It’s a good question. Due to the potential of higher concentration levels indoors, indoor pollution may impact health more than outdoor pollution. This has been mentioned in numerous studies. While many people associate pollution primarily with outdoor environments, the overlooked dangers of indoor pollution can significantly age the body. This includes the skin. This article explores the sources of indoor pollution, its effects on your health, and practical ways to minimise the pollution and its ageing effects.
Cooking
Table of Contents
Whenever anything is heated, it has the potential to give off particles, fumes, gases and smoke. When you think of being in the kitchen, you will know where some of these things come from, but there are plenty of sources you probably did not consider. Let’s start with what the food is cooked with.
Cooking With Gas
In a 2023 study, cooking on gas was linked to an increased incidence of asthma (1). When you consider burning gas can give off Nitrogen oxides (NOx) and volatile Organic Compounds (VOCs), such as Benzene, Toluene, Ethylbenzene, and Xylenes, alongside the possibility of Polycyclic Aromatic Hydrocarbons (PAHs). It would be logical to think that other diseases may also result from burning gas indoors.
Towards the bottom of the page, we list all the chemicals mentioned in this article and explain their health implications.
Advice: Open windows and turn on extractor fans when cooking with gas, even when warming up the oven. Look to stop cooking with gas when possible.
Cooking with Solid Fuel
There have been warnings around for a while about open fires and wood burners. The same warnings hold weight for solid wood stoves. You might think they are sealed, with all the smoke and the rest of the pollutants going up the chimney. This is mostly the case, but opening the door to add more wood releases many toxic chemicals. We do not know how all the chemicals present in wood smoke affect our skin, but at least the following four are known to have detrimental consequences to it:
- Particulate Matter (PM2.5)
- Polycyclic Aromatic Hydrocarbons (PAHs)
- (VOCs)
- Nitrogen Oxides (NOx)
Wood smoke also contains:
- Carbon Monoxide (CO)
- Formaldehyde (A type of VOC)
- Benzene
- Acrolein
- Methane
- Dioxins
We came across two linked Chinese studies that found that women cooking indoors with solid fuel were linked to a more severe facial wrinkle appearance (2) and an increased risk of fine wrinkles on the back of their hands, independent of other factors. When considering the possibility that Chinese households may have less ventilation and use more coal, you could discount this as not affecting you too much in the UK. It’s still worth knowing. When opening the door, your solid fuel AGA may just be giving off more airborne pollution than you think.
Hazardous air pollutants, such as carbon monoxide, volatile organic compounds, nitrogen oxides, benzene, and formaldehyde, pose serious health risks. Particle pollution, in particular, is concerning as these minuscule particles can penetrate deep into the organs.
Advice: Avoid cooking with solid fuel where possible. Ventilate when opening fuel doors. Use seasoned wood for less smoke. Service equipment regularly. Install carbon monoxide detectors. Avoid petroleum products for fire starting. Reduce fuel loads for better combustion. Never burn treated wood.
The Cooking Itself
Frying and roasting foods, especially at high temperatures, can generate substantial amounts of fine particulate matter (PM2.5) and ultrafine particles (UFP). These particles can have organic substances like polycyclic aromatic hydrocarbons (PAHs) adsorbed on their surface, which are known to cause skin ageing.
Certain cooking methods, such as grilling, frying, or broiling meat at high temperatures, can form heterocyclic amines (HCAs). Animal studies have shown that HCAs can cause DNA changes that could lead to cancer.
Cooking, especially frying, can produce gaseous pollutants such as formaldehyde, acetaldehyde, and acrolein.
Burning food, like toast, can release smoke and fumes, contributing to indoor air pollution.
Advice: Avoid cooking at high temperatures to minimise the formation of harmful pollutants and carcinogens like PAHs and HCAs. Favour steaming, boiling, or using a slow cooker over frying, grilling, or baking to reduce exposure to toxic compounds. Ventilate properly. Monitor cooking closely to prevent food from burning. Keep stoves clean to prevent the buildup of greases and residues that can smoke when heated.
Oven Cleaning
If you have a pyrolytic oven, also known as a self-cleaning oven, you will know it gets very hot. Hot enough to burn everything and leave you with a light sooty residue to wipe down. They are a great time-saver, but If you use one and the oven is reasonably clean in the first place, you may not notice the burning smell, and you may not think to put on the extractor fan as you would when cooking.
Advice: Try to avoid the self-clean option. If you do use it give the oven a clean first. Time the clean to allow for more ventilation and fewer people in the kitchen when using the self-clean setting.
Gas Heating
Gas boilers will have flues to remove the pollutants released by burning gas. This is not the case with open gas fires. As with gas cooking, these fires release harmful chemicals into your indoor living space. To make matters worse, using these fires does not usually go hand in hand with ventilation.
Advice: Avoid open gas fires where possible. Service them regularly. Ventilate. Install carbon monoxide detectors.
