International Indoor Air Quality Standards


(Chapter 1)

CHAPTER 1. History of Indoor Air Quality standards 

A. The Black Hole of Calcutta, Prisoners-of-War and Ancient Prisons 

The first well-documented and well-publicized indoor air quality incident occurred on June 20, 1756 in Calcutta, India.  This incident is known as “the black hole of Calcutta.”   

In this indoor air quality situation, 146 captured British soldiers were imprisoned in a 14 x 18 foot prison cell.  This cell only had 1 door  with a small, 1 square foot opening.  Over night, most of the soldiers died.  Only 23 survived.   The description of the symptoms from the survivors was consistent with oxygen deprivation and suffocation. Some symptoms were also consistent with acidosis due to very high carbon dioxide exposure levels.  

The British government made this incident a rallying cry for an increased war effort against the Nawab of Bengal, Siraj ud-Daulah. However, while claiming improper treatment of their war prisoners, the British government practiced similar culling methods.   

American Revolutionary Prisoners-of-War

In 1780, only 24 years after the Black Hole of Calcutta scandal, the British had anchored a flotilla of 12 former men-of-war ships in Brooklyn, New York, Wallabout Bay to house prisoners from the war with the US. Prisoners captured by the British military were crowded into these ships.   Conditions in the ships were extremely unsanitary. Further, prisoners were given little food, no medical attention and a great deal of abuse.  This neglect was intended to motivate these troops to change sides and join the King's Navy and fight the colonialist revolutionary army.   

Aboard these unsanitary ships, disease was rampant. The corpses of those who died (between 11,500 and 12,500 men) were either rowed to shore and placed in shallow graves or unceremoniously tossed overboard by their British captors. 

The worst of these prison ships was the HMS Jersey, a decommissioned warship, on which 1,100 men were crowded together between decks. About a dozen prisoners died each night aboard the Jersey from dysentery, typhoid, smallpox, yellow fever, food poisoning, starvation and torture. When the war ended in 1783 only 1,400 survivors were found on the 12 prison ships.  All of them were ill and emaciated. 

Ancient Prisons

Historically, the use of inadequately ventilated cells to cull large numbers of prisoners of war was a common practice going back hundreds of years.  Cell overcrowding was a common prisoner reduction tool in many prisons. Well documented cases in the literature show this technique was routinely practiced in Istanbul and Romania. 

In addition to cell overcrowding to reduce the number of prisoners, a second technique was also used. Ancient prisons had essentially no sanitary controls. Ancient prisons also had many lower levels.  Consequently, human waste products would flow down to the lower levels of the prison, producing air quality that in most cases lead to illness and early death.   Being sentenced to a lower level of a prison was essentially a death sentence, especially with the addition of inadequate nutrition.  

B. The Londonderry 

The next well-publicized IAQ incident happened on a cruise ship called the Londonderry on December 3, 1848.  In this case, the Packet Steamer Londonderry was caught in a storm at sea.  In order to protect the passengers, the captain ordered that they all go below deck.   Further, due to the high waves, he ordered that tarpaulins be placed over the deck openings to prevent water from entering the ship.   However, the effect of placing the tarpaulins over the deck openings was to eliminate any fresh air flow to the lower decks.   Over the next 30 hours, over half of the 174 passengers suffocated.   

Sadly,  “Dr Miller, having examined the bodies, gave his opinion that “ . . . those persons had come by their death through many persons having been in too small a place, and having an imperfect supply of air...the steerage accommodation being more cramped than the Black Hole of Calcutta.” 

The inquest jury found that the passengers had died of suffocation and charged the Captain, Alexander Johnson, as well as the first and second mates, with manslaughter, calling for better conditions for steerage passengers.  Needless to say, the practice of closing off deck ventilation openings during storms was no longer permitted.  

