If you were asking yourself if you should keep your windows wholly shut because of COVID-19, the answer is an emphatic no, open up your windows!
The research tells us that indoor air quality (IAQ) in the average apartment—or home, for that matter—is worse than that of the outdoor air quality, and this usually includes highly polluted urban environments such as Beijing or London.
How often should you air out your apartment? You should air out your apartment daily, between 15 and 30 minutes, because the air inside an apartment is often more polluted than the air outside. Your apartment will contain pollutants arising from cooking, household cleaning products, as well as mold and fungus spores. These factors make it necessary to air out your home apartment every day.
We’re all pretty sure that many will remember 2020 as the year of the virus since the world has talked about little else. Social distancing, constant handwashing, and lockdowns have been the order of the day.
While trying to minimize the threat of contagious airborne viruses, you could be causing more harm than good by not ventilating your home. In this article, we’ll explain how often you should ventilate your apartment.
So, What About The COVID-19 Issue?
The concern may be that by living in fairly close proximity with others in an apartment environment, opening one’s windows and doors to ventilate an apartment may be opening you up to the spread of the virus.
What are the chances of infected droplets wafting through your windows or front door and landing in your apartment? The straight answer to that is that no one knows for sure.
The virus that causes COVID-19 is transmitted mainly through droplets when an infected person coughs, sneezes, or speaks. This virus may remain active for a few hours or a few days—no one knows at this stage.
Hence the importance of regular handwashing, avoiding touching your face, and disinfecting surfaces of high contact, such as TV remotes, door handles, mobile phones, and so on.
Beyond these basic precautions, it depends on how germophobic one is as to whether you’re going to attempt to seal yourself off from the rest of civilization.
Why Ventilate?
There are perhaps three main reasons to air your home daily.
First, to allow volatile substances from furnishings, electronics, and cleaning materials to disperse
Second, to disperse bad smells from cooking, and other combustion (smoking, fireplaces, candles)
Third, to disperse moisture and humidity, which accumulates from the kitchen, bathroom, and our breathing and perspiration.
If not allowed to disperse, this humidity accumulates in closets, on walls, and cold surfaces as condensation, causing mold and fungus.
For the same reasons, bedding should be aired as often as possible, preferably by doing as the Italians do—hanging it out the window. However, this usually presupposes a sunny climate.
Sunshine has a natural bleaching effect from the ultraviolet rays — which is why colors fade in sunlight — and is a powerful natural disinfectant without the use of the harsh chemicals that go to make household bleach.
In fact, air-drying is the safest and healthiest way to dry most items, hence the popularity of the “airing closet” in many UK homes.
This space accommodates the geyser or hot water tank for the apartment or home and provides a useful and low-cost means of air-drying damp clothing. It is also a convenient storage space for towels and linen, keeping them dry and fresh.
Main Sources of Home Air Pollution
It may not be pleasant to think of one’s apartment—your home—as being polluted. The fact of the matter is that it is.
Most researchers agree that the quality of the indoor air in most dwellings is lower than the outdoor air quality — up to five times worse than outdoor air quality (source)
This is not only true of homes. A 2018 study of some London schools found that children were exposed to higher levels of damaging pollution inside the classroom than without.
The study conceded, however, that the pollution was primarily caused by outdoor pollution from motor vehicle exhausts penetrating the buildings, and that the problem would not be resolved merely by opening and closing windows and doors.
The sources of the pollution itself needed to be eradicated, so what are the main causes within the home?
Indoor air pollution is not always as readily understood—or recognized—as outdoor pollution, which tends to be more visible as with exhaust smoke belching from a semi-trailer, or pollution from an industrial smokestack or coal-fired power plant.
Since we spend up to 90% of our time indoors, it is as well to pay attention to what may be polluting the air we breathe.
The sources of indoor pollution are many and varied. Some are obvious and spring readily to mind: tobacco smoke and some domestic cleaning solutions such as ammonia and caustic soda, for example.
Others are less obvious or visible: ozone, nitrogen oxides, bio-aerosols, spores, fungus, and mold in places that accumulate dust and damp such as closets and bathrooms.
