Pennsylvania’s Compuiterized Air Monitoring System

The Pennsylvania Air Pollution Commission has developed a regulatory program based upon the control of local air pollution problems and reduction of pollutant levels in air basins. The geographical boundaries of 10 air basins have been established. The Commission’s air basin regulations will provide for the reduction of over-all pollutant levels and for emergency procedures in the event of adverse meteorological conditions. The paper discusses the format and objectives of the program.

In order to effectively enforce the air basin regulations and maintain the necessary surveillance of the state’s air quality, a "computerized real time on-line integrated air monitoring-data handling system" has been designed. The system will incorporate a network to constantly monitor the air in each air basin.The primary objectives of the system are: 1. Constant surveillance of air pollution in the air basins.

2. Provide information on air pollution potential alerts.

3. Aid in further development of air quality criteria and regulations.

The air monitoring network is estimated to include approximately 25 remote stations. Each remote will contain air pollution and meteorological sampling equipment and hardware to telemeter to a central station. The data will be transmitted over leased telephone lines. The central station in Harrisburg will contain the necessary hardware to receive and process data, calculate and display results and permit supervisory control of the network. Output options will include immediate display of edited data, command and alarm information, and presentation of statistical results.

Although the air monitoring system is one of the principle ingredients of the program, the air basin concept encompasses other component systems designed to knit together the entire air pollution control program in Pennsylvania.     

Air Pollution Administrative Trends—the Canadian Scene

A re-organized local agency for the administration of an air pollution by-law in a group of adjoining municipalities now employs professional staff together with laboratories for air quality analyses, source testing, and applied research and new ideas in the development of improved fuel-burning and control equipment. The agency functions to prevent new sources of pollution, to disseminate information and advice and to provide leadership in the community. Its administrative activities include the use of consultants and outside research organizations for special problems and subjects of a political or controversial nature. However, to deal with the rare and complex contaminants which may be harmful to health now necessitates some assistance from the higher governments. The practices discussed have been employed for several years with general success in the Municipality, following closely the recommendations of a Select Committee of the Legislative Assembly of the Province which traveled and held hearings 1955 to 1957 in the major cities of the U.S.A. and Canada.     

Stainless Steel Anti-Smog Mufflers—Cut Air Pollution

An automatic process gas chromatograph has been developed for use on the recovery furnace stack of a Kraft pulp mill. The instrument analyzes for widely varying concentrations of H₂S, SO₂, CH₃SH and higher order sulfur compounds. It is insensitive to the fixed gases and water vapor, and performs its analysis in approximately ten minutes. The instrument features a microcoulometric detector giving it sensitivity to H₂S as low as 0.1 ppm, and SO₂ and CH₃SH as low as 0.5 ppm. The major limit to even higher sensitivity at this stage of development lies with two problems: the background noise level in the detector and the sulfur compound absorption in the Porapak Q chromatograph column. At the reported sensitivity, a 40-ml gas sample was used. The instrument also contains a data analysis system supplementary to the usual strip chart recorder. This system is made up of a digital voltmeter, a digital translator, and a teletype and hence allows the transfer of the output data to a digital computer for processing. The processed data are usually presented in the form of ppm quantities of the component gases in the stack gas. The instrument has worked successfully on small furnace effluent for periods of 25 hr but has not been tried on recovery furnace stacks. It has also run on prepared samples for periods of up to seven days with no maintenance or attendance necessary.     

Air quality modeling in the South Coast Air Basin of California: what do the numbers really mean?

