Original Research

The effect of cool-mist humidifier on concentration of air pollutants and indoor environmental conditions

Abstract

Introduction: Indoor air pollution poses significant health risks, given the substantial time individuals spend indoors. Cool-mist humidifiers have been proposed as a potential intervention for enhancing indoor air quality
by influencing pollutant concentrations. This study investigates the effects of gas dissolution in vapor particles generated by a cool-mist humidifier on indoor air pollutants.
Materials and methods: A controlled laboratory experiment was conducted within a 1 m³ insulated plastic chamber to monitor key parameters, including Carbon monoxide (CO), Carbon dioxide (CO₂), Oxygen (O₂), Total Volatile Organic Compounds (TVOCs), temperature, and Relative Humidity (RH). Pollutants were introduced using a lit candle and formaldehyde, and air quality was measured using a digital gas analyzer (CEM GD-3803) and a TVOC analyzer (QB2000N/T). Baseline pollutant levels without humidification were compared to levels observed with a cool-mist humidifier operating at various humidification rates (110–370 mL/h) over an 8-h period.
Results: The results indicated consistent reductions in CO₂ and TVOC concentrations across all tested humidification rates, accompanied by increases in temperature and relative humidity. CO concentrations exhibited more variable behavior, with alternating increases and decreases over the testing periods.
Conclusion: These findings underscore the potential of cool-mist humidifiers as an effective strategy for reducing indoor air pollutants, particularly CO₂ and TVOCs. This has meaningful implications for enhancing indoor air quality and protecting public health.

