Woodward_Final by wuzhengqin

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									                                                                             Maggie Woodward
                                                                                   4 May 2011
                                                                PUBP 714 – Comprehensive Exam


                   Transportation and Human Health: Hurtful and Helpful

       Transportation affects human heath in a myriad of ways. Vehicles produce pollution,

which directly impact the quality of air people breathe. Dependence on automobiles has lead to

the creation of an environment that is more conducive to driving than to walking or biking.

Transportation can even act as a vector for disease, transporting pathogens and their hosts across

continents to new populations of susceptible persons. Though each of these effects can be

somewhat controlled, each also causes concern for the future. Transportation needs to be adapted

to minimize its health impacts on humans. Reform, however, is likely to be costly and time

consuming. Existing modes of transportation are firmly ingrained in societies, and overcoming

their negative impacts may require the development of cleaner technologies, changes in human

behavior, or strict regulations, each of which can be difficult to achieve.

       Air pollution from transportation is a major concern for human health. Exhaust from

vehicles is a major source of carbon monoxide, nitrogen dioxide, sulfur dioxide, and particulate

matter emissions (Office of Air Quality Planning and Standards 2010). Ozone is produced as a

secondary pollutant, when nitrogen oxides react with volatile organic compounds, which are also

found in vehicle exhaust. In humans, these pollutants act primarily to inhibit the respiratory

system (Friedman, et al. 2001). Inhalation can lead to difficulty breathing, reduced oxygen

carrying capacity of blood, lung infections, and, most commonly, asthma. The Environmental

Protection Agency (EPA) is responsible for regulating for each of these pollutants under the

Clean Air Act. The standards set by the EPA, called the National Ambient Air Quality Standards

(NAAQS), specify the concentration of the pollutant in air that is acceptable (Office of Air

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Quality Planning and Standards 2010). States must then formulate plans to manage emissions so

that they are in accordance with the NAAQS. Pollutant control measures include emissions

limits; enhanced public transportation systems; disincentives for driving, such as tolls and taxes;

and incentives for car-sharing, such as carpool lanes. Past efforts by the EPA to curb specific

pollutants from automobiles have been successful. Air concentrations of lead, which can impair

the nervous systems as well as human development, were reduced 94 percent between 1980 and

1999, largely due requirements from the EPA that lead be removed from gasoline (U.S.

Environmental Proctction Agency 2010). However, reducing emissions of other air pollutants

will not be as easy. A combination of technological innovations, to reduce or eliminate pollutants

from engine exhaust, and behavioral change, to decrease the reliance of Americans on

automobiles, will be necessary to significantly decrease transportations contributions to air

pollution (Zimmerman 2002). These solutions require time to develop and can be costly to

implement. Furthermore, consistent monitoring of air quality is necessary, and target

concentrations for pollutants need to be periodically reviewed. The maintenance of good air

quality requires constant vigilance on behalf of the regulating bodies.

       Transportation can facilitate a sedentary lifestyle, which contributes to the epidemic of

obesity in America. Obesity is linked to serious medical conditions, such as asthma, type II

diabetes, and heart disease, which can cause life-long complications and result in premature

death (Ebbeling, Pawlak and Ludwig 2002). Public infrastructure in the United States has largely

been built to accommodate automobiles. Priority is given to facilitating motorized travel, often at

the expense of non-motorized travel (Cortright 2009). Highways and large intersections can be

difficult or impossible to navigate on foot or by bicycle, and attempting to do so can be very

dangerous. Thus, the continued use of automobiles for even short journeys is reinforced by the



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built environment. Efforts are being made to reshape communities to make them more

“walkable”. The goal of a walkable neighborhood is to make businesses and workplaces more

accessible through non-automotive transport (Leinberger 2007). By increasing the ease with

which the community can be navigated on foot, a walkable neighborhood provides its citizens

with increased opportunities for physical and social activity, enhancing both physical and mental

health (Cortright 2009). Some enhancements, such as better crosswalks at intersections and the

creation and maintenance of sidewalks, are relatively inexpensive and require little adaptation of

the existing infrastructure. Others, such as the implementation of mixed use zoning and the

development of public transportation systems, are more costly and take much longer to realize.

Though newer communities can be established with the principles of walkability in mind, older

neighborhoods may require major modifications to become walkable.

