Industrial Air Pollution & Temperature Inversions

How the Health Impact of Industrial Emissions has been Understood by Public Health Officials and Relayed to Society

Imagine waking up on a warm, sunny November morning. The forecast for the next few days includes highs between 67 and 71 degrees.[1] You decide to enjoy the unseasonably warm weather. However, the moment you walk outside you’re met with a yellowish haze and air that smells of rotten eggs. Even worse and more alarming, the brief time that you’re outdoors causes heart palpitations. This happened to Germaine Patterson, a resident of Clairton, Pennsylvania when she stepped outside to exercise in her backyard.[2]  Patterson, who lives less than a mile from the Clairton Coke Works knew that what she was experiencing “was due to the air quality.”[3]

Located about 20 miles south of Pittsburgh along the Monongahela River, Clairton is home to the Clairton Coke Works owned by U.S. Steel, which is the largest coke works in North America. The plant fires coal at around 2,000° Fahrenheit to create coke used in steel manufacturing. Unfortunately, this process releases harmful gases and particulates into the atmosphere. In normal weather and operating conditions, the gasses, while still dangerous, are generally diluted by airflow and/or captured by functioning pollution control systems.

However, in early November 2020, Patterson and the residents of Clairton were exposed to a temperature inversion which concentrated the emissions from the Clairton Coke Works over their town and the surrounding area. Temperature inversions often occur during the colder winter months when a layer of warm air traps colder air beneath it, like a lid. Industrial areas along river valleys are often prone to this type of weather event, however they can occur in most geological settings. When coupled with air pollution, they can cause respiratory and cardiac issues, sometimes with deadly results. During this time, residents of Clairton were exposed to “seven straight days” of emissions that exceeded “the state limit for hydrogen sulfide, a pollutant that smells like rotten eggs and is associated with production of coke used in steelmaking”[4]

U.S. Steel Clairton Coke Works

While temperature inversions often concentrate emissions to hazardous and potentially deadly levels, even when the coke plant’s emissions are diluted, there are other adverse health effects. The residents in the surrounding area have dealt with continuing health issues since air quality levels began to decline in 2014. According to Dave Meckel a resident of Glassport, located across the Monongahela River from the coking facility, “We have to put up with low-grade headaches, eyes watering and a little burn in the nasal passages,” he said. “You have to be like a little turtle and go inside and hide. But I’m not a turtle, and I don’t like living in my shell.”[5]

Since 2019 the plant has been charged with 340 air pollution violations often relating to high levels of sulfur dioxide or SO2, which is a known pulmonary irritant. According to Dr. Jane Koenig, professor emeritus and former director of the EPA’s Northwest Research Center for Particulate Air Pollution and Health, “subjects with asthma are extremely sensitive to inhaled SO2 and therefore may be at risk for adverse respiratory effects in communities where SO2 concentrations are elevated for short periods of time.”[6] For those with asthma, exposure to SO2 at low concentrations for less than 10 minutes “can cause significant airway narrowing.”[7]   Think about how quickly a small amount can impact those with asthma and imagine living in a town that routinely surpasses the allowed maximum in the air. Now, imagine air quality prior to the concept of emission standards.

Temperature inversions are one of many air pollution elements that cause adverse health effects and historically were often the subject of government sponsored studies because of their disastrous nature and high morbidity rates. While day-to-day encounters with air pollution also have adverse health consequences, temperature inversions historically received more substantial public health inquiries and public engagement because of their immediate consequences which are often easier to quantify than long-term health effects.

The temperature inversions of today, although still unhealthy, can look substantially different from those that punctuated the history of air pollution as major environmental disasters of the early-to-mid-20th century. One big visual change comes from the elimination of coal soot. Much of the larger particulates that visibly darkened the air are gone, but other irritants and potentially deadly components remain depending on the composition of emissions. Although each locale produces different emission footprints, the broad strokes examined by historic public health officials give us a window into how these episodes were thought about by the scientific community and relayed to the broader public.

Since air pollution is such an extensive, nuanced topic, this article mainly examines how temperature inversions and larger scientific studies shaped public health officials’ knowledge and understanding of the health effects relating to air pollution. When possible, it also explains how that information was presented to the public. Like Erwin Ackernecht described in his plea for the “behavioralist” approach, there is often a lag between what is known in elite medicine and how it is practiced.[8] To better understand how we reached today’s air quality standards, clean air legislation, and public health practices, let’s jump back in time.

During the late 19th and early 20th centuries, cities plagued by coal smoke, such as London, St. Louis, and Pittsburgh, began various abatement movements with the goal of reducing visible smoke. At that time, there wasn’t a way to measure the various gasses or particulate levels associated with air pollution.[9] Visible smoke was generally viewed as a nuisance and often the main subject of air pollution studies until the 1940s. Civic groups lobbying local governments to pass regulations on smoke had the broad goal of lessening or abating the predominant visual and nuisance effects of smoke-filled cities.

