An Air Quality Data Analysis System for Interrelating Effects,Standards, and Needed Source Reductions: Part 3. Vegetation Injury

Acute leaf injury data are analyzed for 19 plant species exposed to ozone or sulfur dioxide. The data can be depicted by a new leaf injury mathematical model with two characteristics: (1) a constant percentage of leaf surface is injured by an air pollutant concentration that is inversely proportional to exposure duration raised to an exponent; (2) for a given exposure duration, the percent leaf injury as a function of pollutant concentration tends to fit a lognormal frequency distribution. Leaf injury as a function of laboratory exposure duration is modeled and compared with ambient air pollutant concentration measurements for various averaging times to determine which exposure durations are probably most important for setting ambient air quality standards to prevent or reduce visible leaf injury. The 8 hour average appears to be most important for most of the plants investigated for most sites, 1 hr concentrations are important for most plants at a few sites, and 3 hr S0₂ concentrations are important for some plants, especially those exposed to isolated point sources of the pollutant. The 1, 3, and 8 hr threshold injury concentrations are listed for each of the 19 plant species studied. To prevent or reduce acute leaf injury, fixed, nonoverlapping ambient air quality measurements and standards are recommended for averaging times of 1, 3, and 8hr.     

An Air Quality Data Analysis System for Interrelating Effects,Standards, and Needed Source Reductions: Part 4. A Three-Parameter Averaging-Time Model

Urban air pollutant concentration data often tend to fit a two-parameter averaging-time model having three characteristics: (1) pollutant concentrations are (two-parameter) lognormally distributed for all averaging times; (2) median concentrations are proportional to averaging time raised to an exponent; and (3) maximum concentrations are approximately inversely proportional to averaging time raised to an exponent. Concentration data obtained near many isolated point sources and in some urban areas often do not fit a two-parameter lognormal distribution. An increment (either positive or negative) can be added to each such concentration in order to fit the data instead to a three-parameter lognormal distribution. This increment has been incorporated as the third parameter in a new three-parameter averaging-time model that can be used in both point-source and urban settings. Examples show how this new model can be used to analyze SO₂ concentration data obtained near a point source to determine the degree of emission reduction needed to achieve the national ambient air quality standards.     

An Air Quality Data Analysis System for Interrelating Effects,Standards, and Needed Source Reductions: Part 6. Calculating Concentration Reductions Needed to Achieve the New National Ozone Standard

The new ozone National Ambient Air Quality Standard specifies that the expected number of days per calendar year that the 1 hour average ozone concentration can exceed 0.12 ppm must be equal to or less than 1. This paper describes a method to calculate design frequency, design concentration, and the percentage concentration reduction necessary to achieve this standard. The design frequency is once per year (1/365) if daily maximum hour ozone concentrations are available at a particular site for an equal number of days in summer (April through September) and winter (October through March). An equation is used to adjust design frequency as a function of the number of summer and winter samples available. The design concentration (the ambient concentration measured at the design frequency) needs to be reduced to 0.12 ppm. Graphical and digital methods for determining the design concentration are presented. Percentage concentration reductions needed to achieve the standard are calculated for each site which has ozone concentration data available in the National Aerometric Data Bank for at least half of the days in one summer of years 1975 through 1977. The degree of reduction calculated for the site with the highest concentrations in each county is indicated by shading on a map of the United States.     

An Air Quality Data Analysis System for Interrelating Effects,Standards, and Needed Source Reductions: Part 10. Potential Ambient O3 Standards to Limit Soybean Crop Reduction

Soybean percent crop reduction was estimated as a function of ambient O₃ concentrations for each of 80 agricultural sites in the National Aerometric Data Bank (NADB) for each available year of data for years 1981-1985. Fourteen O₃ concentration statistics were calculated for each of the resulting 320 site-years of data. The two statistics that correlated best with estimated crop reduction were an effective mean O₃ concentration (1 percent of variance unexplained) and an arithmetic mean O₃ concentration (4 percent unexplained). The worst correlation of the 14 was for the statistic used in the present O₃ National Ambient Air Quality Standard (NAAQS), the second highest daily maximum 1-h O₃ concentration (42 percent unexplained). The number of site-years for estimated percent soybean yield reductions was plotted versus increasing O₃ concentrations for each of the 14 O₃ statistics. A maximum crop reduction line was drawn on each plot. These lines were used to estimate (and list) potential ambient O₃ standards for each of the 14 statistics that would limit soybean crop reduction at agricultural. NADB sites to 5, 10, 15, or 20 percent.     