1. Asadi E, Costa JJ, Gameiro da Silva M. Indoor air quality audit and certification of buildings in Portugal. Energy optimization conference and exhibition [in Persian]. 2019.
2. khanzadi A, JaliliyanS, Moradi S, Heidariyan M. Analyzing Effects of Environment Quality Improvement on Life Expectancy in Iran (Based on Economic Approach). Journal of Environmental Science and Technology. 2020;1(22):336-49.
3. S. AM. A Survey of the Air Quality of Kermanshah City in Terms of Dust phenomenon and its Effect on Tourism Activity. the third international conference on management, accounting and knowledge based economy with an emphasis on resistance economy1396. 2005-2011.
4. Fazlzadeh M, Rostami R, Hazrati S. Concentrations of Carbon Monoxide in Outdoor and Indoor Air of Residential Buildings in Ardabil. Journal of Sabzevar University of Medical Sciences. 2016;23(1):161-8.
5. Sohrabi pirdosti p, sahraei j. Indoor air quality assessment in a multistorey Car Park. Journal of Environmental Science Studies. 2019;4(2):1389-400.
6. http://daneshyari.com/isi/articles/indoor_air. 2022.
7. Pulimeno M, Piscitelli P, Colazzo S, Colao A, Miani A. Indoor air quality at school and students' performance: Recommendations of the UNESCO Chair on Health Education and Sustainable Development & the Italian Society of Environmental Medicine (SIMA). Health Promot Perspect. 2020;10(3):169-74.
8. Wolkoff P, Kjaergaard SK. The dichotomy of relative humidity on indoor air quality. Environ Int. 2007;33(6):850-7.
9. Liu F, Ma Q, Marjub MM, Suthammanont AK, Sun S, Yao H, et al. Reactive air disinfection technologies: principles and applications in bioaerosol removal. ACS ES&T Engineering. 2023;3(5):602-15.
10. Aarnink AJA, Landman WJM, Melse RW, Zhao Y, Ploegaert JPM, Huynh TTT. Scrubber capabilities to remove airborne microorganisms and other aerial pollutants from the exhaust air of animal houses. Transactions of the ASABE. 2011;54(5):1921-30.
11. https://mosbatesabz.com/mag/how_cold_humidifier_works/. [
12. Norrefeldt V, Mayer F, Herbig B, Ströhlein R, Wargocki P, Lei F. Effect of Increased Cabin Recirculation Airflow Fraction on Relative Humidity, CO2 and TVOC. Aerospace. 2021;8(1):15.
13. Justo Alonso M, Moazami TN, Liu P, Jørgensen RB, Mathisen HM. Assessing the indoor air quality and their predictor variable in 21 home offices during the Covid-19 pandemic in Norway. Build Environ. 2022;225:109580.
14. Olesen BW. Standards for Ventilation and Indoor
Air Quality in relation to the EPBD. rehva journal. january 2011.
15. Lara-Ibeas I, Torresin S, Ricciuti S, Babich F. Hemp concrete walls: evaluation of the relationship between CO2 and TVOC. 2022.
16. Fan M, Fu Z, Wang J, Wang Z, Suo H, Kong X, et al. A review of different ventilation modes on thermal comfort, air quality and virus spread control. Build Environ. 2022;212:108831.
17. Li Y, He L, Xie D, Zhao A, Wang L, Kreisberg NM, et al. Strong temperature influence and indiscernible ventilation effect on dynamics of some semivolatile organic compounds in the indoor air of an office. Environment International. 2022;165:107305.
18. Cabovská B, Bekö G, Teli D, Ekberg L, Dalenbäck J-O, Wargocki P, et al. Ventilation strategies and indoor air quality in Swedish primary school classrooms. Building and Environment. 2022;226:109744.
19. Emhofer W, Lichtenegger K, Haslinger W, Hofbauer H, Schmutzer-Roseneder I, Aigenbauer S, et al. Ventilation of Carbon Monoxide from a Biomass Pellet Storage Tank—A Study of the Effects of Variation of Temperature and Cross-ventilation on the Efficiency of Natural Ventilation. The Annals of Occupational Hygiene. 2014;59(1):79-90.
20. Wang Z, Gao T, Jiang Z, Min Y, Mo J, Gao Y. Effect of ventilation on distributions, concentrations, and emissions of air pollutants in a manure-belt layer house. Journal of Applied Poultry Research. 2014;23(4):763-72.
21. Collignan B, Flori J-P, Kirchner S, Laurent A-M, Le Moullec Y, Ramalho O, et al., editors. Experimental study on the impact of ventilation parameters on pollutants transfer from outdoor air into a dwelling. 22nd annual AIVC conference; 2001.
22. Fang L, Clausen G, Fanger PO. Temperature and humidity: important factors for perception ofair quality and for ventilation requirements. 2000.
23. Nguyen MKD, Imai T, Yoshida W, Dang LTT, Higuchi T, Kanno A, et al. Performance of a Carbon Dioxide Removal Process Using a Water Scrubber with the Aid of a Water-Film-Forming Apparatus. Waste and Biomass Valorization. 2018;9(10):1827-39.
24. Lamb AB, Bray WC, Frazer JCW. The Removal of Carbon Monoxide from Air. Ind Eng Chem. 1920;12(3):213-21.
25. Hassanpour S, Rashidi F, Jamshidi E, Ghoreishi H. Study on the Performance of a New Dynamic Scrubber for Removal of SO2. Journal of Petroleum Research. 2013;21(66):76-82.
26. Kalantar Hormozi M, Ahmadvand AM, Aelami H. A System Dynamics Model to Evaluate Emissions in A Combined Cycle Power Plant. Quarterly Journal of Energy Policy and Planning Research. 2020;6(2):85-113.
27. Zhou X, Desmarais G, Carl S, Mannes D, Derome D, Carmeliet J. Investigation of coupled vapor and heat transport in hygroscopic material during adsorption and desorption. Building and Environment. 2022;214:108845.
28. meter C. High CO2 Levels Indoors Will Surprise You 2024 [Available from: https://www.co2meter.com/en-in/blogs/news/high-carbon-dioxide-co2-levels-indoors.
29. Lu X, Pang Z, Fu Y, O'Neill Z. The nexus of the indoor CO2 concentration and ventilation demands underlying CO2-based demand-controlled ventilation in commercial buildings: A critical review. Building and Environment. 2022;218:109116.
Files
IssueVol 10 No 2 (2025): Spring 2025 QRcode
SectionOriginal Research
Keywords
Air pollution; Indoor air quality; Humidification; Carbon dioxide; Volatile organic compounds (VOCs)Environmental pollution; El Salvador

Rights and permissions
Creative Commons License This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
How to Cite
1.
Malekbala M, Heydari Z, Mousavi SF, Arshian Far Z, Khalilnezhad Z, Rostami R. The effect of cool-mist humidifier on concentration of air pollutants and indoor environmental conditions. JAPH. 2025;10(2):207-224.