How do air purifiers help reduce stress?

Scientific interest in the link between air pollution (indoor and outdoor alike) and mental health has grown within the last decade. Studies have begun focusing their efforts on determining the impact of air pollution exposure on brain health, finding that air pollution leads to a variety of psychological disorders including dementia, anxiety, depression, fatigue, and stress. The latter is a subject of growing importance. What is stress? How does air pollution contribute to its onset? How can an air purifier benefit those suffering from stress? Read on to learn more.

A stressed man sitting on a bench

What is stress?

Stress is often associated with the feeling of mental tension or worry that is caused by situations that are difficult. More generally, stress is the body’s response to demands that require more effort than usual1. The feeling of stress is a natural response to everyday life challenges or events that we do not feel able to control or manage2.

Everyone has a different relationship with stress and, thus, different symptoms when it occurs. We all experience it to some degree, but for some individuals, it can be a crippling emotion that severely impacts quality of life and longevity.

What are stress hormones?

When a stressful situation occurs, the information is first sent to the amygdala. This is the part of the brain where emotions are processed. Upon interpreting the information, if the brain senses that the situation is dangerous, distress signals (stress hormones) will then be sent to the hypothalamus. Referred to as the brain’s ‘command centre’, the hypothalamus uses the autonomic nervous system to communicate with the rest of the body. The two components of the autonomic nervous system – the sympathetic and parasympathetic systems – balance the body’s ability to react to a stressful situation by initiating ‘fight or flight’ in response to a stressful situation, then ‘rest and digest’ to calm the body back down afterwards3.

What are the main stress hormones sent out by the body? The body releases three main stress hormones: cortisol, epinephrine (adrenaline), and norepinephrine.

  • Cortisol: this hormone slows down all non-essential functions when the body is experiencing a ‘fight or flight’ response, like suppressing the digestive system
  • Epinephrine (adrenaline): this hormone is released in large amounts in stressful situations, boosting your energy levels by increasing your heart rate and blood pressure and enabling you to ‘flight’ if warranted
  • Norepinephrine (noradrenaline): this hormone is released in smaller quantities and increases alertness and vigilance1,4

Chronic exposure to stress hormones

Long-term exposure to stress hormones, especially catecholamines (which include epinephrine and norepinephrine), impacts many aspects of human health. It may lead to increased risk of anxiety, depression, digestive problems, chronic pain, headaches, heart disease, problems sleeping, and problems with memory and concentration4.

A stressed woman looking at her laptop

PM2.5 and stress

Particulate matter, especially PM2.5, and ozone at home and in the office are considered to be the two airborne pollutants that have the greatest impact on morbidity and mortality. In fact, the Global Burden of Disease estimates that 4.2 million people die every year as a result of particulate matter exposure and 254,000 deaths as a result of ozone exposure.

Air pollution impacts nearly all of the systems in the human body: respiratory (increasing the risk of causing and aggravating respiratory diseases and conditions like allergies), cardiac (increasing the risk of  causing and aggravating heart conditions), reproductive (increasing the risk of infertility), metabolic mechanisms, and neurological, to name a few, though studies suggest that ‘the societal impact of air pollutants may actually be greater than currently appreciated’5.

PM2.5’s impact on human stress levels

Recent scientific studies have shown that particulate matter (PM) exposure may act as stressors, causing the body to elicit stress responses. More specifically, high PM2.5 exposure in our indoor and outdoor spaces activates the hypothalamus-pituitary-adrenal and sympathetic-adrenal-medullary axes6. Exposure to PM2.5 leads to higher blood pressure, insulin resistance, and other biomarkers of oxidative stress and inflammation amongst participants7. This shows that the human body’s central nervous system undergoes changes when exposed to PM.

Another study was performed in 2021 on college-aged students in China. It found that during days of high pollution, students reported a severe prevalence of mental stress. It reported that university students residing in highly-polluted cities were 6.67 times more likely to suffer from severe mental stress8. Similar results were reported in a 2019 study on elderly individuals who reported mood changes and higher stress levels when exposed to higher levels of air pollution9.