An Air Quality Data Analysis System for Interrelating Effects,Standards, and Needed Source Reductions: Part 8. An Effective Mean O3 Crop Reduction Mathematical Model

A plant injury mathematical model, applied previously to acute and chronic leaf injury data, is used here to model National Crop Loss Assessment Network (NCLAN) data for 15 cultivars and to calculate species parameters from the cultivar analyses. Percent crop yield reduction is estimated as a function of a new parameter, the effective mean O₃ concentration: m_e = [(Σ c_h ^?1/v)/n]^?v, where c_h is the hourly average ambient O₃ concentration for each daytime hour (defined here as 9:00 A.M.–4:00 P.M., always standard time) of data available at an air sampling site for summer (defined here as June 1–August 31), n is the total number of such available hours, and v is an exposure time-concentration parameter, calculated here to be approximately –0.376. Crop yield reduction for soybean is calculated here as z = 0.478 In (tm_e ^2-66) – 0.42, where z is the Gaussian transform of percent crop reduction, t is the hours of exposure (525 h is used here; 7 h/day for 75 days), and In indicates that the natural logarithm is taken of the quantity within parentheses. Crop yield reductions for seven plant species are estimated with similar equations for each of the 1824 site-years of 1981–1983 hourly O₃ concentration data available in the National Aerometric Data Bank (NADB). County-average effective mean O₃ concentrations are indicated by shading on a U.S. map. State-average O₃ parameters and estimated percent crop yield reductions are tabulated. The National Ambient Air Quality Standard (NAAQS) for O₃ specifies that, on the average, the second highest daily maximum 1-h average O₃ concentration in a year shall not exceed 0.12 ppm. For years 1981-1983,71% of the NADB sites recorded annual second highest daily maximum 1-h average O3 concentrations below 0.125 ppm (for summer daytime hours). Ambient O₃ concentrations reduced the total U.S. crop yield an estimated 5% for years 1981–1983. (Summer, daytime, and all acronyms are always used herein as defined above.)     

An Air Quality Data Analysis System for Interrelating Effects,Standards, and Needed Source Reductions: Part 11. A Lognormal Model Relating Human Lung Function Decrease to O3 Exposure

Forced expiratory volume in 1 second (FEV1) was measured in 21 men exercising while exposed to four O₃ concentrations (0.0,0.08,0.10, and 0.12 ppm). A lognormal multiple linear regression model was fitted to their mean FEV1 measurements to predict FEV1 percent decrease as a function of O₃ concentration and exposure duration. The exercise level used was probably comparable to heavy manual labor. The longest O₃, exposure studied was 6 h. Extrapolating cautiously to an 8-h workday of heavy manual labor, the model predicts that O3 concentrations of 0.08, 0.10, and 0.12 ppm would decrease FEV1 by 9,15, and 20 percent, respectively.     

Air Quality Standards National And International

The advantages and disadvantages of establishingworldwide air quality standards are reviewed. Inter-national standards would represent the best and mostadvanced procedures and might lead to improvementin standards in some countries where air quality isfar from adequate. International standards alsowould permit accurate comparisons of air pollutionamong countries and would provide a sound basis forcombatting pollution.     

An Approach to Air Quality Management Standards

The Clean Air Amendments of 1970 impose a stringent set of uniform air quality standards and a rigid timetable for achieving them. Such an approach is open to serious question, since it fails to take account of variations in relevant local conditions. This paper sketches a proposal for a more realistic approach to air quality. It suggests a program of management standards that would reflect the needs and circumstances of particular regions. An institutional framework is outlined that would consider the technical, economic, and social constraints that determine how quickly and how much any area can improve its air quality. The framework would provide the needed flexibility, and would employ a feedback approach that avoids the need to resolve all uncertainties before any progress can be made. At the same time, it would impose a timetable and planning process to assure that all feasible progress in air quality improvement is realized nationwide.     