This study evaluates air quality model sensitivity to input and to model components. Simulations are performed using the California Institute of Technology (CIT) airshed model. Results show the impacts on ozone (O3) concentration in the South Coast Air Basin (SCAB) of California because of changes in: (1) input data, including meteorological conditions (temperature, UV radiation, mixing height, and wind speed), boundary conditions, and initial conditions (ICs); and (2) model components, including advection solver and chemical mechanism. O3 concentrations are strongly affected by meteorological conditions and, in particular, by temperature. ICs also affect O3 concentrations, especially in the first 2 days of simulation. On the other hand, boundary conditions do not significantly affect the absolute peak O3 concentration, although they do affect concentrations near the inflow boundaries. Moreover, predicted O3 concentrations are impacted considerably by the chemical mechanism. In addition, dispersion of pollutants is affected by the advection routine used to calculate its transport. Comparison among CIT, California Photochemical Grid Model (CALGRID), and Urban Airshed Model air quality models suggests that differences in O3 predictions are mainly caused by the different chemical mechanisms used. Additionally, advection solvers contribute to the differences observed among model predictions. Uncertainty in predicted peak O3 concentration suggests that air quality evaluation should not be based solely on this single value but also on trends predicted by air quality models using a number of chemical mechanisms and with an advection solver that is mass conservative.     

Air Quality Modeling in the South Coast Air Basin of California: What Do the Numbers Really Mean?

Abstract

This study evaluates air quality model sensitivity to input and to model components. Simulations are performed using the California Institute of Technology (CIT) airshed model. Results show the impacts on ozone (O₃) concentration in the South Coast Air Basin (SCAB) of California because of changes in: (1) input data, including meteorological conditions (temperature, UV radiation, mixing height, and wind speed), boundary conditions, and initial conditions (ICs); and (2) model components, including advection solver and chemical mechanism. O₃ concentrations are strongly affected by meteorological conditions and, in particular, by temperature. ICs also affect O₃ concentrations, especially in the first 2 days of simulation. On the other hand, boundary conditions do not significantly affect the absolute peak O₃ concentration, although they do affect concentrations near the inflow boundaries. Moreover, predicted O₃ concentrations are impacted considerably by the chemical mechanism. In addition, dispersion of pollutants is affected by the advection routine used to calculate its transport. Comparison among CIT, California Photochemical Grid Model (CALGRID), and Urban Airshed Model air quality models suggests that differences in O₃ predictions are mainly caused by the different chemical mechanisms used. Additionally, advection solvers contribute to the differences observed among model predictions. Uncertainty in predicted peak O₃ concentration suggests that air quality evaluation should not be based solely on this single value but also on trends predicted by air quality models using a number of chemical mechanisms and with an advection solver that is mass conservative.     

Canada’s Mobile Sources Air Pollution Control Program

The chemical and optical properties of particle emissions from onroad vehicles were investigated at the Allegheny Tunnel on the Pennsylvania Turnpike during July 1981. The optical results are in agreement with earlier data: (1) in terms of light extinction per km driven, diesel particle emissions are at least an order of magnitude more important than particle emissions from spark-ignition vehicles; (2) for diesel particle emissions, light absorption is about twice as efficient as light scattering. Chemical analyses showed that: (1) 24% of the vehicle aerosol was extractable material, (2) 75% of the total mass was carbon, (3) 55% of the total mass was unextractable (elemental) carbon, and (4) the stoichiometry of the extractable fraction of the diesel particle emissions was C_nH_t.7nN_0.05n , i.e., the extractable material was composed predominantly of alkanes. The results of the chemical analyses allow the calculation of the massspecific light absorption coefficient for the elemental carbon component of the diesel particle emissions, i.e., 10.9 ± 1.8 m²/g (500 nm).     

SWO-NK’s Air Quality Criteria and Emission Regulations

The bi-state area around Cincinnati has more than a million people in 70 political jurisdictions located in four counties. An air pollution survey was organized to prepare a plan for an air resource management program for the area. The author chaired the air quality subcommittee which recommended air quality criteria and emission regulations to the Technical Committee of SWO-NK. This paper outlines the recommendations which were subsequently adopted by the Technical Committee and the basis for them.     

