emissions, outside air exchange, in-house air movement, and deposition on "sink" surfaces.