A Summary of the A&WMA/EPA International Specialty Conference

“Visibility and Fine Particles“, the fourth in a series of international specialty conferences on atmospheric visibility, was sponsored by the Air and Waste Management Association and the U.S. Environmental Protection Agency. The purpose of this conference was to provide a forum to disseminate the results of recent advances in visibility and fine particles. The 110 papers presented at the conference covered six topics: policy and regulatory issues, visibility and fine particle measurements, human perception of visibility, meteorological factors affecting visibility, economic valuation of visibility, and visibility and fine particle modeling and source apportionment. Eighty-five of those papers are included in the conference Transactions and are summarized in this article.     

Summary of the 1991 EPA/A&WMA International Symposium: Measurement of Toxic and Related Air Pollutants

A joint conference cosponsored for the sixth year by the Atmospheric Research and Exposure Assessment Laboratory (AREAL) of the U.S. Environmental Protection Agency and the Air & Waste Management Association was held in Durham, North Carolina, May 6–10, 1991. The technical program consisted of 220 presentations, held in 25 technical sessions, on recent advances in ambient and source atmospheres. Covering a wide range of measurement topics and supported by 78 exhibitors of instrumentation and consulting services, the symposium was attended by almost a thousand professionals from the United States and other countries. This overview highlights a selection of the technical presentations, and includes a synopsis of the keynote address.     

Summary of the 1989 EPA/A&WMA International Symposium: Measurement of Toxic and Related Air Pollutants

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.     

Regional Photochemical Measurement and Modeling Studies: A Summary of the Air & Waste Management Association International Specialty Conference

Abstract

This paper summarizes the Air & Waste Management Association’s International Specialty Conference, "Regional Photochemical Measurement and Modeling Studies," held in San Diego, California, on November 8-12,1993. The purpose of the conference was to facilitate exchange of information and to initiate better communication and interaction among scientists, air quality managers, regulators, and others involved in or applying tools (models and measurements to support the modeling efforts) that can be used to develop equitable and effective emissions management practices for attainment of ozone standards. Attendees heard more than 350 presentations from authors representing nearly 30 air quality and meteorological measurement and modeling studies from 18 countries. While the primary emphasis of the conference was technical, two policy sessions were included (Plenary and Concluding Sessions) to place the technical results in perspective with the policy issues. The technical agenda was divided into three subjects: Analysis of Field Measurements (results and interpretation), Modeling (status and results), and Other Topics. Papers presented at the conference are being published in a variety of journals or books to meet the needs of the scientific and policy communities. A complete bibliographical listing of the papers presented at the conference is included with this paper.

An unexpected outcome of the conference has been the development of an initiative for continuing the intercomparison of goals and scientific findings from regional air quality studies in Europe and North America, entitled “Regional Oxidants Programs Intercomparison” (ROxPIn). This paper will also discuss the goals and objectives of ROxPIn.     

The Annual Average: An Alternative to the Second Highest Value as a Measure of Air Quality

It is common practice to use the second highest value both in determining compliance with the once-per-year air quality standards (AQS) and as a measure of air quality in pollutant trend studies and rollback calculations. A study of the variation in the second highest 8 hr carbon monoxide concentration observed at the CAMP stations 1962-72 is presented. It is shown that, for a given annual average, the second highest value can differ by a factor of 2 due to random variation. The annual average is linearly related to the observed average of the second highest value and is shown to be a good predictor of the percent of time the carbon monoxide AQS is exceeded. It is concluded that the annual average, which is less variable and not as greatly influenced by erroneous measurements, is the preferred measure of air quality for trend studies and air quality projections.     

