The 1966 New York City smog was a major air-pollution episode and environmental disaster, coinciding with that year's Thanksgiving holiday weekend. Smog covered the city and its surrounding area from November 23 to 26, filling the city's air with damaging levels of several toxic pollutants. It was the third major smog in New York City, following events of similar scale in 1953 and 1963.
On November 23, a large mass of stagnant air over the East Coast trapped pollutants in the city's air. For three days, New York City was engulfed in dangerously high levels of carbon monoxide, sulfur dioxide, smoke, and haze. Pockets of air pollution pervaded the greater New York metropolitan area, including parts of New Jersey and Connecticut. By November 25, the smog became severe enough that regional leaders announced a "first-stage alert". During the alert, leaders of local and state governments asked residents and industry to take voluntary steps to minimize emissions. Health officials advised people with respiratory or heart conditions to remain indoors. The city shut off garbage incinerators, requiring massive hauling of garbage to landfills. A cold front dispersed the smog on November 26, and the alert ended.
In the months that followed, medical researchers studied the smog's impact on health. City officials initially maintained that the smog had not caused any deaths, but it soon became clear that the smog had significantly harmed public health. A study published in December 1966 estimated that 10% of the city's population had suffered adverse health effects, such as stinging eyes, coughing, and respiratory distress. A statistical analysis published in October 1967 found that 168 deaths had likely been caused by the smog.
The smog catalyzed greater national awareness of air pollution as a serious health problem and a political issue. The government of New York City updated local laws on air-pollution control. Prompted by the smog, President Lyndon B. Johnson and members of Congress worked to pass federal legislation regulating air pollution in the United States, culminating in the 1967 Air Quality Act and the 1970 Clean Air Act. The extent of harms from subsequent pollution events, including the health effects of pollution from the September 11 attacks and incidents of pollution in China, have been judged by reference to the 1966 smog in New York.
Background
Smog in general and types of smog
The word "smog" (a portmanteau of "smoke" and "fog") is used to describe several forms of air pollution commonly found in urban and industrialized areas. There are several ways to define and categorize types of smog, with some sources defining two main types of smog: smoky "London Pea soup"-style smog and hazy "Los Angeles"-style smog.
- London smog describes particulate matter (for example sulfur dioxide, smoke, and soot) from stationary industrial sources (typically coal combustion from industrial chimneys) mixing with naturally occurring fog.
- Los Angeles smog, or photochemical smog, results from the combustion of petroleum (and other petrochemicals) and emission of exhaust gas, usually by motor vehicles and petrochemical plants. More precisely, photochemical smog is the product of "secondary" pollutants (ozone, oxidants) that form when hydrocarbons (or volatile organic compounds), carbon monoxide, nitrogen oxides, and other chemicals react together in sunlight. Photochemical smog arrived in modern cities in the 1940s and 1950s with the popularization of motor vehicles and development of new power plants.
London smog and Los Angeles smog are not exclusive to their namesake cities by any means. They are found in urban areas throughout the world, and both types of smog are commonly found intermingled within the same region. At the time of the 1966 smog—and for two decades prior—air pollution in New York City combined the characteristics of London smog and Los Angeles smog. The city's smog in that period was caused by a combination of stationary sources, such as industrial coal-burning, and mobile sources, such as motor vehicles.
Although smog is generally a chronic condition, unfavorable weather conditions and excessive pollutants can cause intense concentrations of smog that can cause acute illness and death. Because of their unusual visibility and lethality, these intense smog events have often been publicized in the media. In news reports, acute smogs have historically been characterized as disasters or, more specifically, environmental disasters. An acute "smog event" may also be called simply "a smog", a smog "episode", or a "killer smog" (if it caused, or had the potential to cause, deaths).
Smog in the United States and New York City before 1966
Even before the 1966 smog episode, scientists, city officials, and the general public recognized that New York City—and most other major American cities—had serious air-pollution problems. According to scientific studies from the period, more than 60 metropolitan areas in the US suffered from "extremely serious air pollution problems", and "probably no American city of more than [50,000] inhabitants enjoys clean air the year round." The air "over much of the eastern half of the country [was] chronically polluted", and the nation's most-polluted population centers were New York City, Chicago, Los Angeles, St. Louis, and Philadelphia.
New York City's pre-1966 air pollution was reportedly the worst of any American city. Although the "persistently glaring" photochemical smog of Los Angeles was more visible, more "infamous," and subject to a greater degree of public attention, New York City had more total emissions and many more emissions proportional to its land area. However, New York's surrounding landscape and climate were naturally conducive to atmospheric circulation, which ordinarily prevented high concentration of smog within the city. As such, the problem was mostly invisible most of the time. While Los Angeles is surrounded by mountains that tend to trap airborne pollutants, New York City's open topography and favorable wind conditions usually disperse pollutants before they can form concentrated smog. If a city with the climate and landscape of Los Angeles had had the high emissions of mid-1960s New York, rapid accumulation of airborne pollutants would have quickly rendered it uninhabitable.
New York's smog event of 1966 was preceded by two other major episodes: the first in November 1953, the second in January–February 1963. Medical scientists led by Leonard Greenburg compared the number of deaths recorded during periods of acute smog with the number of deaths from the same time in other years. Based on their statistical analysis, Greenburg's team determined that the smogs coincided with excess deaths. Greenburg inferred that the smog caused or contributed to those deaths. An estimated 220–240 deaths were caused by the six-day 1953 smog; an estimated 300–405 deaths were caused by the two-week 1963 smog. Other minor episodes of smog occurred in the city before 1966, but they were not accompanied by statistically significant excess deaths.
