Abstract
Urban air pollution represents one of the biggest environmental risks to health. This problem is growing rapidly, due to high rates of urbanization. The urban population ratio has increased from 46.5% in 2000 to 55.3% in 2018, globally, and is projected to reach 64% in the next two decades. In Iran, the urban population accounted for 75% of the total population in 2018 (World Bank data, 2020). Air pollution affects the ecosystem, damages buildings and reduces visibility. It has been associated with increased disease and related hospital and emergency department visits, as well as with an increased loss of work and school days. These effects come with significant economic and social costs. Governments face a wide array of competing development challenges; monetizing the costs of pollution can help them decide how best to allocate scarce resources to better the lives of their citizens (World Bank, 2016). Using economic analyses and benefit-to-cost ratios to estimate air pollution costs of large urban projects, can provide useful guidance for urban developers and managers. Furthermore, many studies have shown that premature mortality is the largest cost of pollution, thus, valuing the costs of premature deaths associated with pollution helps to highlight the size and severity of the problem (World Bank, 2016). Heat triggers more air conditioning power usage in buildings and cars, and this additional power usage emits more air pollution. Heat and sun also transform primary particles into secondary, smaller particles that can be more toxic. These secondary particles, which are photochemically produced by sunlight, are of crucial importance: they are ubiquitous and can make up to 90 percent (in number) of the total particulate matter. Secondary particles are smaller than one thousandth of a millimeter (very fine particles) and even smaller (ultra fine particles). They can enter deep into the lung airways when inhaled, and even penetrate the blood (Teqoya, 2019). Ambient air pollution have been widely associated with premature mortality. Based on recent estimates, 8.9 million deaths were attributed to ambient air pollution, globally, in 2015 (Burnett et al., 2018). Tehran is the largest urban settlement in Iran, with a population of 9 million and growing, thus it is representative of an increasing number of megacities in middle-income countries. The aim of the paper is not only to quantify the current burden of air pollution for population health, but also to highlight the potential health and economic benefits of reducing local air pollution to a range of attainable targets. The present study confirms the impact of PM2.5 on health and the resulting economic burden, which significantly hamper the progress and well-being of Tehran. A burden of more than 7,000 deaths or 100,000 years of life lost, and the related economic cost of some USD 3 billion in 2017, corresponding to 4.8% of Tehran’s GDP calls for focused attention at government level and from the policy makers responsible for this metropolitan area. Significant cost savings could be gained through decisive and sustainable air pollution abatement strategies. (Bayat et al. 2019). Due to the growth of urbanization and various scenarios of population growth and the use of fossil fuels, the effects of air pollution on health and costs can be estimated for the future of Hot Cities.