In London, a greater call for smoke regulation and abatement developed when cultural attitudes changed from believing that smoke was healthy and cured miasma. Prior to the acceptance of germ theory, many physicians and public health officials believed that disease was caused by miasma or “bad air”” associated with “overcrowding, filth, dampness, faulty drainage, vicinity of graveyards, unwholesome water, and unwholesome food.”[10] For a time, the smell of coal smoke replaced some of the “bad air” smells and was considered healthier. However, by the mid-19th century, Londoners began to see smoke as a sign of industrial waste, that also contributed to poor health. Peter Thorsheim, author of Inventing Pollution, argues that there were two main strategies for enacting change in England; engaging and educating the public in the hopes that they will change personal coal consumption practices and working to get regulation passed through local or national governmental bodies.

In the United States, early smoke abatement efforts in cities such as Pittsburgh, Chicago, and Cincinnati attempted to reduce smoke by focusing their efforts on individual offensive smokestacks.[11] However, this method was generally ineffective as cities grew and smokestacks proliferated. Many civic organizations began to call for emission regulations focusing mainly on industrial smokestacks, since the regulation of residential smoke was generally viewed as infringing on personal freedom.[12] Similar reasoning also existed in London, where the government believed it was overstepping its bounds to regulate domestic use.[13] Generally speaking, coal smoke continued to be considered a nuance that blocked out the sun and coated the city in a black film. The health effects were rarely studied until a temperature inversion in the Meuse Valley raised alarms about the deadly effects of concentrated air pollution.

The Meuse Valley Inversion & Early 20th Century Scholarship

On December 3, 1930, the Meuse River Valley in Belgium was struck by what is now recognized as the first known deadly air pollution disaster that was the result of a temperature inversion. The residents along a 12 mile stretch exhibited “hoarseness and irritation of the larynx, chest pain, coughing, nausea and vomiting, and even foaming at the mouth.”[14] Within 24 hours, 60 people were dead. At the time the cause was unknown and speculation about the mysterious red fog that was deemed the “shower of blood” included a poison gas attack from an unknown enemy (sometimes also believed to be remnants from WWI) or flu as folks recalled the abruptness of the 1918 epidemic.[15]

After the event, the Lancet included a few articles warning “that despite the unusual conditions of the Meuse Valley event, the same amalgamation of factors was likely to occur elsewhere.”[16] This air pollution disaster led to the first scientific proof of atmospheric pollution having the potential to cause deaths and disease. An official report was presented to the Royal Academy of Medicine of Belgium on May 19, 1931 and later published as part of a book on air pollution in 1933.[17]

Funeral Precession for air pollution victims in the Meuse Valley, Belgium, 1931
Funeral Precession for air pollution victims in the Meuse Valley, Belgium, 1931

Unfortunately, the official scientific findings were not relayed to the American Public. Instead, early speculation in February 1931 was disseminated to the public in the form of a newspaper article by Dr. Morris Fishbein, editor of the Journal of the American Medical Association. Dr. Fishbein claimed “British authorities” had found that the deaths were from “a severe spell of fog and cold.”[18] Fears of a poison attack or potential epidemic were laid to rest, but industrial pollution was not brought to the public’s attention. Later, a 1932 newspaper article touting a discovery of a method to test for sulfur dioxide, associated with coal smoke, linked SO2 to the fog deaths in Belgium.[19] However, this did not track with Belgium investigation, which found fluoride gas to be the chemical culprit. Dr. Devra Davis, renowned epidemiologist and author of When Smoke Ran Like Water, explained that sulfur “in heavy doses leaves distinct marks on the linings of the lungs, but fluoride gasses do not. They pass right into the bloodstream and attach the heart and other organs, without marring the nasal passages, throat, or lungs. The lungs of those who died in Liège (Belgium) were clean.”[20] The Lancet’s calls for additional study essentially went unheeded until 18 years later a similar disaster would occur in Donora, Pennsylvania.

In the meantime, limited work on air pollution studies progressed. When looking at the PubMed database, articles that include the term “air pollution” only go back to 1930. Over the next 18 years, only 20 scholarly articles on this topic are written. In 1948, prior to the Donora Smog, Dr. Clarence Mills, a professor at the University of Cincinnati examined the correlation between urban air pollution and “high death rates due to respiratory disease.”[21] Dr. Mills’ study examined coal “sootfall” in Cincinnati, Pittsburgh, Detroit, and Chicago as a method of looking at “the relation(ship) of respiratory disease rates to sootfall within the various districts of each city.” He mapped the levels of sootfall in Chicago, along with the city’s occurrences of pneumonia, pulmonary tuberculosis, and cancer. Side-by-side the maps reveal staggering overlaps.

The rise in number of articles containing the term “Air Pollution.” The first instance occurs in 1930.