Floor and wall coverings, shower curtains, glues and fabrics used in the making of furniture, adhesives, toys, cosmetics, and pet dander — microscopic flecks of skin and hair shed by cats, dogs, and other furry and feathered pets — are also familiar sources of household pollution.
Their impact on health also varies depending on one’s susceptibility to allergies and respiratory diseases such as asthma, and most household pollution can be kept at bay by a regular regime of cleanliness, hygiene, and avoidance (source).
The age of the building is not always a defining factor in whether or not the air is polluted provided that it is adequately ventilated, either naturally by opening windows and doors or artificially via an HVAC (heating, ventilation, and air conditioning) system.
A study of older buildings in China, however, found that fine particulate matter (PM2.5) was able to enter older homes at a faster rate and that these fine particles have a more damaging effect on health since they’re able to enter the lungs and bloodstream (source).
The World Health Organization has found that complications from breathing dirty indoor air accounts for over four million premature deaths each year, mostly in developing countries that are still reliant on coal and wood for indoor heating and cooking.
If you are in the habit of stoking up a roaring log fire on a winter’s evening, you would be well advised to ventilate your home the next morning.
A log fire will not only expel poisonous gases which build up in the closed environment through combustion but also ventilate the odor of wood and coal smoke, which is an inevitable consequence of those cheerful hearths.
The effects of air pollution can be just as damaging from your daily cooking activities on a gas stove if not adequately ventilated.
Gas cooking generates nitrogen dioxide and carbon dioxide. Unless occupants expel these gases outside—usually through a range hood—they will breathe these in to irritate the lungs, in much the same way as car exhaust does.
The same caution applies to some cleaning products containing VOCs (volatile organic compounds), air fresheners, personal care products—even scented candles.
Be particularly careful of the build-up of these compounds in closets where these products are stored.
Read the labels. In a very real sense, ensuring that your apartment is hygienically clean using these products may be damaging your health in other ways.
How Long Should We Ventilate For?
It is clear from this that regular ventilation of your living spaces with fresh outdoor air is crucial to health.
The evidence indicates that as short a time as 5 to 15 minutes a day—up to an hour, weather permitting—may be enough to ventilate an apartment adequately.
This ventilation simply entails opening a window or windows on opposite sides of the apartment—or the front door—to create a through-draft of fresh air throughout the apartment.
Take a look at this article for more details on how long it takes to exchange air in a house.
What about the Weather?
Weather is a factor in airing your apartment, of course, and may explain the reluctance to expose one’s snugly heated apartment to the sometimes below-freezing elements outdoors.
Just remember that 15 minutes a day may be all that is needed, preferably before 9:00 a.m. or after 5:00 p.m. when outdoor air quality is optimized.
The same reluctance to open up to the outside world applies in warmer climes where outdoor temperatures may rise above 104°F daily.
In that case, the thought of allowing that hot, humid, and dusty outdoor air into your air-conditioned apartment seems like a bad idea.
Common sense is needed, of course. You’re not going to air your apartment in the middle of a winter blizzard or when there’s a desert dust storm engulfing the apartment.
Is Sick Building Syndrome Real?
Much has been written and debated since the advent of high-rise buildings, particularly those that are fully sealed off from the outside and reliant on ducted air-conditioning, over sickness in buildings.
Most of the debate centers around whether entire buildings can become “sick” and pass on their ailments to those living and working in them.
The various descriptions for these effects include “sick building syndrome” (SBS) or the complementary “building-related illness” (BRI).
Much of the myth surrounding SBS is just that: urban legend. In the majority of cases, the ill effects of poorly ventilated buildings are a result of inadequate maintenance and repair or defective materials (source).
The cure is simply to improve the indoor air quality (IAQ) of the building or remove toxins such as laminate flooring in the home or deteriorating fiberglass structures in the HVAC system.
Contractors install increasingly sophisticated HVAC systems in modern high-rises, and government and industry legislation has kept pace with—and led—the drive for clean and safe building environments, including air quality.
These HVAC systems include air purifiers and filters, which ensure that they do not continuously recirculate stale, used air throughout the building.
Ducted air-conditioning provides a clean, dry (non-humid) source of ventilation.
The air has passed through a series of HEPA (High-Efficiency Particulate Air/Absorbing/Arrestance) filters and purifiers while providing a temperature- and climate-controlled living environment.
