In 1935, after numerous experiments, scientist Austin Chung invented and manufactured the world's first heat exchange device capable of filtering air pollution.
In the mid-20th century, the German Standards Organization (DIN) published a revision to Part II of DIN 1964, "Ventilation and Air Conditioning: Technical and Hygienic Requirements." In Germany, residential ventilation systems had become an integral part of buildings.
In 1956, the British government enacted the Clean Air Act for the first time.
In 1958, Europe pioneered the concept of modern indoor fresh air and simultaneously introduced low-noise, high-static-pressure fans suitable for various locations. These fans improved indoor air circulation and facilitated ventilation through mechanical air delivery.
In 1970, the United States enacted the Clean Air Act, setting legal limits for the levels of each air pollutant.
In 1974, France introduced fresh air systems; the United Kingdom enacted the Air Pollution Control Act; and in the same year, China produced its first ventilation fan, representing an early prototype of fresh air systems. In the 1970s, over 90% of newly built homes in Spain were equipped with central ventilation systems. In 1987, China promulgated the "Design Code for Heating, Ventilation and Air Conditioning". In 1989, the American Society for Air Quality (ASHRAE) developed the "Indoor Air Quality Ventilation Code". From 1977 to 1999, sales of ventilation systems in the UK exceeded 75 million units, with 97.81% of households having installed them [18]. In 1999, sales of ventilation systems in the UK reached 75 million units, with 97.81% of indoor environments equipped with ventilation systems. In 2000, the European Union standardized residential ventilation. In 2003, Japan included the installation of ventilation systems in its regulations, making them standard equipment in homes; in the same year, China's first national standard jointly formulated by the Ministry of Health, the State Environmental Protection Administration, and the State Administration for Quality Supervision, Inspection and Quarantine, the "Indoor Air Quality Standard", was officially implemented. In 2005, annual sales of fresh air systems in the United States exceeded 21 million units.
In 2008, sales of fresh air systems in Japan reached 15 million units.
In 2014, China's "Technical Specification for Residential Fresh Air Systems" was included in the national development plan.
By 2017, the penetration rate of fresh air systems in European and American households had reached 96.56%.
In 2018, China's first national standard for fresh air systems, "Air Purification Devices for Ventilation Systems," was officially approved and implemented.