While also examining the breakdowns for sex and race, Mills noticed a correlation of higher rates of respiratory issues in neighborhoods that were closest to industrial areas. Many of these neighborhoods were occupied predominately by people of color and/or the socio-economically disadvantaged. His work is one of the first to examine the disproportionate impact of urban air pollution on people of color. Mills also acknowledged that the “sootfall figure give(s) only a crude measure of prevailing air pollution,” but at the time “no better source of information (was) yet available.”[22] A section from this study almost perfectly describes a temperature inversion,

“Pollution reaches its most damaging concentrations during prolonger periods of fog or smog, when lack of air motion holds the foul air stagnant over the city. Basin topography, with industrial and railroad activity concentrated in the low-lying districts, renders the pollution situation most acute. Such level-land cities as Detroit and Chicago, however, are cursed with smogs when windless winter days bring conditions which hold flue products as a stagnant shroud over even their flat topography.”[23]

Dr. Mills mentions that nearly 50-years earlier, “the young science of public health cut its teeth on the problems of polluted city water supplies.”[24] He asserts that air pollution may be as serious of a health hazard as polluted water.[25] Mills also makes a point to mention the successes in St. Louis, which sought to decrease its carbon/soot problem from highly volatile, soft coal fired, residential stoves. The compulsory switch from soft bituminous coal to harder, less volatile, anthracite reduced the problematic soot and was seen as a “remarkable victory over the carbon and sulfur oxide factors.”[26] In keeping with the time, St. Louis achieves a “victory” in its quest for visibly cleaner air, while not addressing chemical and smaller particulate components.

The Fight for Visibly Clear Air in St. Louis

            St. Louis, Missouri was a city that had witnessed several organized smoke abatement efforts since 1893. Civic groups such as the Citizen’s Smoke Abatement League and the Women’s Organization for Smoke Abatement attempted to promote cleaner air through educational campaigns and the enforcement of smoke reduction by watching and regulating the smoke being emitted by smokestacks.[27] Unfortunately, these efforts did little to reduce the quantity of smoke in the city. In order to foster change, the city needed a new strategy.

            In 1934, Raymond Tucker, a professor of mechanical engineering at Washington University, was appointed by Mayor Bernard Dickmann to be his personal secretary. Mayor Dickmann was interested in pursuing clean air in the city and instructed Tucker to “clarify the air as a previous administration had clarified the water.”[28] St. Louis had recently tackled the public health issue of water pollution by filtering it at the source and removing impurities before distribution. Using this model, Tucker investigated regulating fuel prior to distribution.[29] This proved to be a challenge since St. Louis was a city that received 94% of its soft bituminous coal from “counties just across the river in Illinois.”[30] Attempting a change would be difficult and likely unpopular since bituminous coal was cheaper and the switch to cleaner burning fuels could be seen as placing an economic burden on the residents of the city. However, the mayor supported this plan and formed a citizen’s committee to advocate for the restriction of soft coal.[31] Meanwhile, Tucker hired Osborn Monnett, a mechanical engineer and authority on smoke abatement who had worked on Chicago’s abatement program. Monnett recommended that large consumers, such as industry and apartment buildings, should use only mechanical stokers, and smaller consumers, including private residences should switch to smokeless fuels.[32] Tucker further recommended “washing” the coal to remove impurities and reduce sulfur and fly ash.

            The bill was hotly contested in 1937 because of Tucker’s “washing clause”. Opponents, such as a nearby chamber of commerce wrote an open letter offering for St. Louis industry to move across the river to save on the impending cost doubling of fuel. Illinois coal workers also claimed that the clause would force closure of the mines.[33] The Post-Dispatch, a prominent St. Louis newspaper, accused the bill of “unnecessarily antagonizing the city’s Illinois neighbors.”[34] Part of the debate centered on whether or not the city had the right to demand for coal to meet certain quality standards.[35] When the law passed with the “washing clause” and Monnett’s recommendations, a regulation precedent was set in the city. Tucker explained that the smoke ordinance “established the fundamental principle that the City of St. Louis has a right to dictate the type of fuel which may be burned in the City of St. Louis.”[36] However, after two years of regulation, the city was still riddled with smoke.  Tucker responded to the lingering smoke by stating, “At present, St. Louis has passed an ordinance that is not the ultimate solution of the problem.”[37]

            In November 1939, the city descended into a 9-day black haze. “Black Tuesday”, as it has been deemed by the city’s history, was a smog caused by a temperature inversion that elicited nationwide coverage in Life Magazine and Business Week. The Post-Dispatch, which had become an advocate for the anti-smoke campaign, ran front page articles on the subject for almost fifteen days in a row.[38] While calling for action, the Post-Dispatch also vehemently opposed the “wreaking of the great soft coal industry in Southern Illinois.”[39] In an editorial, the Post-Dispatch recommended that the city purchase coal for distribution at reasonable prices, a suggestion which would be heeded in the following year.

            The public outcry and interest from “Black Tuesday” prompted Mayor Dickmann to convene a meeting of fifty-two civic leaders to discuss the smoke problem. Out of the meeting a new citizen’s smoke elimination committee was formed and soon recommended that the city take drastic measures to abate the smoke. [40]  All of the recommendations had previously been considered too drastic to pass. However, with the advent of “Black Tuesday” the city was more inclined to consider the committee’s six major recommendations,

               “1. That all those burning a high volatile fuel must employ mechanical fuel burning equipment to burn it smokelessly; 2. That all others must use smokeless fuel; 3. That in case of emergency or necessary control, the city administration be authorized to engage in the purchase, sale, and distribution of fuel; 4. That railroads should conform to suggestions made in the report; 5. That the city schools and state buildings not subject to city regulation should be asked to cooperate; 6. That the Division of Smoke Regulation be enlarged to meet the increased demands upon it in carrying out the powers of the revised new ordinance.”[41]

