Ventilation and Public Health: A Fraught History.

Since the beginning of the COVID-19 pandemic, a vigorous public health discussion has arisen over indoor air quality and ventilation. In popular press articles, bestselling books, and the US Environmental Protection Agency's recently announced Clean Air in Buildings Challenge, scholars and policy experts have claimed that improved ventilation systems can lead to better productivity and performance. By reevaluating those claims in light of the history of public health in Great Britain and the United States, we found that better ventilation has frequently been proposed as a cost-effective and nonintrusive means of improving health in institutions experiencing structural and environmental public health problems. Furthermore, our examination of efforts to provide ventilation for enslaved people, incarcerated people, and the urban poor revealed a consistent lack of government regulation and a disassociation of air quality concerns from broader environmental, social, and economic realities. By continuing to ignore these broader contexts, current ventilation efforts risk repeating this pattern. (Am J Public Health. 2024;114(8):798-804. https://doi.org/10.2105/AJPH.2024.307670).

Uncovering eco-friendly design in the ancient bronze goose-and-fish lamp: an unnoticeable gap boosts ventilation.

The bronze goose-and-fish lamp exhibited in the national museum of China is a 2,000-y-old artifact once used for indoor lighting by nobility in the Western Han dynasty (206 BCE TO 25 CE). The beauty of this national treasure arises from its elegant shape vividly showing a goose catching fish with beautiful colors painted over the whole body. Beyond the artistic and historical value, what enchants people most is the eco-design concept of this oil-burning lamp. It is widely believed that the smoke generated by burning animal oil can flow into the goose belly through its long neck, then be absorbed by prefilled water in the belly, hence mitigating indoor air pollution. Although different mechanistic hypotheses such as natural convection and even the siphon effect have been proposed to qualitatively rationalize the above-claimed pollution mitigation function, due to the absence of a true scientific analysis, the definitive mechanism remains a mystery. By rigorous modeling of the nonisothermal fluid flow coupled with convection-diffusion of pollutant within and out of the lamp, we discover that it is the unnoticeable gap between goose body and lamp tray (i.e., an intrinsic feature of the multicompartmental design) that can offer definitive ventilation in the lamp. The ventilation is facilitated by natural convection due to oil burning. Adequate ventilation plays a key role in enabling pollution mitigation, as it allows pollutant to reach the goose belly, travel over and be absorbed by the water.

Reflections on the history of indoor air science, focusing on the last 50 years.

The scientific articles and Indoor Air conference publications of the indoor air sciences (IAS) during the last 50 years are summarized. In total 7524 presentations, from 79 countries, have been made at Indoor Air conferences held between 1978 (49 presentations) and 2014 (1049 presentations). In the Web of Science, 26 992 articles on indoor air research (with the word "indoor" as a search term) have been found (as of 1 Jan 2016) of which 70% were published during the last 10 years. The modern scientific history started in the 1970s with a question: "did indoor air pose a threat to health as did outdoor air?" Soon it was recognized that indoor air is more important, from a health point of view, than outdoor air. Topics of concern were first radon, environmental tobacco smoke, and lung cancer, followed by volatile organic compounds, formaldehyde and sick building syndrome, house dust-mites, asthma and allergies, Legionnaires disease, and other airborne infections. Later emerged dampness/mold-associated allergies and today's concern with "modern exposures-modern diseases." Ventilation, thermal comfort, indoor air chemistry, semi-volatile organic compounds, building simulation by computational fluid dynamics, and fine particulate matter are common topics today. From their beginning in Denmark and Sweden, then in the USA, the indoor air sciences now show increasing activity in East and Southeast Asia.

Household air pollution from wood burning in two reconstructed houses from the Danish Viking Age.

