Different pathogens are known to thrive in particular conditions , e . g . in places with relative humidity ( RH ) of below 40 % and above 60 %; in dump spaces ; in spaces with poor conditions of lighting ; in places with low levels of ventilation allowing their recirculation in the air and increasing their probability of infecting humans .
Many pathogens also thrive in low temperatures and in places where the materials used in construction and finishes provide conducive environments for their propagation , a case in point is dust mites that breed under carpets .
Healthy Buildings in African Context
In the African context , most of the issues raised in this commentary can easily be dealt with through building regulations . The problem is that most of those regulations are not up to date , and do not respond to the predominant local conditions .
It is quite difficult to maintain building standards specified in the codes in informal settlements , where construction is basic , lighting is compromised and keeping out weather elements is not taken into account .
Ironically , the challenge is also experienced in expensive high-rise office building blocks , where standards for many “ modern innovations ” are missing . Natural ventilation is absent favouring mechanical heating , ventilation and air conditioning ( HVAC ) systems , with no standards to deal with the levels of volatile organic compounds ( VOCs ), which they emit .
Unchecked levels of VOCs can cause eye , nose , throat irritation , headaches , loss of coordination and nausea . It can damage the liver , kidney and central nervous system . Some of these compounds have been proven to cause cancer .
Wall to wall carpets are common in “ big people ’ s offices ” and hotels all over Africa . The carpets allow dust mites to thrive . Poor lighting conditions imply reliance on artificial lighting throughout the day with the challenges highlighted earlier . The buildings are literal green houses where temperatures soar in absence of HVAC systems . Apart from basic accommodation , buildings typologies have already been developed in vernacular architecture in
Africa that take cognisant of prevailing natural environments , including local materials and construction approaches , to provide healthy buildings . An example is Swahili Architecture at the East African Coast . Key elements of this are described below .
Natural ventilation is dealt with through the following strategies : Generous openings , that have been optimized and standardised through thousands of years of practice , that are normally aligned to external air movements of “ Kusi ” but located to be shaded from the more violent northern winds “ kaskazi ” that come with driving rain ; The high “ makuti ” ( palm leaves ) breathing roofs help in air circulation , in and out of the building ; Contemporary designs also include wind driven fans , eliminating the need for air conditioning .
Regulation of Diurnal Temperatures : This is controlled mainly through partial shading on western walls using verandas ; Thick coral walls are key to regulating indoor temperatures , with very low diurnal temperature range ; The “ makuti ” or shaded coral roofs being key to ensuring that the building does not overheat .
Humidity is dealt with through building construction techniques , including : Site location on elevated areas , elevating the ground floors ; Use of lime plaster finish , which is often coloured and smooth , like marble , provides spaces that are easily cleanable , eliminating spaces for pathogens ; Effective plumbing and drainage techniques ( Did you know that some of the earliest plumbing and drainage in buildings on earth was done in the Kenyan coastal town of Lamu , soon after it was established by the Swahili around 1370 AD ?)
Lighting is key in Swahili Architecture , with strategies including the following : Large openings for doors and windows allowing adequate light into the spaces ; Courtyards allow adequate light deep into building interior spaces ; Building orientation ensures sun shading from hostile western sun while allowing the morning softer eastern sun into the spaces . Ambient lighting is mainly from North and South facing openings ; Even in very dense spaces residents have access to the roof , where they can get natural lighting ; Glare is dealt with through a system of sun shading verandas , and louvered , open-able , timber screens over doors and windows .
Lessons for Covid-19
Studies have shown that though environmental factors alone do not explain the spread of Covid-19 , it is a major contributor nonetheless . The unhealthy living and working environments described in this write can help propagate the virus by providing appropriate temperature , humidity , surfaces and circumstances for its propagation .
Further , lockdown in confined homes , compelling people to stay in the same internal environment for extended periods of time would expose the residents to other conditions that would compromise their immunity and make the impacts of the virus more lethal . Such unhealthy environments would provide an infrastructure for spread of the virus .
We note the following highlights in terms of space and the spread of Covid 19 : Smooth surfaces are better as they are easier to clean and the virus may not stick there for too long ; Air recirculation in poorly ventilated surfaces is perfect for the spread of the virus , this is one of the major reasons why the spread of the virus was linked to air travels ; Thermal comfort with low w = swings in daily temperatures from the norm is actually a good deterrent of SARs ; studies have linked drop in temperatures increase in infection rates ; It is understandable that weather alone does not explain the spread , but is a major contributing factor .
As this write up indicates , there are useful insights that one can glean from building construction of vernacular architecture in Africa , which will contribute to healthier buildings . As more research reveals the nature of Covid-19 , this will be a good basis to build on to contribute to eliminating conditions that allow the virus to spread , in addition to eliminating other pathogens and promoting human health generally .
Prof . Alfred Omenya , B . Arch , M . Arch , PhD is an Architect and Urban Development Expert and the Chief Executive Officer of Eco- Build Africa . You can engage him on this or related matters via email at : AOmenya2002 @ yahoo . co . uk .