JAPCA最新文献

Although the Superfund remedial action decision process is a complex process involving a variety of technical, political, and public health issues, the primary goal of remedial action is the protection of public health. We performed an in-depth analysis of 50 post-SARA Records of Decision in order to characterize the role of risk assessment in the decision-making process and determine whether decisions are being made in an effective and environmentally protective manner. Our findings indicate that the majority of decisions to remediate Superfund sites are based on the existence of contamination per se and not on actual public health risk. Although hypothetical risk is an essential consideration, this gray area is not well-defined in the current decision-making process. The lack of assessment of the degree of risk reduction associated with the remedial alternatives evaluated and the lack of support indicating the effectiveness of the remedial alternatives selected also constitute major weaknesses in the majority of decisions. These inadequacies undermine rationales regarding the protectiveness and cost-effectiveness of the remedial alternatives selected. The fact that objectives beyond addressing public health risk are often unclear in the decision-making process also weakens rationales for cost-effectiveness.

The purpose of this study was to characterize and measure indoor air quality in public facilities and office buildings. The pollutants of interest were particulate matter smaller than 2.5 microns in diameter, PM-2.5, and environmental tobacco smoke (ETS). Integrated PM-2.5 samples were taken on Teflon membrane filters using Harvard Aerosol Impactors as a pre-size selector. Filters were analyzed by gravimetric analysis. Nicotine, which was used as a marker for ETS, was collected on sodium-bisulfate-impregnanted, glass-fiber filters and was analyzed by gas chromatography. Twenty-one structures were monitored in Metropolitan Boston. Measured particle concentrations ranged from 6.0 micrograms/m3 to about 550 micrograms/m3. Nicotine concentrations were as high as 26 micrograms/m3 in a designated smoking room. Real-time measurements were also taken using two types of nephelometers; a Handheld Aerosol Monitor (HAM) and a Miniature Real-Time Aerosol Monitor (MINIRAM). Short-term field measurements with these instruments correlated better with the integrated PM-2.5 concentrations in smoking locations than with concentrations in non-smoking areas.

A joint conference, for the fourth straight year cosponsored by the Air & Waste Management Association's TP-6, TP-7, and ITF-2 technical committees, and the Atmospheric Research and Exposure Assessment Laboratory of the U.S. Environmental Protection Agency, was held at Raleigh, North Carolina, May 2-5, 1989. The technical program consisted of 145 presentations, held in 14 separate technical sessions, on recent advances in the measurement and monitoring of toxic and related pollutants found in ambient and source atmospheres. Covering a wide range of measurement topics and superbly supported by 57 exhibitors of instrumentation and consulting services, the symposium was enthusiastically received by more than 700 attendees from the United States and other countries. This overview contains a selection of the highlights from the technical presentations. A synopsis of the keynote address to the symposium is also included.

A number of investigations have attributed the control of the nasal to oral/nasal ventilation transition to nasal resistance. To investigate possible changes in nasal resistance due to sulfur dioxide (SO2) exposure, 14 subjects (7 men and 7 women), healthy non-smokers, between the ages of 20 and 46 years, were exposed for 30 minutes to filtered air while free breathing and to 2.0 ppm SO2 with either free breathing, forced oral or forced nasal breathing with continuous exercise at a workload 300 kg.m/min below the workload which initiated cross-over from nasal to oral/nasal breathing in a preliminary incremental workload test. An incremental work test under the ambient conditions was performed immediately following the 30-minute exercise to ascertain any change in the cross-over ventilation. Pre- and post-measures of pulmonary functions were obtained to ascertain any changes in these parameters due to the exposure. There was a significant difference in the workload at which cross-over occurred following forced oral breathing in 2.0 ppm sulfur dioxide. The nasal ventilation prior to cross-over and the nasal component of ventilation were significantly smaller for this exposure condition, indicating a possible change in nasal dynamics following the 30 minutes of forced oral breathing in 2.0 ppm SO2. Lack of concomitant changes in pulmonary function tests including airway resistance suggests that breathing 2.0 ppm SO2 does not affect normal subjects whether administration is by free, forced oral or forced nasal breathing.

