Air Quality Essentials – A Deep Dive into Air Purification and Its Health Benefits

Air quality is a critical aspect of our daily lives, directly impacting our health and well-being. This article focuses on air purification systems, revealing their essential role in enhancing indoor air environments. By examining the latest advancements in air filtration technology and their health benefits, we provide insights into how these systems contribute to cleaner, healthier living and working spaces. Understanding the connection between purified air and improved health is vital for creating a safer and more comfortable environment at home or work.

Introduction

Air quality is defined as the condition of the air within our surroundings, which plays a pivotal role in our well-being and the environmental balance. 

The human respiratory system is a complex biological mechanism for gas exchange – primarily oxygen intake and carbon dioxide expulsion. When resting, an adult inhales and exhales about 7 or 8 liters of air per minute equaling 10,000 to 12,000 liters daily.(1) This in itself underlines the necessity for clean air for optimal physiological function. The quality of air inhaled directly influences respiratory efficiency and overall health. Read more about the respiratory system from the Biohacker's Handbook's Exercise Chapter.

Globally, air quality varies significantly and is influenced by natural phenomena and human activities. Industrial emissions, vehicle exhausts, and agricultural activities are predominant anthropogenic contributors to air pollution.(2) In contrast, rural areas often experience better air quality, though they are not immune to pollutants like ozone and particulates. This variance underscores the diverse challenges faced in different regions regarding air quality management. 

According to the World Health Organization, Finland has the cleanest air in the world (Tampere, a city in Southern Finland, in particular). The level of airborne particles in Finland is, on average, six micrograms per cubic meter – the lowest level for any individual country. Finland's vast forests play an essential role, as well as countless lakes. Forests cover more than 75% of Finland's land area.(3-4)

Air Quality and Its Health Effects 

Inhaling pure air is fundamental to optimal health and well-being. The absence of pollutants in the air plays a significant role in preventing and mitigating health issues, particularly those related to the respiratory system.(5) According to the World Health Organization (WHO), clean air access is fundamental to a healthy environment and directly influences general well-being.(6)

Source: Activesustainability.com (2019)

Outdoor Air Pollution

Air pollution primarily affects the respiratory system, leading to various diseases, especially when the particulate matter is less than 2.5 micrometers (PM2.5) present for example in smog. These particles enter the lungs and cause inflammation that worsens conditions such as asthma, chronic bronchitis and emphysema.(7-8)  

Long-term exposure to some air pollutants, such as benzene and polycyclic aromatic hydrocarbons, has also been associated with higher lung cancer rates. Epidemiological evidence on outdoor air pollution and the risk of other types of cancer, such as breast cancer is more limited.(9)

Pure air significantly lowers the risk of chronic respiratory diseases. Long-term exposure to cleaner air substantially reduces the incidence of chronic obstructive pulmonary disease (COPD) and bronchitis.(10-11) The absence of harmful particulates and chemicals in the air allows the lungs to function without the stress of filtering out pollutants, thereby reducing inflammation and wear on respiratory tissues.

Numerous studies have linked the improvement in air quality with a decrease in the rates of asthma and allergies.(12-13) Clean air lacks allergens such as pollen, mold spores and pollutants that trigger asthma attacks and allergic reactions, reducing the frequency and severity of these conditions.(14)

Clean air has extensive long-term health benefits, including reduced heart disease, lung cancer and stroke risk. Based on comprehensive research across the globe, improved air quality contributes to longer life expectancy due to the decreased disease burden on the body's vital systems.(15) Increased mortality from all ambient air pollution is estimated at 8.8 (7.11–10.41) million/year globally, with a loss of life expectancy (LLE) of 2.9 (2.3–3.5) years and shockingly, exceeding that of tobacco smoking.(16) 

The psychological benefits of breathing clean air are usually neglected. Environmental psychology research findings prove that clean air can reduce stress levels, alleviate anxiety and reduce symptoms of depression. The assessment of the well-being of the people living in the areas with better air quality was better mental health and higher life satisfaction.(17-18)

