Air pollution history
The history of air pollution traces back thousands of years, beginning with the advent of agriculture as humans cleared forests and burned wood, which released methane and carbon dioxide into the atmosphere. Although noticeable air pollution became more evident during the Industrial Revolution of the eighteenth and nineteenth centuries, early human activities, including metal smelting and land clearing, had already contributed to atmospheric changes. The expansion of industrial society marked a significant increase in pollutants, driven by fossil fuel consumption and population growth. Urban centers, particularly in Europe, began to grapple with the consequences of rising smoke and noxious odors, mainly from wood and coal burning. By the fourteenth century, people started to become aware of the unpleasant effects of air pollution, although the more harmful pollutants were largely overlooked. As the understanding of air quality evolved, it became clear that even non-toxic substances like carbon dioxide could significantly impact climate as greenhouse gases. This historical perspective emphasizes the long-standing interplay between human activity and atmospheric changes, prompting a reevaluation of what constitutes air pollution over time.
Air pollution history
Air pollution resulting from human action dates primarily from the Industrial Revolution. Humans, however, have had some impact on the environment for at least five thousand years. As industrialized agriculture and manufacturing have increased, humans have added increasing amounts of pollutants to the atmosphere.
Background
The history of anthropogenic air pollution is generally traced from the Industrial Revolution of the eighteenth and nineteenth centuries. As by-products of manufacturing processes and through burning the coal and oil necessary to power them, industries added substantial amounts of heavy metals, acidic compounds (such as sulfur dioxide), and carbon dioxide (CO2) to the atmosphere. The first significant effect on the air occurred, however, when humans cleared land for agriculture. This effect increased over time as more land was cleared and small-scale industry developed. Thus, before the Industrial Revolution began, human activity was already generating air pollution.
The Development of Agriculture
At least five thousand years ago, humans began to clear forests for agriculture. Burning of the cleared wood, livestock emissions, and human waste produced methane gas, which is a greenhouse gas (GHG). The gradual increase in Earth’s human population contributes to an increasing amount of methane being added to the atmosphere. As more complex agriculture developed, forest clearance increased, leading to a gradual increase in the amount of CO2 in the atmosphere. The impact of land clearing varied, but the activity continued to add methane and CO2 to the atmosphere. By the thirteenth century, much of England, for example, had been deforested. Agriculture created pollutants that were not direct health hazards, that added to the levels of GHGs in the atmosphere.
Ancient Societies
The increase of human population that started several thousand years ago was initially quite slow. As ancient societies became more complex, it became necessary to create larger numbers of tools, to mine and refine the materials used for production, and to develop more complex energy sources. Each of these processes contributed to air pollution, though it is difficult to quantify their individual contributions. Aside from smoke and odors, most people were unaware of air pollution.
Smelting metals and creating tools added small amounts of heavy metals and sulfur and nitrogen oxides to the atmosphere. At times, these pollutants were carried by wind currents for considerable distances. For example, traces of the pollutants derived from Roman metal smelting may be found in Greenland’s ice cap. Smelting also required energy; this energy was produced by burning wood. Thus, early proto-industrial concerns added to air pollution, both through cutting down trees and through burning their wood. Ancient Romans and early medieval Europeans were unaware of this pollution except for the occasional downdrafts of smoke from a nearby smelter or the increase of smoke from heating in towns.
The Middle Ages
By the fourteenth century, an awareness of some negative effects of air pollution began to develop. Some of the awareness focused on unpleasant and noxious odors that resulted from butchering and from human waste in cities such as London. There was also concern over the increasing amount of smoke in the air in urban areas such as London or Paris. The smoke at the time was primarily wood smoke, although some coal was also being used to heat homes and provide power. Official concern tended to focus on the dirt that resulted from burning fossil fuels and the noxious odors that came from burning coal in particular. More harmful pollutants, such as sulfur and nitrogen oxides, were ignored because people were unaware of their existence. They were equally unaware of the GHGs that were a by-product of burning fossil fuels.