Air Quality Standards for Fluoride Vegetation Effects

Facts that must be taken into consideration in developing fluoride standards for vegetation effects include: (1) Fluoride is an accumulative toxicant and injury is usually associated with long-term exposure; (2) gaseous and particulate fluorides differ in their phytotoxicity; (3) plant species and varieties differ greatly in susceptibility to fluoride; (4) extremely low concentrations can cause damage to sensitive species. Three possible approaches to standards are discussed: Atmospheric fluoride concentration, vegetation fluoride concentration, and the presence of leaf necrosis or chlorosis. Atmospheric fluoride concentration has the advantage that it fits the conventional concept of standards and that it is objective. Accurately measuring low fluoride concentrations, separating gaseous from particulate fluorides in the air sample, and establishing a safe concentration present technical problems, however. Vegetation analysis may more closely represent fluorides available to affect the plant. The presence of significant amounts of fluoride-induced leaf necrosis (e.g., 3% of the leaf area) may be the most practical approach to standards for fluoride vegetation effects. Advantages are that the combined effects of the forms of fluoride, species and varieties, and concentration-time relationships are all manifest in the factor that is measured. Relatively little time is required to examine the vegetation in a large area and only 2 or 3 surveys a year are required.     

A Method for Determining Source Reduction Required to Meet Air Quality Standards

Governmental boundaries which divide our states frequently do not coincide with the natural geographic and atmospheric conditions affecting regional air pollution problems. Moreover, the control regulations of one state may vary from those of its neighbors. Such areal synthesis of air pollution control measures might only minimally curb the difficulties.

Continuity of control will require cooperation among contiguous states. In this study the attitudes of incumbent elected officials and air pollution experts (both from within the Philadelphia metropolitan area) toward governmental responsiveness have been investigated. It was hypothesized that politicians would want to demonstrate a status quo approach while experts would advocate the creation of an environmental agency for the Philadelphia region’s pollution problems. However, both sample groups responded to the questionnaire survey affirming that they want government to establish an environmental regional control agency, based upon an interstate compact, that has authority strong enough to be a strict enforcing agent. This regional agency should meet all federal conditions and thus receive maximum federal financial assistance. The policy level officials of this agency should be appointed experts—so as to avoid partisan politics, and to acquire the most qualified personnel.     

Application of Gas-Aerosol Adsorption Data to the Selection of Air Quality Standards

A quantitative approach is presented for selecting air quality standards which take into account pollutant gas-aerosol synergistic effects. These synergistic health effects have been postulated to be due to the adsorption or absorption of the pollutant gas by the aerosol particles. The approach presented in this paper assumes that the synergistic toxic agent is the adsorbed pollutant gas. Therefore, limiting the concentration of the adsorbed pollutant gas limits the magnitude of the synergistic effects. The concentration of the adsorbed pollutant gas is related to the concentrations of the gaseous phase pollutant gas and the atmospheric aerosol using the Langmuir adsorption isotherm. An example is presented of the selection of air quality standards for sulfur dioxide and the atmospheric aerosol using concentration data for these two pollutants along with health effect data.     

Elemental Composition of Airborne Particulates And Source Identification: Data Analysis Techniques

Approaches are discussed and illustrated for the analysis of the very large trace element data set obtained by instrumental neutron activation and emission spectroscopic analysis of over 700, 24 hour ambient air particulate samples collected at 16 sites in Cleveland, OH from August 1971 to October 1972. Examples are presented of the use of pairwise correlation statistics, cluster analysis algorithms, enrichment factors, and pollutant concentration roses to identify sources. It is demonstrated that some elemental constituents of the Cleveland suspended particulate can be related to specific source types: earth’s crust (Al, Si, Sc, Ti, V, La, Sn, Eu, Oy, Th), automotive exhaust (Pb, Br), metallurgy (Fe, Cr, Co) and specific industries (Sb, Hg). Even with 24 hr samples, some sources can be geographically located by the directional characteristics of the element.     