During 13 winter weeks, an experimental archeology project was undertaken in two Danish reconstructed Viking Age houses with indoor open fireplaces. Volunteers inhabited the houses under living conditions similar to those of the Viking Age, including cooking and heating by wood fire. Carbon monoxide (CO) and particulate matter (PM2.5 ) were measured at varying distances to the fireplace. Near the fireplaces CO (mean) was 16 ppm. PM2.5 (mean) was 3.40 mg/m(3) , however, measured in one house only. The CO:PM mass ratio was found to increase from 6.4 to 22 when increasing the distance to the fire. Two persons carried CO sensors. Average personal exposure was 6.9 ppm, and from this, a personal PM2.5 exposure of 0.41 mg/m(3) was estimated. The levels found here were higher than reported from modern studies conducted in dwellings using biomass for cooking and heating. While this may be due to the Viking house design, the volunteer's lack of training in attending a fire maybe also played a role. Even so, when comparing to today's issues arising from the use of open fires, it must be assumed that also during the Viking Age, the exposure to woodsmoke was a contributing factor to health problems.

Modern indoor climate research in Denmark from 1962 to the early 1990s: an eyewitness report.

UNLABELLED: Modern, holistic indoor climate research started with the formation of an interdisciplinary 'Indoor Climate Research Group' in 1962 at the Institute of Hygiene, University of Aarhus, Denmark. After some years, other groups started similar research in Denmark and Sweden, and later - after the First International Indoor Air Symposium in Copenhagen 1978--this research spread to many countries and today it is carried out globally by probably 2000 scientists. This paper recounts the history of Danish indoor climate research, focusing on the three decades from the early 1960s to the founding of the Indoor Air journal in 1991. The aim of this paper is to summarize what was learned in those earlier years and to call to the attention of researchers in this area the need of multidisciplinary research, mingling epidemiological fact-finding field studies with climate chamber studies and laboratory investigations. PRACTICAL IMPLICATIONS: The review may be of interest to indoor climate researchers who want to know more about the early development of research on this multidisciplinary subject, as it emerged in a small country that undertook pioneering studies.

Indoor Air: the first 10 years.

UNLABELLED: This paper recounts the first 10 years of the Indoor Air journal from the perspective of the founding editor. It represents personal recollections of the journal's founding and initial publication. It describes some of the amazing changes that have occurred since the decade of the 1990s when it was first published. PRACTICAL IMPLICATIONS: It is useful to reflect back periodically to earlier times when the Indoor Air journal was just beginning to understand the conditions that led to its founding. Wise people have contributed much to create this outstanding journal. Their contributions should not be forgotten.

Reflections on the state of research: indoor environmental quality.

UNLABELLED: More than 30 years after the First International Indoor Climate Symposium, ten researchers from the USA, Slovakia, Sweden, and Denmark gathered to review the current status of indoor environmental research. We initiated our review with discussions during the 1-day meeting and followed that with parallel research and writing efforts culminating with internal review and revision cycles. In this paper, we present our choices for the most important research findings on indoor environmental quality from the past three decades followed by a discussion of the most important research questions in our field today. We then continue with a discussion on whether there are research areas for which we can 'close the book' and say that we already know what is needed. Finally, we discuss whether we can maintain our identity in the future or it is time to team up with new partners. PRACTICAL IMPLICATIONS: In the early years of this field, the accumulated knowledge was small and it was possible for any researcher to acquire a complete understanding. To do so has become impossible today as what we know has grown to exceed the learning capacity of any person. These circumstances challenge us to work collectively to synthesize what we do know and to define clearly what remains to be learned. If we fail to do these things well, we risk repeating research without memory, an inefficiency that we cannot afford.

[The healthiness of the air: historical analysis of the studies on the relationship between health and air pollution in living and working places]. / La "salubrità" dell'aria: analisi storica degli studi della correlazione tra salute ed inquinamento dell'aria negli ambienti di vita e di lavoro.

