Air Pollution, Reactive Oxygen Species (ROS), and Autonomic Nervous System Interactions Modulate Cardiac Oxidative Stress and Electrophysiological Changes

1.1 Air pollution: A global overview In the last decades we witnessed unprecedented rapid deterioration in the environment as a consequence of intense anthropogenic activity. Air pollution, and more precisely particulate matter (PM) is both an alarming environmental problem and a public health concern that affects many regions of the world. Ambient air pollution has been associated with increased respiratory mucosal symptoms, exacerbation of asthma, chronic obstructive pulmonary disease (COPD) as well as cardiovascular diseases and mortality [World Health Organization (WHO) working group et al., 2003]. This association is based on observational epidemiological studies of disease occurrence in the human populations and in in-vitro and in-vivo studies of animals and humans [Health Effect Institute [HEI] et al., 2002]. Some groups in the population are more susceptible to air pollution induced health risks. Children are particularly at risk for deleterious respiratory outcomes due to the immaturity of their respiratory organ systems. They spend significantly more time outdoors than adults, especially during the summer months when smog and ozone levels are highest. Elderly, diabetics, people affected by underlying heart or lung disease, lower socioeconomic population living in proximity to sources of pollution [Mohai et al., 2009], are among the groups that experience increased risk for both pulmonary and cardiovascular system diseases. Sources of pollutants differ in different regions and are influenced by many factors. Air pollution levels are higher in the vicinity of specific sources such as roads, chemical plants, oil refineries, manufacturing facilities, and other industrial facilities. Meteorological factors determine the distribution of pollutants, since they can travel far from the original source, influenced by the wind, along with the topography of the regions and phenomena of temperature inversion, a meteorological condition that traps pollutants at ground level instead of circulating them away, and it is often responsible for episodes of sudden noxious toxin and particle concentrations in small areas. The increase of the world population and the consequent increase in the production and consumption of resources in particular of fossil fuels, influence the concentration and the quality of the