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World Resources 1996-97 (A joint publication by The World Resource Institute, The United Nations Environment Programme, The United Nations Development Programme, and the World Bank) (Data edited by Dr. Róbinson Rojas)
5. Urban Priorities for Action PRIORITIES FOR ACTION: AIR POLLUTION
For health, environmental, and economic reasons, strategies to reduce air pollution are critical in many cities of the developed and, especially, the developing world. Ambient air pollution emanates from three major sources--energy generation, industry, and transportation--all of which tend to increase with economic growth.
At the most basic level, addressing urban air problems requires an understanding of the air basin in which the city is situated and the pollution sources that affect it. Forming or participating in an air basin management district or other regional regulatory body is often the best way for cities to develop this understanding and to coordinate basinwide efforts to control pollution, including the drafting and enforcement of ambient air quality standards. Developing a local air monitoring capability is essential to both policymaking and enforcement efforts. In Bombay, for example, citywide air monitoring since 1969 has provided an extensive database that is used to assess both daily air quality and regional pollution trends (90).
In many cities in the developing world, however, the most critical health threat stems from exposure to indoor air pollution. Reducing this threat requires a different set of strategies.
Addressing Indoor Air Pollution
For many city residents, air pollution from indoor smoke, usually from biomass fuels, poses a greater health risk than outdoor air pollution. The optimal strategy to reduce the exposure of lower-income residents to indoor air pollutants is to facilitate their switch from dirty fuels, for example, by providing clean-burning gas or by establishing programs to make kerosene stoves more affordable. However, for many poor residents of areas without access to city services, this transition to higher-priced fuels will not be possible for some time. For this population, the most promising interim measures are the distribution of improved cookstoves and the fostering of improved house design with better ventilation.
Programs to design and disseminate cleaner-burning stoves have been under way for many years in countries such as China, India, Kenya, and Nepal. However, most stove programs are designed to improve efficiency, not reduce air pollution. One of the most successful urban stove projects has been the Kenya Ceramic Jiko initiative. More than 500,000 stoves have been distributed since the mid-1980s. The stove is a modification of the traditional stove that can be built locally from easily accessible materials and that burns charcoal more efficiently (91). Despite the program's apparent success, penetration of this new stove was limited to middle-class neighborhoods in Nairobi. In addition, ensuring the quality of the new stoves has been difficult.
In higher-income residences and commercial buildings, in both developing and developed countries, indoor pollutants are more likely to come from cigarette smoking, unvented or improperly vented stoves or heaters, airborne contaminants such as asbestos or molds and fungi, and the release of gases from construction materials and furnishings such as rugs and upholstery.
Several strategies are available to address indoor pollution in higher-income settings. Smoking indoors and in public places can be discouraged through public information campaigns alerting residents to the dangers of secondhand smoke. To minimize combustion products indoors, city environmental managers can establish programs to check home heaters and stoves to ensure proper venting and maintenance. Local ordinances can be enacted to restrict the use of asbestos insulation and fireproofing in new construction. And building codes can direct attention to the provision of adequate ventilation, particularly in new commercial buildings with closed- loop heating and cooling systems.
Reducing Energy Sector Emissions
Cutting emissions from the energy sector, particularly coal- or oil-fired power plants, is critical to controlling outdoor air pollution in many urban areas. Unfortunately, many of the factors determining energy sector pollution--such as the price of energy, the siting of state-owned power plants, the level of investment in new technologies or alternative energy sources, and the privatization of local utilities to improve their capitalization and management--are frequently determined at a national or state level. Nonetheless, cities often have considerable influence over how local utilities are run and over the energy consumption patterns of city residents.
Reducing pollution from coal- and oil-fired power plants can come via three routes: upgrading the generating efficiency and pollution-control capabilities of the plants themselves so that they emit fewer pollutants; cleaning up fuels, either by cleaning the coal before burning or by switching to cleaner-burning natural gas; or reducing the demand for power through energy conservation. Attention to proper operation and maintenance procedures is required in any case to keep the performance of power plants from declining over time--an acute problem in many developing countries.
These same strategies of retrofitting with new technology and cleaning up or switching fuels can also be applied at the building or individual household level to cut energy-related emissions within neighborhoods. Replacing or installing pollution control devices on aging coal-fired boilers in commercial and residential buildings in temperate zone cities can increase efficiency and decrease pollutants; converting them to gas can reduce their impact on local air problems still more.
