Poverty, Pollution and Population

To the public, the most sensitive issue of air pollution is undoubtedly its impacts on human health.

According to WHO (2014), SO₂, NO₂ and O₃ all affect the respiratory system and lung functions. More health-damaging is particulate matter, which is of complex composition and varying sizes. The smaller the particles are the greater problem they pose: While lager particles are filtered in the nose and throat, PM₁₀ can settle as far as in the bronchi and lungs. PM_2.5 even gets into the alveoli, where gas exchange takes place. The smallest particles may penetrate through membranes and migrate into other organs - including the heart and the brain – via bloodstream and cause cardiovascular and cerebrovascular diseases and cancers. The composition of particulate matter depends on its source. Major components include sulphate, nitrates, ammonia, but also black carbon, which has a large surface area and adsorbs further fine carcinogens. This sarcastic animation demonstrate the journey of PM_2.5 in human body:

The WHO Global Burden of Disease study estimated that ambient air pollution (PM₁₀ pollution here specifically) caused 3.7 million premature deaths worldwide in 2012 (WHO,2014). Rohde and Muller (2015) calculated that in China, 1.6 million premature deaths per year alone can be attributed to PM_2.5 pollution by adopting the WHO model which computes the mortality due to impacts of pollution on five diseases: ischemic heart disease, stroke, chronic obstructive pulmonary disease, lung cancer and acute lower respiratory infection (Burnett et al., 2014). This is equivalent to 4,000 deaths per day or 17% of all death in a year (Rohde and Muller, 2015). Another study by Yang etal. (2013) identified ambient air particulate matter pollution as the 4^th leading risk factor and suggested that it caused 25,227,000 DALYs in 2010. DALY is short for disability-adjusted life year, a measure of overall disease burden as the sum of years of life lost due to disease, disability and premature death across the population (WHO, n.d.).

Air pollution also causes damage to the whole ecosystem. Though relatively well-studied, these impacts – compared to the impacts on human health – rarely enter the public discourse: Wildlife inhale health-damaging contents in the air just like humans do. SO₂ and NO_x are main precursors of acid rain; NO_x also causes eutrophication. When deposited, they change the chemistry of soil or water bodies and further stress plants and animals. As a powerful oxidant, ground-level ozone enters plants through stomata and oxidizes plant tissue, eventually causing cell death and reducing photosynthesis. Deposition of particulate matter to vegetation surface may also interfere with photosynthesis by blocking the stomata (Grantz, Garner and Johnson, 2003).

Both human health and environmental effects of air pollution bring about economic impacts. A joint research of the StateEnvironmental Protection Administration (SEPA, predecessor of the Ministry ofEnvironmental Protection) and the World Bank (2007) stated that acid rain alone cost 30 billion RMB in crop damage and 7 billion RMB in material damage each year. The same study pointed out that based on conservative estimations, the cost of air pollution – taking both premature mortality and morbidity into account – was 157.3 billion RMB in 2003, or 1.16 % of the GDP. However, when using the willingness-to-pay measures to value premature deaths, the cost was raised to 3.8 % of the GDP, for Chinese people “value improvements in health beyond productivity gains” (SEPA and World Bank, 2007, pp. xv).

Over the last three decades, China achieved rapid economic growth and lifted 680 million people out of poverty (TheEconomist, 2013) at the expense of the environment. In recent years, the growth rate has been slowing down, while a demographic crisis is looming and the cost of environmental degradation has only just begun to appear (for most people, that is). Based on the various research results presented above, it is not hard to conclude that if air pollution were tackled efficiently, a healthier, longer living and thus more productive population would in turn boost the economy.