            The bill passed with all recommendations and within months St. Louis began to benefit from visibly clean air. By August 1940, violators of the new anti-smoke ordinance were already being prosecuted.[42] While there was still some opposition from coal dealers[43] and Illinois’ miners who threatened to boycott St. Louis goods, the bill began to be perceived as a “victory.” An article from December 1940 exclaimed that “St. Louis appears to have won its 50-year fight for smoke elimination.”[44] The change in air quality was so incredible that St. Louis newspapers began to tease the neighboring communities about their smoky atmosphere.[45] The Post-Dispatch even printed a cartoon on November 19, 1940 that mockingly asked “Where’s My Smoke?”[46] An editorial from the St. Louis Star-Times asked Life Magazine to reprint the pictures of “Black Tuesday” alongside new pictures of the city after the ordinance.[47] The reprinted editorial lauds the city’s progress, “The machinery through which the ordinance was prepared, and through which public opinion was educated to accept it, deserves more than local attention, because it has worked. It thus has set an example for other smoke-ridden Midwestern cities located near great bituminous coal fields.”[48]

            The clean air measures in St. Louis were the first successful coal smoke abatement regulations, the passage of which would not have happened without combined public and governmental support. The health concerns which arose from the “Black Tuesday” temperature inversion allowed Mayor Dickmann and Raymond Tucker to pursue their clean air agenda without watering down the bill. Passing the bill with stiff, enforceable regulations was central to its success. Once St. Louis gained notoriety as an example of a smoky city which solved the problem of visible coal smoke pollution, other U.S. cities such as Cleveland and Pittsburgh followed suit. Despite pockets of urban air cleanup, many industrial cities and towns continued to deal with harmful emissions.

The 1948 Donora Smog

On early Tuesday, October 26, 1948 a fog caused by a temperature inversion closed over the town of Donora, PA.  As the air stagnated and blackened with emissions from the local steel, coke, and zinc plants, industry which was the economic lifeblood of area, became deadly. An excerpt from the New Yorker described the escalating situation from Tuesday to Friday;

 “The weather was raw, cloudy, and dead calm, and it stayed that way as the fog piled up all that day and the next. By Thursday, it had stiffened adhesively into a motionless clot of smoke. That afternoon, it was just possible to see across the street. Except for the stacks, the mills had vanished. The air began to have a sickening smell, almost a taste…”[49]

Dr. Devra Davis, an epidemiologist born in Donora, examined the disaster through a personal and community lens in her book When Smoke Ran Like Water, wherein she interviewed residents who lived through and retained vivid memories of the event. Outside of the official reports, Davis provides a window into the experience, with stories that illustrate the conditions and Donora’s determined culture. For example, the smog event did not prevent a Halloween parade on Friday evening or a high school football game on Saturday. Regarding Halloween, Davis’ mother recalled, “Of course we all went. The fog was heavy, but there was only one Halloween every year. Only this time we could not see much.”[50] At that point, there was no news of deaths or heightened danger to health.

The 1948 Smog at Donora

The football game took place as scheduled on Saturday. However, the game was halted briefly for an announcement ordering Donora’s “star tight end,’” Stanley Sawa, to “Go home!” after his father fell ill at the mill. Tragically, Sawa’s father had already passed before he returned home. By the time the game was over, folks learned that nine people had passed away before 10am.[51]

Another community member, Arnold Hirsh, an attorney and WWII veteran, planned to attend the football game with his brother Wallace. However, after climbing the 5th street steps, neither of the normally healthy brothers could “take another step.”  Arnold recalled, “We did not say another word to each other. We could barely talk. We turned and headed straight home.” It was lucky they did because they found their mother in a state of distress, unable to catch her breath. When Hirsh finally got one of the eight town doctors on the phone he was told, “The whole town is sick. Even healthy fellas are dropping. Get your mother the hell out of town!”[52]

Donora’s 5th Street Steps, which the Hirsh brothers climbed during the 1948 Smog on their way to the Saturday football game.

They drove into the mountains away from the fog. Although Mrs. Hirsh survived, she only lived another two years, “barely into her fifties.”[53] She’d already developed respiratory problems from living in the town and her plight falls under what Clarence Mills would call the ‘non-killed,’ or those who “went on to suffer in various poorly understood ways.”[54]   By the end of the weekend, 20 people died and thousands of others were sick. Those who continued to die after the smog lifted are not counted in the official records of the disaster.

The tragedy was widely covered in the news and sparked public concern. In its wake, the first large scale epidemiological investigation into temperature inversions and their resulting health effects came months after the October 1948 smog. Newspaper statements announcing the report findings often include the quote,

“We can now say positively what couldn’t be said before with scientific proof – that contamination of air in industrial areas can cause serious acute disabling diseases.”[55]

This statement exposes a conflict with framing temperature inversions to the public eye. The earlier temperature inversions and scientific reports laid a foundation of scientific proof that was not disseminated to the public. The “lag” and lack of mobilization by government and public health officials is covered by framing this as the ‘first event with scientific proof’ despite an abundance of ignored data.

