Urban Air Pollution
Urban populations across the United States are at a high risk of disease and death because of air pollution. While the degree of air pollution varies from one city to another, all city dwellers are at risk of harm from air pollutants (Stevens, 2011, p. 5). Those with respiratory and heart conditions are most vulnerable to air pollutants but even healthier individuals are at risk. While regulations to maintain clean air exist for many large cities such as New York, they are ineffective in eliminating ozone and fine particulate matter, and several other air pollutants. The burning of fuel by motor vehicles and industries near or within urban centers increases the concentration of air pollutants in these areas (Peltier et al., 2011, p. 485). The paper examines the problem of air pollution in the cities of the United States and the measures adopted to respond to it with some reference to Los Angeles and New York cities.
Sources of Air Pollution in Urban Areas
The main air pollutants in urban areas include fine particles, ozone, and nitrogen oxides. Fine particles of up to 2.5µm in diameter are a common type of air pollutant in many cities. These particles include nickel, carbon, lead, zinc, and aluminum (Peltier et al., 2011, p. 485). For example, the cities of Los Angeles and New York are some of the worst-hit areas by fine particles pollution (Schweitzer & Zhou, 2010, p. 364). These particles are released during fuel combustion in vehicles, electric power plants that use fossil fuels, large machines used in construction sites, and cooking equipment in food manufacturing industries. Other processes that generate fine particles include metal fabrication, demolition, or the sweeping up of dust from roads into the urban air by wind. Ozone is a product of multiple chemical reactions between nitrogen oxides and volatile organic compounds when exposed to sunlight (Stevens, 2011, p. 5). The sources of air pollutants can be inside or outside the given city. Remote sources of air pollutants are the main sources of air pollution in urban areas while sources within the city explain the variations in the level of air pollution in different parts of the city. For example, large cities such as New York and Los Angeles have a high volume of traffic and tall buildings on either side of nearly all their streets, especially the city center (Mead, 2008, p. 289). These buildings trap smoke and gaseous emissions from motor vehicles, thus increasing the concentration of the pollutants in certain parts of the city. According to Schweitzer & Zhou (2010, p. 364), certain aspects of city design such as compactness can affect the distribution of air pollutants but local factors such as street canyons can render some areas more dangerous than others in terms of air quality.
Urban air pollution poses significant health risks to urban residents. For example, particulate matter pollution is responsible for at least 5000 serious cases of heart and lung infections and nearly 6000 cases of asthma in New York City each year (Stevens, 2011, p. 20). In addition, ozone affects at least 5000 New York residents each year leading to deaths and hospitalizations (Stevens, 2011, p. 28). Fine particles enter the lungs and the blood system via inhalation. Once in the lungs, these particles cause inflammation of air passages, hypersensitivity of the immune system, high blood pressure, irregular heart rhythm, and lung malfunction (Peltier et al., 2011, p. 485). Acute exposure to gaseous pollutants from fossil fuel combustion can cause respiratory and cardiac problems while long-time exposure causes chronic diseases and reduced life expectancy. Exposure to ozone results in lung inflammation, irritation of air passages, coughing, and increased asthma symptoms (Rawlins, 2013, p. 230). In addition, ozone destroys the environment by damaging plant foliage and animal tissues.
Response to Urban Air Pollution: Government Policies
The United States began developing an Air Quality Management framework to address the problem of air quality in urban areas in the 1960s. Although this approach has managed to improve air quality in most cities, it lacks the level of integration and scope necessary to reduce air pollutants to harmless levels (National Research Council, 2007, p. 113). The U.S. Congress enacted a broad environmental law called the Clean Air Act as part of its nationwide effort to reduce air pollution in 1963. Government response to air pollution began in the 1950s following the increased realization of the negative impact of industrial emissions on the environment. However, air pollution control was initially limited to municipal county and state governments because a national regulatory framework was lacking. The federal government began participating in air pollution control in the 1960s when it established the National Air Pollution Control Administration to assist with research and technical advice (National Research Council, 2007, p. 114). National efforts intensified with the creation of the U.S. Environmental Protection Agency (EPA) in 1970. The purpose of EPA was to establish and supervise the implementation of environmental standards to ensure clean air, soil and water through research and policy development. After its creation, EPA established the National Ambient Air Quality Standards to ensure a uniform and coordinated response to air pollution at national, state, and local levels (National Research Council, 2007, p. 114).
