Number of Downlaods: 94
Published Date: Oct 26, 2020
Ambient air quality refers to the condition or quality of air surrounding us in the outdoors and the ambient air refers to the atmospheric air in its natural state (typically 78% nitrogen and 21% oxygen, the extra 1% is made up of a combination of carbon dioxide, helium, methane, argon & hydrogen), not contaminated by air-borne pollutants. The closer the air is to sea level, the higher the percentage of oxygen. Generally, carbon monoxide (CO), oxides of nitrogen (NO2), sulfur dioxide SO2, ozone (O3 particulate matter (PM) and Lead (Pb) are considered pollutants of priority concerns regarding ambient air quality and public health. Some other pollutants of concern for ambient air quality and health are dioxins (PCDD), mercury (Hg), cadmium (Cd) and arsenic (As). The characteristics, sources of emission and their specific health effects of these air pollutants on general public & vulnerable population have been briefly described and reported by Khwaja et al. (2019).
Manufacturing processes and the burning of fossil fuels have directly impacted ambient air quality by releasing a high level of chemical pollutants such as carbon monoxide (CO), ozone (O3), oxides of nitrogen (NOx), sulfur dioxide (SO2), lead (Pb) and suspended particulate matter – TSP total suspended particulates (TSP) and PM10 particulate matter less than 10 μm in diameter (Aziz, 2006). Generally, industries, households, cars and trucks emit complex mixtures of pollutants to the air, many of which are harmful to health. Fine particulate matter has the greatest effect on human health which is aggravated by meteorological conditions and a combination of population dentistry and urbanization. While air pollution is generally considered to be an urban phenomenon, it is becoming a rural problem with the penetration of transport, expansion of industry, open (point/non-point) burning and the rapid spread/growth of brick kilns. Presently, air pollution monitoring and control efforts in Pakistan are both inadequate and tend to be urban-centered. (Khwaja 2005)
Globally, air pollution is estimated to cause about 29% of lung cancer deaths, 43% of COPD deaths, about 25% of ischemic heart disease deaths and 24% of stroke deaths. Particulate matter pollution is an environmental health problem that affects people worldwide, but low- and middle-income countries disproportionately experience this burden (World Health Organization [WHO] 2007). In terms of total disability-adjusted life years (DALYs) lost due to urban air pollution, mortality accounts for an estimated 60 %. Of this, premature adult mortality has the largest portion. Urban air pollution in terms of particulate matter is estimated to cause around 22,000 deaths among adults and 700 deaths among young children, annually. Indoor air pollution causes the deaths of more than 30,000 children per year (World Bank 2006). For children and adults, both short- and long-term exposure to ambient air pollution can lead to reduced lung function, respiratory infections and aggravated asthma. Maternal exposure to ambient air pollution is associated with adverse birth outcomes, such as low birth weight, pre-term birth and small gestational age births. Emerging evidence also suggests ambient air pollution may affect diabetes and neurological development in children. 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 also be influenced (Cohen et al 2005; Huang and Ghio, 2006; Kunzli and Tager, 2005; Sharma and Agrawal, 2005). It is well established and reported that air pollutants contribute to increased mortality and hospital admissions (Kampa & Castanas 2008).
The World Bank has estimated that the mean annual damage to the environment in Pakistan is 6% of GDP, or Rs. 365 billion per annum. Damages from indoor pollution have been estimated at Rs. 67 billion while damage from urban air pollution has been estimated at Rs. 65 billion or about 1% of GDP (World Bank, 2006). The health impact of the winter fog is estimated at 40% of total urban population in Pakistan and about Rs 25.7 billion each year. A study in Pakistan demonstrated that a 40 per cent reduction in rice crop yields was due to the presence of air pollutants (Hameed et al, 2009). A recent study at Sustainable Development Policy Institute by Khalid & Khavar assessed and explored the situation of air pollution in the country and analyzed the role, gaps and hindrances of multiple institutions that were responsible for tackling air pollution (Khalid & Khavar 2019).