HOBEL @HOME: HEALTHY AIR QUALITY PRACTICES AT YOUR HOME

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Think about how much time you plan to spend outdoors today? Research shows that we spend approximately 90% of our lifetime in enclosed spaces, while as much as 69% of that time is within the home.1 While cooking, cleaning or even comfortably resting on a sofa, we are exposed to a myriad of tiny and invisible air contaminants, that can easily enter our lungs and put us at risk for health problems. Over the recent decades, indoor air quality has become one of the greatest concerns for human health, being responsible for numerous short- and long-term illnesses that can range in severity. In the most recent global burden of disease study, household air pollution was rated as the third most important cause of ill health for the world’s population!2 This alarming statistics could be attributed to the lack of regulation and awareness around this topic. As a result, our homes have become more dangerous than outdoor spaces, which is also corroborated by the fact that concentrations of common indoor air contaminants can be 2-5 times (and even up to 100 times) higher than outdoor levels.3

Personally, I have been long interested in the intersections between built environment, indoor air quality, and human exposure and health. As an assistant professor at EPFL, I am able to advocate for awareness of how the air that we breathe impacts humans and to offer do-it-yourself simple solutions to the invisible problems of indoor air pollution in your home.

Not sure where to start? Here are the top three strategies at little or no cost to improve indoor air quality at your homes:

  1. Prevention is better than cure.

Max von Pettenkofer (1818–1901), a pioneer of modern hygiene and preventive medicine, once said “If there is a pile of manure in a space, do not try to remove the odor by ventilation − Remove the pile of manure.” Here I echo his point by saying that, without any doubt, the most effective way to curb air pollution at your homes is to eliminate individual sources or to reduce their emissions.

Eliminate combustion. Combustion-related emissions, mostly from cooking and space heating, are often the major and underappreciated sources of air pollution in homes.4 In addition to unavoidable air pollutants emitted from the food itself, cooking-related emissions can be detrimental to indoor air quality through creating harmful combustion byproducts such as carbon monoxide, nitrogen dioxide and small particles. This shouldn’t compel us to abandon cooking, but should encourage us to opt for non-combustion products, for example for induction stoves. Although candles, wood and gas fireplaces have aesthetic benefits, such or any other combustion activities at your home should be avoided.

Choose the right materials. Various chemicals continue to be used in the manufacture of building materials, despite known or suspected health hazards. In fact, an estimated 95% of chemicals largely used in construction lack sufficient data on human health effects.5 As a result, building materials, furnishings (e.g., carpets and furniture finishes), fabrics, cleaning products, paints, sealants and adhesives can all emit volatile organic compounds or semi-volatile organic compounds into the home environments.6 Most of the dangers of chemical off-gassing can be eliminated by proper material selection. Always select those that have low-emission certification labels. Consider also giving up on your carpets – they are warm and cozy, but they often harbor allergens, dust, bacteria, and other pollutants that can affect indoor air quality and cause health problems.7 And finally, remember to trust yourself – if something has a “new smell”, get rid of it or let it air out outside.

Avoid scented products. The best smell is no smell. Air fresheners, incense, personal care products and other commercially available products don’t do any good to our lungs. They emit a bouquet of volatile chemicals and usually serve only to mask rather than eliminate odors. For example, air fresheners emit chemicals such as limonene and pinene that, when mixed with other airborne pollutants, can produce cancer-causing agents.8 Such kind of scented products should be discarded or replaced by unscented alternatives. Personal care products, including spray perfumes, deodorants, nail polish and hair sprays contain chemicals that in reaction ozone produce dangerous secondary pollutants.9 They should be sparingly used, and whenever used, it should be done outdoors or in well-ventilated areas.

  1. To change your life, change your habits.

Even if we do our best to minimize individual sources of air pollution in our homes, there are still many unavoidable ones. The good news is that we can still take several actions to further curb the indoor pollution levels. In fact, human behavior is rated as one of the top three components that affect generation and persistence of pollutants in our homes.10

Let the fresh air in. Did you know that our routine in-home activities and hobbies generate millions and millions of particles and gaseous molecules that could harm our health? Vacuuming, cooking, cleaning, printing, folding clothes and blankets, making a bed, and even walking around and sitting on furniture all increase indoor pollution levels!11 Whenever weather permits, make sure to crack your windows open and let fresh air in. This is especially important to do during high-polluting activities such as cooking or cleaning. Even when you comfortably sleep at night, your metabolism generates carbon-dioxide and other pollutants that could affect the quality of your sleep and next-day performance.12 So keeping at least a tiny bit of a window open (yes, even when weather outside is cold) should be part of your everyday practice. Remember that an open mind is like an open window – it lets the fresh air in.

