Sulfur Dioxide Removal and Recovery from Pulp Mill Power Plants

The use of soda ash liquor to scrub SO₂ rich power plant flue gases was studied using an Airetron pilot scrubber with a maximum capacity of 3000 cfm. The relative effects of the major operating variables— temperature, soda ash concentration, and the gas/liquid flow ratio—on the absorption phenomenon were determined. Orthogonal factorial experiments were used to derive a response function relating mass transfer values to operating variables. The economics of a full scale NSSC installation are discussed.     

A Program Analysis

A comprehensive analysis of inspection maintenance programs is proposed. Effectiveness, costs to the state and to the individual, distribution of cost and benefits, and political and administrative feasibility are examined. Effectiveness is probably the most difficult aspect to project because of changes in design and consequences of maintenance repair on performance. However, using sensitivity analysis, substantial reductions in hydrocarbons and carbon monoxide are foreseen, along with a slight increase in NO_x emissions.

The cost to the state to administer the program is estimated to be between $2.00 and $2.50 per vehicle, which could be covered by the inspection fee. The other direct costs for the driver, lost time, travel, and repairs, may be offset by fuel and tuneup savings which could amount to as much as 50% of the repair bill. Analysis of distribution costs and indirect social consequences cannot be completed until additional information about the effect of income on maintenance is generated. Politically the program is feasible but depends on public support which in turn is sensitive to direct repair costs. Administratively the program suffers greatly if private repair facilities do not have enough adequately trained mechanics.

It is concluded that the benefits of an inspection program do not convincingly outweigh the high costs, possible adverse social impacts, and public opposition and that other alternatives should be examined.     

A Model for Gaseous Pollutant Sorption by Leaves

A model simulating pollutant exchange with isolated leaves that integrates factors which have been found to be important in regulating pollutant uptake by leaves is presented. The model is patterned after an electrical analogue simulator and was designed to emphasize the effects of pollutant and leaf properties on the process. The article discusses the relative significance of factors affecting gas transfer, sorption of pollutants by leaf surfaces, and pollutant solubility and fate on the uptake process. Data is presented showing uptake of ozone by exposed mesophyll and several epidermal surfaces chosen for their different surface characteristics. The model was used to derive a mathematical expression for the exchange process which was rearranged to define internal (average) pollutant solute concentration in terms of external concentration, leaf and boundary layer diffusion resistance, surface sorption and pollutant solubility. The importance of estimating internal solute concentration is discussed.     

An Air Pollution Incident Due to a Stationary Front

In January 1971, the New York City area experienced a period of high pollution in which concentrations exceeded the present criteria for Stage I of the New York City Alert-Warning System. The incident was unusual because the high concentrations were associated with a weak frontal system which moved back and forth over the area and not with a stagnating anticyclone. Concentrations of pollutants were found to be closely related to the movement of the frontal system as well as to changes in wind speed and stability. Climatological criteria for identifying-periods of potential high air pollution and the criteria for mixing heights, transport wind speed and ventilation factors necessary for the issuance of an official advisory from the National Meteorological Center were not met during this incident. Therefore, some re-evaluation and redefinition of these criteria are recommended.     

Episode control criteria and strategy for carbon monoxide

With respect to health effects and types of emission sources, carbon monoxide is different from SO₂ and airborne participates. The effects of nontoxic CO levels are temporary and reversible. The primary sources are automobiles and trucks, and concentrations are often highly localized. Episode control strategies developed for other pollutants are not applicable for coping with CO episodes.     

Honorary Memberships

Honorary Memberships are conferred by the Air Pollution Control Association on persons of widely recognized eminence in some part of the field of air pollution control or who have rendered especially meritorious service to the Association. Honorary Memberships were awarded this year to Dr. Leonard Greenburg and Mr. Milton Reizenstein, both past presidents of APCA.     

Forecasting COH Levels at Six Outlying Sampling Stations in Allegheny County Using Statistical Correlations Derived from the Downtown Station

Verification of forecasts of COH levels at the Downtown Sampling Station using our objective forecast method developed in conjunction with the Allegheny County Bureau of Air Pollution Control gave excellent results. The next step was to expand the area of forecast coverage.

COH data taken from July 1968 through June 1969 from six sampling stations located roughly in a large concentric arc around the Downtown Station were studied. Three of the stations are located in river valleys near large industrial plants and the other three are located on higher terrain in suburban areas.

COH levels of Low, Moderate, High, and Very High (where Low = 0–0.9, Moderate = 1.0–1.9, High = 2.0–3.0, and Very High = >3.0) were used.

The total number of occurrences of High and Very High COHS at the Downtown Station was 10.7% of the total data sample. This was more than twice the frequency of any of the outlying stations.

An evaluation of the statistical frequencies indicate the Downtown Station can safely be used as a “control station” in forecasting Low or Moderate COH levels for the six surrounding stations. However, the occurrence of High or Very High COH levels at the six outlying stations do not occur with a high enough statistical consistency to be predicted by using the forecast value of the Downtown Station.

The valley stations exhibit the characteristics of separate sub air basins particularly during a period in which morning inversions occur for two or more consecutive days and the average daily wind speed does not exceed 4 m/sec.

The results show it is possible to forecast only Low or Moderate COH levels for each of the six outlying stations by using statistical correlations derived from the Downtown Station. Separate objective forecasts which relate the pollution buildup in each valley sub air basin must be used when High or Very High COHS are forecast at the Downtown Station.     

Automotive Exhaust Emission Levels by Geographic Area and Vehicle Make A Nationwide Survey

Gross average automotive exhaust emissions data collected by the Atlantic Richfield Clean Air Caravan during the summer of 1970 showed only slight geographical variations when the specific makes were ignored. When considering specific makes, significant differences were found on an average emissions basis. Vehicle population—emission distributions showed wide variations in the 50% population levels and in the percent of vehicles with emissions greater than specified values. Hydrocarbon (HC) and carbon monoxide (CO) data are given on a gross basis for the 1970, 1968-69, 1966-67, and pre-1966 model year group vehicles. Average HC and CO emissions and vehicle population-Idle emissions distribution curves are included for specific make vehicles in selected areas.