Reduction of Air Pollution Potential through Environmental Planning

Amelioration of the air pollution problem, whether the result of mobile or stationary source emissions, will depend primarily upon mechanical controls and fuel and process changes. Urban and transportation planning, however, may provide supplementary means for reducing both emissions of pollutants and the exposure of persons to undesirably high ambient concentrations. The body of information in this paper is directed to the planners and policy-makers whose decisions influence the nature of our environment. Three general areas are identified in which the policies, plans, and standards developed by environmental planners influence the air pollution problem : 1. Long-term, large-scale urban planning involving entire or substantial parts of metropolitan areas.

2. Design and operation of transportation systems.

3. Location, design, and construction of individual roadways and structures.

In each of these three areas, the Air Pollution Control Office has initiated projects that will assist planners in evaluating the air pollution implications of their activities. One study estimates motor vehicle emissions for two alternative metropolitan land use plans proposed for the Puget Sound Region. Because land-use patterns differ, the location and intensity of transportation demands also differ. Total motor vehicle pollutant emissions are found to vary appreciably between the two plans. A second study measures the variation in pollutant concentrations at various vertical and horizontal distances from existing roadways. Relationships are being established between meteorological factors, traffic flow characteristics, and pollutant concentrations that will assist in predicting the environmental impact of proposed roadways.     

Surface Air Pollutant Concentration Frequency Distributions: Implications for Urban Modeling

With the development of ambient air quality standards (AAQS), the need arises to describe the characteristics of regional surface air-pollutant concentration frequency distributions. In the evaluation of land use plans, numerous agencies will be concerned with evaluating the effectiveness of emission zoning and/or control actions. On a regional basis, one means of performing this assessment lies in determining the changes in the pollutant frequency distributions resulting from control actions.

This study presents new data concerning the surface air-pollutant concentration frequency distributions observed for area sources and continuous point sources, and compares these distributions with those of the pertinent meteorological variables describing the transport and diffusion of the pollutant. The observed surface air pollutant frequency distributions are compared to those corresponding to simple modeling concepts from either an urban area source or a continuous point source. For an urban source and a relatively inert pollutant like CO, we found that the observed frequency distribution for CO surface air concentration parallels the approximately log-normal frequency distribution of the reciprocal of the wind speed. We show that the constant relating these two well-correlated frequency distributions can be determined either experimentally or with a numerical simulation model of air pollution. The usefulness of numerical models in air pollution is discussed.     

A Regulatory Analysis

The information presented in this paper is directed to those individuals interested in future air quality control programs aimed at areas that are attaining one or more air quality ambient standards. Section 116 of the Clean Air Act, as amended, requires the Environmental Protection Agency to promulgate regulations for the prevention of significant deterioration (PSD) of air quality in order to protect the nation's clean air resources from hydrocarbons, carbon monoxide, ozone, nitrogen oxides, and lead (Set II pollutants). This program will affect industry siting in many areas of the country, particularly in the rural, undeveloped areas. Among the many alternatives currently being considered by EPA to meet the PSD Set II goals are emission management systems, marketable emission permits, air quality increments, emission fees, and control of transportation related sources. The final regulation may be a combination of several options or may present several alternatives from which a State would choose its specific program.     

Environmental Impact of Residential Wood Combustion Emissions and its Implications

Currently available information suggests a substantial environmental impact from residential wood combustion emissions. Air pollution from this source is widespread and increasing. Current ambient measurements, surveys, and model predictions indicate winter respirable (<2 μm) emissions from residential wood combustion can easily exceed all other sources. Both the chemical potency and deliverability of the emissions from this source are of concern. The emissions are almost entirely in the inhalable size range and contain toxic and priority pollutants, carcinogens, co-carcinogens, cilia toxic, mucus coagulating agents, and other respiratory irritants such as phenols, aldehydes, etc. This source is contributing substantially to the nonattainment of current particulate, carbon monoxide, and hydrocarbon ambient air quality standards and will almost certainly have a significant impact on potential future standards such as inhalable particulates, visibility, and other chemically specific standards. Emission from this growing source is likely to require additional expenditures by industry for air pollution control equipment in nonattainment areas.     