How do PM2.5 and stress affect sleep?

High cortisol levels due to air pollution-aggravated stress impact sleep quality, duration, deep sleep abilities, and ability to fall asleep. Chronic stress also leads to dysregulation of sleep patterns and the sleep-wake cycle, even leading to sleep disorders and sleep-related diseases like sleep apnoea and insomnia. Air pollution (including allergens like pollen and dust, but also PM) also leads to higher incidence of allergies, symptoms of which may further impact sleep quality.

Multiple studies have analysed air pollution (especially PM2.5) in causing poor sleep quality. Higher levels of indoor PM2.5 have been linked to lower sleep efficiency10. Additionally, a 2021 study found links between indoor air pollution exposure and sleep disordered breathing in children and adolescents11. Another 2019 study observed that air pollution impacts sleep health across all age groups including otherwise healthy, university-aged students12.

A stressed woman at work

How can medical-grade air purifiers help reduce stress?

The good news is that using a high-quality air purifier to remove indoor air pollution helps significantly reduce stress levels and benefits overall health. Reducing indoor air pollutant particles helps to ease the body’s air pollution-induced stress response.

Reduce levels of stress hormones

Scientific studies have reported that indoor air purification demonstrated short-term reductions in stress hormones, favourably reducing levels of stress in study participants6.

Another study found that interventions like incorporating an air purifier to remove airborne pollutant particles, particularly if it contains a HEPA (high efficiency particulate air)-certified filter, can help protect against many adverse health effects caused by air pollution exposure. According to the study, this includes reducing the effects air pollution has on oxidative stress, insulin resistance, blood pressure, and inflammation. Furthermore, an indoor air purifier helps curtail the activation of the sympathetic nervous system and hypothalamic-pituitary-adrenal axis caused by PM2.5, helping to reduce air pollution-induced stress13.

It is worth noting that not all air purifiers are capable of cleaning fine particulate matter from the air. Air purifiers equipped with HEPA-certified filters are designed to remove 99.97% of all airborne pollutant particles down to a size of 0.01 microns from your indoor air in a single pass, including unpleasant odours if equipped with an activated carbon filter. Air purifiers with filters that claim to be ‘HEPA-type’, although cheaper, do not guarantee the same level of pollutant removal as they do not undergo third-party testing. All Eoleaf devices contain medical-grade H13 filters as part of our proprietary 8-step filtration method, efficiently removing biological pollution (pathogens and allergens like pollen, dust, and mould spores), chemical pollution (like volatile organic compounds, or VOCs), bad odours, and fine particle pollution.

Enhance sleep quality

Naturally, with lower concentrations of air pollution in your indoor space like your home, flat, or office, your sleep quality will improve. Deeper sleep will be achieved including more rapid-eye movement (REM), high-quality sleep. Additionally, by removing toxic airborne chemicals, allergens (like dust and pollen), and odours from your indoor air, unpleasant health symptoms like allergies and disturbances caused by odours will be reduced, further encouraging better sleep.

The soothing effect of fresh air: white noise

The presence of an air purifier not only improves overall well-being, but a bonus feature of an air purifier in the home is its ability to act as a white noise machine. Studies have shown that white noise machines reduce the time it takes to fall asleep by 40% for healthy individuals and also helps babies and children fall asleep more quickly14,15. To reiterate, better, longer sleep leads to lower stress levels.

The Eoleaf difference

We at Eoleaf put your health first. By investing in an air purifier to reduce indoor pollutant and airborne chemical concentrations, you are investing in your overall health (especially your respiratory and cardiac health). Reach out to our team of air quality experts with any questions you may have. Also refer to our in-depth Buying Guide to find the Eoleaf device that is perfect for your needs.