Comment on “Mortality and Air Pollution: Revisited”

Abstract

Test-to-test variability has been observed by many current testing methods, including the Federal Test Procedure, the IM240 dynamometer test, the idle test common to many Inspection and Maintenance programs, and on-road remote sensing. The variability is attributable to the vehicle, not to the testing procedure. Because the vehicles are the dominant source of variability, the only way such vehicles can be reliably identified is through the use of multiple tests. The emissions variability increases with increasing average emissions, and it appears to be prevalent among the few newer technology vehicles with defective, but untampered, closed-loop emissions control systems (1981 and newer models). In one fleet the variable emitters constitute 2.2% to 4.8% of the vehicles and contribute 8.5% to 22% of the total carbon monoxide emissions. Scheduled I/M programs that fail to ensure repair of these vehicles allow a significant portion of vehicles with excess emissions to escape reduction measures.     

The Province of Ontario’s Air Pollution Control Program

The Province passed an Air Pollution Control Act in 1958 which delegated control of all types of air pollution to the municipalities. This was amended in 1963 with the Province assuming control of industrial sources of air pollution and the municipalities retaining control of combustion sources. The paper outlines the comprehensive program adopted by the Province. It points out that while control is a primary function, other functions such as ambient air quality sampling, the collection of micro meteorological data, co-operation with other governmental agencies in agriculture, planning and zoning, economics and development, and water pollution are a vital part of the program. In light of the experience to date, an attempt is made to predict the organization necessary for the future.     

The Estimation of Personal Exposures to Air Pollutants for a Community-Based Study of Health Effects in Asthmatics—Design and Results of Air Monitoring

In order to provide reliable pollutant and meteorological exposure estimates for an epidemiological study of asthmatics residing in two Houston neighborhoods, a dedicated three-tier air monitoring system was established. This consisted of fixed site ambient air monitoring at the center of each study area, a mobile van performing simultaneous indoor and outdoor measurements at selected residences of study participants, and a limited amount of direct personal monitoring for half of the participants. Monitored pollutants Included all criteria pollutant gases, as well as aeroallergens, aldehydes, TSP, and IP. Laboratory analyses provided concentrations of sulfate, nitrate, and trace elements. Continuous measurements of several meteorological parameters also were obtained. Intensive quality assurance and data validation efforts resulted in a high percentage of valid data for most pollutants. Ozone was the only measured pollutant that exceeded the NAAQS during the six-month (May to October) study period. The monitoring scheme allowed important pollutant concentration differences to be detected between day and night, between Indoors and outdoors, and among various indoor environments. The use of these monitoring data in combination with personal activity and household characteristics data to generate estimates of personal exposures for the epidemiological analysis will be described in a subsequent paper.     

National Air Quality Standards for Automotive Pollutants – A Critical Review

The recently promulgated national air quality standards for carbon monoxide, nitrogen dioxide, hydrocarbons, and photochemical oxidant are critically reviewed.This review indicates that the standards are more restrictive than can be supported by available data.     

Air quality measurements in urban green areas – a case study

The influence of traffic-induced pollutants (e.g. CO, NO, NO₂ and O₃) on the air quality of urban areas was investigated in the city of Essen, North Rhine-Westphalia (NRW), Germany. Twelve air hygiene profile measuring trips were made to analyse the trace gas distribution in the urban area with high spatial resolution and to compare the air hygiene situation of urban green areas with the overall situation of urban pollution. Seventeen measurements were made to determine the diurnal concentration courses within urban parks (summer conditions: 13 measurements, 530 30 min mean values, winter conditions: 4 measurements, 128 30 min mean values). The measurements were carried out during mainly calm wind and cloudless conditions between February 1995 and March 1996. It was possible to establish highly differentiated spatial concentration patterns within the urban area. These patterns were correlated with five general types of land use (motorway, main road, secondary road, residential area, green area) which were influenced to varying degrees by traffic emissions. Urban parks downwind from the main emission sources show the following typical temporal concentration courses: In summer rush-hour-dependent CO, NO and NO₂ maxima only occurred in the morning. A high NO₂/NO ratio was established during weather conditions with high global radiation intensities (K>800 W m⁻²), which may result in a high O₃ formation potential. Some of the values measured found in one of the parks investigated (Gruga Park, Essen, area: 0.7 km²), which were as high as 275 μg m⁻³ O₃ (30-min mean value) were significantly higher than the German air quality standard of 120 μg m⁻³ (30-min mean value, VDI Guideline 2310, 1996) which currently applies in Germany and about 20% above the maximum values measured on the same day by the network of the North Rhine–Westphalian State Environment Agency. In winter high CO and NO concentrations occur in the morning and during the afternoon rush-hour. The highest concentrations (CO=4.3 mg m⁻³, NO=368 μg m⁻³, 30-min mean values) coincide with the increase in the evening inversion. The maximum measured values for CO, NO and NO₂ do not, however, exceed the German air quality standards in winter and summer.     