As noted by Benjamin Linsky, a professor who specialized in air pollution, “The fact that the Donora disaster was the second major, publicly recognizable air pollution disaster within 20 years served to embarrass these specialists and others in public health and industrial environment work. A “first” disaster of any type…is frequently shrugged off as “a most unusual confluence of conditions –it will never happen again.”…A second disaster cannot easily be shrugged off by responsible specialists…”[56]

Oscar Ewing, then head of the Federal Security Agency (now the Department of Health and Human Services), summed up the popular public sentiment in his commentary on the official Donora report, “To most of us this as a new and unexpected source of danger. Although we have been concerned for many years with the general problem of pollution of the air in connection with smoke, we have regarded that as a nuisance and annoyance rather than a serious hazard to health.”[57] Here, smoke as a nuisance was still the prevailing concern for those not privy to the scientific reports and reflected an attitude more akin to the late 19th/early 20th century.

The Surgeon General, Leonard Scheele, also weighed in with a similar sentiment, “We have realized, during our growing impatience with the annoyance of smoke, that pollution from gasses, fumes, and microscopic particles was also a factor to be reckoned with. But it was not until the tragic impact of Donora that the Nation as a whole became aware that there might be a serious danger to health from air contaminants.”[58]

Scheele also acknowledged the Meuse Valley disaster’s scientific inquiry into the fatalities but sets the Donora report apart by asserting that it examines “every facet of an air-pollution problem, including health effects as well as deaths.” According to Scheele, the report confirms “two beliefs”:

  1. “It has shown with great clarity how little fundamental knowledge exists regarding the possible effects of atmospheric pollution on health.”
  2. “Donora has emphasized how long-range and complex is this job of overcoming the problem of air pollution—after we get the basic knowledge of its effects.”

The conclusions of the report are unable to point to a single substance as the cause of fatalities and illness. They hypothesize that it may have been a combination of chemicals rather than a single culprit.[59] In an attempt to replicate the original conditions, the Public Health Service conducted 4 days of testing at Donora while trying to examine the equivalent of a planned smog. This caused 90 people to complain of “coughing, wheezing, and shortness of breath.”[60] The wind picked up on the 3rd day of testing and conditions never reached October 1948 levels, but a public health inquiry briefly put those with health conditions at additional risk.

The Technical Conference on Air Pollution

After the report was released, scientific action appeared to progress. In May 1950, the Truman Administration called a Technical Conference on Air Pollution which included “600 scientists, technicians, and engineers.”[61] President Truman hoped “that the exchange of specialized information… (would) contribute toward prompt initiation of corrective measures.” [62]  However, his opening address also reveals the limits of what he believed the Federal Government should do. In this instance it amounted to taking leadership in research but not regulation. This policy stance essentially remained in effect for another decade.

President Truman’s opening remarks at the conference, revealed that he believed air pollution to be a local problem, a cultural view that would largely shift by 1970 to understand the interconnectedness of global climate.[63] At the time, Truman’s legislative plan relied on each locality studying “its own situation and draft(ing) laws adapted to local conditions.” As a result, more “exchange of information” happened, but substantial action would have to wait.

1952 Great Smog of London

In December 1952, one of the deadliest temperature inversions occurred over the city of London. Like Donora, a dense fog enveloped the city for four days, effectively shutting down the London metropolis from December 5th-10th. According to several articles in the London Times, the city virtually came to a halt; road, rail and air travel were interrupted, all shipping stopped on the Thames, most bus services stopped, and traffic accidents increased.[64] The dense, dark smoke-filled air contributed to the deaths of approximately 4,000 people during this short span. [65]  Nothing like this had occurred in London’s history of frequent smog. The official government report described the unusual severity of the weather:

“The fog was notable for its density and its duration and an important feature was the almost complete absence of remissions, either in density or in temperature, during the four days. In a city traditionally notorious for its fogs there was a general agreement on its exceptional severity on this occasion.”[66]

Due to the amount of death and respiratory sickness, the public demanded to know what caused the fog and its excessive intensity. In response to the concern, the Ministry of Health formed a committee, to “examine the nature, causes and effects of air pollution and the efficacy of present preventive measures…”[67] The Interim Report found that up to 60% of the smoke in the fog was due to domestic fires.[68]  It also estimated that ‘smokeless fuels’ only made up 16% of the total annual fuel usage for both industrial and domestic consumption.[69] Conspicuously missing from the report is the mention of “nutty slack”, a low-quality highly polluting coal product that was encouraged by the National Coal Board for use by household consumers during the winter of 1952.[70] “Cheaper than ordinary house coal” and available in abundance after December 1, 1952[71], the widespread use of this material is likely a partial cause of the Great Smog which occurred four days later.

