of incomplete information about which company pollutes and at what scale the damage was caused by the pollution. fossil fuel related industries outdoor air pollution attributable to fossil fuel use alone causes ~3.61 million deaths annually, making it one of the top contributors to human death, beyond being a major driver of climate change whereby greenhouse gases are considered per se as a form of pollution (see above). socially optimal level society derives some indirect utility from pollution; otherwise, there would be no incentive to pollute. this utility may come from the consumption of goods and services that inherently create pollution (albeit the level can vary) or lower prices or lower required efforts (or inconvenience) to abandon or substitute these goods and services. therefore, it is important that policymakers attempt to balance these indirect benefits with the costs of pollution in order to achieve an efficient outcome. a visual comparison of the free market and socially optimal outcomes it is possible to use environmental economics to determine which level of pollution is deemed the social optimum. for economists, pollution is an "external cost and occurs only when one or more individuals suffer a loss of welfare". there is a socially optimal level of pollution at which welfare is maximized. this is because consumers derive utility from the good or service manufactured, which will outweigh the social cost of pollution until a certain point. at this point the damage of one extra unit of pollution to society, the marginal cost of pollution, is exactly equal to the marginal benefit of consuming one more unit of the good or service. moreover, the feasibility of pollution reduction rates could also be a factor of calculating optimal levels. while a study puts the global mean loss of life expectancy (lle; similar to ypll) from air pollution in 2015 at 2.9 years (substantially more than, for example, 0.3 years from all forms of direct violence), it also indicated that a significant fraction of the lle is unavoidable in terms of current economical-technological feasibility such as aeolian dust and wildfire emission control. in markets with pollution, or other negative externalities in production, the free market equilibrium will not account for the costs of pollution on society. if the social costs of pollution are higher than the private costs incurred by the firm, then the true supply curve will be higher. the point at which the social marginal cost and market demand intersect gives the socially optimal level of pollution. at this point, the quantity will be lower and the price will be higher in comparison to the free market equilibrium. therefore, the free market outcome could be considered a market failure because it "does not maximize efficiency". this model can be used as a basis to evaluate different methods of internalizing the externality. some examples include tariffs, a carbon tax and cap and trade systems. history prior to 19th century air pollution has always accompanied civilizations. pollution started from prehistoric times, when man created the first fires. according to a 1983 article in the journal science, "soot" found on ceilings of prehistoric caves provides ample evidence of the high levels of pollution that was associated with inadequate ventilation of open fires." metal forging appears to be a key turning point in the creation of significant air pollution levels outside the home. core samples of glaciers in greenland indicate increases in pollution associated with greek, roman, and chinese metal production.air pollution in the us, 1973 the burning of coal and wood, and the presence of many horses in concentrated areas made the cities the primary sources of pollution. king edward i of england banned the burning of sea-coal by proclamation in london in 1272, after its smoke became a problem; the fuel was so common in england that this earliest of names for it was acquired because it could be carted away from some shores by the wheelbarrow. 19th century it was the industrial revolution that gave birth to environmental pollution as we know it today. london also recorded one of the earlier extreme cases of water quality problems with the great stink on the thames of 1858, which led to construction of the london sewerage system soon afterward. pollution issues escalated as population growth far exceeded viability of neighborhoods to handle their waste problem. reformers began to demand sewer systems and clean water. in 1870, the sanitary conditions in berlin were among the worst in europe. august bebel recalled conditions before a modern sewer system was built in the late 1870s: waste-water from the houses collected in the gutters running alongside the curbs and emitted a truly fearsome smell. there were no public toilets in the streets or squares. visitors, especially women, often became desperate when nature called. in the public buildings the sanitary facilities were unbelievably primitive....as a metropolis, berlin did not emerge from a state of barbarism into civilization until after 1870. 