Federal Regulations for New Source Performance Standards

Section 111 of the Clean Air Act Amendments of 1970 authorizes the U.S. Environmental Protection Agency (EPA) to impose emission standards (NSPS) on those stationary sources that are determined to be significant contributors to air pollution and that consequently endanger the public health or welfare. In five years EPA promulgated 19 final and 1 proposed NSPS for stationary sources. Section 112 of the Act authorizes EPA to promulgate national emission standards for hazardous air pollutants (NESHAPS). EPA promulgated three final and 1 proposed regulation under Section 112. In addition, EPA promulgated NSPS for three "designated" pollutants from specific sources under Section Hid. EPA’s use of Section 111 and 112 authority provides for a quick response emission control program compared to the relatively slow process of establishing additional ambient air quality standards and having the states adopt implementation plans (Section 109). Three court cases, argued in the U.S. Court of Appeals for the District of Columbia, established basic guidelines for future promulgation of NSPS although certain legal actions are still pending. Proposed amendments to the Clean Air Act would further broaden and strengthen EPA’s direct regulatory authority.     

Impact of three interactive Texas state regulatory programs to decrease ambient air toxic levels

The Federal Clean Air Act (FCAA) framework envisions a federal-state partnership whereby the development of regulations may be at the federal level or state level with federal oversight. The U.S. Environmental Protection Agency (EPA) establishes National Ambient Air Quality Standards to describe “safe” ambient levels of criteria pollutants. For air toxics, the EPA establishes control technology standards for the 187 listed hazardous air pollutants (HAPs) but does not establish ambient standards for HAPs or other air toxics. Thus, states must ensure that ambient concentrations are not at harmful levels. The Texas Clean Air Act authorizes the Texas Commission on Environmental Quality (TCEQ), the Texas state environmental agency, to control air pollution and protect public health and welfare. The TCEQ employs three interactive programs to ensure that concentrations of air toxics do not exceed levels of potential health concern (LOCs): air permitting, ambient air monitoring, and the Air Pollutant Watch List (APWL). Comprehensive air permit reviews involve the application of best available control technology for new and modified equipment and ensure that permits protect public health and welfare. Protectiveness may be demonstrated by a number of means, including a demonstration that the predicted ground-level concentrations for the permitted emissions, evaluated on a case-by-case and chemical-by-chemical basis, do not cause or contribute to a LOC. The TCEQ's ambient air monitoring program is extensive and provides data to help assess the potential for adverse effects from all operational equipment in an area. If air toxics are persistently monitored at a LOC, an APWL area is established. The purpose of the APWL is to reduce ambient air toxic concentrations below LOCs by focusing TCEQ resources and heightening awareness. This paper will discuss examples of decreases in air toxic levels in Houston and Corpus Christi, Texas, resulting from the interactive nature of these programs.

Implications: Texas recognized through the collection of ambient monitoring data that additional measures beyond federal regulations must be taken to ensure that public health is protected. Texas integrates comprehensive air permitting, extensive ambient air monitoring, and the Air Pollutant Watch List (APWL) to protect the public from hazardous air toxics. Texas issues air permits that are protective of public health and also assesses ambient air to verify that concentrations remain below levels of concern in heavily industrialized areas. Texas developed the APWL to improve air quality in those areas where monitoring indicates a potential concern. This paper illustrates how Texas engaged its three interactive programs to successfully address elevated air toxic levels in Houston and Corpus Christi.     

