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 a task force headed by norman cousins (pictured c. 1976) warned that the pollution in new york city was excessive and "could become a gas chamber" in the wrong weather conditions. 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 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. sulfur dioxide (so2) carbon monoxide (co) smoke november 19–23: stagnant air traps pollutants smog trapped under an inversion in almaty, kazakhstan—similar to the atmospheric conditions of the 1966 new york city smog. 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. unlike atmospheric convection—the ordinary process of lower, warm air rising—inversions leave cooler air suspended below warm air, preventing the lower air from rising and trapping airborne pollutants that would ordinarily disperse in the atmosphere. such weather events are common, but they are usually followed by a strong cold front that brings an influx of clean air and disperses pollutants before they have enough time to become highly concentrated; in this case, a cold front approaching west through southern canada was delayed. when explained in less formal terms, the process of an inversion causing a smog event has been compared to a lid that holds in pollutants or a balloon that fills with pollutants. in general, smog events occur not because of a sudden increase in a region's output of pollution, but rather because weather conditions like stagnant air prevent the dispersal of pollutants that were already present. the inversion prevented air pollutants from rising, thereby trapping them within the city. the smog event itself started on wednesday november 23, coinciding with the beginning of the long thanksgiving weekend. the material sources of the smog were particulates and chemicals from factories, chimneys, and vehicles. sulfur dioxide levels rose and smoke shade—a measure of visibility interference in the atmosphere—was two to three times higher than usual. these weather maps show winds at 18,000 feet from november 21–26, 1966. a mass of warm air spreading east and south above the east coast created the inversion that trapped pollutants near the ground. november 24: thanksgiving day we were flying at about two thousand feet, through a curiously greasy-looking and pervasive haze. the ground could just be made out below—cars, roads, houses, all dim but visible. then we began to climb. in less than a minute the ground had vanished. cars, roads, houses, the very earth itself had been blotted out. we were circling in bright sunlight, above an apparently limitless bank of opaque, polluted air. the smog extended to the horizon in every direction. at a distance, the slanting rays of the sun gave it a coppery, rather handsome appearance. nearer at hand it merely looked yellow and ugly, like nothing so much as a vast and unappetizing sea of chicken soup. william wise, describing his view from an airplane delayed in landing at john f. kennedy international airport. wise was returning from london, where he had been researching the 1952 great smog of london. the city chose not to declare a smog alert on thanksgiving day, but the new york times later reported that city officials had been "on the verge" of calling an alert. austin heller, the city's commissioner of air pollution control, said he nearly declared a first-stage alert between 6 a.m. and 10 a.m. on november 24. heller said the index had reached a high of 60.6–10 points higher than the "emergency" mark—between 8 and 9 p.m., and the 60.6 reading was possibly the highest in the city's history. after a nighttime lull, heller cautioned, the smog would likely spike again in the morning. the unusually heavy smog was evident to the crowd of one million onlookers at the macy's thanksgiving day parade. tabloids and newspapers that ordinarily ran front-page stories about the parade instead carried stories about the smog. health officials cautioned those with chronic lung diseases to stay indoors and advised patients that symptoms of pollution-related illness usually lagged 24 hours after exposure. that day, the city closed all 11 of its municipal garbage incinerators. energy companies consolidated edison (called con ed for short) and long island lighting company were asked to burn natural gas rather than fuel oil to minimize the release of sulfur dioxide; both companies voluntarily cut back emissions, with con ed reducing its emissions by 50 percent. the city told 18 inspectors "to forget their turkey dinners and start looking for dirty air," and they issued an "unusually high" number of citations for emissions violations, including two for con ed plants. representative william fitts ryan of manhattan sent a telegram to secretary of health, education and welfare john w. gardner to request an emergency meeting with new york governor nelson rockefeller, new jersey governor richard j. hughes, and other regional leaders. november 25: first-stage alert declared new yorkers went to work in acrid, sour-tasting air that was almost dead calm. many had headaches that were not the product, they thought, of holiday over-eating. their throats scratched. but no deaths were attributed to the smog... homer bigart, "smog emergency called for city," front-page article for the november 26, 1966 edition of the new york times by friday november 25, a first-stage alert for the new york metropolitan area, including parts of new jersey and connecticut, was declared through newspaper, radio, and television announcements. governors rockefeller and heller attended a press conference with deputy mayor robert price standing in for mayor lindsay, who was on vacation in bermuda. the announcement "was believed to be the first appeal ever made to new york's citizens in connection with a smog problem". conrad simon, who acted as a liaison between the scientific and political communities during the crisis, later said "we came close to closing the city down." pollution was not as high in new jersey or connecticut as in new york, but it was still significant. new jersey reported what was then its worst-ever smog. elizabeth, new jersey had smog at half the levels of new york city. a connecticut health official reported air pollution four times higher than average, but the impact in greenwich, connecticut was considered minimal. the nearby new york counties of nassau, suffolk, and westchester reported very little smog. although not part of the area covered by the alert, unusually high smog was reported as far as philadelphia, pennsylvania and boston, massachusetts, whose mayor issued a similar health warning. the alert was declared upon the advice of the interstate sanitation commission. members of the commission had been monitoring the smog situation in shifts for three days, nonstop. thomas r. glenn jr., the commission's director and chief engineer, recommended the alert at 11:25 a.m. after seeing instruments in new york and new jersey that showed carbon monoxide greater than 10 ppm (parts-per-million) and smoke greater than 7.5 ppm, both for more than four consecutive hours. in new york, the city asked commuters to avoid driving unless necessary, and apartment buildings to stop incinerating their residents' garbage and turn heating down to 60 °f (15 °c). new jersey and connecticut asked their residents not to travel, and to use less power and heat. although it was a workday, traffic was light in new york city. a check on 303 buildings of the new york city housing authority later found near-total cooperation with the city's requests. private residences were believed to have had a high rate of voluntary cooperation with the city's plea to cut energy consumption. the weather forecast called for the heat inversion to end that day, followed by a cold wind that would disperse the smog. nevertheless, heller said that if the wind did not come, a first-stage alert would likely remain in effect and it might become necessary to declare a second-stage alert if conditions worsened. november 26: cold front arrives external audio "commissioner heller announces lifting of air-pollution emergency" (november 26, 1966) — press conference with commissioner heller announcing the end of the alert. from the wnyc archives. rain came in the night. the cold front that would blow away the smog was forecasted to arrive between 5 a.m. and 9 a.m. shortly after 9 a.m. the wind arrived, moving mostly from the northeast between 6–10 miles per hour and bringing cooler temperatures in the 50s °f (10–15 °c). glenn at the interstate sanitation commission sent a message advising the alert to end at 9:40 a.m., based on weather and air readings. shortly after noon, governor rockefeller declared the end of the alert; new jersey and connecticut also ended their alerts that day. health effects from the smog were downplayed in most early reports. some hospitals reported increased admissions of patients with asthma. an official at the city department of health noted that some hospitals were receiving fewer asthma patients, and attributed the reported increases to ordinary random fluctuations. the official told the new york times that "n not one is a pattern emerging which would suggest we are dealing with an important health hazard as of this moment." by this time, the inability to incinerate garbage had generated a large amount of excess waste. hundreds of sanitation workers worked overtime to transport garbage to landfills in the bronx, brooklyn, and staten island, with the bulk going to fresh kills in staten