Evaluation of Episode Control Schemes Through Air Quality Data Analysis

Prediction performance of various air pollution episode models are first compared with that of a persistence model which is based on the assumption that present concentrations persist to a future time. The comparisons are made by computing a correlation coefficient for different lead times between the observed and predicted values, and an auto-correlation function of the air quality data to which the episode model is applied. The persistence of high levels of air pollution is next examined, using existing air quality data, by constructing frequency distributions of air pollution episode duration for various concentration thresholds. Based on the results of persistence analysis, the flaws of currently used episode management schemes are discussed and some alternative episode management schemes are presented. Methodologies and parameters to evaluate the anticipated performances of episode management schemes are developed and some examples are worked out. In conclusion, it is suggested that a combination of episode persistence analysis and air pollution meteorological forecasting could lead to a workable air pollution episode management scheme.     

Forecasting Daily Source Air Quality Using Multivariate Statistical Analysis and Radial Basis Function Networks

Abstract

It is vital to forecast gas and particle matter concentrations and emission rates (GPCER) from livestock production facilities to assess the impact of airborne pollutants on human health, ecological environment, and global warming. Modeling source air quality is a complex process because of abundant nonlinear interactions between GPCER and other factors. The objective of this study was to introduce statistical methods and radial basis function (RBF) neural network to predict daily source air quality in Iowa swine deep-pit finishing buildings. The results show that four variables (outdoor and indoor temperature, animal units, and ventilation rates) were identified as relative important model inputs using statistical methods. It can be further demonstrated that only two factors, the environment factor and the animal factor, were capable of explaining more than 94% of the total variability after performing principal component analysis. The introduction of fewer uncorrelated variables to the neural network would result in the reduction of the model structure complexity, minimize computation cost, and eliminate model overfitting problems. The obtained results of RBF network prediction were in good agreement with the actual measurements, with values of the correlation coefficient between 0.741 and 0.995 and very low values of systemic performance indexes for all the models. The good results indicated the RBF network could be trained to model these highly nonlinear relationships. Thus, the RBF neural network technology combined with multivariate statistical methods is a promising tool for air pollutant emissions modeling.     

Health Effects of Air Quality Regulations in Delhi, India

This, the first systematic study, quantifies the health effects of air quality regulations in Delhi, which adopted radical measures to improve air quality, including, for example, the conversion of all commercial vehicles to compressed natural gas (CNG), and the closure of polluting industries in residential areas from 2000 to 2002. Air pollution data, collected at 113 sites (spread across Delhi and its neighboring areas) from July-December 2003, were used to compute exposure at the place of residence of 3,989 subjects. A socio-economic and respiratory health survey was administered in 1,576 households. This survey collected time-use, residence histories, demographic information, and direct measurements of lung function with subjects. The optimal interpolation methods were used to link air pollution and respiratory health data at the place of their residence. Resident histories, in combination with secondary data, were used to impute cumulative exposure prior to the air-quality interventions, and the effects of recent air quality measures on lung function were then evaluated. Three important findings emerge from the analysis. First, the interventions were associated with a significant improvement in respiratory health. Second, the effect of these interventions varied significantly by gender and income. Third, consistent with a causal interpretation of these results, effects were the strongest among those individuals who spend a disproportionate share of their time out-of-doors.     

The Characterization of Ozone and Sulfur Dioxide Air Quality Data for Assessing Possible Vegetation Effects

Since the 1960s, much effort has been devoted to collecting and formatting air quality data. This paper discusses 1) the availability of air quality data for assessing potential biological impacts associated with ozone and sulfur dioxide ambient exposures, 2) examples of how air quality data can be characterized for assessing vegetation effects, and 3) the limitations associated with some exposure parameters used for developing relevant vegetation doseresponse yield reduction models. Data are presented showing that some ozone monitoring sites not continuously affected by local urban sources experience consecutive hourly ozone exposures ≥0.10 ppm in the late evening and early morning hours. These sites experience their maximum ozone concentrations either in the spring or summer months. Sites influenced by local rural sources experience their maximum ozone concentrations during the summer months. It is suggested that further research be performed to identify whether the sensitivity of a target organism at the time of exposure, as well as the pollutant concentration and chemical form that enters into the target organism, is as important in defining effects as air pollutant exposure alone.     

An Air Quality Study in the Vicinity of Lewiston,Idaho, and Clarkston,Washington

This report summarizes data and conclusions from a one-year, interstate air quality study conducted in 1962 in the vicinity of Lewiston, Idaho, and Clarkston, Wash.^{1, 6, 7} The sampling and analyses techniques were selected to permit differentiation between possible sources and types of air pollutants.