       Transportation can also have adverse effects on human health by serving as a vector for

disease. When humans are closely confined, such as in an airplane, infectious diseases have more

opportunities to be transferred from host to host (Budd, Warren and Bell 2011). Planes, boats,

and trucks can also move disease-hosting organisms, such as mosquitoes or ticks, to new

environments. Transport to a new population, where there is little to immunity amongst potential

hosts, can allow a disease to be more readily transmitted and have more devastating effects. The

speed and regularity of global transportation means that a local health threat can rapidly become

a worldwide epidemic if countries are unprepared. Fundamental preventative measures for the

control of infectious diseases include vaccines and basic sanitation measures (Centers for

Disease Control and Prevention 2002). These help to increase immunity to a disease within a

population and limit the opportunities for disease to spread, respectively. Proper treatment of

modes of transportation can help eliminate pathogens and their hosts, preventing them from



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being transferred to a new environment during travel. Planes may be disinsceted, or sprayed with

pesticide, before takeoff (Gratz, Steffen and Cocks 2000). Similarly, cargo aboard ships, or the

ships themselves, may be treated. Development of standardized, international procedures for

preventing the transport of disease-carrying insects and animals is critical. Furthermore, control

efforts must be managed so that humans are not exposed to potentially toxic chemicals. Once an

outbreak has occurred, quarantines of infected persons and travel restrictions to and from places

of high prevalence may become appropriate (Mangili and Gendreau 2005). Internationally

agreed upon standards for the treatment of infected persons are needed.

       Though transportation can cause, contribute to, and spread disease, it is also beneficial to

human health in several ways. Transportation allows for the rapid movement of sick or injured

persons to appropriate care facilities. From car rides to a doctor for preventative care to

emergency air lifts from the scene of a traumatic injury, transportation allows even persons in

remote environments access to health care. Transportation enriches the diets of humans, making

fresh foods available throughout the year. Fruits and vegetables that would otherwise be out of

season can be imported from temperate locations during winter, providing people with a quality

source of vitamins and minerals. Transportation has also allowed for the movement of people

and idea across the world, helping to build a globalized society in which the standard of living of

all people can be raised. Transportation allows for developed nations to share their knowledge

about health and disease with developing nations, providing better care for all people. These

positive impacts on health underscore the need to adapt transportation. As the global population

increases and more of the world becomes industrialized, transportation will play an ever

increasing role in the lives of humans. Developing clean, efficient, and sensible modes of

transport, and the infrastructure to support them, is of utmost importance.



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                                               References

Budd, Lucy, Adam Warren, and Morag Bell. "Safeguarding public health at UK airports: an examination

        of current health security practices." Transportation Planning and Technology, February 2011:

        19-31.


Centers for Disease Control and Prevention. Guideline for Hand Hygiene in Health-Care Settings.

        Morbidity and Mortality Weekly Report, Atlanta, GA: Epidemiology Program Office, 2002.


Cortright, Joe. Walking the Walk: How Walkability Raises Home Values in U.S. Cities. Washington, D.C.:

        CEOs for Cities, 2009.


Ebbeling, Cara B., Dorota B. Pawlak, and David S. Ludwig. "Childhood obesity: public-health crisis,

        common sense cure." The Lancet, 2002: 473-482.


Friedman, Michael S., Kenneth E. Powell, Lori Hutwagner, LeRoy M. Graham, and W. Gerald Teague.

        "Impact of Changes in Transportation and Commuting Behaviors During the 1996 Summer

        Olympic Games in Atlanta on Air Quality and Childhood Asthma." Journal of hte American

        Medical Association, 2001: 897-905.


Gratz, Norman G., Robert Steffen, and William Cocks. "Why Aircraft Disinsection?" Bulletin of the World

        Health Organization, 2000: 995-1004.


Leinberger, Christopher B. Footloose and Fancy Free: A Field Survey of Walkable Urban Places in the Top

        30 U.S. Metropolitan Areas. field survey, Washington, D.C.: Brookings Institution Metropolitan

        Policy Program, 2007.


Mangili, Alexandra, and Mark A. Gendreau. "Transmission of infectious diseae during commercial air

        travel." The Lancet, March 12, 2005: 989-994.



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Office of Air Quality Planning and Standards. Our Nation's Air: Status and Trands Through 2008. Status

        Report, Washington, D.C.: U.S. Environmental Protection Agency, 2010.


U.S. Environmental Proctction Agency. Lead in Air. December 27, 2010.

        http://epa.gov/airquality/lead/index.html (accessed April 27, 2011).


Zimmerman, Rae. "Global Climate Change and Transportation Infrastructure: Lessons from the New York

        Area." The Potential Impacts of Climate Change on Transportation. Washington, D.C.: U.S.

        Department of Transportation Center for Climate Change and Environmental Forecasting, 2002.

        91-102.




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