Parliament was historically resistant to regulating domestic energy use through government intervention.[72] In regard to coal smoke, this policy essentially remained in effect until the “Great Smog” of 1952. When this environmental tragedy occurred, it became apparent that a regulative response was necessary to prevent future deaths. Unfortunately, the ultimate legislative resolution resulted in “pollution displacement” rather than reduction. The Clean Air Act of 1956, tightened restrictions on industrial coal smoke and fostered the switch from coal to coke, gas, and electricity.[73]  Four years after the great smog killed thousands, Parliament began to debate the Clean Air Act which would restrict the domestic use of coal. The most convenient substitute was coke, a cleaner burning coal derivative that caused concentrated ground, water, and air pollution at its manufacturing locations. The use of coke would localize pollution, making Britain’s sky clearer while sacrificing the air, water, and soil in other areas to this cause.

U.S. Federal Air Pollution Legislation

Going back to the U.S., in 1955, Congress passed the first federal legislation dealing with air pollution. The Air Pollution Control Act of 1955 allocated funds for research and authorized the Surgeon General to investigate air pollution but contained no provisions for combatting problems. It was very much in line with President Truman’s vision outlined in his 1950 conference comments.

With no substantial federal air quality regulations, temperature inversions hit New York City several times, causing an estimated 700-800 deaths from three inversion episodes in 1953, 1963, and 1966 respectively.[74]  The 1966 inversion took place over Thanksgiving weekend and contributed to the U.S. Public Health Service classifying it as “the nation’s most smog-ridden city.” Although the city took steps to reduce pollution levels, progress came slowly. By 1969, sulfur dioxide emissions were reduced by almost 56%, but carbon monoxide and hydrocarbons, mainly released by automobiles, only reduced by 13% and 11% respectively.[75] Abatement technology had not caught up to the automobile and remains problematic to this day.

The 1966 Thanksgiving Temperature Inversion over New York City

With changing times, The Clean Air Act of 1970 finally received the ability to develop “comprehensive federal and state regulations to limit emissions from both stationary (industrial) sources and mobile sources.”[76] Additionally, regulatory programs including air quality and emissions standards were enacted and the enforcement authority was substantially expanded. This landmark legislation occurred at approximately the same time as the National Environmental Policy Act which established the U.S. Environmental Protection Agency (EPA), on December 2, 1970 to implement the new requirements associated with these Acts.[77]

As a society, we are still working towards understanding the vast impact air pollution has on public health. In the past 2 years several studies have been released exploring the connection between air pollution and higher rates of Covid-19 mortality. In June 2020 a study published in the International Journal of Environmental Research and Public Health  found a correlation “between the spread of the virus and air pollution” noting that particulate matter (PM) “induces inflammation in lung cells”[78] As a result, exposure to particulate matter could potentially “increase the susceptibility and severity of the COVID-19 patient symptoms.” Additionally, (PM) may “create a suitable environment for transporting the virus at greater distance.”[79] Another study in Italy found a correlation between higher Covid-19 mortality in the presence of higher levels of PM10 (inhalable particulate matter with a diameter of 10 microns or less).[80]  The concern is enough to warrant it being called “one of the greatest challenges of our millennium.”[81] The current studies are geared towards physicians, environmental scientists, and those working in public health. Although the research is recent, this is an instance where “lag” and delays with disseminating the work to the public can cost additional lives. There should be a  better mechanism for sharing this knowledge outside of scientific circles and increasing public awareness of the health risks associated with air pollution and Covid-19.

Rachel Carson’s oft cited Silent Spring provided a roadmap for public engagement and contributed to the creation of the Clean Air Act of 1970 and the EPA. Public concern after Donora laid the foundation for air pollution research and early legislation, but without further public engagement action stagnated and slowed. It took 40 years to create emission standards and regulations after the first scientific proof of lethal air pollution. Public engagement is necessary to bridge the gap between scientific studies and actionable change. In 2019, journalist Tim Smedley, attempted to follow in Carson’s footsteps with his book, Clearing the Air.[82] Like Carson, he breaks a singular environmental issue into digestible chapters that presents many aspects of the problem. In truth, as far as strategy goes, not much has changed since Victorian England, and the strategies Peter Thorsheim, revealed in Inventing Pollution[83]. We still primarily work towards engaging and educating the public in the hopes that they will change personal practices and advocate for legislative action.

The link between air pollutants and Covid-19 is one of many issues that society faces. There are still lingering effects of industrial pollution that impact the public daily. For the residents of Clairton, who experienced the 2020 air inversion, a fire and neglect also subjected the town to higher-than-normal levels of sulfur dioxide and other emissions in 2018/2019. Neglect and a leak led to the destruction of the Clairton Coke Works’ air pollution control system. After being missed by inspections for years, a continuing drip in control room #2 essentially disintegrated a pipe joint in the sprinkler system, causing the network of pipes to come crashing down. In the process, it broke a pipe with lubricating oil which ignited and caused a massive fire.[84] The controls for the plant’s pollution control system went up in literal smoke.

 Instead of “hot idling” the plant until repairs could be U.S. Steel opted to continue operations and subjected the area to high levels of sulfur dioxide.[85] To disperse the concentration, U.S. Steet flared the gas at several surrounding plant locations. While it may have reduced the concentration in one area, it also meant that more people were impacted by the emissions, which at the time were approximately 70,000 pounds of sulfur dioxide per day, five times the permitted amount.[86] The change didn’t go unnoticed as “’thousands of complaints poured into the health department.”[87] However, in the face of a mounting health crisis, the county failed to let the public know for over two weeks that they were at higher risk.[88] Even the mayor of Clairton was kept in the dark by both U.S. Steel and the Health Department.[89]  Imagine if this had happened in 2020 during the most recent air inversion and amid a pandemic. For those already at risk, it could have been life and death.