C.  Early Indoor Air Quality Litigation  

1.  The Park Avenue Tunnel of the New York Central Railroad 

Many early railroad tunnels lacked any specific ventilation.   One such tunnel in New York City became both an indoor air quality litigation case.   This was the Park Avenue tunnel.  It was the first train tunnel to Manhattan Island.   It was 3 miles long and essentially was  unventilated.   Trains traversing this tunnel were coal fired and moved relatively slow compared to today’s standards.   This meant that people and the train spent considerable time in this tunnel with constantly deteriorating air quality.  A traverse time of 15-20 minutes would not have been unusual. 

Below is an excerpt from the newspaper article of Wednesday, July 27, 1901 about the investigation of this tunnel. 


Dr. Cyrus Edson's Report on the Park Avenue Tunnel.

He describes to the Grand Jury the sufferings of passengers

and the danger to health they incur. 

“In July 1901, during the Grand Jury's investigation of the nuisance existing in the Park Avenue Tunnel between Fifty- sixth and Ninety-sixth Streets, in New York City, I was retained by the District Attorney of New York County as engineering expert on ventilation, and in my testimony before the Grand Jury. 

In my opinion, the tunnel is the cause of a very serious public nuisance, affecting the health and comfort of a very large number of persons. Each car contains less than 5,000 cubic feet of airspace, and, therefore, allows only about 56 cubic feet of air for each person. In the case of the 'Black Hole' of Calcutta, 146 persons were thrown into a room the size of an eighteen-foot cube at eight o'clock in the evening. The room contained a door and two windows. The latter were open. Each man had about 38 cubic feet of air space. The car was lighted with oil-lamps. 

On Wednesday, July 24, I made a number of observations of cars in transit through the tunnel. One was on the 12.15 P-M- train on the Harlem road. The temperature of the car at starting was 86.5 degrees. Within four minutes, during transit, it had risen to 91 degrees, and the humidity rose from 70 to 76 per cent. The air was very irritating and several persons were seized with coughing spells. On entering the tunnel my pulse was beating at the rate of 70 per minute. At the exit it had risen to 96 per minute. 

The temperature in these cars during the warm weather varies from 85 degrees to 105 degrees. I have noted a temperature of 111 degrees, with a high percentage of humidity. The gases of combustion, plainly apparent to the senses while the cars are passing through the tunnel, are very poisonous, and in sufficient quantities will destroy animal life. 

This system of ventilating tunnels is by no means untried or new, as you can find the description of a similar method in the English paper, Engineering, of April 21, 1871, where Mr. Rams- bottom (a well-known English engineer) describes the mechanical ventilation of the Liverpool Tunnel of the London and Northwestern Railway. 

A carbon dioxide standard in 1871 

It is very interesting to note in that Dr.Cyrus Edson quoted Mr. Rams-bottom’s used of a carbon dioxide exposure standard from 1871  of 800 ppm.  Here is his an except from his presentation: Topic No. 2." The Ventilation of Tunnels, Subways and Kindred Constructions."  





“The amount of carbonic acid found in the air is generally taken in ventilation work as the index of its purity, and what is commonly considered as pure country air ordinarily averages about 4 parts per 10,000 of carbonic acid. Eight parts per 10,000 of carbonic acid is commonly considered as a standard of purity in the ventilation of buildings, while in this tunnel should the carbonic acid present occasionally reach 12 parts per 10,000, no serious inconvenience would be experienced by the passengers, and therefore taking twelve parts per 10,000 as a maximum allowance, with fans of sufficient capacity to exhaust all the air from this tunnel every two minutes, this result could be obtained.” 

2. The Cole County Courthouse Indoor Air Quality CASE 

The first indoor air quality litigation case was probably the County of Coles, Illinois courthouse building on July 11, 1898. 

A suit was filed by county employees to justify the construction of a new courthouse.  The suit by employees to require the county to building a new building alleged amongst other things that the air quality in the building was a health hazard to employees.   A specific mention was the mention was the office for the county treasurer. 

“the office provided for the county treasurer was….. located between the ladies’ water closet and the main water closet; that it had no ventilation; (and) that it was contaminated with the poisonous gases from those closets.” 