Research has also shown a direct correlation between air quality and cognitive abilities. Exposure to higher air quality improves cognitive function, enhances memory retention and increases concentration. Various pollutants can impair brain function, while cleaner air can improve cognitive outcomes.(19) Based on epidemiological studies, air pollution exposure is also linked to dementia.(20)

Indoor Air Pollution

Indoor air pollution is as big a problem as outdoor air pollution. Globally, over four million deaths are attributed to indoor air pollution. Numerous factors influence individual exposure to household air pollutants. These include household elements, combustion of solid fuels, cooking practices, allergens from household pests, dampness and indoor molds.(21-22) High indoor air pollution is influenced by household characteristics, occupant activities, and factors like cigarette smoking, gas appliances, and household products, with air exchange rates negatively associated.(23) 

Mold toxicity seems to be a rising issue and problem in many households, social housing and public structures.(24-26) Mold exposure can cause various human diseases, including asthma, allergic rhinitis and hypersensitivity pneumonitis, through well-defined physiological mechanisms.(27)

Volatile Organic Compounds (VOCs) are carbon-based chemicals that evaporate fast at room temperature. They are commonly found in everyday items like paints, cleaning products, and fuels, as well as in wood and wood-based panels.(28-29)  

VOCs enter the body through inhalation, skin contact, or ingestion, causing cellular damage and physiological disruptions. VOCs pose health risks that vary based on the type and level of exposure. Short-term effects include irritation of the eyes, nose, and throat, headaches and dizziness.(30) Long-term exposure can lead to more severe issues such as cancer, liver and kidney damage and central nervous system disorders.(31-32) VOC exposure may also contribute to the onset and progression of autoimmune diseases by promoting chronic inflammation and immune breakdown.(33) 

Building Materials	Home & Personal Care Products	Activities
Paint, varnishes, caulks, adhesives	Air fresheners, cleaning products	Smoking
Carpet, vinyl flooring	Cosmetics	Dry cleaning, photocopiers
Composite wood products	Fuel oil, gasoline	Cooking, hobbies
Upholstery and foam		Burning wood

Table: Sources of VOCs

• VOCs are found at higher levels in indoor air (10s to 100s of μg/m3) than in outdoor air
• Besides carcinogenicity, VOCs are potent central nervous system toxicants.
• VOCs are metabolized quickly and yield several toxic metabolites excreted in urine
• Up to 38 VOC metabolites can be measured in urine at concentrations of hundreds to thousands of ng/mL
• Urinary VOC metabolites are valuable biomarkers to link the health effects of these chemicals

Source: Li, A. & Pal, V.  & Kannan, K. (2021). A review of environmental occurrence, toxicity, biotransformation and biomonitoring of volatile organic compounds. Environmental Chemistry and Ecotoxicology 3: 91–116.

Volatile Organic Compounds have also been linked to possibly increasing the risk of asthma and allergies.(34) Workplaces with high VOC concentrations, such as auto paint shops, dry cleaners, restaurants and photocopy centers, pose significant health risks, with cancer risks up to 310 times greater than acceptable limits.(35) Among VOCs, trichloroethylene and vinyl chloride are the most toxic and carcinogenic compounds.(36) 

Using low-VOC products and improving ventilation is crucial in minimizing exposure and protecting from adverse health effects.

Technologies for Air Filtration and Purification

Effective removal of chemicals in the indoor environment is critical to human health.  Developing new air filtration technologies has brought several ways to reduce air pollution. HEPA filters are very effective in entrapping airborne pollutants. Active carbon filters have a high capability to absorb gases and odors, while UV light is effective in neutralizing microbial contaminants. Ionizers are based on attracting and neutralizing pollutants by electrically charged ions. Individually, these technologies have unique mechanisms that greatly enhance indoor air quality.(37-39)

Image: Indoor air pollutants and air cleaning technologies.