Infrared images of pollutants coming off a gas flare at U.S. Steel’s Irvin Plant, West Mifflin, Pa. on March 11, 2019


[1] “Imperial, PA Weather History,” Weather Underground.  Accessed December 8, 2021.

[2] Peeples, Lynne. “Winter Inversions Threaten to Increase Air Pollution, COVID-19 Risks.” Environmental Health News, December 10, 2020.–2649414867.html. Accessed December 10, 2021.

[3] ibid.

[4] Hopey, Don. “After 7 Days of Exceedances, Mon Valley’s Air Pollution Still a Big Problem.” Pittsburgh Post-Gazette. November 20, 2020. Accessed December 9, 2021


[6] Koenig, Jane Q. Health Effects of Ambient Air Pollution: How Safe Is the Air We Breathe. Boston: Kluwer Academic Publishers, 2000. P. 100.

[7] Koenig, p. 95.

[8] Ackerknecht, Erwin H. “A Plea for a ‘Behaviorist’ Approach in Writing the History of Medicine.” Journal of the History of Medicine and Allied Sciences 22, no. 3 (July 1967): 211–14.

[9] As referenced later, Dr, Clarence Mills was measuring “sootfall” through approximately 1948. Instrumentation was not yet available to measure particulates or chemical levels in the air. One of the earliest instruments available was the “Capnometer”, developed by the Mellon Institute in 1930, which was able to measure smoke levels independently of smoke stacks.

[10]Erwin H. Ackerknecht, “Anticontagionism between 1821 and 1867: The Fielding H.

Garrison lecture,” International Journal of Epidemiology 38, no.1 (2009): p.7

[11] Stradling, David. Smokestacks and Progressives: Environmentalists, Engineers, and Air Quality in America, 1881–1951. Baltimore: The Johns Hopkins University Press, 1999. P. 38

[12] ibid

[13]Peter Thorsheim, Inventing Pollution: Coal, Smoke, and Culture in Britain since 1800. Athens, Ohio:  Ohio University Press, 2006, p.129.

[14] Jacobs, Elizabeth T. “The Donora Smog Revisited: 70 Years After the Event That Inspired the Clean Air Act.” AJPH 108, no. 52 (2018): p.585

[15] “Evening Star. [Volume] (Washington, D.C.) 1854-1972, January 25, 1931, Image 74,” January 25, 1931.

[16] Jacobs, Elizabeth T. “The Donora Smog Revisited: 70 Years After the Event That Inspired the Clean Air Act.” AJPH 108, no. 52 (2018): p.585

[17] Nemery, Benoit, Peter HM Hoet, and Abderrahim Nemmar. “The Meuse Valley Fog of 1930: An Air Pollution Disaster.” The Lancet 357, no. 9257 (March 3, 2001): 704–8.

[18] Fishbein, Morris, “Belgian ‘Fog Death’ Cause Revealed,” Indianapolis Times. (Indianapolis [Ind.]), February 12, 1931, Home Edition, Image 4,” Accessed December 12, 2021.

[19] “Science Wins War on ‘Death Fog.’” Evening Star. (Washington, D.C.) July 29, 1932, Image 16,” Accessed December 12, 2021.

[20] Davis, Devra. When Smoke Ran Like Water: Tales of Environmental Deception and the Battle Against Pollution. New York: Basic Books, 2002. P.20

[21] Mills, Clarence. “Health Costs of Urban Air Pollution.” Occupational Medicine 5, no. 6 (1948): 614–33.

[22] Mills, p. 615

[23] Ibid

[24] Mills, p. 614

[25] Mills, p. 615

[26] Mills, p. 632

[27] Stradling, Smokestacks and Progressives,163-164.

[28] Ibid.

[29] Tarr, Joel A.  Devastation and Renewal: An Environmental History of Pittsburgh and Its Region. Pittsburgh: University of Pittsburgh Press, 2005. P.149.

[30] Stradling, Smokestacks and Progressives,164.

[31] Ibid.

[32] Ibid.

[33] Ibid.

[34] Stradling, Smokestacks and Progressives, p.165.

[35] Uekoetter, Frank The Age of Smoke: Environmental Policy in Germany and the United States, 1880-1970. Pittsburgh: University of Pittsburgh Press. 2009. P. 78.

[36] Ibid.

[37] Ibid.

[38] Stradling, Smokestacks and Progressives, 165.

[39] Ibid.

[40] Stradling, Smokestacks and Progressives, 166.

[41] “Cities fight Smoke,” Business Week,  6 April 1940, 33.

[42] “St. Louis Coal Blues,” Business Week,  31 August 1940, 20.

[43] Coal dealers faced an increased hardship because they needed to increase the supply that they kept on hand. Since anthracite coal was shipped in from Arkansas, Virginia and West Virgini it took longer to arrive. Previously they had been able to order coal as needed from Illinois and receive it the next day.