Based on this description and the lack of stack venting on plumbing of that time, this office must have been particularly odiferous.   

D. The First Indoor Air Quality Survey 

During the early 1800s, tuberculosis and other diseases were rampant in the poorer segment of the population.   The incidence of these diseases and fatalities was also consistent with their unsanitary and crowded housing conditions.   

However, with the dawn of the industrial revolution, the need for labor greatly expanded.  Sick and debilitated people did not make good workers.  Hence, significant economic interest developed to determine the reasons for worker illness and the methods for producing healthier and more productive workers.   

Surgeon Major F. de Chamount, M. D. began some of the initial research into the relationship of indoor air quality and reports of ill health.   He was the first researcher to perform an “indoor air quality survey.   

Below is a copy of the questions from his survey and the responses.  Interestingly, these questions are very similar to question found on IAQ survey’s almost 140 years later! 


Please rate the air quality in your room based on the following descriptions 

“Fresh or not” “Rather close” “Close” that “Very close” “Extremely close”

differing sensi- that is, the point is, the point that is, the point that is, the

bly from the at which the or- at which the  at which the point at which

external air ganic matter be- organic matter organic matter the maximum

      gins to be ap- begins to be begins to be of- point of differen  preciated by the decidedly dis- fensive and op- tiation by the

      senses. agreeable to the pressive to the senses is

      senses senses  reached 

Moran also measured the carbon dioxide, temperature and absolute humidity in the surveyed spaces. 

His analysis of the carbon dioxide concentration and humidity showed the following relationships to the following subjective ratings: 

Good Ventilation “Fresh”

<200 ppm CO2 above outside background   

absolute humidity less than 4.7 grains/ft3   (55% RH @ 72°F) 

Not good ventilation

>400 ppm CO2 above outside background   

absolute humidity >4.9 grains/ft(56% RH @ 72 °F) 

Bad Ventilation

>600 ppm CO2 above outside background  

absolute humidity >4.9 grains/ft(56% RH @ 72 °F) 

Very Bad Ventilation

>800 ppm CO2 above outside background   

absolute humidity >5 grains/ft3  (57% RH @ 72 °F) 

It is interesting to note that the COvaried significantly more than the absolute humidity.  This is not unlike similar research today that shows carbon dioxide concentrations to be a better indicator of indoor air quality.  

Moran’s research on the relationship of individually reported adverse health effects lead to the establishment of the first comprehensive ventilation standards in England. In 1867, the first general ventilation standards were proposed by General Morin, Director of Conservation, Imperial Art and Meters, in England. The table below shows the recommended minimal ventilation standards.   Interestingly, these ventilation standards are not significantly different that those recommended by ASHRAE today.    

TABLE 1 : General Morin, Institute of Mechanical Engineering 1867.  On the Ventilation of Public Buildings.  

      Ventilation Rate Per Hour CFM/Person 

Hospital for ordinary Patients 2,000 to 24,000

Hospital for epidemic 5,000

Workshops, ordinary trades 2,000

Workshops, unhealthy trades 3,500

Prisons 1,700

Theatres 1,400 to 1,700

Meeting Halls 1,000 to 2,000

Schools for Children 400-500

Schools for Adults 800-1,000 

It is ironic, that in the almost 30 years since 1981,  when financial interests resulted in lowered ventilation rates to the point of causing sick workers with sick building syndrome (see section ),  required ventilation rates have now returned to level recommended over 150 years ago, again to the original intent of producing healthier working environments.  

REF. Surgeon Major F. de Chamount, M. D. On the theory of ventilation: an attempt to establish a positive basis for calculation of the amount of Fresh Air required for an Inhabited Air-space. Philosophical Transactions of the Royal Society 1875 Volume 23 p. 187-200. 

E. The First Indoor Air Quality Standards 

The first indoor air quality standard was developed in Germany by Peterkoffer.   His standard targeted carbon monoxide.   The reason this gas was targeted had to do with the technology used for indoor lighting at that time.   