Short Term Air Quality Standards for Suspended Particulate Matter in New York State

The Clean Air Act of 1970 requires each state to submit plans for implementation, maintenance, and enforcement of national ambient air quality standards subsequent to promulgation. Such plans have been geared to meet annual averages and maximum values. Based on experience in implementing the abatement plan it was found that air quality standards for averaging times shorter than one year are needed to shorten the time required to show contravention and to provide a basis for early corrective measures to regulate specific sources. This paper reports on the need and procedures used by New York State to develop such standards for suspended particulates. Daily suspended particulate data were analyzed by the Kolmogorov-Smirnov method goodness of fit technique to determine that the form of the distribution was log normal. A method developed by Larsen for predicting short term maximum concentrations for log normally distributed data was used to determine numerical values for one, two, and three month standards. Monthly, bi-monthly, and tri-monthly suspended particulate standards of 130, 110, and 100 µg/m³, respectively are proposed for the most extensively developed areas of New York State and correspondingly lower values for other areas. The methods used in this development are generally applicable to other air contaminants.     

Air pollution and health studies in China--policy implications

During the rapid economic development in China, ambient air pollutants in major cities, including PM10 (particulate matter with aerodynamic diameter < or =10 microm) and SO2 have been reduced due to various measures taken to reduce or control sources of emissions, whereas NO2 is stable or slightly increased. However, air pollution levels in China are still at the higher end of the world level. Less information is available regarding changes in national levels of other pollutants such as PM2.5 and ozone. The Chinese Ministry of Environmental Protection (MOEP) set an index for "controlling/reducing total SO2 emissions" to evaluate the efficacy of air pollution control strategy in the country. Total SO2 emissions declined for the first time in 2007. Chinese epidemiologic studies evidenced adverse health effects of ambient air pollution similar to those reported from developed countries, though risk estimates on mortality/morbidity per unit increase of air pollutant are somewhat smaller than those reported in developed countries. Disease burden on health attributable to air pollution is relatively greater in China because of higher pollution levels. Improving ambient air quality has substantial and measurable public health benefits in China. It is recommended that the current Chinese air quality standards be updated/revised and the target for "controlling/reducing total SO2 emissions" be maintained and another target for "reducing total NO2 emissions" be added in view of rapid increase in motor vehicles. Continuous and persistent efforts should be taken to improve ambient air quality.     

Selected International Receptor-Based Air Quality Standards

Abstract

The ambient air quality standards (AAQS) of twenty-one nations for eight commonly regulated substances are presented. Many countries are adding a receptor-based component to their air quality management, which traditionally have been emission oriented. Automation of air quality monitoring stations has meant that local air quality evaluation can now be more easily achieved. However, a majority of countries have no active air quality standards (emission or receptor-based) or ambient air quality monitoring. One possible monitoring procedure is outlined and the variation in international standards is discussed.     

The state of ambient air quality in Pakistan—a review

Background and purpose  

Pakistan, during the last decade, has seen an extensive escalation in population growth, urbanization, and industrialization, together with a great increase in motorization and energy use. As a result, a substantial rise has taken place in the types and number of emission sources of various air pollutants. However, due to the lack of air quality management capabilities, the country is suffering from deterioration of air quality. Evidence from various governmental organizations and international bodies has indicated that air pollution is a significant risk to the environment, quality of life, and health of the population. The Government has taken positive steps toward air quality management in the form of the Pakistan Clean Air Program and has recently established a small number of continuous monitoring stations. However, ambient air quality standards have not yet been established. This paper reviews the data being available on the criteria air pollutants: particulate matter (PM), sulfur dioxide, ozone, carbon monoxide, nitrogen dioxide, and lead.     