City air monitoring
In 1953, the city opened a laboratory to monitor pollution that would become its Department of Air Pollution Control. At the time of the 1966 smog, air quality measurements were recorded from only a single station, the Harlem Courthouse building on East 121st Street, run by Braverman and his staff of 15. Taking measurements from a single station meant that the index reflected conditions in the immediately surrounding area, but served as a crude, unrepresentative gauge of overall air quality across the entire city. The Interstate Sanitation Commission, a regional agency run by New York, New Jersey, and Connecticut and headquartered at Columbus Circle, also relied on the Harlem Courthouse laboratory. Formed in 1936, the advisory agency was authorized in 1962 by New York and New Jersey to oversee air pollution issues.
The department quantified pollution using an air quality index (AQI), a single number based on combined measurements of several pollutants. AQI measurements in the United States are now standardized and overseen by the EPA, but in the 1960s, local governments in different regions used "a confusing and scientifically inconsistent array of air quality reporting methods".
By 1964, the Department of Air Pollution Control had developed an AQI called the SCS Air Pollution Index (SCS API), combining measurements of sulfur dioxide (SO2), carbon monoxide (CO), and coefficient of haze (also called smoke shade) into a single number. The city laboratory recorded the presence of those three pollutants measured in amount (by concentration in the air) and duration. SO2 and CO were measured by parts-per-million (ppm) and smoke shade was measured in millions of particles per cubic foot (mppcf). The department continuously monitored these pollutant levels and recorded the hourly averages. The data for those three pollutants were combined into a single number using a weighted formula developed by department co-founder Moe Mordecai Braverman. The SCS API formula was as follows:
The index average was 12, with an "emergency" level if the index was higher than 50 for a 24-hour period. The average of 12 was determined from data collected between 1957 and 1964 showing average levels of 0.18 ppm SO2, 3 ppm CO, and 2.7 mppcf smoke levels. The "emergency" level of 50 was announced in 1964. The index system used by the city in 1966 is not in use anywhere today and was unique to the city even at the time; the 1966 smog itself prompted scientists to reexamine and improve the city's methodology for recording air-pollutant levels.
Using the SCS API, the city adopted an air-pollution alert system with three stages of alert, matching increasingly severe levels of pollution with corresponding counteractions. The city announced its only first-stage alert in 1966; second- and third-stage alerts were never reached.
Braverman later admitted that the "emergency" alert level of 50 SCS API had been chosen on an essentially arbitrary basis. After the department determined the average level of smog in the city was 12, Braverman said,
No one knew what to do next ... so I just said, "If it's four times as high, that's an emergency."
Another defect of the SCS API alert system was that it relied on a balance of multiple pollutants but would disregard fatal levels of any one pollutant under certain conditions. Critics pointed out that the index could have potentially allowed the city to reach lethal concentrations of carbon monoxide without triggering any alert at all, so long as the levels of other pollutants remained low. The department acknowledged the SCS API's flaws and later said it had been implemented for lack of a clearly superior alternative. When the system had been adopted, there were no generally accepted standards or best practices for recording air pollution.
Warnings
In 1963, Helmut F. Landsberg—a climate scientist with the federal Weather Bureau—predicted that the Northeastern and Great Lakes regions could anticipate a major smog event every three years due to the confluence of weather events and trends like growing population, industrialization, and increased emissions from cars and central heating. In early 1966, Dr. Walter Orr Roberts—director of the National Center for Atmospheric Research—warned of the imminent threat of a smog event with the potential to kill as many as 10,000 people. Roberts identified Los Angeles and New York City as the cities most potentially vulnerable to a large-scale lethal smog in the United States, and further named London, Hamburg, or Santiago as the other most vulnerable cities internationally. Asked if "many" American cities were vulnerable to a disaster smog event, Roberts replied: "Yes. I have been worried that we would wake up some morning to an unusual meteorological situation that prevented the air from circulating and that we might find thousands of people dead as the result of the air they were forced to breathe in that smog situation."
The same year, the New York mayor's office established a 10-member task force headed by Norman Cousins (known as the editor of the weekly magazine Saturday Review) to study the problem of air pollution. The task force published a 102-page report in May 1963, finding that the city had the most polluted air of any major city in the United States, with a wider range and greater total tonnage of pollutants than Los Angeles. The task force criticized the city for lax enforcement of pollution laws, even naming the city itself the biggest violator, with municipal garbage incinerators "operat[ing] in almost constant violation" of its own laws. The report warned "all the ingredients now exist for an air-pollution disaster of major proportions" and that the city "could become a gas chamber" in the wrong weather conditions.
A July 1966 report by the New York Academy of Medicine Committee on Public Health cautioned that New York City's air-pollution problem made it susceptible to acute, lethal episodes. The academy recommended a reduction of air pollution. Further, their report cautioned that it was unlikely scientists had identified every harmful pollutant in the air or the full range of health effects that could be caused by air pollution.
Timeline of smog event
Air quality measurements, November 19–30
The following charts show the daily mean values of sulfur dioxide, carbon monoxide, and smoke measurements in New York City from November 19–30, 1966.
November 19–23: stagnant air traps pollutants
In November 1966, New York City was experiencing an unseasonably warm "Indian summer". A cold front from Canada brought clean air to the city on November 19, but the cold front was held in place by pressure from the higher atmosphere. An anticyclonic temperature inversion—in other words, a warm, mostly stationary air mass located atop a cooler air mass—formed over the East Coast on November 20.