During the late 18th  and 19th century, Town gas or oil lights were installed in homes and buildings, prior to the development of electric lighting.   The gas that was burned in these interior lights was not the natural gas that we are used to today.   In the 1800s the technology for drilling and collecting natural gas had not been developed.   

In the 1800s, the gas that was burned was called “town gas.”  Town gas was generated by burning coal in an oxygen deficient atmosphere.  The coal would break down into methane, carbon monoxide, and a little carbon dioxide.  The health problem from Town gas occurred when the gas pipes leaked and when the gas light would accidentally be extinguished, but the gas would still continue to leak out of the light fixture.  

Peterkoffer researched the health affects of carbon monoxide and recommended an exposure standard of 50 ppm in 1849.  Interestingly, the current occupational exposure limit for carbon monoxide is essentially the same today.  

Following Peterkoffers work others also recommended various indoor air quality standards in the 1800s.  These are listed below: 

    • 1849 :   In Germany, Peterkoffer proposes first known exposure standard for carbon dioxide of 1,000 ppm. 

    • 1860 :   In England, Moran published ventilation standards for various occupancies based on the first indoor air quality survey. 

    • 1874  :  English Army Surgeon F. deChamont conducts first indoor air quality survey relating five levels of symptoms to indoor carbon dioxide concentrations.  He proposes a carbon dioxide IAQ standard of 200 ppm above outdoor levels, approximately 500 ppm. 

    • 1883 :   In Germany, Max Gruber, of the Hygienic Institute at Munich proposes the first occupational exposure standard for carbon monoxide standard of 200 ppm. 

    • 1887 :   In England, Carnelley, Anderson and Haldane propose “air purity” standards for carbon dioxide, particulates, organic matter, mold and bacteria. 

< 19,355 total bacteria (with a maximum mold level of 645 cfu/m3.)

If mold levels are higher, the total level of culturable bacteria and mold should be no more than 20,000 cfu/m3. 

    List standards

    carbon dioxide,


    organic matter 

F. 1923 School ventilation standards 

During the early 1920s,  the effectiveness of public education to produce educated workers and healthy children was of significant interest to public health officials and educators.   A consortium of research was done on this subject involving school officials, public health physicians and ventilation engineers.  This researched involved studying schools in NYC, Chicago, St Louis. Etc. 

This research compared heating systems, window configuration, ventilation rates, student test scores, capital costs, and other factors.    The study concluded that a steam heating system with windows that open, and a ventilation system that provided 30 cfm of  fresh air per student, was the most healthy and cost effective method for constructing school.   By 1924, over 60 years after the enactment of the English ventilation standards by Morin, 30 cfm per student of fresh air was embodied into law in 21 US states by statutes and board regulations. 224 

G. Swedish Ventilation Standards 1500s 

Sweden has always been at the forefront of research on the general health of its population.   Sweden has been tracking the health effects of chemical exposure since the 1500s.   Though the science toxicology at that time was not developed,  Swedish Public Health researchers clearly noted increased morbidity and mortality in workers exposed to hazardous chemicals in various industries.  Most importantly, they noticed that in factories where ventilation was used to expel the “bad air”,  the incidence of worker morbidity significantly decreased.   Consequently, Sweden developed and mandated specific amounts of ventilation various industrial processes in the early 1600s.  They expanded these standards continually over the next 200 years.  Eventually, other European countries developed similar ventilation standards.  

What is so interesting about these earliest of ventilation standards is that they were symptom based – not chemical exposure level.  This meant that if a ventilation system did produce the desired reduction in symptoms, more ventilation would be mandated.  

This was unique in that if you had a susceptible or sensitive population, symptom relief was mandated, not just numerical amounts of ventilation, which is the standard today.  

H. IAQ in Outer Space - The Story of MIR 

The MIR space station was launch by Russia in 1989?.   It remained in orbit for 10+? years.  During this time it was always occupied by at least 2 astronauts.  During 1989 and 1990, the US also had a visiting astronaut on this MIR space station.   