Outdoor and indoor factors influencing particulate matter and carbon dioxide levels in naturally ventilated urban homes

ABSTRACT

The present study investigated indoor and outdoor concentrations of two particulate matter size fractions (PM₁₀ and PM_2.5) and CO₂ in 20 urban homes ventilated naturally and located in one congested residential and commercial area in the city of Alexandria, Egypt. The results indicate that the daily mean PM_2.5 concentrations measured in the ambient air, living rooms, and kitchens of all sampling sites exceeded the WHO guideline by 100%, 65%, and 95%, respectively. The daily mean outdoor and indoor PM₁₀ levels in all sampling sites were found to exceed the WHO guideline by 100% and 80%, respectively. The indoor PM₁₀ and PM_2.5 concentrations were significantly correlated with their corresponding outdoor levels, as natural ventilation through opening doors and windows allowed direct transfer of outdoor airborne particles into the indoor air. Most of the kitchens investigated had higher indoor concentrations of PM_2.5 and CO₂ than in living rooms. The elevated levels of PM_2.5 and CO₂ in domestic kitchens were probably related to inadequate ventilation. The current study attempted to understand the sources and the various indoor and outdoor factors that affect indoor PM₁₀, PM_2.5 and CO₂ concentrations. Several domestic activities, such as smoking, cooking, and cleaning, were found to constitute important sources of indoor air pollution. The indoor pollution caused by PM_2.5 was also found to be more serious in the domestic kitchens than in the living rooms and the results suggest that exposure to PM_2.5 is high and highlights the need for more effective control measures.

Implications: Indoor air pollution is a complex problem that involves many determinant factors. Understanding the relationships and the influence of various indoor and outdoor factors on indoor air quality is very important to prioritize control measures and mitigation action plans. There is currently a lack of research studies in Egypt to investigate determinant factors controlling indoor air quality for urban homes. The present study characterizes the indoor and outdoor concentrations of PM₁₀, PM_2.5, and CO₂ in residential buildings in Alexandria city. The study also determines the indoor and outdoor factors which influence the indoor PM and CO₂ concentrations as well as it evaluates the potential indoor sources in the selected homes. This research will help in the development of future indoor air quality standards for Egypt.     

The New Clean Air Act Operating Permit Program: EPA’s Proposed Regulations

The 1990 Clean Air Act Amendments added a new Title V to the Act which establishes an operating permit program for numerous sources of air pollution. Certain sources are currently required to obtain a construction or “new source review” permit; the 1990 Amendments will require many more sources to apply for a permit which will give them permission to operate. CAA Title V was modeled on the National Pollutant Discharge Elimination System (NPDES) permit provisions of the Clean Water Act, but there are important differences between the two statutes.

Although many states already have their own operating permit programs, by late 1993 every state must establish a program that meets the requirements of Title V and EPA’s implementing regulations. EPA recently proposed these regulations, and by the statutory deadline of November 15, 1991 hopes to issue final regulations establishing the minimum elements of state operating permit programs. These regulations will significantly affect implementation of air pollution measures for years to come because a Title V operating permit will have to assure compliance with all applicable CAA requirements. In addition, permitted sources will be required to pay fees to cover the costs of the permit program.     

California Experience with Air Quality Standards

Air quality standards have existed in California for almost six years. They have become an important part of the State’s air pollution control program.

The two principal uses of the standards have been to establish the goals for controlling motor vehicle emissions and to provide a basis for evaluating air quality throughout the State. The standards have also proved to be valuable as a means of communicating on air pollution problems with legislators, administrators, the press, the public, and dischargers of pollutants.

Lack of adequate data on the effects of varying concentrations of contaminants of concern in air pollution is a serious limitation in any effort to establish air quality standards.It is important that this data be obtained.

The concept of employing air quality standards as administrative goals is not unique to the air pollution field but is part of a broad trend to utilize standards for insuring a satisfactory environment. Those engaged in the air pollution field can expect to see increasing emphasis on such standards.

Air quality standards do not provide a magic formula for eliminating air pollution; they are but one element in a comprehensive program. They have limitations and are no better than the data upon which they are based. The standards, however, can play an important role in preserving satisfactory air quality and protecting man’s health.

