Tracing the Evolution of Air Ionisation Research in Romania. Nearly a Century of Scientific Progress and Interdisciplinary Perspectives

Air ionisation is an important component of atmospheric electricity, with implications for environmental quality, bioclimatology, and human health. Although research on this phenomenon has a long tradition in Romania, its historical development and diversification across scientific disciplines require systematic synthesis. This study employs a historical-descriptive review of scientific publications, research reports, conference proceedings, and studies conducted in Romania from 1938 to 2026. The literature was examined chronologically and thematically, focusing on major scientific contributions, measurement approaches, investigated environments, and reported relationships between air ionisation and environmental factors. The earliest measurements were conducted by Mircea Herovanu in 1938–1939, followed by systematic atmospheric observations and biomedical investigations developed by Salvator Cupcea and Mauriciu Deleanu. Subsequent research expanded toward geographical and bioclimatic assessments, particularly in Romanian spa resorts. The national symposia organized in Botoșani in 1984 and 1986 contributed to interdisciplinary collaboration and methodological development. More recent studies have investigated underground, urban, and indoor environments. Measurements in the Cacica Salt Mine revealed total ion concentrations ranging from 9,026.5 to 11,464.5 ions/cm³, while research in the Suceava Metropolitan Area demonstrated pronounced seasonal and spatial differences between positive and negative ion concentrations. Recent investigations have also incorporated aeroionic measurements into indoor air quality assessments. Romanian research on air ionization has evolved from isolated atmospheric observations into a diversified interdisciplinary field encompassing environmental, geographical, biomedical, and indoor microclimate studies. Further standardized measurements and long-term investigations are necessary to improve comparability and clarify the relationships between air ionization, environmental conditions, and potential health effects.