HEPA is the industry efficiency standard for air filters, ensuring the removal of 99.97% of air particles from the air-conditioning system.
One may miss the idea of being able to open a window to get a breath of fresh air, but the air that you breathe in a high-rise is probably as fresh and clean as it’s going to get.
Nevertheless, it is true that, without proper routine maintenance, there is a danger that filters may become clogged and unhygienic, leading to health issues for those who suffer from respiratory ailments.
The stringent building regulations and health safety and environmental (HSE) legislation of today are, in most cases, enough to ensure that your apartment air is safe to breathe.
The impact of living in a sealed environment where you can’t open a window may be more psychological than physical.
But it’s also not enough to simply open your windows or doors for some time to let in some fresh air. Ventilation also applies to spaces that might usually remain closed, such as closets and cabinets.
Are your clothes neatly folded on a shelf? When last did you remove them, shake them out—or even wear them?
Clothing stored in a closet, especially in a humid climate, may accumulate moisture, leading to fungi and mold. Mold is often first noticeable on shoes in a closet, so make sure that closets are aired regularly too, or install a dehumidifier.
Fans are an excellent aid to getting air to circulate freely in confined spaces such as closets—or if you can’t open a window or two.
Open up the closet doors, turn on the fan, and make sure that you rotate your clothing and linen regularly to ensure moisture and dust are not trapped or accumulated amidst infrequently used items.
Ventilating in Extreme Climates
Ventilating an apartment in excessively cold and hot climates presents similar but opposing challenges. Both environments discourage the occupant from opening up a window to allow fresh air to enter and stale air to escape.
Despite the advances in interior climate control achieved in recent years, scientists still advocate the benefits of allowing the exchange of fresh air from the outside.
Let’s look at a few examples where this challenge has been overcome.
The UAE: Masdar City and The Burj Khalifa
The United Arab Emirates (UAE) is best known for glitzy Dubai and its shopping malls, but the summer months of May through September can be punishing for their heat and dust.
Averaging 104°F with high humidity, keeping an apartment cool and fresh is a challenge.
Masdar City is an eco-friendly sustainable development just outside the capital city of Abu Dhabi, which aims to achieve carbon-neutral status by its completion in 2025.
One central feature of the development is a vast wind tower, a traditional Arabic structure still to be seen in many of the older dwellings alongside Dubai’s historic Creek area (source).
The open-ended tower captures air and funnels it down the center, forcing cooling air into the dwelling.
The build-up of positive pressure inside the tower automatically creates negative pressure on the outside, drawing that stale air away.
The same principle operates in many sealed-building air conditioning systems by pushing fresh air into the building and sucking used and stale air out.
The 150-feet Masdar City tower, combined with a cooling mist of spray, is used effectively—and sustainably—to reduce the ambient temperature in the central plaza of the city by as much as 40°F.
In a city like Dubai, where artificial air conditioning accounts for as much as 70% of electricity consumption in summer, this return to more natural ventilation and cooling is a welcome and healthier innovation.
While air-conditioning provides immediate reduction of indoor temperatures, wind towers fulfill a different function of eliminating the constant build-up of CO2 and reducing stuffiness—exactly what air-ventilating your apartment is designed to do.
Somewhat ironically, the tallest building in the world, the iconic Burj Khalifa (translation: Khalifa Tower) in the neighboring Emirate of Dubai, uses ice-chilled water—rather than air—to cool the building.
There are, however, four air-cooled chillers to support the data centers as a back-up, if needed.
Amazon’s Seattle Offices
On the other side of the world, and in a climate utterly opposite to the UAE, the company Amazon uses the heat generated by its data center across the street to heat its Seattle offices.
The positive impact on ventilation is mostly in terms of pollution prevention: Amazon claims that the recycling of waste heat will save sixty-five million pounds of coal-burning CO2 emissions.
Final Thoughts
If you’re worried about the wasted cost of reheating or cooling your apartment after opening a few windows, remember that the airing time is short (weather permitting).
The benefits of a cleaner environment—less mold, fungus, moisture, dust—are also significant health-wise.
These benefits are not only physical: after living for a while in a sealed apartment, the thing you’ll probably miss the most is your ability to open a window and let in some fresh air quickly.