Air pollution in the United States

Looking down from the Hollywood Hills, with Griffith Observatory on the hill in the foreground, air pollution is visible in downtown Los Angeles on a late afternoon.

Air pollution is the introduction of chemicals, particulate matter, or biological materials that cause harm or discomfort to humans or other living organisms, or damages the natural environment into the atmosphere. Ever since the beginning of the Industrial Revolution in the United States, America has had much trouble with environmental issues, air pollution in particular. According to a 2009 report, around "60 percent of Americans live in areas where air pollution has reached unhealthy levels that can make people sick". Pollution in the United States has plummeted in the recent decade, with pollutants such as nitrogen dioxide decreasing despite the fact the number of vehicles on the road isn't. This is due to better regulations, economic shifts, and technological innovations. With respect to nitrogen dioxide, NASA reported a 32% decrease in New York City and a 42% decrease in Atlanta between the periods of 2005-2007 and 2009-2011. California has the worst air quality of any state, and in most surveys the cities in California rank in the top 5 or top 10 of most polluted air in the United States.

Clean Air Acts

In the 1960s, 1970s, and 1990s, the United States Congress enacted a series of Clean Air Acts which significantly strengthened regulation of air pollution. Individual U.S. states, some European nations and eventually the European Union followed these initiatives. The Clean Air Act sets numerical limits on the concentrations of a basic group of air pollutants and provide reporting and enforcement mechanisms.

In 1999, the United States Environmental Protection Agency (EPA) replaced the Pollution Standards Index (PSI) with the Air Quality Index (AQI) to incorporate new PM2.5 and Ozone standards.

The effects of these laws have been very positive. In the United States between 1970 and 2006, citizens enjoyed the following reductions in annual pollution emissions:

• carbon monoxide emissions fell from 197 million tons to 89 million tons
• nitrogen oxide emissions fell from 27 million tons to 19 million tons
• sulfur dioxide emissions fell from 31 million tons to 15 million tons
• particulate emissions fell by 80%
• lead emissions fell by more than 98%

In an October 2006 letter to EPA, the agency's independent scientific advisors warned that the ozone smog standard “needs to be substantially reduced” and that there is “no scientific justification” for retaining the current, weaker standard. The scientists unanimously recommended a smog threshold of 60 to 70 ppb after they conducted an extensive review of the evidence.

The EPA has proposed, in June 2007, a new threshold of 75 ppb. This is less strict than the scientific recommendation, but is more strict than the current standard.

Some industries are lobbying to keep the current standards in place. Environmentalists and public health advocates are mobilizing to support the scientific recommendations.

International pollution

An outpouring of dust layered with man-made sulfates, smog, industrial fumes, carbon grit, and nitrates is crossing the Pacific Ocean on prevailing winds from booming Asian economies in plumes so vast they alter the climate. Almost a third of the air over Los Angeles and San Francisco can be traced directly to Asia. With it comes up to three-quarters of the black carbon particulate pollution that reaches the West Coast.

In the United States unhealthy levels of pollution are measured by the Environmental Protection Agency and independent researchers or agencies, like the American Lung Association. Federal limits and pollution standards are set by the Clean Air Act.

Race and ethnicity

Environmental racism and air pollution

Environmental racism is the academic term that describes how certain environmental injustices can be viewed as discriminatory towards communities of racial minorities. The term highlights any disproportionate exposure to toxins or inaccessibility to ecological benefits such as water, clean air, and natural resources. Also, environmental racism is concerned with when government and large corporations target minority communities in order to commence environmentally damaging projects. They find that in these communities, there is often much less resistance and pressure to terminate these projects. When these projects are undertaken, nearby households and small businesses in these minority communities are negatively affected, sparking health problems among children and an overall decrease in the standard of living.

According to the 2014 Census, the median household income for both African-Americans and Hispanics was about $43,300. On the other hand, white household income was around $71,300. Also, over 91% of African-Americans and 86% of Hispanics live in urban areas, whereas only about 70% of whites live in urban areas. Furthermore, in April of 2017, three environmental groups-- Environmental Justice and Health Alliance for Chemical Policy Reform, Coming Clean, and Center for Effective Government-- completed a study regarding the disproportionate spread of environmental burdens. They define "fenceline zones" as areas within the vicinity of U.S. chemical facilities that are at highest risk for death or injury after a potential chemical accident. They found that the 134 million people living in "fenceline zones" are 75% more likely to be African-American, 60% more likely to be Latino, and 50% more likely to be classified as having low socioeconomic status. The study was meant to underline the idea that the United States government fails to justly protect its communities and push the government to update chemical safety regulations nationwide. These factors greatly contribute to the fact minority exposure to harmful air pollutants ranges from 40% to 60% higher than whites even when air quality is slowly improving as a whole.