Eoleaf's AEROPRO 100 air purifier


Resources

1 BodyLogicMD. (2022, December 20). What are stress hormones and how do they impact you?. BodyLogicMD. https://www.bodylogicmd.com/blog/what-are-stress-hormones/

2 World Health Organization. (2023, February 21). Stress. World Health Organization. https://www.who.int/news-room/questions-and-answers/item/stress

3 Understanding the stress response. Harvard Health. (2020, July 6). https://www.health.harvard.edu/staying-healthy/understanding-the-stress-response

4 Mayo Foundation for Medical Education and Research. (2023, August 1). Chronic stress puts your health at risk. Mayo Clinic. https://www.mayoclinic.org/healthy-lifestyle/stress-management/in-depth/stress/art-20046037

5 Thomson EM. Air Pollution, Stress, and Allostatic Load: Linking Systemic and Central Nervous System Impacts. J Alzheimers Dis. 2019;69(3):597-614. doi: 10.3233/JAD-190015. PMID: 31127781; PMCID: PMC6598002.

6 Li H, Cai J, Chen R, Zhao Z, Ying Z, Wang L, Chen J, Hao K, Kinney PL, Chen H, Kan H. Particulate Matter Exposure and Stress Hormone Levels: A Randomized, Double-Blind, Crossover Trial of Air Purification. Circulation. 2017 Aug 15;136(7):618-627. doi: 10.1161/CIRCULATIONAHA.116.026796. Erratum in: Circulation. 2017 Sep 12;136(11):e199. PMID: 28808144.

7 Li, H., Cai, J., Chen, R., Zhao, Z., Ying, Z., Wang, L., Chen, J., Hao, K., Kinney, P. L., Chen, H., & Kan, H. (2017). Particulate matter exposure and stress hormone levels. Circulation, 136(7), 618–627. doi:10.1161/circulationaha.116.026796

8 Zhang, W., Peng, S., Fu, J., Xu, K., Wang, H., Jin, Y., Yang, T., & Cottrell, R. R. (2021). Urban air pollution and mental stress: A nationwide study of university students in China. Frontiers in Public Health, 9. doi:10.3389/fpubh.2021.685431

9 Nuyts V, Nawrot TS, Scheers H, Nemery B, Casas L. Air pollution and self-perceived stress and mood: A one-year panel study of healthy elderly persons. Environ Res. 2019 Oct;177:108644. doi: 10.1016/j.envres.2019.108644. Epub 2019 Aug 9. PMID: 31421443.

10 Horvath, E. (2023, April 18). Study links air pollution, heat, noise & more to reduced sleep - penn medicine. Study Links Air Pollution, Heat, Noise & More to Reduced Sleep - Penn Medicine. https://www.pennmedicine.org/news/news-releases/2023/april/sleep-efficiency

11 Liu J, Wu T, Liu Q, Wu S, Chen JC. Air pollution exposure and adverse sleep health across the life course: A systematic review. Environ Pollut. 2020 Jul;262:114263. doi: 10.1016/j.envpol.2020.114263. Epub 2020 Feb 24. PMID: 32443219; PMCID: PMC7877449.

12 Yu H, Chen P, Paige Gordon S, Yu M, Wang Y. The Association between Air Pollution and Sleep Duration: A Cohort Study of Freshmen at a University in Beijing, China. Int J Environ Res Public Health. 2019 Sep 11;16(18):3362. doi: 10.3390/ijerph16183362. PMID: 31514480; PMCID: PMC6766077.

13 Brook, R. D., & Rajagopalan, S. (2017). “Stressed” about Air Pollution. Circulation, 136(7), 628–631. doi:10.1161/circulationaha.117.029688

14 Messineo L, Taranto-Montemurro L, Sands SA, Oliveira Marques MD, Azabarzin A, Wellman DA. Broadband Sound Administration Improves Sleep Onset Latency in Healthy Subjects in a Model of Transient Insomnia. Front Neurol. 2017 Dec 21;8:718. doi: 10.3389/fneur.2017.00718. PMID: 29312136; PMCID: PMC5742584.

15 Spencer JA, Moran DJ, Lee A, Talbert D. White noise and sleep induction. Arch Dis Child. 1990 Jan;65(1):135-7. doi: 10.1136/adc.65.1.135. PMID: 2405784; PMCID: PMC1792397.

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