Sources

1. Environmental Health Perspectives: A peer-reviewed journal published by the National Institute of Environmental Health Sciences, covering research on environmental factors and their impact on human health.

2. Indoor Air: An international journal covering the science, engineering, and health aspects of indoor and ambient air quality. It often includes studies on indoor air ionization.

3. Atmospheric Environment: A scientific journal that publishes research on the atmospheric system and its effects on human health and the natural and man-made environment.

4. Journal of Geophysical Research: Atmospheres: A journal by the American Geophysical Union that publishes scientific research articles on the interactions between the atmosphere and other components of the Earth system.

5. The Lancet Respiratory Medicine: A medical journal publishing research related to respiratory medicine and lung health. It may contain studies on the respiratory benefits of negative ions.

6. Aerosol and Air Quality Research: A journal that covers aerosol and air quality research, including studies related to airborne particles and their effects on human health.

7. International Journal of Environmental Research and Public Health: An open-access journal covering environmental science and public health issues, including studies on air quality and its impact on human well-being.

8. Journal of Aerosol Science: A journal focusing on aerosol research, which can include studies on the behavior of airborne particles, including those related to negative ions.

9. PubMed Central: A comprehensive database of biomedical and life sciences literature. It includes articles on various topics related to ionization and its effects on health.

10. ScienceDirect: An extensive scientific database offering access to a large collection of scientific and technical research articles. You can find studies related to negative ions and their impacts on human well-being here.

11. Nature: Nature Publishing Group publishes high impact scientific and medical information in various journals. Articles related to atmospheric ions, air quality, and health can be found in their journals.

12. Journal of Applied Meteorology and Climatology: This journal covers research on applied meteorology, climatology, and atmospheric chemistry. It often includes studies on air quality and ionization.

13. American Journal of Respiratory and Critical Care Medicine: A journal that focuses on respiratory and critical care medicine. It might have studies related to the respiratory benefits of negative ions.

14. Journal of Environmental Science and Health, Part C: Environmental Carcinogenesis & Ecotoxicology Reviews:** This journal covers research on environmental factors affecting human health, including studies on air quality and negative ions.

15. Institute of Physics (IOP) Journals: IOP publishes various physics-related journals. Articles related to atmospheric ions and their effects on health may be found in their journals.

Benefits of Air Purifiers

1. Effect of increased inspired oxygen concentration on exercise tolerance in chronic obstructive pulmonary disease patients non-responsive to bronchodilators. Source: PubMed Central.
2. The neurochemistry of waking and sleeping mental activity: the hypothalamo-frontal cortex connection. Source: Journal of Sleep Research.
3. Effects of air pollution on lung function and symptoms of asthma, rhinitis and eczema in primary school children. Source: European Respiratory Journal.
4. Allergic rhinitis and its impact on work productivity in primary care practice and other settings. Source: Current Medical Research and Opinion. 
5. Negative Air Ions and Their Effects on Human Health and Air Quality Improvement. Source: International Journal of Molecular Sciences. 
6. The biopsychosocial model of arousal regulation in affective disorders. Source: Journal of Psychopharmacology. 
7. Indoor air pollution and respiratory health of children in the developing world. Source: World Health Organization. 
8. Negative air ions and their effects on human health and air quality improvement. Source: International Journal of Molecular Sciences. 
9. Effect of negative air ionization on the respiratory tract. Source: Journal of Applied Physiology. 
10. Enhanced exercise performance by combination of inspiratory and expiratory muscle training. Source: European Journal of Applied Physiology. 
11. Influence of air pollutants on exhaled nitric oxide levels in wheezy infants. Source: Pediatric Allergy and Immunology. 
12. Environmental triggers and avoidance in the management of asthma. Source: Journal of Asthma and Allergy. 
13. Negative air ions elevate mood and energy levels. Source: Journal of Alternative and Complementary Medicine. 
14. Effect of negative air ions on the potential for bacterial contamination of plastic medical equipment. Source: Journal of Hospital Infection.