As forests were consumed in the late Middle Ages in Western Europe, producers of goods turned increasingly to coal as an energy source. Burning coal led to an increase in various air pollutants in the atmosphere, although the amounts were still quite small throughout the sixteenth and seventeenth centuries. Increased population led to increased demand for goods, as well as for home heating, food, and building construction. All of these demands contributed to a further clearing of land for agriculture and lumber production, although now the lands cleared were often in North and South America and Asia rather than in Europe.
Industrialization
The Industrial Revolution of the eighteenth and nineteenth centuries led to a dramatic increase in atmospheric pollutants. The growth of industrial society was accompanied by an increase in population, which further drove increased industrial and agricultural production. The magnitude of industrialization dating from the early nineteenth century led to a drastic increase in the use of fossil fuels, first coal and then oil. Burning these fossil fuels added CO2 to the atmosphere, as well as pollutants such as sulfur and nitrogen oxides. Burning fossil fuels and metal fabrication also led to the addition of heavy metals to the atmosphere. Later, other pollutants, such as chlorofluorocarbons, were generated as by-products of industrial society.
Context
Human activity has affected Earth’s atmosphere for thousands of years, and the atmospheric concentration of anthropogenic substances has increased with humanity’s population and technological sophistication. The increase in anthropogenic influences on the atmosphere has led to an increased awareness and understanding of air quality and pollution, which has caused a shift in the definitions of those terms. Until the late twentieth century, only foreign substances with direct toxic or pathogenic effects were considered pollutants. For example, CO2—which occurs naturally in the atmosphere and is not directly toxic—was not categorized as a pollutant. The discovery of the greenhouse effect, and of the role of CO2 and other gasses in that effect, has led many scientists and governments to reconsider their earlier definitions, and many now classify all GHGs as air pollutants. This discovery has also led historians to reconsider the history of air pollution itself and to see in a new light the role that early agriculture played in shaping atmospheric chemistry. By considering the evolution of human technology over several millennia in relation to the global atmosphere and climate, scientists can gain a fuller understanding of the extent to which anthropogenic inputs to the atmosphere may have contributed to changes in the climate.
Key Concepts
air pollution: degradation of air quality through human or natural meansanthropogenic: derived from human actions or sourcesforest clearing: destruction of forests in order to create land suitable for human habitation or usegreenhouse gasses (GHGs): anthropogenic and natural gasses that trap heat within the atmosphere, increasing Earth’s surface temperaturehealth hazard: pollution that produces potential harm to human healthindustrialization: development and dissemination of mechanical, mass-production technologies
Bibliography
Fowler, David, et al. “A Chronology of Global Air Quality.” Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, vol. 378, no. 2183, 28 Sept. 2020, doi.org/10.1098/rsta.2019.0314. Accessed 11 Jan. 2023.
Goudie, Andrew. The Human Impact on the Natural Environment: Past, Present, and Future. 6th ed. Malden, Mass.: Blackwell, 2006. Provides concise analysis of the nature of air pollution as affected by human action.
Ruddiman, William F. Plows, Plagues, and Petroleum. Princeton, N.J.: Princeton University Press, 2005. Ruddiman, a leading climate researcher, argues that human pollution has had a long-term, increasing, and negative impact on the climate.
Somerville, Richard C. J. The Forgiving Air. Berkeley: University of California Press, 1996. Good overview of the interaction of technology and environmental change in the atmosphere.
Theilmann, J. M. “The Regulation of Public Health in Late Medieval England.” In The Age of Richard II, edited by James L. Gillespie. New York: St. Martin’s Press, 1997. Good analysis of various forms of pollution, including air pollution, that uses late medieval England as a case study.
Williams, Michael. Deforesting the Earth. Chicago: University of Chicago Press, 2003. Comprehensive account of the various effects, including air pollution, of the human deforestation of the Earth.