Source: Mata, T.  et al. (2022). Indoor air quality: a review of cleaning technologies. Environments 9 (9): 118.

Read more detailed descriptions of different air purification and filtration technologies below:

Image: An artistic and visionary view of a future air purifier.

High-Efficiency Particulate Air (HEPA) Filters

HEPA filters operate on interception, impaction and diffusion mechanisms. They are designed to trap particles as small as 0.3 microns with an efficiency of 99.97%.(40) The fibers in the filter are arranged in a complex web that traps and holds particles through physical processes as air flows through the filter.(41) HEPA filters are widely used in household air purifiers. They are highly effective at capturing airborne particles, including dust, pollen and pet dander – thus HEPA filters are often recommended for people with allergies or asthma.

Activated Carbon Filters (ACF)

These use a form of carbon processed to have tiny, low-volume pores that increase the surface area for adsorption or chemical reactions. ACFs are particularly effective in removing volatile organic compounds (VOCs), odors and gases from the air through adsorption, where pollutants adhere to the surface of the carbon particles. They are especially effective at reducing home odors, smoke and chemical vapors.(42-43)

Ultraviolet (UV) Light Purifiers

UV purifiers have short-wavelength ultraviolet light (UV-C light) to kill or inactivate microorganisms by destroying nucleic acids and disrupting their DNA, preventing them from performing vital cellular functions. UV purifiers inactivate airborne pathogens and microorganisms, like bacteria and viruses. This technology often combines with other filtration methods to ensure comprehensive air purification.(44)

Ionizers (ionic air purifiers)

Ionizers emit (negative) charged ions into the air that attach to particles and microbes. Charged particles are then attracted to oppositely charged surfaces (like walls or floors) or each other, forming larger particles that filters can more easily trap. The latest scientific evidence shows that negative air ions, including ultrafine PM, could efficiently remove particulate matter (PM). The latest innovations in ionization technology have focused on reducing ozone emissions to safe levels (ozone is a byproduct of the ionization process).(45-46)

Photocatalytic Oxidation (PCO)

PCO technology combines UV light with a photocatalyst, typically titanium dioxide, to produce hydroxyl radicals. These highly reactive radicals oxidize bacteria, viruses and VOCs into harmless substances like water and carbon dioxide. Some advanced air purifiers available to consumers incorporate PCO technology.(47)

Electrostatic Precipitators

These devices use an electrical charge to collect particles from the air. Air is drawn through an ionization section where particles receive a charge. The charged particles are then attracted to a series of plates with an opposite charge, effectively removing them from the air stream. Electrostatic precipitators are less common than HEPA filters but are also available for home use.(48)

Some studies have found adverse health effects when using electrostatic precipitators, such as modifying cardiorespiratory function associated with negative air ions – this fact may outweigh the potential benefits from PM reductions. Electronic filters may also generate dangerous charged particles or other pollutants.(49-50)

Smart Air Purifiers

Smart Air Purifiers use IoT (Internet of Things) technology and can be controlled remotely. Settings can be adjusted based on real-time air quality readings. They often feature advanced sensors and algorithms to optimize purification efficiency and energy use. With the rise of smart home technology, smart air purifiers have become popular.(51) 

Ozone Generators

Ozone is a powerful oxidant and, as such, a dangerous substance for humans. While ozone generators are controversial due to potential health risks, they intentionally produce ozone to eliminate bacteria, viruses and odors. Due to ozone's potential respiratory hazards, they are generally recommended for use in unoccupied spaces and are not for consumer use.(52)

Conclusion

The critical importance of air quality to human health cannot be overstated, and the role of air filtration systems in improving it is equally significant. By delving into various air purification technologies, each system's effectiveness and unique benefits in enhancing indoor environments become evident. The strong correlation between clean air and improved health outcomes, including respiratory well-being and overall quality of life, highlights the urgency of addressing air quality issues. As environmental challenges persist, adopting effective air purification methods is a convenience and a necessity for maintaining health and creating sustainable, healthy living spaces. 

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