Impact of NOx Emissions Released from a Gas Turbine-Based Power Plant on the Ambient Air Quality

The number of gas turbine- (GT-) based power plants is rapidly increasing to meet the world’s power demands. Until a few years ago, fossil fuel, and specifically fuel oil, was considered the major energy source for gas turbine operation. Due to the high amount of pollution that fuel oil generates, natural gas has become a popular source of energy due to its lower emissions compared to fuel oil. As a result, many GTs have switched to natural gas as an alternative to fuel oil. However, pollutants expelled from GT-based power plants operating on natural gas impact surrounding air quality. The objective of this study was to examine the dispersion of nitrogen oxides (NO_x) emitted from a GT-based power plant located in the Sultanate of Oman. Supported by CALPUFF dispersion modeling software, six scenarios were investigated in this study. The first four scenarios considered a case where the GT-based power plant was operating on natural gas during winter and summer and for open and combined cycle modes. The remaining two scenarios considered, for both open and combined cycle modes, the case where the GT-based power plant was operating on fuel oil. Whether run by natural gas or fuel oil, CALPUFF simulation results for both seasons showed that NO_x concentrations were higher when GTs were used in the combined cycle mode. The concentrations were still lower than the allowable concentrations set by the United States Environmental Protection Agency (U.S. EPA) standards. In contrast, for the case where the power plant operated on fuel oil, the NO_x one-hour average simulated results exceeded the allowable limits only when the combined cycle mode was activated.     

The Impact of Migration on Air Quality Dose-Response Functions: A Case Study of Jacksonville,Florida

The purpose of this study was to analyze quantitative relationships between air pollution and mortality, and to examine the impact of migration on pollution-related mortality functions. Dose-response functions were estimated for intra-urban variations in ambient air quality for the city of Jacksonville, Florida. Indices of air pollution used in this study were sulfur dioxide (SO₂) and total suspended particulates (TSP). Ambient air quality was measured by the dispersion of TSP and SO₂ across census tracts using the SYMAP dispersion model in conjunction with air quality monitoring stations.

Holding other things constant, TSP apeared to have no statistically significant association with mortality rates. By contrast, the significance of the estimated coefficient for the pollution variable, SO₂, supported the contention that there is a positive and statistically significant relationship between air pollution and mortality rates. However, after making a limited test of the impact of migration on dose-response functions, the SO₂ pollution variable was no longer statistically significant. That is, recent migrants may have limited exposure to the existing level of SO₂ in Jacksonville, Florida, but carry with them long term exposure to more heavily polluted areas in the Northern United States. The results of this study suggest that further epidemiological studies and economic analysis of the health effects on air pollution should make some attempt to control the migration effect.     

A New Method for the Rapid Determination of Volatile Organic Compound Breakthrough Times for a Sorbent at Concentrations Relevant to Indoor Air Quality

Abstract

The use of sorbents has been proposed to remove volatile organic compounds (VOCs) present in ambient air at concentrations in the parts-per-billion (ppb) range, which is typical of indoor air quality applications. Sorbent materials, such as granular activated carbon and molecular sieves, are used to remove VOCs from gas streams in industrial applications, where VOC concentrations are typically in the parts-per-million range. A method for evaluating the VOC removal performance of sorbent materials using toluene concentrations in the ppb range is described. Breakthrough times for toluene at concentrations from 2 to 7500 ppb are presented for a hydrophobic molecular sieve at 25% relative humidity. By increasing the ratio of challenge gas flow rate to the mass of the sorbent bed and decreasing both the mass of sorbent in the bed and the sorbent particle size, this method reduces the required experimental times by a factor of up to several hundred compared with the proposed American Society of Heating, Refrigerating, and Air-Conditioning Engineers method, ASHRAE 145P, making sorbent performance evaluation for ppb-range VOC removal more convenient. The method can be applied to screen sorbent materials for application in the removal of VOCs from indoor air.     

Contribution of Ecosystem Services to Air Quality and Climate Change Mitigation Policies: The Case of Urban Forests in Barcelona,Spain

Mounting research highlights the contribution of ecosystem services provided by urban forests to quality of life in cities, yet these services are rarely explicitly considered in environmental policy targets. We quantify regulating services provided by urban forests and evaluate their contribution to comply with policy targets of air quality and climate change mitigation in the municipality of Barcelona, Spain. We apply the i-Tree Eco model to quantify in biophysical and monetary terms the ecosystem services “air purification,” “global climate regulation,” and the ecosystem disservice “air pollution” associated with biogenic emissions. Our results show that the contribution of urban forests regulating services to abate pollution is substantial in absolute terms, yet modest when compared to overall city levels of air pollution and GHG emissions. We conclude that in order to be effective, green infrastructure-based efforts to offset urban pollution at the municipal level have to be coordinated with territorial policies at broader spatial scales.