Air pollution in California

California's air is the most polluted in the U.S.A.

Air Pollution and Low SES Communities in California

The U.S. Environmental Protection Agency's interactive online map - EJSCREEN - features the low socioeconomic communities across the country that are more vulnerable to air pollution and its associated health risks. As exhibited in this map, Southeast Los Angeles County neighborhoods, primarily impoverished areas in the San Joaquin Valley and Inland Empire, face a higher exposure to air pollution and environmental injustices.

Los Angeles Air pollution

Los Angeles has some of the most contaminated air in the country. With a population of roughly over 10 million, the Los Angeles area is a large basin with the Pacific Ocean to the west, and several mountain ranges with 11,000-foot peaks to the east and south. Diesel engines, ports, motor vehicles, and industries are main sources of air pollution in Los Angeles. Frequent sunny days and low rainfall contribute to ozone formation, as well as high levels of fine particles and dust.

Air pollution in Los Angeles has caused widespread concerns. In 2011, the Public Policy Institute of California (PPIC) Survey on Californians and the Environment showed that 45% of citizens in Los Angeles consider air pollution to be a “big problem”, and 47% believe that the air quality of Los Angeles is worse than it was 10 years ago. In 2013, the Los Angeles-Long Beach-Riverside area ranked the 1st most ozone-polluted city, the 4th most polluted city by annual particle pollution, and the 4th most polluted city by 24-hour particle pollution.

Both ozone and particle pollution are dangerous to human health. The Environmental Protection Agency (EPA) engaged a panel of expert scientists, the Clean Air Scientific Advisory Committee, to help them assess the evidence. The EPA released their most recent review of the current research on health threat of ozone and particle pollution.

EPA Concludes Ozone Pollution Poses Serious Health Threats

• Causes respiratory harm (e.g. worsened asthma, worsened COPD, inflammation)
• Likely to cause early death (both short-term and long-term exposure)
• Likely to cause cardiovascular harm (e.g. heart attacks, strokes, heart disease, congestive heart failure)
• May cause harm to the central nervous system
• May cause reproductive and developmental harm

- U.S. Environmental Protection Agency, Integrated Science Assessment for Ozone and Related Photochemical Oxidants, 2013. EPA/600/R-10/076F.

EPA Concludes Fine Particle Pollution Poses Serious Health Threats

• Causes early death (both short-term and long-term exposure)
• Causes cardiovascular harm (e.g. heart attacks, strokes, heart disease, congestive heart failure)
• Likely to cause respiratory harm (e.g. worsened asthma, worsened COPD, inflammation)
• May cause cancer
• May cause reproductive and developmental harm

-U.S. Environmental Protection Agency, Integrated Science Assessment for Particulate Matter, December 2009. EPA 600/R-08/139F.

Helping the area to meet the national air quality standards and improve the health of local residents continues to be a priority for the EPA. One of EPA's highest priorities is to support the reduction of diesel emissions from ships, trucks, locomotives, and other diesel engines. In 2005, Congress authorized funding for the Diesel Emissions Reduction Act (DERA), a grant program, administrated by the EPA, to selectively retrofit or replace the older diesel engines most likely to impact human health. Since 2008, the DERA program has achieved impressive out outcome of improving air quality. The EPA also works with state and local partners to decrease emissions from port operations and to improve the efficient transportation of goods through the region. Both the EPA and the Port of Los Angeles are partners of the San Pedro Bay Ports Clean Air Action Plan, a sweeping plan aimed at significantly reducing the health risks posed by air pollution from port-related ships, trains, trucks, terminal equipment and harbor craft. For environmental justice, air pollution in low-income LA communities has received more attention. In 2011, the “Clean up Green up” campaign was launched to designate four low-income LA communities- Pacoima, Boyle Heights and Wilmington. This campaign aims to push green industries through incentives, including help obtaining permits and tax and utility rebates.

Although Los Angeles air pollution level has declined for the last few decades, citizens in Los Angeles still suffer from high level air pollution.