[44] “Smogless St. Louis,” Business Week, 14 December 1940, 29.

[45] Ibid.

[46] Stradling, Smokestacks and Progressives, 168.

[47] “Speaking of Pictures…These Show how a smoky city cleaned up,” Life Magazine, 13 January 1941, 6.

[48] Ibid.

[49] Davis, Devra. When Smoke Ran Like Water: Tales of Environmental Deception and the Battle Against Pollution. New York: Basic Books, 2002. P.15-16 Excerpt reprinted.

[50] Davis p.16

[51] Davis, p.17

[52] Davis, p. 17

[53] Davis, p.18

[54] Davis, p.29

[55] “Smog Preventable Scientists Now Reveal,” Toledo Union Journal. (Toledo, Ohio), October 21, 1949, Image 2,” October 21, 1949.

[56] “Preface,” Air Pollution in Donora: An Analysis of the Extreme Effects of Smog. New York: Maxwell Reprint Company, 1970.

[57] Air Pollution in Donora: An Analysis of the Extreme Effects of Smog. New York: Maxwell Reprint Company, 1970. p.ii.

[58] Scheele, Leonard, “Surgeon General’s Statement,” Air Pollution in Donora: An Analysis of the Extreme Effects of Smog. New York: Maxwell Reprint Company, 1970.

[59] Air Pollution in Donora: An Analysis of the Extreme Effects of Smog. New York: Maxwell Reprint Company, 1970.p. 161-162

[60] “U.S. Experiment with Smog at Donora in Final Stage,” Evening Star. (Washington, D.C.) 1854-1972, April 21, 1949, Image 8,” Accessed December 12, 2021.

[61] “Air Pollution – A New Problem for Science,” Evening star. (Washington, D.C.), 04 May 1950. Chronicling America: Historic American Newspapers. Lib. of Congress. Accessed December 12, 2021.

[62] Truman, Harry S. “Message to the United States Technical Conference on Air Pollution,” Harry S. Truman Presidential Library., Accessed December 12, 2021.

[63] Hill, Gladwin, “Introduction,” Air Pollution in Donora: An Analysis of the Extreme Effects of Smog. New York: Maxwell Reprint Company, 1970.

[64] “Transport Dislocated by Three Days of Fog,” The Times, 8 December 1952, p.8.

[65] Ministry of Health, Mortality and Morbidity during the London Fog of December 1952: Report by a Committee of Departmental Officers and Expert Advisers appointed by the Minister of Health, (London: Her Majesty’s Stationary Office, 1954),p. 1.

[66] Ibid.

[67] Committee on Air Pollution.  Interim Report. London: Her Majesty’s Stationary. 1953, p. 4.

[68] Committee on Air Pollution.  Interim Report. P. 6.

[69] Ibid., 12.

[70] Thorsheim, Inventing Pollution, p. 162.

[71] Ibid.

[72] Thorsheim, Inventing Pollution, p. 110.

[73] Ibid. 173.

[74] 1953, caused roughly 200 deaths. In 1963 a 2-week smog caused roughly 300-400 deaths, and in 1966 an estimated 168 people died.

[75] Hill, Gladwin, “Introduction,” Air Pollution in Donora: An Analysis of the Extreme Effects of Smog. New York: Maxwell Reprint Company, 1970.

[76] US EPA, OAR. “Evolution of the Clean Air Act.” Overviews and Factsheets, May 29, 2015.

[77] US EPA, OAR. “Evolution of the Clean Air Act.” Overviews and Factsheets, May 29, 2015. Accessed December 12, 2021.

[78] Comunian, Silvia, Dario Dongo, Chiara Milani, and Paola Palestini. “Air Pollution and COVID-19: The Role of Particulate Matter in the Spread and Increase of COVID-19’s Morbidity and Mortality.” International Journal of Environmental Research and Public Health 17, no. 12 (June 2020): 4487.

[79] ibid

[80] Dettori, Marco. “Air Pollutants and Risk of Death Due to COVID-19 in Italy.” Environmental Research 192 (2021). Accessed December 12, 2021.

[81] Comunian, Silvia, Dario Dongo, Chiara Milani, and Paola Palestini. “Air Pollution and COVID-19: The Role of Particulate Matter in the Spread and Increase of COVID-19’s Morbidity and Mortality.” International Journal of Environmental Research and Public Health 17, no. 12 (June 2020): 4487.

[82] Smedley, Tim. Clearing the Air: The Beginning and the End of Air Pollution. London: Bloomsburg Sigma, 2019.

[83] Thorsheim, p.129.


[85] The bricks in coke ovens can crack when cooled to below 800° F, so even in times of crisis they remain in operation.

[86] Frazier, Reid. “‘Razorblades and Feathers in My Throat’ – The Allegheny Front,” April 16, 2019. Accessed December 11, 2021.

[87] ibid

[88] ibid

[89] Frazier, Reid. “RESIDENTS IN CLAIRTON HEAR FROM U.S. STEEL ON PLANT FIRE, POLLUTION ISSUES.” Allegheny Front. Accessed December 11, 2021.