Early in its life MIR was a very reliable space craft.  However, after about 10 years, the space because developing a number of electrical problems.  The most serious electrical problem results in a fire in one of its pods.  It also had a seal failure on one of its air locks.  

This may not seem unusual given the age of the space craft, however, age was not the cause of the problems.   The cause turned out to mutated mold and bacteria that ate the electric wire insulation as well as attached this silicone rubber on the air lock seals.  

This was so serious of a problem for future space travel that one of the two visits the US made to MIR was dedicated microbial sampling.   Though much of the microbial sampling data remains secret in the US, at least one story did appear in the literature.    

The initial air sampling by the US astronaut was done with a  SAS sampler.  This sampler uses a standard culturable plate and typically samples 1 m3 of air.   A typical culturable plate is then incubated for 2-3 days to let the mold and bacteria spores germinate and grow into visible colonies.   

However, this was not the case on MIR.   The next day when the US astronaut was checking the culturable plates for any signs of growth,  he found that the plates were overgrown with mold and bacteria.  The species of mold and bacteria in the air on MIR has mutated and were growing almost 10 times faster than the same species on earth.  This was very usual and very scary.  What would happen to earth if a common species of mold suddenly started to grow 10 times faster? Would food rot 10 times faster?  What about wood structures in humid environments, would they decay 10 times faster? 

Clearly, what was alive on MIR could not be permitted to return to earth intact and viable and be released into environment.    This information was never released to the public.  Instead, it was decided (wisely) to let MIR burn up in the earths atmosphere. Ironically,  one US music disc jockey made fun of the decision to let MIR up.  If he had only known what really was going on.   

What the research on MIR had shown was that water vapor in the air from the human astronauts condensed on the interior surface of the exterior walls. This water allowed mold and bacteria to survive on these exterior surfaces rather than die from normal dehydration. Over time, they were exposed to significant cosmic radiation and eventually mutated to apparently rapidly growing species.   

From an evolutionary and survivability viewpoint, the survivability and mutation to a rapidly growing species makes sense.  The reason for this is that the genetic material I mold and bacteria can be easily be destroyed by radiation.  This is why radiation sterilization is used on food and medical devices.  Therefore, only if a species can rapidly reproduce and grow, will it be able to survive in an elevated radiation environment.   

One can imagine the potential risk to food safety, if this rapid growth ability for microbes was passed on to a pathogenic species of bacteria or mold.  This is not unlikely since bacteria “trade” DNA when they normally pass each other in the environment.  

The story does not end there.  The research on mutated mold and bacteria problems on MIR was a fundamental design challenge in the new International Space Station. Clearly, water vapor had to be prevented from condensing on the exterior walls.  This seems simple, just keep the walls warmer.  However, with an outside temperature that can reach below -200 °F, this is easier said than done.  The ISS is well insulated, but one of the factors in dealing with water condensation is the need to dry out areas where condensation has occurred.  Further, if water does spill on the ISS and it works its way to the exterior skin, it has to somehow be forcibly evaporated.  

What the ISS designers decided to do is build a 1” air space all round the exterior of the ISS.  Air is constantly circulates through this air space.   If any water condenses during the dark side exposure, the forced air will evaporate the water about an hour later when the ISS enters the sunny side of the earth on each orbit. This standard air gap design is required for all modules of the ISS. 

In mid 2009, the Russians announced that they intend to keep their sections of the ISS in orbit as a space station, even after the ISS is supposed to be decommissioned around 2030.   The Russians stated that they learned a lot about maintaining a space craft for many years and feel that even though other countries may think that their space station modules have exceeded their useful life, Russia’s modules can be used for many more years into the future.  

I. A Cause of IAQ Problems - ASHRAE 62-1981 

Even though IAQ was an issue during the turn of 19th century and the industrial revolution, the benefits of the industrial revolution and its huge leap of knowledge human capability was wasted with the mass production of military weapons and two world wars. All of the knowledge about IAQ that was discovered in the later 1800s was lost and forgotten.