Research in California

Diabetes in Los Angeles County Latino children

In 2017, researchers found that diabetes in Latin(x) children living in Los Angeles has been linked to air quality. A study led by the University of Southern California was the first of its kind to follow the health and residential air pollution levels of the same children over a span of years. The subjects of the study were overweight Latin(x) children, between the ages of eight and fifteen, residing in areas with excess particulate matter. The results demonstrated that the children possessed significantly increased risk factors for Type 2 diabetes by the time they turned eighteen, such as diminished efficiency in the insulin-secreting cells of the pancreas.

Proximity of schools to vehicle traffic in Culver City

The spatial arrangement of Californian communities plays a large role in determining exposure to the concentrated air pollution of the state's southern regions. In one suburb of Los Angeles, El Marino Language School sits adjacent to the ten-lane Interstate 405. Students of schools like these, often elementary-aged and undergoing critical stages of development, are subject to dramatically increased levels of pollution from automobile emissions, including carcinogenic compounds. In addition, minority and low-income students have a higher prevalence of attendance in public schools of urban areas, such as the big cities in which busy roads and schools share territory.

Fracking violations in Shafter school zones

Oil fracking is a process that involves a high pressure injection of fluid into the ground to extract oil. The adverse environmental effects of this natural gas extraction are the subject of much study, the primary concerns of which surround the contamination of surrounding water and air sources. These risks result when underground drinking water and surface water are exposed to discharges of the chemically-infused fracking fluid due to faulty construction, disposal leaks, or other unintended byproducts like the release of hazardous volatile compounds into the air.

In 2015, a study revealed that there were forty-five fracking sites within 1.5 miles of one junior high in the town of Shafter, which is one of California's top ten most polluted communities. The students of this community suffered from the state's decision to allow oil companies to continue hydraulic fracturing within close proximity of their schools. Parents observed severe and unexplainable health complications amongst their children, including asthma and epilepsy, that may have been correlated with air toxins from the nearby wells.

Inequalities in cumulative environmental burdens among three urbanized counties in California

In 2012, this research used the method of cumulative environmental hazard inequality Index (CEHII), which is a model developed to environmental inequality in air pollution hazards., to analyze the environmental inequality in three counties in California: Alameda, San Diego and Los Angeles (Jason et al. 2012). The result indicated that color community bear greater air pollution including NO2, PM 2.5, PM 10, and heat stress compared to predominately white and more affluent community. Also, the research verified that poverty status is consistent with the trend of disproportion burden of the racial-ethic status. As a future direction of study, it plans to classify the inequality exists in African American, Hispanic, Asian, and other ethnic groups. Furthermore, the technique used in this research provided a way to assess environmental inequality and the results can be used to assist decision makers in efforts to address environmental inequality issues.

Pollution level rankings

Most polluted US cities by short-term particulate matter Rank City 1 Bakersfield-Delano, CA 2 Fresno-Madera, CA 3 Hanford-Corcoran, CA 4 Los Angeles-Long Beach-Riverside, CA 5 Modesto, CA 6 Salt Lake City-Ogden-Clearfield, UT 7 Pittsburgh-New Castle, PA 8 Merced, CA 9 Fairbanks, AK 10 Logan, UT-ID

Most polluted US cities by ozone levels Rank City 1 Los Angeles-Long Beach-Riverside, CA 2 Visalia-Porterville, CA 3 Bakersfield-Delano, CA 4 Fresno-Madera, CA 5 Hanford-Corcoran, CA 6 Sacramento—Arden-Arcade—Yuba City, CA-NV 7 Houston-Baytown-Huntsville, TX 8 Dallas-Fort Worth, TX 9 Washington-Baltimore-Northern Virginia, DC-MD-VA-WV 10 El Centro, CA

Most polluted US cities by year-round particulate matter Rank City 1 Bakersfield-Delano, CA 2 Merced, CA 3 Fresno-Madera, CA 4 Hanford-Corcoran, CA 5 Los Angeles-Long Beach-Riverside, CA 6 Modesto, CA 7 Visalia-Porterville, CA 8 Pittsburgh-New Castle, PA 9 El Centro, CA 10 Cincinnati-Middletown-Wilmington, OH-KY-IN

See also

• National Ambient Air Quality Standards
• Spare the Air program (California)
• Greenhouse gas emissions by the United States
• Climate change in the United States

External links

• American Lung Association State of the Air 2013