Solid Fuel
Open fires are not so common these days, but anyone who has been in a room with one will tell you that not all the smoke goes up the chimney. Log burners are better, but as with the wood stove above, the opening of the doors can cause a plume of airborne pollutants to enter the room.
Advice: See Cooking with Solid Fuel above
Household Products
Cleaning chemicals and air fresheners are major culprits for indoor pollution. These products release harmful substances into the air, harming your health and skin.
One of the main pollutants emitted by these household products is VOCs. In a November 2023 U.S. study, (3) researchers found 530 VOCs across 28 cleaning products and two air fresheners. Another concerning group of chemicals found in these products are phthalates. Phthalates are used as plastic softeners and to hold fragrances. Animal studies have linked phthalates to hormonal disruptions.
When air freshener chemicals react with ozone, they form secondary pollutants such as formaldehyde, secondary organic aerosol (SOA), oxidative products, UFP. These pollutants can damage the central nervous system, alter hormone levels, and adversely affect the pulmonary and cardiovascular systems.
Cleaning products and air fresheners release other hazardous substances like acetaldehyde, acetone, picric acid, methyl vinyl ketone, and p-dichlorobenzene. Continuous or high-level exposure to these chemicals can pose significant health risks.
Exposure to these indoor pollutants has been associated with:
- Aggravated asthma and reduced lung capacity
- Respiratory symptoms and sensory irritation
- Dysfunction of the lungs
- Migraine headaches and breathing difficulties
- Neurological problems
- Even cancer in high doses
It’s important to note that while individual exposure to these pollutants may be low, the ubiquity of cleaning and air freshening products can lead to continuous indoor exposure, potentially worsening reactions over time. Certain populations, such as infants, custodial workers, and those with asthma or allergies, may be more susceptible to the adverse health effects of these chemicals.
For those thinking that ‘green’ products might be lesser polluters, 2023 research indicates that while green cleaning products emit a different composition of VOCs, they are not necessarily safer regarding their impact on indoor air pollution than conventional products. (4) More harmful VOCs, such as terpinoline, were present in the non-green products. Both standard and ‘green’ cleaners contribute to the indoor emission of VOCs and the generation of secondary pollutants, with variations depending on the specific VOCs emitted. The study in question calls for more comprehensive regulations and clearer consumer information to help mitigate the potential health and environmental impacts of cleaning product emissions.
Advice: Go back to the old school with cleaning products. We are talking bicarbonate of soda, vinegar, lemon and others. If you have to use commercial products, read the label. Ventilate when cleaning. Break up from air fresheners and use natural as much as possibl
Candles and Indoor Pollution
Candles deserve a section all to themselves. When burned, candles, especially scented ones, will contribute to indoor air pollution. While they provide a pleasant ambience and aroma, they also release potentially harmful substances into the air.
When candles are lit, they release (VOCs). The emissions from paraffin candles contain many of the same toxins produced by burning diesel fuel.
In addition to VOCs, candles produce soot, a mixture of carbon, aerosolised chemicals, and tar-like substances. Soot can contaminate the air and even enter the bloodstream, potentially contributing to neurological and other issues.
Scented candles, which often contain synthetic fragrances and phthalates, can be even more problematic. These additives can cause allergic reactions and hormonal disruptions in some individuals.
While occasional candle use is unlikely to pose significant health risks for most people, those with sensitivities, allergies, asthma, or other respiratory conditions may want to limit their exposure. Burning too many candles in an unventilated space can exacerbate the negative effects.
Advice: Go for candles made from natural waxes like soy or beeswax instead of paraffin. Choosing unscented candles or those scented with natural essential oils. Trim wicks. Again, ventilate.
Personal Care
Nail Polish
Nail polish and removers can contain VOCs. Although the levels you might be exposed to at home are small compared to nail salons, they will nonetheless contribute to your overall toxic load. Many studies have quantified the health problems of working in a nail salon. If you work in one or visit regularly, ensure they have good ventilation or don’t use them.
Advice: Read the labels. Look for 3,5,7 free. Read the documentation online to make sure they have not replaced one ingredient with another questionable one. There are reports online of this kind of thing. Ventilate when using.
Makeup and Fragranced Products
Fragranced products contain chemicals extremely difficult to quantify. Questionable products are everywhere. Even though we are supposed to follow EU directives in the UK, the situation is unclear exactly what is in fragranced goods and what is allowed. Greenpeace stated in 2014 that at least 36 perfume brands contained chemicals that were both hazardous to health and the environment. In January 2023, the Independent reported that makeup brands used forever chemicals in their products. One brand, Revolution, was found to contain these and also stated that they were compliant with UK and EU regulations.
Advice: Stay informed. Seek brand transparency. Limit use.
Building Materials
VOCs are in all sorts of building materials, including paints, varnishes, glues, new carpets, and probably a lot more. These products undergo a process of ‘off gassing’, meaning the VOCs are released into the air and turn to gas. This might go on for years, depending on the product. Carpets, which used to give off a lot of VOCs, have cleaned up their act and have cut down on VOCs, but this may vary from country to country. Painted or varnished items may give off VOCs for some months after their initial use.