In using air quality standards, one should keep in mind the comments of H. W. Streeter⁵ on water quality standards—“Let us devise them, try them, revise them, and apply them, but also remember that they are but ’feeble instruments of the human will’ and like all other such tools are made to be discarded for better ones when they become worn out.“     

Coupling air quality and land use modeling within an optimization framework

Land use regulations and air quality standards can be effective tools to control air pollution. Atmospheric transport/chemistry simulation models could be used to develop suitable regulations and standards; however, these models are not as efficient as air quality management models developed from embedding governing equations for atmospheric transport/chemistry into an optimization framework. Formulations of two steady-state air quality management models are presented to facilitate the development or evaluation of land use strategies to protect regional air quality from pollution generated from distributed point or nonpoint sources. Both models are linear programs constructed with equations that describe steady-state atmospheric pollutant fate and transport. The first model determines feasible pollutant loading patterns for multiple land use activities to accommodate the greatest regional population. The second model ascertains patterns of expanded land use which have a minimum impact on air quality. The primary goal of this paper is to explain how air pollution and land use modeling may be coupled to create an effective management tool to aid scientists and engineers with decisions affecting air quality and land use. The secondary goal is to show the types of air quality and regulatory information which could be obtained from these models. This latter goal is attained with general conclusions as consequence of applying ‘duality theory.’     

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.     

Will the circle be unbroken: a history of the U.S. National Ambient Air Quality Standards

In celebration of the 100th anniversary of the Air & Waste Management Association, this review examines the history of air quality management (AQM) in the United States over the last century, with an emphasis on the ambient standards programs established by the landmark 1970 Clean Air Act (CAA) Amendments. The current CAA system is a hybrid of several distinct air pollution control philosophies, including the recursive or circular system driven by ambient standards. Although this evolving system has resulted in tremendous improvements in air quality, it has been far from perfect in terms of timeliness and effectiveness. The paper looks at several periods in the history of the U.S. program, including: (1) 1900-1970, spanning the early smoke abatement and smog control programs, the first federal involvement, and the development of a hybrid AQM approach in the 1970 CAA; (2) 1971-1976, when the first National Ambient Air Quality Standards (NAAQS) were set and implemented; (3) 1977-1993, a period of the first revisions to the standards, new CAA Amendments, delays in implementation and decision-making, and key science/policy/legislative developments that would alter both the focus and scale of air pollution programs and how they are implemented; and (4) 1993-2006, the second and third wave of NAAQS revisions and their implementation in the context of the 1990 CAA. This discussion examines where NAAQS have helped drive implementation programs and how improvements in both effects and air quality/control sciences influenced policy and legislation to enhance the effectiveness of the system over time. The review concludes with a look toward the future of AQM, emphasizing challenges and ways to meet them. The most significant of these is the need to make more efficient progress toward air quality goals, while adjusting the system to address the growing intersections between air quality management and climate change.     

Air Quality in Selected Megacities

Abstract

About half of the world's population now lives in urban areas because of the opportunity for a better quality of life. Many of these urban centers are expanding rapidly, leading to the growth of megacities, which are often defined as metropolitan areas with populations exceeding 10 million inhabitants. These concentrations of people and activity are exerting increasing stress on the natural environment, with impacts at urban, regional and global levels. In recent decades, air pollution has become one of the most important problems of megacities. Initially, the main air pollutants of concern were sulfur compounds, which were generated mostly by burning coal. Today, photochemical smog—induced primarily from traffic, but also from industrial activities, power generation, and solvents—has become the main source of concern for air quality, while sulfur is still a major problem in many cities of the developing world. Air pollution has serious impacts on public health, causes urban and regional haze, and has the potential to contribute significantly to global climate change. Yet, with appropriate planning megacities can efficiently address their air quality problems through measures such as application of new emission control technologies and development of mass transit systems.

