Abstract
Air pollution, especially in urban areas, has been for a long time a very important risk factor for a range of health problems including premature deaths, but in particular with cardiovascular adverse effects and respiratory diseases. Air pollution is a dangerous environmental process that pollutes the Earth’s atmosphere with toxic and oxidative pollutants. The adverse effects on health as observed from epidemiological studies conducted raised a series of questions concerning the biological and toxicological mechanisms that may operate under chronic exposure conditions. According to the latest Global Burden of Diseases Study (GBD), air pollution was the 4th leading risk factor for early (premature) deaths worldwide in 2019, surpassed only by lifestyle factors (i.e., high blood pressure, tobacco use, and obesity/poor diet), and was the largest environmental risk factor. In 2019 air pollution (outdoor and indoor) contributed to 6.67 million premature deaths worldwide. In the last decades, airborne particulate matter (PM) established a prominent position in the list of toxic exposure risks to humans, especially for the respiratory system and the cardiovascular organs. More than two million hospital admissions and premature deaths are estimated to occur globally each year as a direct consequence of air pollution through damage to the lungs and the respiratory system. Among these deaths, around 2.1 and 0.47 million are caused by airborne fine particulate matter (PM10, PM2.5) and ozone, (O3) respectively. A great number of studies and epidemiological evidence showed that ambient fine particulate matter (PM with aerodynamic diameter of 2.5 μm or less, PM2.5) have a series of adverse healyh effects on urban people. Global studies collected data from many countries and estimated that PM contributed to 2.9 million deaths and 83 million disability-adjusted life-years globally in 2017, of which CHD (Chronic Heart Diseases) accounted for nearly 30%. Ambient PM2.5 pollution has become a major public health problem in the world, causing serious adverse health effects and large global disease burden, especially in developing countries, such as China and India. This review contain some of most up to date research investigations and collected health data worldwide for carciovascular effects and damage to the respiratory system by PM. Studies in the last decade have demonstrated increased markers for pulmonary inflammation following exposure to a variety of different airborne particle types. Airway inflammation increases airway responsiveness to irritants and may reduce lung function by causing bronchoconstriction. At a cellular level, PM can damage or kill cells and compromise the integrity of the alveolar-capillary barrier. Long-term exposure to PM aggravates the initial injury and promotes chronic inflammation with cellular proliferation and extracellular matrix reorganization. The overall balance between injury (inflammatory activity) and repair (anti-inflammatory defenses) plays an important role in the pathogenesis and progression of inflammatory respiratory diseases such as asthma by airborne particulate matter (PM).This review contains a selected numbers of recent review and epidemiological research papers.