Advice: Look for low-VOC products. Ventilate, especially so with new products. Lean towards natural materials.
Furniture
Mattresses and sofas can emit VOCs. Polyurethane foam, commonly used in these products, is a significant source of VOC emissions. There are many studies around this. One study showed that under simulated sleeping conditions, such as higher temperature and humidity, VOC emissions from mattresses increase significantly, raising concerns about exposure levels, particularly for sleeping children and infants.
Advice: Try to find low-emission furniture and items using natural materials.
Mould
Mould is considered an environmental stressor and a potential allergen. We found no link between skin health and mould except a study suggesting mould is a trigger for atopic dermatitis. The complex and delicate physiological processes involved in skin health could easily be upset by mould in your environment.
Advice: Control humidity. Use dehumidifiers to control moisture and prevent mould growth. Dry down bathrooms. Encourage air movement.
Electrical Devices
Electrical devices in the home and elsewhere emit VOCs, including formaldehyde, xylene, and benzene. Electrical cooking devices can also emit particle matter. Printers and photocopiers should only be used in ventilated areas as they can emit UFP, ozone, and VOCs. Many studies have looked into the health aspect of printers, some showing minor physiological changes, although not clinically relevant.
Advice: Check omissions for your exact devices. Try not to use them in living areas. Ventilate when using. Limit use. Keep them free from dust to increase efficiency.
Take a Comprehensive Approach to Your Air
Simple measures such as ensuring proper ventilation, regularly cleaning the home, using low-VOC products, and maintaining a healthy humidity level can go a long way in protecting the skin from the damaging effects of indoor pollutants. Investing in a high-quality air purifier with HEPA and activated carbon filters can help remove particulate matter, gases, and VOCs from the air, further reducing the skin’s exposure to these harmful substances. Taking a comprehensive approach to indoor air quality management. Your body and also your skin will thank you for it.
| Indoor Pollutant | Effects on Skin Health |
|---|---|
| Particulate Matter (PM2.5) | – Penetrates the skin or can be inhaled – Leads to oxidative stress – Accelerates skin aging by damaging collagen and elastin |
| Polycyclic Aromatic Hydrocarbons (PAHs) | – Activates receptors in the skin – Leads to inflammation and oxidative stress – Contributes to the degradation of collagen and elastin |
| Volatile Organic Compounds (VOCs) | – Generates free radicals – Causes oxidative damage to skin cells and tissues – Potentially leads to premature aging |
| Nitrogen Oxides (NOx) | – Interacts with other pollutants to form ground-level ozone – Depletes antioxidants in the skin – Causes oxidative stress, contributing to skin aging |
| Ozone | – Causes oxidative stress in the skin – Leads to inflammation and premature aging – Weakens the skin barrier |
| Phthalates | – Disrupts the endocrine system – Potentially leads to hormonal imbalances – May affect skin health, such as increased sebum production and acne |
References
- Gruenwald T, Seals BA, Knibbs LD, Hosgood HD III. Population Attributable Fraction of Gas Stoves and Childhood Asthma in the United States. International Journal of Environmental Research and Public Health. 2023; 20(1):75. https://doi.org/10.3390/ijerph20010075
- Li, Miaozhu et al. “Epidemiological evidence that indoor air pollution from cooking with solid fuels accelerates skin aging in Chinese women.” Journal of dermatological science vol. 79,2 (2015): 148-54. doi:10.1016/j.jdermsci.2015.04.001 https://pubmed.ncbi.nlm.nih.gov/26055797/
- Alexis M. Temkin, Samara L. Geller, Sydney A. Swanson, Nneka S. Leiba, Olga V. Naidenko, David Q. Andrews, Volatile organic compounds emitted by conventional and “green” cleaning products in the U.S. market, Chemosphere, Volume 341, 2023, 139570, ISSN 0045-6535, https://doi.org/10.1016/j.chemosphere.2023.139570.
- Ellen Harding-Smith, David R Shaw , Marvin Shaw , Terry J. Dillon , and Nicola Carslaw, Does Green mean Clean? Volatile Organic Emissions from Regular versus Green Cleaning Products. Department of Environment and Geography, University of York, United Kingdom Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, United Kingdom 3National Centre for Atmospheric Science, University of York, York, United Kingdom https://pubs.rsc.org/en/content/articlelanding/2024/em/d3em00439b#!divAbstract
- Oz, Kira et al. “Volatile Organic Compound Emissions from Polyurethane Mattresses under Variable Environmental Conditions.” Environmental science & technology vol. 53,15 (2019): 9171-9180. doi:10.1021/acs.est.9b01557 https://pubmed.ncbi.nlm.nih.gov/31290311/
- Kholodova, I. N.. “Features of external therapy of allergic skin diseases in children.” Meditsinskiy sovet = Medical Council (2022): n. pag.https://www.semanticscholar.org/paper/Features-of-external-therapy-of-allergic-skin-in-Kholodova/b2137692143755cad9995a40e39106960f2b2198