The relationship between air pollution and health had already been postulated by ancient authors. In the Eighteenth century, Bernardino Ramazzini, the founder of the Occupational Medicine, reported in its works relevant considerations against air pollution and its damages. During the Enlightenment, the studies on the eudiometry conducted by the physic Marsilio Landriani can be considered a first attempt to connect the measurement of air quality to medical issues. In the following centuries, Industrial Revolution and the diffusion of domestic heating were a determining factor in worsening the air quality. Despite specific legislations on smoke abatement, some air pollution "disasters" occurred during the last century. In conclusion, this historical analysis showed the complex evolution of the knowledge on the relationship between health and air pollution. Nowadays, an important contribution to the current scientific and political debate on this issue has been provided also by the Occupational and Environmental Medicine.

A biomarker of exposure to environmental tobacco smoke (ETS) and Ernst Wynder's opinion about ETS and lung cancer.

Ernst Wynder did not believe that environmental tobacco smoke (ETS), also known as secondhand smoke, was a cause of lung cancer because his own data did not support this. His view on the issue may have begun to change with our initial studies, carried out at the American Health Foundation, showing that metabolites of the tobacco-specific lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) were present in the urine of non-smokers exposed to ETS. The metabolites - 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and its glucuronides (NNAL-Glucs) - have now emerged as leading biomarkers for the study of carcinogen exposure in non-smokers exposed to ETS. Subsequent work has consistently demonstrated elevated levels of NNAL plus NNAL-Glucs in the urine of people exposed to ETS in various field studies and throughout life. These studies strongly support the epidemiologic data demonstrating that ETS exposure causes lung cancer in non-smokers and have likely had an impact on tobacco control.

Residential radon and lung cancer: end of the story?

The earliest evidence of increased lung cancer risk associated with radon came largely from studies of highly exposed underground miners. In the United States, concerns about residential exposures became prominent in the early 1980s with the identification of the Watras home, which had remarkably elevated radon concentrations. By then, the problem of indoor radon was already recognized in Europe and the first epidemiological studies on indoor radon had been reported. The concern about the risk of indoor radon motivated a series of case-control studies of residential radon and lung cancer in the United States, Canada, China, and a number of European countries. In 1999, the U.S. National Research Council Committee on the Biological Effects of Ionizing Radiation (BEIR VI) weighed the scientific evidence available at that time on this issue and concluded that residential radon was an important contributor to the lung cancer burden and that risks were appropriately estimated by a linear nonthreshold model. Since individual case-control studies have not provided consistent direct evidence of excess lung cancer risk at residential exposure levels, combined analyses of residential radon studies have been undertaken in both North America and Europe. These combined analyses, including the North American pooled analysis described in this issue, represent an important complement to the findings of the miner studies and further support the linear no-threshold model for cancer risk adopted by the BEIR VI Committee and other groups.

On the history of indoor air quality and health.

UNLABELLED: Indoor air is a dominant exposure for humans. More that half of the body's intake during a lifetime is air inhaled in the home. Thus, most illnesses related to environmental exposures stem from indoor air exposure. Indoor air was believed to be a major environmental factor for more than a hundred years, from the start of the hygienic revolution, around 1850, until outdoor environmental issues entered the scene, and became dominant around 1960. Main environmental issues today are outdoor air quality, energy use, and sustainable buildings, but not indoor air quality (IAQ). But, there is mounting evidence that exposure to IAQ is the cause of excessive morbidity and mortality. In developing regions indoor unvented burning of biomass for cooking is the cause of at least 2,000,000 deaths a year (mainly women and children), and in the developed world IAQ is a main cause of allergies, other hypersensitivity reactions, airway infections, and cancers. Cancer of the lungs is related to indoor radon and ETS exposure. Allergies, airway infections and sick building syndrome are associated with, e.g., "dampness", a low ventilation rate, and plasticizers. In the future more emphasis must be given to IAQ and health issues. PRACTICAL IMPLICATIONS: Indoor air quality plays a major role with regard to public health. The main problems are in the developing countries with the indoor burning of biomass for cooking and heating. The solution is a stove with a chimney. In developed regions, good ventilation, getting rid of "dampness" problems, and adequate testing of new building materials would reduce morbidity and mortality.