In cities where coal is used to fire individual coal stoves, as in many Chinese and Eastern European cities, upgrading the quality of coal used for such heating can bring immediate and significant air quality benefits to neighborhoods. For example, use of coal briquettes--formed from pulverized, washed coal--can improve combustion efficiency in home heaters by 20 to 30 percent and reduce carbon monoxide emissions by 70 percent and particulate emissions by 60 percent. Adding a sulfur absorbent to briquettes can cut sulfur dioxide emissions by about half. Again, where possible, converting residential heating to gas provides further pollution relief. Recognizing this, but committed to using its huge coal reserves, China is building several coal gasification plants to provide gas for urban residential use (92).
Promoting Energy Conservation
While energy policies are generally considered to be the responsibility of national governments, cities are in a position to help lower energy consumption. Cities can use several tools in their quest to lower energy demand, the first being a vigorous public education campaign on the need for and benefits of energy conservation and the options available to residential and commercial energy users. Such options include the use of more efficient appliances and lighting fixtures, and, in cooler climates, the installation of weatherstripping and insulation.
The Urban CO2 Reduction Project, sponsored by the International Council for Local Environmental Initiatives, is a network of 14 cities that are working together to develop local strategies to reduce energy consumption and carbon dioxide emissions. The goal of the project is to show that emission reductions are possible without harming the city's economic productivity. A preliminary study in the city of Toronto showed that the city could reduce per capita emissions of carbon dioxide by 33 percent at net economic savings even without considering the additional benefits of local job creation and the stimulation of new manufacturing industries (93).
Policies adopted by the 14 cities range from economic instruments to regulations to broader strategies such as land use planning and improving public transportation. To achieve its target of 25 percent emission reductions, Hanover, Germany, has proposed the following measures (among others): switching fuels for electricity generation, retrofitting municipal buildings, strengthening energy performance standards in the building codes for new buildings, modifying land use patterns, and improving waste management. Copenhagen, Denmark, has proposed a local energy tax and utility rate reform to reduce energy consumption (94).
The Urban CO2 Reduction Project shows that simple technical fixes such as insulating pipes and repairing leaks in the steam heating systems in residential buildings can translate into reduced energy use (95) (96). For cities in developing countries, reducing energy consumption may not be a top priority, yet in rapidly growing cities where new construction is high, the potential for cutting future energy needs through efficiency standards in building codes is large (97). Building in energy efficiency during initial construction is almost always less costly than retrofitting, and the energy saved--and the power plant emissions prevented--can be substantial.
Encouraging Pollution Prevention
One of the most promising tacks to reducing industrial emissions is to prevent pollution in the first place. Pollution prevention focuses on designing cleaner production processes and material handling procedures. This approach follows a natural hierarchy of industrial waste management options. First, reduce pollutants at the source as much as possible. Second, recycle or reuse as much as possible of the pollutants or wastes that are produced despite these efforts. Third, treat, detoxify, or destroy what remains. And fourth, only as a last resort release pollutants to the surrounding environment (98).
The central rationale for this approach is economic: preventing pollution at the source both reduces pollution control costs and increases the efficiency of production, because fewer materials are lost as waste. Preventing pollution can also be a powerful marketing and public relations tool in areas where environmental awareness has increased and environmental health concerns have made their way onto urban agendas.
Cities can be important catalysts and partners in pollution prevention, mostly by helping to educate both the private sector and the public about the advantages of cleaner manufacturing. Developing and helping to administer information clearinghouses that offer details on alternative technologies and their successful application in other industries are prime means of facilitating a change to cleaner industrial processes. City governments can foster a stronger environmental ethic among local industries by conducting public "green performance" ratings of manufacturing facilities, by encouraging industrial managers to publicly commit to pollution- reduction targets, and by offering awards for exemplary environmental performance.
Cities can enlist the support of the public through education campaigns that make clear the unseen costs of pollution and that encourage consumers to "buy green." Enacting public disclosure laws that force local industries to reveal their annual pollution emissions can also prod local firms to improve their environmental records, lest they acquire a reputation for being insensitive to local citizens and the environment. Such disclosure laws have been quite effective in altering corporate behavior in some developed countries. Encouraging local nongovernmental organizations to act as watchdogs for industrial pollution problems has also proved effective in many instances (99) (100).