Make use of exhaust fans. In addition to kitchens, bathrooms are another hot spots of indoor air pollution. Bathrooms can encourage the growth of mold and mildew, which have been associated with allergic reactions and aggravate lung diseases such as asthma.13 Other than window opening, a great way to increase ventilation and help eliminate pollutants from your home is to make use of exhaust fans (they should be installed in your kitchens and bathrooms). Also ensure that your oven, clothes dryer and other appliances are properly ventilated. This simple ventilation strategy should be used not only for kitchens and bathrooms, but also while you are involved in short-term activities that can generate high levels of pollution — for example, cleaning, vacuuming, painting or others. Let the fans run for another 10-15 minutes after you finish your tasks, to minimize any residual air pollution.

Clean and vacuum often. Have you ever noticed that you sneeze while cleaning or vacuuming your home? Although these activities instantaneously increase the amount of dust, allergens and other pollutants in the air, regular cleaning and vacuuming will improve air quality in your home. Consider investing in a vacuum with a HEPA filter or microfiltration bag, particularly if you are sensitive to allergens, dander, pollen or dust mites. Using a standard or water-filtered vacuum cleaner usually just stirs dust up into the air. Also consider wet instead of dry dusting – this is more efficient way to eliminate dust while preventing its escape into the air and landing on already dusted surfaces. Pay special attention to frequently touched surfaces, such as doorknobs, light switches, faucets, phones… A good practice is to wear an allergy mask (e.g. N-95 respirator) during cleaning and vacuuming to minimize inhalation of tiny dust particles. For do-it-yourself enthusiasts, consider making your own chemical-free cleaner. And of course, never do house chores without ventilating with combination of exhaust fans and window openings.

Keep the dirt out. We already know that painting, gluing, sanding, emptying vacuum cleaner bag or any other pollution generating activity should be done outside, whenever possible. One frequently overlooked and undepreciated source of air pollution is us – humans! As we enter our homes, we inadvertently bring in dust particles, including bacteria, pesticides and other toxins on our clothing, shoes and skin from the outside world.14 Studies have found that there is common occurrence of coliforms and Escherichia coli on our shoes owing to frequent contact with fecal material originating from floors in public restrooms or contact with animal fecal matter.15 Other than laundering your clothes (especially new ones before the first use) and shoes with detergent, which eliminates most of bacteria, next time, try to leave your shoes at the door. If asking your guests to take their shoes off at your door seem too strict, consider doing some sort of walk-off entryway systems. As the simplest solution, get two natural-fiber mats, one for outside and the other for inside your main entrance.

Eliminate secondhand smoke. While this seems obvious, in many countries worldwide, indoor smoking persists. Globally, 93% of population lives in countries not protected by 100% smoke-free regulations.16 In the U.S. as many as 44% of people spends time with a smoker each day.1 There is a strong link between exposure to secondhand smoke and adverse health outcomes, such as heart disease, respiratory infections, lung cancer and asthma.17 In addition to nicotine, cigarettes contain about 600 ingredients that form over 7,000 compounds when burned, of which at least 69 are known to be carcinogenic.17 However, if you think that you are protected only because your family member smokes only when you are not at home – you are wrong. The thirdhand smoke (residual chemicals left on indoor surfaces by tobacco smoke) clings to walls, furniture, clothes, bedding, carpets and other surfaces long after smoking has stopped. So, the only way to protect your home from secondhand and thirdhand smoke is to secure a 100% smoke-free environment.

Conduct mold inspections. Water leaks, poor plumbing, and poorly ventilated bathrooms can create standing water in which microorganisms, such as bacteria and mold, can breed. Humidity levels constantly above 60% in the home can easily cause mold growth, which can lead to odors and cause respiratory irritation and allergies in sensitive individuals.18 As many as 36% of homes across Europe, Canada, and the United States are facing mold, mildew, or water damage.19 Exposure to mold has been linked to asthma, bronchitis, hypersensitivity pneumonitis and lung tumor development.20 The key to mold control is moisture control. A good practice is to conduct regular inspections of plumbing, HVAC equipment, ceilings and roofing to identify sources of moisture and potential condensation issues. If you find moisture or mold, immediately address underlying source of moisture and dry or replace contaminated material. If facing high humidity issues, limit vapor intrusion by using a vapor barrier. Whenever possible, try to maintain relative humidity levels within 30-60% to prevent mold growth and to mitigate odor issues.

  • Rely on active technology.

If you followed the first two strategies, you should be pretty much enjoying the clean and healthy air at your home. However, following the advice given will not necessarily provide complete protection in all situations or against all health hazards that may be caused by air pollution. When outside air is polluted or weather conditions are unfavorable for window opening, indoor pollutant levels can easily increase by insufficient introduction of fresh outdoor air to dilute indoor emissions or by not extracting indoor air pollutants from your home. That is the time for the active systems to kick in.

