{"id":9260,"date":"2026-02-10T08:00:54","date_gmt":"2026-02-10T07:00:54","guid":{"rendered":"https:\/\/www.marquis.rs\/en\/?p=9260"},"modified":"2026-06-27T22:06:07","modified_gmt":"2026-06-27T20:06:07","slug":"pettenkofers-number-co%e2%82%82-and-indoor-air-quality","status":"publish","type":"post","link":"https:\/\/www.marquis.rs\/en\/blog\/pettenkofers-number-co%e2%82%82-and-indoor-air-quality\/","title":{"rendered":"Pettenkofer\u2019s Number – CO\u2082 and Indoor Air Quality"},"content":{"rendered":"

Indoor air quality is increasingly being linked to human health. In this context, carbon dioxide (CO<\/strong>\u2082<\/strong>) and air quality<\/strong> have become inseparable concepts.<\/p>\n

CO\u2082 is not considered an air pollutant in the classical sense. At typical concentrations, it is not toxic. Nevertheless, its concentration is an important indicator of indoor air quality and ventilation efficiency.<\/p>\n

The topic of CO\u2082 and air quality may seem ultra-modern. However, it is not new. As early as the 19th century, Max von Pettenkofer demonstrated that CO\u2082 concentration could serve as an indicator of indoor air quality.<\/p>\n

This text is dedicated to Max von Pettenkofer on the occasion of the 125th anniversary of his death, in remembrance of his key contribution to understanding the relationship between CO\u2082 concentration and indoor air quality.<\/p>\n

Air Quality and Health Before Max von Pettenkofer<\/strong><\/h2>\n

We cannot see air, but we breathe it continuously. It is a fundamental prerequisite for life, health, and everyday functioning.<\/p>\n

As something invisible and difficult to explain, air has always been the subject of reflection by philosophers, physicians, and scientists. Hippocrates pointed out that human health also depends on the environment in which one lives. Pliny the Elder warned that air can become a medium that threatens life.<\/p>\n

Questions related to air accumulated and multiplied over centuries. In the 19th century, they began to receive scientific, measurable answers.<\/p>\n

Pettenkofer\u2019s Contemporaries: Air and Health in the 19th Century<\/strong><\/h2>\n

Pettenkofer was not the only one thinking about the connection between air and health in the 19th century. His era was a period of major changes in medicine and public health.<\/p>\n

In the 19th century, Florence Nightingale, Ignaz Semmelweis, and Joseph Lister demonstrated how environmental conditions, hygiene, and infection prevention could save lives.<\/p>\n

In this context, Pettenkofer\u2019s idea that air could be measured and controlled became part of a broader historical shift. Health thus began to be viewed as a matter of space, not just of the individual.<\/p>\n

See also: Clean Air Heals: Florence Nightingale<\/a>
\nSee also: Ignaz Semmelweis: Savior of Mothers and Newborns<\/a><\/p><\/blockquote>\n

Max von Pettenkofer and Modern Hygiene<\/strong><\/h2>\n

Max von Pettenkofer (1818\u20131901) belonged to the scientific elite of his time and is considered one of the founders of modern hygiene.<\/p>\n

His key idea was that health is not only a matter of treatment, but also of living conditions. He was particularly interested in how space, water, and air affect human health.<\/p>\n

Pettenkofer was among the first to demonstrate that indoor air quality could be regarded as an objective, measurable category. This marked a significant shift in understanding the relationship between space, health, and science.<\/p>\n

CO<\/strong>\u2082<\/strong> Concentration Levels and Air Quality: Pettenkofer<\/strong>\u2019<\/strong>s Number<\/strong><\/h2>\n

The concentration of CO\u2082 in outdoor air is typically around 350\u2013450 ppm. Indoors, however, CO\u2082 levels are usually higher.<\/p>\n

According to expert publications of the Federation of European Heating, Ventilation and Air Conditioning Associations (REHVA<\/a>), CO\u2082 concentration is considered the leading parameter for assessing indoor air quality and ventilation levels.<\/p>\n