and Holgate, 2002). The different c

and Holgate, 2002
). The different composition of air pollut-
ants, the dose and time of exposure and the fact that humans
are usually exposed to pollutant mixtures than to single sub-
stances, can lead to diverse impacts on human health. Human
health effects can range from nausea and difficulty in breath-
ing or skin irritation, to cancer. They also include birth defects,
serious developmental delays in children, and reduced activity
of the immune system, leading to a number of diseases. More-
over, there exist several susceptibility factors such as age, nu-
tritional status and predisposing conditions. Health effects can
be distinguished to acute, chronic not including cancer and
cancerous. Epidemiological and animal model data indicate
that primarily affected systems are the cardiovascular and
the respiratory system. However, the function of several other
organs can be also influenced (
Cohen et al., 2005; Huang and
Ghio, 2006; Kunzli and Tager, 2005; Sharma and Agrawal,
2005
).
4.1. Effects of air pollutants on different organs and
systems
4.1.1. Respiratory system
Numerous studies describe that all types of air pollution, at
high concentration, can affect the airways. Nevertheless, sim-
ilar effects are also observed with long-term exposure to lower
pollutant concentrations. Symptoms such as nose and throat ir-
ritation, followed by bronchoconstriction and dyspnoea, espe-
cially in asthmatic individuals, are usually experienced after
exposure to increased levels of sulphur dioxide (
Balmes
et al., 1987
), nitrogen oxides (
Kagawa, 1985
), and certain
heavy metals such as arsenic, nickel or vanadium. In addition
particulate matter that penetrates the alveolar epithelium (
Ghio
and Huang, 2004
) and ozone initiate lung inflammation (
Uysal
and Schapira, 2003
). In patients with lung lesions or lung dis-
eases, pollutant-initiated inflammation will worsen their con-
dition. Moreover air pollutants such as nitrogen oxides
increase the susceptibility to respiratory infections (
Chauhan
et al., 1998
). Finally chronic exposure to ozone and certain
heavy metals reduces lung function (
Rastogi et al., 1991;
Tager et al., 2005
), while the later are also responsible for
asthma, emphysema, and even lung cancer (
Kuo et al., 2006;
Nawrot et al., 2006
). Emphysema-like lesions have also been
observed in mice exposed to nitrogen dioxide (
Wegmann
et al., 2005
).
4.1.2. Cardiovascular system
Carbon monoxide binds to haemoglobin modifying its con-
formation and reduces its capacity to transfer oxygen (
Badman
and Jaffe, 1996
). This reduced oxygen availability can affect the
function of different organs (and especially high oxygen-
consuming organs such as the brain and the heart), resulting
in impaired concentration, slow reflexes, and confusion. Apart
from lung inflammation, systemic inflammatory changes are in-
duced by particulate matter, affecting equallyblood coagulation
(
Riediker et al., 2004
). Air pollution that induces lung irritation
and changes in blood clotting can obstruct (cardiac) blood
vessels, leading to angina or even to myocardial infraction