2.6 Environmental health factors
According to Corvalan et al. (1999), two types of environmental
threats exist: traditional hazards, which are linked to lack of development,
and modern hazards, related to unsustainable development. While the former is
mainly related to the household's immediate surrounding standard quality and
are quickly expressed as disease, the later is associated to outdoor conditions
lacking health and environment safeguards, and their health effects that take a
long period before they show. Ehrenberg and Ault (2005), classifying the
determinants of health into intrinsic and extrinsic, retained poverty, vector
ecology, and human activities and the environment as part of the extrinsic
factors that affect health. But this definition doesn't outline the
differences between hazards and vulnerability.
More specifically, factors suggested as environmental health
hazards comprise indoor air pollution from solid-fuel use, pollution from
traffic, power line, wastes, and slum-like settlements (Harper et al. 2003,
Maheswaran and Elliott 2003, Nsiah-Gyaabah et al 2004, Greene and Pick 2006,
Campbell and Campbell 2007, Campbell-Lendrum and Corvalan 2007). It should be
noted that unclean settlements may be considered simultaneously as a hazard and
a physical vulnerability. The proximity of slums to each other along with
waste concentration within the interior of or very close to the houses, or the
proximity of human excreta to residences represents a hazardous condition. On
the other hand, high density housing occurring in an environment where air
circulation is poor and compact increases the vulnerability of inhabitants of
these neighborhoods. As underlined by Nsiah-Gyaabah et al. (2004), an
unhealthy environment and overcrowded housing in the slums expose the urban
poor to high rates of infectious diseases such as pneumonia, tuberculosis and
diarrhea. Other environmental risk factors for elevated blood levels in human
body are polluted soil and dust in urban surroundings, and the huge number of
automobiles consuming leaded gasoline (Harper et al. 2003). Consequences
identified associated with air pollution also include higher disease rates,
death, reduced lung function, and neurobehavioral issues (Greene and Pick
2006). Unplanned growth and rapid urbanization are responsible for the
degradation of the environment, the destruction of watersheds and wetlands,
traffic congestion, contamination of water, and increasing population demands
for service which exceed the supply capacity. These conditions place human
health at risk, both physically and mentally (WHO 2001; Moore et al. 2003;
Latkin and Curry 2003; Fernandez et al. 2003; Nsiah-Gyaabah et al. 2004). Many
of these conditions also represent vectors for communicable and
non-communicable diseases and are underpinning of human health deterioration
(WHO 2001). The health effects of these hazards are countless and it is almost
impossible to provide an exhaustive list.
As already stated, the probability aspect in hazard determination
is not easily assessed for many reasons. First, even in developed countries,
it is recognized that most cities do not regularly produce indicators of health
conditions at the neighborhood level, and where they exist, detailed
information is very limited (Pettit et al. 2003). Second, deaths or disease
occurrence are not usually or systematically attributed to a particular health
hazard, the hazard-disaster transmission process is not always materially
perceptible. Another characteristic of health hazards is that they are
man-made, continuous phenomena with no time boundary until their triggers
disappear. Consequently they are not perceived as salient hazards with
immediate life-threatening properties. The deterministic approach is
well-suited to delineate areas where these hazards are likely to occur.
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