This review is focused on nine urban centers, chosen as case studies to assess air quality from distinct perspectives: from cities in the industrialized nations to cities in the developing world. This review considers not only megacities, but also urban centers with somewhat smaller populations, for while each city—its problems, resources, and outlook—is unique, the need for a holistic approach to complex environmental problems is the same. There is no single strategy to reduce air pollution in megacities; a mix of policy measures will be needed to improve air quality. Experience shows that strong political will coupled with public dialogue is essential to effectively implement the regulations required to address air quality.     

Assessing the spatial distribution of nitrogen dioxide in London,Ontario

Land use regression (LUR) models have been widely used to characterize the spatial distribution of urban air pollution and estimate exposure in epidemiologic studies. However, spatial patterns of air pollution vary greatly between cities due to local source type and distribution. London, Ontario, Canada, is a medium-sized city with relatively few and isolated industrial point sources, which allowed the study to focus on the contribution of different transportation sectors to urban air pollution. This study used LUR models to estimate the spatial distribution of nitrogen dioxide (NO₂) and to identify local sources influencing NO₂ concentrations in London, ON. Passive air sampling was conducted at 50 locations throughout London over a 2-week period in May–June 2010. NO₂ concentrations at the monitored locations ranged from 2.8 to 8.9 ppb, with a median of 5.2 ppb. Industrial land use, dwelling density, distance to highway, traffic density, and length of railways were significant predictors of NO₂ concentrations in the final LUR model, which explained 78% of NO₂ variability in London. Traffic and dwelling density explained most of the variation in NO₂ concentrations, which is consistent with LUR models developed in other Canadian cities. We also observed the importance of local characteristics. Specifically, 17% of the variation was explained by distance to highways, which included the impacts of heavily traveled corridors transecting the southern periphery of the city. Two large railway yards and railway lines throughout central areas of the city explained 9% of NO₂ variability. These results confirm the importance of traditional LUR variables and highlight the importance of including a broader array of local sources in LUR modeling. Finally, future analyses will use the model developed in this study to investigate the association between ambient air pollution and cardiovascular disease outcomes, including plaque burden, cholesterol, and hypertension.

Implications: Monitoring and modeling of NO₂ throughout the city of London represents an important step toward assessing air pollution health effects in a mid-sized Canadian city. The study supports the introduction of railways to LUR modeling of NO₂. Railways explained approximately 9% of the variability in ambient NO₂ concentrations in London, which suggests that local sources captured by land-use indicators may contribute to the efficacy of LUR models. These findings provide insights relevant to other medium and smaller sized cities with similar land use and transportation infrastructure. Furthermore, London is a central hub for medical research and treatment in southwestern Ontario, with facilities such as the Robarts Research Institute, London Regional Cancer Program (LRCP), and Stroke Prevention & Atherosclerosis Research Centre (SPARC). The models developed in this study will provide estimates of exposure for future analyses examining air pollution health effects in this data-rich population.     

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.     

experience of the forest products industry in obtaining air quality permits for new and modified sources

A detailed study of the air quality permitting process for 65 different forest products industry projects requiring preconstruction permit approvals from EPA, state, and local air pollution control agencies was conducted. The projects included a wide array of sources including kraft recovery furnaces, lime kilns, fossil fuel and wood residue fired boilers, solid wood products manufacturing facilities, paper coaters, and printing presses. Information concerning the time involved in the permitting process, costs associated with obtaining the permits, use of air quality models and ambient monitoring data, emission control technology determinations, problem areas encountered during the permitting process, perceived benefits and drawbacks of the permitting process, and the effect of permitting requirements on project planning was obtained.

The results indicate that certain permitting requirements such as Best Available Control Technology (BACT) determinations, dispersion modeling results, and use of ambient air quality monitoring data seldom influence the emission limitations ultimately imposed in the final approved permit, with 87% of the final emission limits equivalent to the applicable New Source Performance Standard (NSPS). The 65 permitting case histories also show that obtaining permits for projects subject to Prevention of Significant Deterioration (PSD) requirements takes approximately twice as long and costs twice as much as obtaining permits for projects not subject to PSD requirements.