Air Pollution Impacts to Some Important Species of Pine

In the past, many species of pine have been severely damaged by acute forms of air pollution associated with ore smelting. More recently, damage to ponderosa pine in the state of Washington has been associated with atmospheric fluoride, and this species in particular has also suffered smog damage in southern California. In the East, white pine has been declining in the vicinity of certain soft-coal-burning power plants, and in one case downwind from an oil-burning power plant: also, throughout the East, an atmospheric oxidant of unknown source has caused a type of needle blight on white pine. Trash burners and city dump combustion have led to the hilling of certain pine species, leaving other intermixed pine species unharmed. Localized damage to white pine from automobile exhaust has been observed. Differences in the susceptibility of neighboring trees of the same species to a given air pollutant have been observed repeatedly.     

An Appraisal of Epidemiologic Data Concerning the Effect of Oxidants,Nitrogen Dioxide and Hydrocarbons upon Human Populations

A procedure is developed for determining costs to reduce air pollution emissions in a metropolitan area. Methods are. sufficiently general to be applicable in any region and sufficiently comprehensive to include analysis of all major sources, future trends, control limitations, and other factors of importance in a dynamic community. The analytical procedure examines relationships among emission inventories, regional growth, control trends, alternate control schemes, control costs, and optimum cost-effectiveness.

The cost analysis procedure is tested by application to the Delaware Valley. Costs are determined for reducing emissions to various levels between the years 1960 and 2000. Emissions from private automobiles are projected to decrease below the 1960 emission rate by 1980, at a cost of 150 million dollars per year. Stationary source emissions of sulfur dioxide and particulates can be reduced to 1960 levels by 1980 for 37 million dollars per year if "least cost" procedures are used (selective abatement). Uniform conversion to 0.5% sulfur fuel oil (equiproportional abatement) can effect a similar reduction in emissions for about 94 million dollars per year in 1980. Other cost analysis comparisons are made and projections to the year 2000 are included.     

United States Seen 2.54 Centimeter-ing Its Way to Metric System

On May 3, 1971, the Engineers Joint Council sponsored a panel on metrication at its offices in New York City. Bryce MacDonald of EJC was chairman; he had been instructed to invite representatives of various societies. Its purpose was to “present to the Board of EJC a summation of the situation regarding plans for conversion to the metric system.” The EJC Board will later come to a decision whether it will assume a more active role.

George Arnold of Southern Illinois University, Edwardsville, was named to represent the Air Pollution Control Association on the panel because of his long-standing membership in the Metric Association and his efforts toward exclusive use of international units for pollution measurement.

Twenty-two societies were represented. These included ASME, ASTM, SNAME, ASQC, ASHRAE, ISA, ASEE, ASCE, and ESNE. Among those present was Gregory Schultz of the Material Management Society, who is prominent with the American National Standards Institute and the International Standards Organization. Of the societies present, only six have a firm policy in favor of the metric system. The others are cautiously in favor, or using dual units, or waiting to see what Congress will do about the 1971 Department of Commerce Metric Study Report.     

Emission Standards for Particulates

Promulgation of standards of performance under Section 111 and national emission standards for hazardous pollutants under Section 112 of the Clean Air Act is the responsibility of the Emission Standards and Engineering Division of EPA. The problems encountered and the bases used are examined.     

The Denver Winter Aerosol: A Comprehensive Chemical Characterization

The sampling and chemical analysis of the ambient aerosol collected in Denver, CO, for a 40-day period during November and December, 1978 are described in this report. Parameters included 12-hr TSP measurements, 24-hr respirable and inhalable mass measurements, and 4-hr measurements of mass and chemical species (NO₃?, SO₄ =, NH₄ +, organic and elemental carbon as well as 13 chemical elements) in two size fractions i.e., less than 2.5 μm diameter (fine fraction) and larger than 2.5 μm diameter (coarse fraction). On the basis of the chemical analyses, it was possible to account for all particulate mass in both size fractions. In the fine fraction, the major constituents were organic carbon (21.6%), NH₄NO₃ (20.0%), elemental carbon (15.3%), (NH₄)₂SO₄ (13.6%), and the remainder consisted primarily of soil-like material, lead salts, and adsorbed water. Three quarters of the coarse fraction consisted of soil-like material, with the remainder composed of the same species that dominated the fine fraction.     