In January 1987, an air pollution episode occurred in central and western Europe. Levels of SO2, NO2, black smoke, sulphates and other components were elevated, with 24 hour average concentrations of SO2 reaching a maximum of close to 300 micrograms/m3 in an area in the southeast of the Netherlands. Pulmonary function was measured in a group of children of 6-12 years old at the end of the episode, and also two and three and a half weeks after the episode. A baseline lung function value was obtained about three months before the episode. Pulmonary function growth between baseline and retest dates was estimated from a simple growth model which was validated using measured pulmonary function growth data from a longitudinal study. A decline of pulmonary function (FVC, FEV1 and PEF) from predicted baseline levels was observed, starting on the last day of the episode. Two weeks after the episode, FVC, FEV1, PEF and MMEF were all decreased, and three and a half weeks after the episode, there was still a deficit compared to predicted baseline levels for FVC and FEV1.

Several investigators have developed indoor air quality questionnaires for use in field studies. The approach used in many of them have numerous features in common, but most of them are unique in their content (wording, format, item selection). It is thought that indoor air quality research could be greatly advanced if the primary or fundamental questions and instruments could be consolidated. The use of a basic set of "standard" questions would permit intercomparison of results from different research studies. It is generally agreed that environmental inventory questionnaires (EIQ) help to classify, at least in screening, relative concentration estimates, which precede exposure estimation. Thus, such instruments are not equivalent to monitoring for exposure assessment. However, data linkage and mega data bases are important for some comparative analyses of exposure assessment and exposure-response relationships. Standard instruments such as the EIQ are useful as a screening device to precede other tests to allow identification of potentially high exposure situations. They can also amplify information from other tests. General usage of standard questionnaires and protocols can lead to cumulative improvements in data collection, specificity and effectiveness. This has been the rationale for the present efforts by investigators to form a standardized environmental inventory questionnaire, under the auspices of the U.S. Environmental Protection Agency (EPA), Gas Research Institute (GRI), and Electric Power Research Institute (EPRI).

An ambient air sampling study was conducted around a municipal waste combustor; a primary goal was to develop procedures and methods to evaluate the emissions of organic mutagens resulting from incomplete combustion of municipal waste. The products of incomplete combustion from incineration include complex mixtures of organics, particularly polycyclic aromatic compounds, which are present after atmospheric dilution and cooling in emissions as semi-volatile or particle bound organic compounds. Combustion emissions are generally recognized as a potential cancer risk since they contain many carcinogenic and mutagenic polycyclic aromatic hydrocarbons. Analyzing such a complex mixture for the presence of even a few selected chemicals is difficult and provides risk information on only a fraction of the chemicals present. Bioassay methods, however, may be directly applied to evaluate the mutagenic and potential carcinogenic activity of the complex organics from combustion emissions. The Salmonella (Ames) assay was used to determine the mutagenicity associated with particles from ambient air collected near a municipal waste combustor. Dose-response data was generated, and mutagenicity concentrations were calculated to demonstrate the utility of bioassay in assessing the potential impact of emissions from municipal waste combustion. This phase of study quantified mutagenicity concentrations in ambient air but did not detect organic mutagens that could be attributed to incinerator emissions.

A personal air quality model (PAQM) has been developed to estimate the effect of being indoors on total personal exposure to outdoor-generated air pollution. Designed to improve air toxics risk assessment, PAQM accounts for individual hourly activity patterns, indoor-outdoor differences, physical exercise level, and geographic location for up to 56 different population groups. Unique hourly activity profiles are specified for each population group; group members are assigned each hour to one of up to 10 different indoor and outdoor microenvironments. To illustrate PAQM use, we apply it to two example cases: a long-term example representative of situations where pollutant health impact is related to integrated exposure (as in the case of potentially carcinogenic air toxics) and a short-term example representative of situations where health impact is related to acute exposure to peak concentrations (as with ozone). Case study results illustrate that personal exposure, and thus health risk, attributable to outdoor-generated air pollution is sensitive to indoor-outdoor differences and population mobility. Where health impact is related to long-term integrated exposure (e.g., air toxics), exposure and subsequent risk are likely to be lower than that estimated by previous modeling techniques which do not account for such effects.