Install mechanical ventilation. If you live in area that is noisy or where outside air is polluted and weather conditions are unfavorable for most of the year, your best bet is to install mechanical supply and exhaust ventilation. In a mechanical ventilation system, which is often combined with heating and cooling into an air-conditioning system, the supply and exhaust air are transported by means of mechanical fans. Although this solution usually scales with your utility bill, it offers several advantages over window opening, such as better control of ventilation capacity, air filtration, humidity control and heat recovery. In polluted areas, air filtration that effectively traps dust and other pollutants in the air is crucial component of the system. However, improperly operated or maintained system has been associated with Legionnaire’s disease and symptoms such as dry eyes, skin and throat irritation, fatigue and headache.21 Make sure to change filters and clean your system regularly, following manufacturer’s specifications.

Use air cleaners. Portable room air cleanings can be used to clean the air in specific areas, but they are generally not intended for whole-house air cleaning. However, they can still be useful for homes in which window opening or centralized mechanical ventilation are not viable options. The use of air cleaners is linked to reduced allergic rhinitis and asthma symptoms.22 The performance of air cleaners varies widely, including those highly effective at particle removal, and others, including majority of table-top models, that are much less effective. The performance also depends on maintaining it according to the manufacturer’s instructions. Depending on your house needs, you can select air cleaning device that filters particles and/or gaseous pollutants or even destroy biological pollutants. For example, carbon filters are designed to absorb volatile pollutants and to remove large particles and ozone from the passing air. The major problem of this type of products is that there is no addition of outdoor air into the space, so they should not be used as “ventilation” devices but should rather be combined with some sort of outdoor air supply.

Monitor your air. Some indoor air pollutants can be recognized by their immediate impacts on our body such as throat irritation or watery eyes. Others, which often fly under our olfactory radar are not necessarily benign. According to EPA, some health impacts like respiratory diseases, heart disease and cancer can show up years after exposure. For example, your homes may be contaminated with colorless and odorless gases such as carbon monoxide and radon which are some of the biggest causes of lung cancer worldwide.23 That is why it is important to install air quality sensors and detectors in your homes. Because air quality can fluctuate throughout the day in every household, real-time monitoring is effective way to promptly fix any deviations in indoor quality metrics to minimize exposure. Our markets are becoming flooded with relatively inexpensive and easy to use multi-sensor modules that can monitor key air quality parameters at your home, such as carbon monoxide, carbon dioxide, volatile organic compounds, particulate matter, etc. These measures will not themselves resolve the issue of air pollution, but they certainly raise awareness and are an important first step towards solution.

References

  1. Klepeis NE, Nelson WE, Ott WR, et al. (2001). The National Human Activity Pattern Survey (NHAPS): a resource for assessing exposure to environmental pollutants. J Exp Anal Environ Epidem, 11 (3): 231-52.
  2. Lim SS, Theo V, Flaxman AD, et al. (2010). A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990–2010: a systematic analysis for the Global Burden of Disease Study. The Lancet 380 (9859): 2224-2260.
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  4. Liu J, Mauzerall DL, Chen Q, et al. (2016). Air pollutant emissions from Chinese households: A major and underappreciated ambient pollution source. PNAS. 113 (28): 7756–7761.
  5. Torgal FP, Jalali S, Fucic A. (2012). Toxicity of Building Materials. Woodhead Publishing, Cambridge.
  6. Wallace LA, Pellizzari E, Leaderer B, et al. (1967). Emissions of volatile organic compounds from building materials and consumer products. Atmospheric Environment 21 (2): 385-393.
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  15. Lax S, Hampton-Marcell J.T, Gibbons S.M, et al. (2015). Forensic analysis of the microbiome of phones and shoes. Microbiome 3:21.
  16. WHO World Health Organization. (2015). Global Health Observatory data, Second-hand smoke.
  17. S. Department of Health and Human Services. (2010). How Tobacco Smoke Causes Disease: The Biology and Behavioral Basis for Smoking-Attributable Disease: A Report of the Surgeon General. Atlanta: U.S. Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health.
  18. Arundel AV, Sterling EM, Biggin JH, et al. (1986). Indirect health effects of relative humidity in indoor environments. Environ Health Perspect. 65:351-361.
  19. Cho SH, Reponen T, LeMasters G, et al. (2006). Mold Damage in Homes and Wheezing in Infants. Annals of Allergy, Asthma & Immunology. 97(4):539–45.
  20. Pettigrew HD, Selmi CF, Teuber SS, Gershwin ME. (2009). Mold and Human Health: Separating the Wheat from the Chaff. Clinical Reviews in Allergy & Immunology 38(2-3):148–55.
  21. Mendell MJ, Lei-Gomez Q, Mirer AG, et al. (2008). Risk factors in heating, ventilating, and air-conditioning systems for occupant symptoms in US office buildings: the US EPA BASE study. Indoor Air. 18(4):301-16.
  22. Hacker DW, Sparrow EM. (2005). Use of air-cleaning devices to create airborne particle-free spaces intended to alleviate allergic rhinitis and asthma during sleep. Indoor Air. 15(6):420-431.
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