Modeling the Reduction of Vapor Phase Emissions from Surface Soils Due to Soil Matrix Effects: Porosity/Tortuosity Concepts

ABSTRACT

A major route for transport of volatile organic compounds within porous media is vapor phase diffusion. The diffusion rate through a porous medium is less than that through free-air due to the decreased cross-sectional area available for gas movement and the increased path length due to pore tortuosity. Numerous empirical expressions have been published that relate the diffusion coefficient in porous media to the diffusion coefficient in free-air (unobstructed gas phase). Published measurements of relative diffusivity and air-filled porosity were combined into a database. Empirical expressions available in the literature, including the popular Millington-Quirk equation, were evaluated along with a fourth-degree polynomial expression developed by the authors to determine the best type of equation to predict relative diffusivity as a function of air-filled porosity over the domain of values for porosity ranging from 0.071 to 1 for different types of materials. Mean square deviations were used as the statistical test to compare equations. The polynomial expression developed in this project produced a significantly different effective diffusion coefficient (1.3 x 10^-6 m²/sec) compared to values of 9.2 x 10^-6 m²/sec and 3.1 x 10^-6 m²/ sec predicted by forms of the Millington-Quirk equation for a specific case.     

Closed-Loop Recovery of Site Remediation Gas Phase Contaminants

A novel gas phase treatment system (contaminant absorption and recovery [CAR]) for removal and subsequent recycling of gas phase VOCs from soil vapor extraction/gas stripping systems has been developed. Gas phase removal efficiencies using a packed column contactor exceed 99 percent The VOC-laden absorption fluid is subsequently vacuum-stripped of the VOCs, allowing potential condensation into liquid solvent concentrates. Partition coefficients for trichloroethylene (TCE) in triethylene glycol (TEG) ranged to ca. 5.0 mole fraction gas/mole fraction liquid, indicating a significant capacity for removal from the gas phase. Results of pilot-scale operation indicate favorable removal efficiencies and cost-effective performance in comparison to GAC or thermal destruction processes. System mass transfer coefficient predictions were done, using a variety of mathematical models and compared to experimental results. A modified Mangers and Ponten correlation was found to describe system mass transfer coefficients well. The impact of water carry-over on TCE/TEG partitioning was found to be significant. The standard change in entholpy (ΔH°) and the standard change in volume (ΔV°) values were also calculated, and predictions of temperature and pressure on system performance were evaluated.     

Fine Particles and Oxidant Pollution: Developing an Agenda for Cooperative Research

ABSTRACT

This paper describes a background for the North American Research Strategy for Tropospheric Ozone (NARSTO) cooperative program integrating studies of O₃ and PM_{2 5}. It discusses several important aspects for rationalizing NARSTO's trinational investigative approach, including (1) an outlook on the state of knowledge about fine particles in the troposphere and their origins in Canada, Mexico, and the United States; (2) the need for enhancement and strengthening of key field measurements in relation to tropospheric chemistry and a health effects component; and (3) the use of a central theme for advancing air quality modeling using evolving techniques to integrate and guide key process-oriented field campaigns. The importance of organizing a scientific program to acquire “policy-relevant” information is stressed, noting cooperative research directions that address combined PM_2.5 and O₃ issues, illustrated through exploration of hypothetical pathways of PM_2.5 response to choices of O₃ and PM precursor emission reductions. The information needed for PM_2.5 research is noted to intersect in many cases with those of O₃, but diverge in other cases. Accounting for these distinctions is important for developing NARSTO's strategy over the next decade.     

Calibration of Sharp Cut Impactors for Indoor and Outdoor Particle Sampling

ABSTRACT

A low-flow rate, sharp cut point inertial impaction sampler was developed in 1986 that has been widely used in PM exposure studies in the United States and several other countries. Although sold commercially as the MS&T Area Sampler, this sampler is widely referred to as the Harvard Impactor, since the initial use was at the Harvard School of Public Health. Impactor nozzles for this sampler have been designed and characterized for flows of 4,10, 20, and 23 L/min and cut points of 1, 2, 5, and 10 |im. An improved method for determining the actual collecting efficiency curve was developed and used for the recent impactor calibrations reported here. It consists of placing a multiplet reduction impactor inline just downstream of the vibrating orifice aerosol generator to remove the multiplets, thus allowing only the singlet particle s to penetrate through to the impactor being calibrated.

This paper documents the techniques and results of recent nozzle calibrations for this sampler and compares it with other size-selective inertial impactors. In general, the impactors were found to have sharp cutoff characteristics. Particle interstage losses for all of the impactors were very low, with the exception of the 10-|im cut size 20 L/ min impactor, which had greater losses due to the higher flow rate. All of the cut nozzle laboratory calibrations compare favorably to the U.S. Environmental Protection Agency (EPA) WINS-96 fine particle mass (PM_{2 5}) impactor calibration data.