Category Archives: Environmental Health

A Probable Cause of Asthma

Dear Readers:

It has not been proven what causes asthma in our children, and researchers have not proven the reasons why there has been a dramatic increase in asthma cases worldwide.  So researchers who can find a correlation with other factors often offer their speculative opinions.

In Barbados, incidents of asthma have increased significantly since the 1970’s.  Health researchers have blamed the sub-Saharan African dust and allergens, environmental researchers have blamed pollution, and climate researchers have blamed the climate.

It is very easy and convenient to find a correlation with factors that only God can change.  It allows reputable researchers to go unchallenged and offers no hope to those who are directly affected – mainly the children and their parents.  Since parents are essentially powerless to change the sub-Saharan dust, allergens and the climate, they must resort to treating the symptoms with drugs.

Treating symptoms is not a permanent solution, but it can be an unnecessary lifetime expense.  Therefore, let us turn our attention to this issue in order to bring relief to the sufferers, and to prevent further incidents.

Before we continue, let me note that preparing this article revealed a glaring weakness of peer reviewed documents.  Generally, the reviewer only know as much, or perhaps a little more, of the narrow discipline of their peer, the author.  However, most causal investigations are not confined to only one discipline.  Therefore, single-discipline reviewed research will always be incomplete and substandard.  This should not reflect negatively on the competence of the researcher or the reviewer, but rather, on the effectiveness or the system in which they operate.  I can confidently state that the conclusions of most (if not all) single discipline reviewed causal studies on multi-disciplinary issues that I have read, are as useful as a shoe on a fish.

When trying to solve these types of problems, the most logical place to start is to understand the following.

  • The trend in the number of cases over many years.
  • The variability in cases during any one year
  • The relevant dramatic environmental changes when the symptoms started
  • The relevant environmental changes that increased as the number of cases increased

What environmental factors changed dramatically in the 1970’s across Barbados?  Well, not the climate, not the allergens, and not the sub-Saharan dust.  In Barbados, in was mainly an increase in the construction of concrete-block masonry houses and the purchase of automobiles.

Before, the floors of houses in Barbados were not in direct contact with the ground.  Ground floors in chattel houses and stone masonry houses were normally suspended above the ground as shown below.

House with suspeded floor

Builders constructing concrete-block masonry houses started placing the concrete slab directly on soil as shown below.

Floor on fill

A child sleeping in a room where the floor is in direct contact with the damp soil is not a safe environment.  In recognition of this, national building standards worldwide, including the Caribbean, specified that a Damp Proof Membrane or Vapour Barrier (eg. plastic sheets) be used to prevent moisture from rising through the floor and walls.

Tragically, builders and potential homeowners in Barbados were not made aware of Barbados’ national building standards.  Very few, if any (certainly none that I was aware of before Walbrent College was founded 5 years ago) had a copy of the Barbados National Building Code.  Therefore, either the Damp Proof Membrane was not installed, or it was not installed properly.  In the photo below, the black plastic Damp Proof Membrane is not lapped properly and it is not taped at the laps, allowing moisture to rise.


In the photo below, the Damp Proof Membrane or Vapour Barrier does not extend over the blocks.  Therefore, moisture can rise up the walls.

DPM not over walls

Therefore, all children in single storey concrete-block masonry houses, and all children sleeping in bedrooms that were located on the ground floor of a two-storey house, were in an unhealthy environment.  If they slept in an unventilated room with the room’s door(s) and window(s) closed, then the risk of harm increased significantly.

 Supporting A Plausible Solution

At this point, the significant increase in the number of houses with the floor in contact with the ground is plausible.  Now, let us see if the trends of asthma cases support our proposition.

Since there is increased rainfall in the rainy season of May to October, the ground floor and walls of houses would normally be damper than during the drier season.  The statistics show that there is an almost doubling of asthma cases in the wetter months of May to October.

Further, the number of asthma cases are always higher in the lower catchment area that drains into the Constitution river, where the water table and damp soil is closer to the surface, than in any other part of Barbados.

While this does not prove causation, it certainly makes ‘concrete slab on ground’ construction method a strong contender.  The proof can come by interviewing the sufferers to see whether they resided in such masonry houses.  It should be noted that poorly installed vapour barriers is reportedly a common problem worldwide.  Therefore, it can explain the general global increase in asthma cases.