The Petroleum Refining Industry—Air Pollution Problems and Control Methods

Polyurethane foam was incorporated as a prefilter on standard hi-volume samplers of the National Air Sampling Network (NASN) in an exploratory study. The foam selectively filtered particles of various sizes. The characteristics of the particles passing through the foam approached the respirable size fraction as defined by reports of the Atomic Energy Commission. The respirable fraction was then collected on a glass-fiber filter. Parameters such as pore size and thickness of the foam, air flow rates, and loadings were studied to determine their effects on the filtration of “respirable” dust. Ambient air was the particulate source, and sizing was accomplished by an Andersen sampler coupled with nephelometric analyses. Some sizing was also done microscopically. The foam was evaluated at several locations to account for possible variations in ambient air over areas of different industrial complexity.     

Another Look at New York City’s Air Pollution Problem

An analysis of the ambient air quality in New York City over the past several years has been made. The various sources of the contaminants are identified and evaluated as to their effects on ambient air quality. Meteorological data have been analyzed to develop insight into the influence of weather conditions upon ground level pollution concentrations. The results of these analyses are employed to indicate the approaches that will be most effective in improving air quality.     

State and Local Air Pollution Control Agency Salary Levels—1971

This paper is an examination of the range of salary levels of state, local, and multijurisdictional air pollution control agencies for specific occupational categories. It is based on a manpower and training survey of such agencies conducted by the Office of Air Programs of the Environmental Protection Agency during 1971. Since inadequate salaries have been identified as a primary obstacle in staffing air pollution control agencies, an analysis of salary levels was among the focal points for the survey.

Salaries were found to vary according to occupational category, type of agency, and size of agency. In most instances, salary levels increase as the size of the agency increases. Mean starting salaries have risen significantly since 1968, and salaries for chemists and engineers are becoming more competitive with salaries in private industry.     

What Do the Hydrocarbons from Trees Contribute to Air Pollution?

Plant species release appreciable quantities of volatile organic substances to the atmosphere. The major compounds emitted are monoterpenes (C₁₀) like α-pinene, β-pinene, and limonene and the hemiterpene (C5) isoprene. The rate of emission of isoprene is light dependent and ranges between 0.04 to 2.4 ppb/cm²/min/l for oak, cottonwood, and eucalyptus foliage. The rate of emission of a- and/3-pinene and limonene is dependent on the rate of transpiration, structural integrity of the oil cells and resin glands, and temperature of the foliage. Rates of emission for conifer foliage range from 0.4 to 3.5 ppb/g/min/l. An inventory of North American forest regions for the frequency of occurrence of these chemicals released by different tree species showed that 15% was the lowest value for a specific forest-type that emitted terpenes to the atmosphere. More commonly 100% of the trees of a given forest-type emitted terpenes to the atmosphere. An average of 70% is typical of the United States forested regions as a whole. The annual contribution of forest hydrocarbon emissions to the air pollution problem on a global basis is reflected in the 175 × 10⁶ tons of reactive hydrocarbons from tree foliage sources compared to the 27 × 10⁶ tons from man’s activities; in other words, there is a 6.2-fold greater emission level from natural sources than from man made sources. The fate of these gaseous olefins in the atmosphere is undetermined.