Pollution

Industrial PollutionOur management of Earth's natural systems is impacting air and water quality around the world.  Warmer temperatures associated with climate change increase the formation of tropospheric ozone, a main constituent of smog and contributor to cardiorespiratory disease.  Warmer temperatures and higher atmospheric carbon dioxide concentrations are associated with longer pollen seasons and increased pollen production, intensifying allergic respiratory diseases, such as asthma.  Biomass burning for agriculture in places like equatorial Asia is driving sharp increases in particulate air pollution and associated morbidity and mortality.  In some regions, air pollution has become so pervasive that it obscures the sun, altering regional weather patterns, reducing agricultural yields, and accelerating glacial melting. Man-made pollutants in water bodies pose a threat to drinking supplies. Water-borne pollutants in oceans and terrestrial water systems are also consumed by small organisms and thus enter the food chain.

Learning Objectives

  • L1: Assess the sociocultural, economic and political frameworks that perpetuate polluting activities around the world.
  • L2: Define and describe different types and sources of pollution.
  • L3: Understand the interconnectedness of the 'local' and 'global' in the context of the health impacts of pollution.
  • L4: Explain the natural systems that facilitate the flow of pollutants, highlighting inequalities in impact.

 

Mitchell EAD, Mulhauser B, Mulot M, Mutabazi A, Glauser G, Aebi A. A worldwide survey of neonicotinoids in honey . Science [Internet]. 2017;358 (6359) :109-111. Publisher's VersionAbstract
Growing evidence for global pollinator decline is causing concern for biodiversity conservation and ecosystem services maintenance. Neonicotinoid pesticides have been identified or suspected as a key factor responsible for this decline. We assessed the global exposure of pollinators to neonicotinoids by analyzing 198 honey samples from across the world. We found at least one of five tested compounds (acetamiprid, clothianidin, imidacloprid, thiacloprid, and thiamethoxam) in 75% of all samples, 45% of samples contained two or more of these compounds, and 10% contained four or five. Our results confirm the exposure of bees to neonicotinoids in their food throughout the world. The coexistence of neonicotinoids and other pesticides may increase harm to pollinators. However, the concentrations detected are below the maximum residue level authorized for human consumption (average ± standard error for positive samples: 1.8 ± 0.56 nanograms per gram).
Rohde RA, Muller RA. Air Pollution in China: Mapping of Concentrations and Sources . PLoS ONE [Internet]. 2015. Publisher's VersionAbstract

China has recently made available hourly air pollution data from over 1500 sites, including airborne particulate matter (PM), SO2, NO2, and O3. We apply Kriging interpolation to four months of data to derive pollution maps for eastern China. Consistent with prior findings, the greatest pollution occurs in the east, but significant levels are widespread across northern and central China and are not limited to major cities or geologic basins. Sources of pollution are widespread, but are particularly intense in a northeast corridor that extends from near Shanghai to north of Beijing. During our analysis period, 92% of the population of China experienced >120 hours of unhealthy air (US EPA standard), and 38% experienced average concentrations that were unhealthy. China’s population-weighted average exposure to PM2.5 was 52 μg/m3. The observed air pollution is calculated to contribute to 1.6 million deaths/year in China [0.7–2.2 million deaths/year at 95% confidence], roughly 17% of all deaths in China.

 
 
Ebenstein A, Fan M, Greenstone M, He G, Zhou M. New evidence on the impact of sustained exposure to air pollution on life expectancy from China’s Huai River Policy. Proceedings of the National Academy of Sciences [Internet]. 2017. Publisher's VersionAbstract

This paper finds that a 10-μg/m3 increase in airborne particulate matter [particulate matter smaller than 10 μm (PM10)] reduces life expectancy by 0.64 years (95% confidence interval = 0.21–1.07). This estimate is derived from quasiexperimental variation in PM10 generated by China’s Huai River Policy, which provides free or heavily subsidized coal for indoor heating during the winter to cities north of the Huai River but not to those to the south. The findings are derived from a regression discontinuity design based on distance from the Huai River, and they are robust to using parametric and nonparametric estimation methods, different kernel types and bandwidth sizes, and adjustment for a rich set of demographic and behavioral covariates. Furthermore, the shorter lifespans are almost entirely caused by elevated rates of cardiorespiratory mortality, suggesting that PM10 is the causal factor. The estimates imply that bringing all of China into compliance with its Class I standards for PM10 would save 3.7 billion life-years.

Milner AM, Khamis K, Battin TJ, Brittain JE, Barranda NE, Füreder L, Cauvy-Fraunié S, Gíslason GMár, Jacobsen D, Hannah DM, et al. Glacier shrinkage driving global changes in downstream systems . Proceedings of the National Academy of Sciences [Internet]. 2017;114 (37) :9770–9778. Publisher's VersionAbstract

Glaciers cover ∼10% of the Earth’s land surface, but they are shrinking rapidly across most parts of the world, leading to cascading impacts on downstream systems. Glaciers impart unique footprints on river flow at times when other water sources are low. Changes in river hydrology and morphology caused by climate-induced glacier loss are projected to be the greatest of any hydrological system, with major implications for riverine and near-shore marine environments. Here, we synthesize current evidence of how glacier shrinkage will alter hydrological regimes, sediment transport, and biogeochemical and contaminant fluxes from rivers to oceans. This will profoundly influence the natural environment, including many facets of biodiversity, and the ecosystem services that glacier-fed rivers provide to humans, particularly provision of water for agriculture, hydropower, and consumption. We conclude that human society must plan adaptation and mitigation measures for the full breadth of impacts in all affected regions caused by glacier shrinkage.

 
Sinha E, Michalak AM, Balaji V. Eutrophication will increase during the 21st century as a result of precipitation changes . Science [Internet]. 2017;357 (6349) :405-408. Publisher's VersionAbstract

Eutrophication, or excessive nutrient enrichment, threatens water resources across the globe. We show that climate change–induced precipitation changes alone will substantially increase (19 ± 14%) riverine total nitrogen loading within the continental United States by the end of the century for the “business-as-usual” scenario. The impacts, driven by projected increases in both total and extreme precipitation, will be especially strong for the Northeast and the corn belt of the United States. Offsetting this increase would require a 33 ± 24% reduction in nitrogen inputs, representing a massive management challenge. Globally, changes in precipitation are especially likely to also exacerbate eutrophication in India, China, and Southeast Asia. It is therefore imperative that water quality management strategies account for the impact of projected future changes in precipitation on nitrogen loading.

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