Investigating the Increase in Automobiles

For completeness, we should investigate the increase in cars, and thus car exhaust emissions, as a possible cause.  If cars were the reason for the increase in asthma cases, then we would expect to see significantly lower cases in the windward eastern side of the island.  However, generally, there are a higher number of cases per 1,000 people in the better ventilated windward side of the island than on the western side, excluding the Constitution’ river’s drainage catchment area.

Help for All Parents

So what can parents do?  My suggestions follow, which would improve the quality of the interior house environment, even if another reason is later proved to cause asthma.

All new houses should have a properly installed Damp Proofing Membranes (continuous plastic sheet, lapped and taped) under the ground floor slab and walls, to prevent the damp from rising into the house.

All existing houses should have the external walls plastered and waterproofed.  If you are renting, then ask the tenant to do this.  The photo below shows a typical single-storey plastered masonry house.  Note the rising damp areas at the base of the wall.

Plastered house

What you cannot see is that the builder did not plaster all the way to the footings.  Please be advised that this is typical.  Therefore, the walls below the ground are normally damp, and the damp rises into the house – especially if the Damp Proofing Membrane does not extend over the blocks.  Note that the right side of this damp area is drier, only because the soil has been removed.

Unplastered foundation wall

The photo below shows a bituminous waterproofing agent applied to the plastered wall.

Waterproofed wall

I wish you well.

Best regards,


Note: All photos are copyrighted by the author.

Lead in the Balance

Dear Readers:

Three weeks ago I suggested 5 ways in which parents can encourage students who were not performing well academically. However, for the sake of completion, there are several environmental factors that can frustrate the best parental encouragement. One major environmental factor that is known to impair learning is lead, and the likely sources are leaded paint, automobile emissions, and water.

Lead poisoning is easy to misdiagnose since its symptoms are similar to those of other ailments. In young children, they include hyperactivity and headaches. In older children they include irritability, poor muscle coordination, high blood pressure, poor memory and poor concentration. If children are not treated early, it can retard mental and physical development, reduce attention spans, and lead to irreversible brain damage. Testing of blood for lead is available in Barbados, however such tests are reportedly very rarely requested.

Leaded Gasoline
In 1999, the government, in a highly responsible initiative, banned leaded gasoline, thus significantly reducing the risk of direct exposure to lead by students who walked to school along heavily trafficked roadways. However residential and school properties that bounded these roadways could have previously accumulated significant residues of lead. If this lead was not properly removed, then it could negatively affect the health of the residents.

It would be useful for the government to investigate whether a correlation exists between children whose homes lie within 15 metres of a busy roadway, and their academic achievement and complaints of illnesses. It would also be useful for the government to test dust samples around such properties for lead.

Should the investigation reveal a correlation, and should significant lead residues be found, then those currently living, working, and studying in such vulnerable areas should be tested, and if required, treated for lead poisoning. They should also be examined for the harmful effects of other automobile emissions, especially those that cause and aggravate asthma attacks and other respiratory problems.

Leaded Paint
Most paint used in Barbados after the mid 1970’s probably only contained trace amounts of lead. However before that time, the paint could have been heavily leaded. Exposure to lead from lead based paint mainly occurs when the paint deteriorates or is removed improperly, and the dust particles are ingested or inhaled.

The government’s Edutech program, which includes rehabilitating old schools, is a highly responsible initiative. However removing heavily leaded paint is a very dangerous construction activity that can place those near the paint removal activity, their families, and the students and teachers who will subsequently use the school, at severe risk of exposure to lead.

Removing lead based paint should not simply be left up to the Contractor. The Contractor should be made to follow the removal and disposal directives of the Environmental Engineering Department, or internationally accepted protocols in this regard.

Leaded Water Pipes
Prior to around the mid 1980’s, lead pipes were installed to be convey water to houses and schools in Barbados. In a highly responsible initiative, the Barbados Water Authority has discontinued the use of lead water pipes in Barbados, and if lead pipes are discovered during pipe repair activities, they are replaced with pipes of another material. However, in residential, commercial, and public buildings, including schools, lead solders are used to join hot water copper pipes, and brass faucets that leach lead are generally being used.

Barbados’ water has a high mineral content, which results in a build-up of a protective layer within the pipe. However, the build-up process can take approximately 5 years to completely cover the lead areas. Therefore houses, schools, or plumbing that are less than 5 years old are potential sources of lead poisoning. To reduce the risk of lead poisoning, water that is to be ingested should be drawn from the cold-water tap, and the initial 30-second morning draw should not be ingested but collected for other uses.

For the sake of our children’s future, the use of all lead based: paint, pipes, brass faucets, plumbing fittings and solders should be immediately restricted in Barbados.