20th and 21st century the primitive conditions were intolerable for a world national capital, and the imperial german government brought in its scientists, engineers, and urban planners to not only solve the deficiencies, but to forge berlin as the world's model city. a british expert in 1906 concluded that berlin represented "the most complete application of science, order and method of public life," adding "it is a marvel of civic administration, the most modern and most perfectly organized city that there is." the emergence of great factories and consumption of immense quantities of coal gave rise to unprecedented air pollution and the large volume of industrial chemical discharges added to the growing load of untreated human waste. chicago and cincinnati were the first two american cities to enact laws ensuring cleaner air in 1881. pollution became a major issue in the united states in the early twentieth century, as progressive reformers took issue with air pollution caused by coal burning, water pollution caused by bad sanitation, and street pollution caused by the three million horses who worked in american cities in 1900, generating large quantities of urine and manure. as historian martin melosi notes, the generation that first saw automobiles replacing the horses saw cars as "miracles of cleanliness". by the 1940s, automobile-caused smog was a major issue in los angeles. other cities followed around the country until early in the 20th century, when the short lived office of air pollution was created under the department of the interior. extreme smog events were experienced by the cities of los angeles and donora, pennsylvania, in the late 1940s, serving as another public reminder. air pollution would continue to be a problem in england, especially later during the industrial revolution, and extending into the recent past with the great smog of 1952. awareness of atmospheric pollution spread widely after world war ii, with fears triggered by reports of radioactive fallout from atomic warfare and testing. then a non-nuclear event – the great smog of 1952 in london – killed at least 4000 people. this prompted some of the first major modern environmental legislation: the clean air act of 1956. pollution began to draw major public attention in the united states between the mid-1950s and early 1970s, when congress passed the noise control act, the clean air act, the clean water act, and the national environmental policy act. smog pollution in taiwan severe incidents of pollution helped increase consciousness. pcb dumping in the hudson river resulted in a ban by the epa on consumption of its fish in 1974. national news stories in the late 1970s – especially the long-term dioxin contamination at love canal starting in 1947 and uncontrolled dumping in valley of the drums – led to the superfund legislation of 1980. the pollution of industrial land gave rise to the name brownfield, a term now common in city planning. the development of nuclear science introduced radioactive contamination, which can remain lethally radioactive for hundreds of thousands of years. lake karachay – named by the worldwatch institute as the "most polluted spot" on earth – served as a disposal site for the soviet union throughout the 1950s and 1960s. chelyabinsk, russia, is considered the "most polluted place on the planet". nuclear weapons continued to be tested in the cold war, especially in the earlier stages of their development. the toll on the worst-affected populations and the growth since then in understanding about the critical threat to human health posed by radioactivity has also been a prohibitive complication associated with nuclear power. though extreme care is practiced in that industry, the potential for disaster suggested by incidents such as those at three mile island, chernobyl, and fukushima pose a lingering specter of public mistrust. worldwide publicity has been intense on those disasters. widespread support for test ban treaties has ended almost all nuclear testing in the atmosphere. international catastrophes such as the wreck of the amoco cadiz oil tanker off the coast of brittany in 1978 and the bhopal disaster in 1984 have demonstrated the universality of such events and the scale on which efforts to address them needed to engage. the borderless nature of atmosphere and oceans inevitably resulted in the implication of pollution on a planetary level with the issue of global warming. most recently the term persistent organic pollutant (pop) has come to describe a group of chemicals such as pbdes and pfcs among others. though their effects remain somewhat less well understood owing to a lack of experimental data, they have been detected in various ecological habitats far removed from industrial activity such as the arctic, demonstrating diffusion and bioaccumulation after only a relatively brief period of widespread use. a much more recently discovered problem is the great pacific garbage patch, a huge concentration of plastics, chemical sludge and other debris which has been collected into a large area of the pacific ocean by the north pacific gyre. this is a less well known pollution problem than the others described above, but nonetheless has multiple and serious consequences such as increasing wildlife mortality, the spread of invasive species and human ingestion of toxic chemicals. organizations such as 5 gyres have researched the pollution and, along with artists like marina debris, are working toward publicizing the issue. pollution introduced by light at night is becoming a global problem, more severe in urban centres, but nonetheless contaminating also large territories, far away from towns. growing evidence of local and global pollution and an increasingly informed public over time have given rise to environmentalism and the environmental movement, which generally seek to limit human impact on the environment.