Efforts to Reduce Air Pollution at City-Level
Los Angeles is one of the earliest cities in the United States to implement coordinated air pollution control measures. According to the National Research Council (2007, p. 277), the city rose to prominence as a manufacturing and transportation hub in the first half of the 20th century. Air pollution became a major problem and sometimes smog would engulf the city reducing visibility significantly. Los Angeles city authorities began implementing pollution control measures in 1945. In 1947, the state of California enacted the Air Pollution Control Act (APCA) that required every county in California to create an air pollution control district (APCD) (National Research Council, 2007, p. 277). The first county to create an APCD in the United States was Los Angeles. The Los Angeles APCD focused on minimizing emissions from incinerators, factories, gasoline reservoirs, and service stations. However, the increased use of automobiles in the city made it impossible to achieve clean air. This led to the establishment of the California Motor Vehicle Pollution Control Board in 1959, whose mission was to recommend new technology to control motor vehicle emissions. The Board was the first in the United States to attempt to reduce emissions from motor vehicle fuels by reducing olefin content. From 1970, the United States government ended the use of lead in vehicle fuel and adopted new technology (catalytic converters) to reduce hydrocarbon emissions. The state of California established the California Air Resources Board (CARB) in 1967 (National Research Council, 2007, p. 289). CARB has been very instrumental in ensuring motor vehicles adhere to air quality standards through cleaning up fuels and adopting air-friendly fuel technology.
Effectiveness of Responses
As the case of Los Angeles, air pollution response reveals, municipal, county, and state governments need to work together to address air pollution problems. While the federal government provides a general regulatory framework through its national environmental laws, the effectiveness of such laws depends on the implementation efforts of state and local governments. As a result, different cities in the United States experience air pollution at different levels depending on the level of exposure to air pollutants and the local policies to achieve ambient air quality (Rawlins, 2013, p. 126). Los Angeles has achieved much improvement in air quality during its more than five decades of air pollution regulation. However, owing to its continuous growth in terms of fuel consumption and population, the current air pollution efforts will require the necessary adjustments to achieve higher levels of air cleanliness (National Research Council, 2007, p. 296). In fact, Los Angeles still leads to levels of fine particles pollution in the United States.
In addition, the response to air pollution throughout the United States adopts the general view that air pollution affects city residents equally. However, numerous studies reveal that some populations are more exposed to air pollutants than others are. For example, Rawlins (2013, p. 226) found that people living close to highways and near gas industries are in greater danger of illness due to higher concentrations of air pollutants in these areas. Another study, by Houston, Li & Wu (2014, p. 156), reported that people living near highways experience higher levels of exposure to particulate matter and these people tend to belong to minority ethnic groups and low social-economic status. Furthermore, the distribution of urban forests affects the level of gaseous pollutants in the air but response efforts have ignored the role of urban trees in urban air pollution (Nowak, Crane, & Stevens, 2006, p. 115).
Urban air pollution remains a major health threat to city residents in the United States. Measures to reduce urban air pollution have focused on minimizing emissions of particulate matter and ozone from fuel consumption activities including energy generation and automobile use. However, research indicates that air pollution regulation lacks sensitivity to the disparity in the distribution of the health effects of air pollution. People living near highways and energy generation plants are more vulnerable to the adverse effects of air pollution and thus response efforts should pay more attention to such people to ensure environmental justice.
Houston, D., Wei, L., Jun, W. (2014). Disparities in exposure to automobile and truck traffic and vehicle emissions near the Los Angeles-long beach port complex. American Journal of Public Health 104(1):156-164.
Mead, M. (2008). Canyons up the pollution ante. Environmental Health Perspectives, 116(7), A280.
National Research Council, (2007). Energy futures and urban air pollution: Challenges for China and the United States. Washington, DC: The National Academies Press.
Nowak, D. J., Crane, D. E. & Stevens, J. C. (2006). Air pollution removal by urban trees and shrubs in the United States. Urban Forestry & Urban Greening 4, 115-123.
Peltier, R., Cromar, K., Ma, Y., Fan, Z., & Lippmann, M. (2011). Spatial and seasonal distribution of aerosol chemical components in New York City: (2) Road dust and other tracers of traffic-generated air pollution. Journal of Exposure Science & Environmental Epidemiology, 21(5), 484-494. doi:10.1038/jes.2011.15
Rawlins, R. (2013). Planning for fracking on the Barnett Shale: Urban air pollution, improving health based regulation, and the role of local governments. Virginial Environmental Law Journal 31, 226-306.
Schweitzer, L., & Zhou, J. (2010). Neighborhood air quality, respiratory health, and vulnerable populations in compact and sprawled regions. Journal of the American Planning Association, 76(3), 363-371. doi:10.1080/01944363.2010.486623
Stevens, L. M. (2011). Air pollution and the health of new Yorkers: The impact of fine particles and ozone. http://www.nyc.gov/html/doh/downloads/pdf/eode/eode-air-quality-impact.pdf