Visiting the Gulf of Guinea --- Priceless – in more ways than one (from October 2013)

The Gulf of Guinea is a body of water that lies just to the south of Nigeria, Benin, Togo, Ghana, and Cote d’Ivore (ivory coast).   This is not just any body of water as it connects to the Atlantic Ocean.  In these times, folks are looking for oil in these warm waters and in fact they are finding it.  Nigeria and Equatorial Guinea have been the winners of the oil finds but off shore drilling is occurring today and will continue in the foreseeable future for the oil hungry countries of China, USA and India. 

Oil Rig in the Gulf of Guinea 

Ships transporting oil from the Gulf of Guinea

But with a strange twist, the Gulf of Guinea has an important role in climate, with it being the primary source of water vapor to all of West Africa during the Wet Season (April-November).  Since at least the mid 1970s researchers have focused on whether the temperatures in this body of water are warmer or colder than normal.    These are formally known as warm sea surface temperature anomalies (warm SSTAs) and cold sea surface temperature anomalies (cold SSTAs)).  They are important because they seem to determine if the land regions to the north in West Africa will be drier or wetter.   When Cold SSTAs are found, the region just south of the Saharan Desert known as the Sahel tend to be wetter, while then there are warm SSTAs the Sahel tends to be drier.  Much of what we know about the linkage between the Gulf of Guinea and wetter/drier patterns of rainfall comes from work done by the late Dr. Peter Lamb who passed away last month.  He inspired many young scientists to study and improve our insights and understanding of forcing that produced the drying patterns during the late 20^th century in West Africa.  In fact, U of Illinois was the high on my list of graduate programs because of Dr. Lamb.  But the corn field were too much for me to handle after visiting the U of Illinois.    

The Late Dr. Peter Lamb

The value of knowing if the Gulf of Guinea temperatures will be warmer or colder than normal has value in potentially preparing farmers, water resource managers and government officials for what may be expected for rainfall during the wet season.  The work in the last 10 -15 years show that other oceans are also important in determining how much rain will fall in West Africa.  So one of the most important things to do, while I visited Abidjan last October (when I started this blog but never finished) was to see the Gulf of Guinea with my own eyes.  I have read so many scientific papers about the Gulf of Guinea that it is like an old friend that I have only know from maps but never in person.  

When I reached the Gulf of Guinea, put my hands in the warm water and looked out towards the horizon, I felt the deep connection to something much bigger than me.   This body of water has touched the lives of many people, controlled the economies of countries in West Africa, caused pastoralist to move onward to new areas and accelerated urbanization because of drought in West African coastal cities during the 20^th century. 

The World's addiction to fossil fuel and the accumulation of greenhouse gases will warm and influence the sea surface temperature anomalies in the Gulf of Guinea and hence the patterns of summertime rainfall in West Africa.   The warming of ocean temperatures of the Atlantic, Indian and Pacific oceans will also influence rainfall in West Africa during this century.   That in turn will determine the quality of life for approximately a half billion people north of this body of water in mid to late 21^st century.   

But my experience of coming face to face with an old but awesome friend that I have studies for many years was priceless.

Sunset over the Gulf of Guinea

The environmental cost of Saharan dust in West Africa: Lower life expectancy

Last week I returned from a two week visit in Senegal, with a goal of finishing up a project but also continuing my quest to understand how dust from the Sahara may be impacting the health of people, but especially those who are vulnerable (young, elderly and those with Asthma).   The Sahara desert is the world's largest desert with approximately 800 billion to 1.4 trillion pounds of dust transported from the desert each year.  From the months of December through April this dust can race along the ground creating fog like conditions, while during the summer it is normally located above the ground some 2000-5000 feet above the ground. 

There are three health aspects that I have been chasing over the last year (1) The linkages between Saharan dust and Meningitis; (2) The seasonal impact of dust on Asthma, COPD and other respiratory diseases; (3) The mystery of the dust haze around Dakar.

First the basics.  Saharan dust has a size range of 0.1 microns (0.0000001 meter) (ultrafine) to probably 20 microns (giant) with most of the particles falling between 1-10 microns.  By comparison a human air has a diameter that can be 80-100 microns which means that dust particles are 5 times to 100 times smaller than a human hair The closer that you are to the source, the larger the particles are more likely to be.  The small particles can be suspended or carried for thousands of miles downstream -- for example to the Caribbean or the United States.

The large particles (known as PM10) have a negative impact on the upper respiratory tract.  You breath them through in through your nose and mouth.  Your natural defenses such as the hair in your nose has the ability to trap a portion of these particles.  Quite often, you will develop a cough in the presence these large particles, but when they are abundant, the visibility is limited and it looks like a fog -so it is visible.

Upper Respiratory Tract where PM 10 particles have their greatest impact.

The smaller particles (known as PM2.5) have a negative impact on the lower respiratory system, because these particles are smaller and evade the filtering system of the nose.

Lower Respiratory System where PM 2.5 or smaller particles have their greatest impact

The smaller particles can enter into the lungs and inhibit the ability to breath.  Hence people with Asthma, Bronchitis, Emphysema and COPD are often negatively impacted.

Finally, the ultra-fine particles (0.1) microns can enter deep into the respiratory system and may even be able to enter into cell structures.  There is not much known about the effects of ultrafine particles on human health, but studies with rats should that they negatively impact the ability of the rats to breath and there are tumors that often form around the sites where the particles are interacting with the cells. These ultra-fine particles can be either single or form as groups (aggregates).

1. The linkages between Saharan dust and Meningitis

Key facts about Meningitis from the World Health Organization

Young boy suffering from Meningitis (WHO)

• Meningococcal meningitis is a bacterial form of meningitis, a serious infection of the thin lining that surrounds the brain and spinal cord.
• The meningitis belt of sub-Saharan Africa, stretching from Senegal in the west to Ethiopia in the east, has the highest rates of the disease.
• Group A meningococcus accounts for an estimated 80–85% of all cases in the meningitis belt, with epidemics occurring at intervals of 7–14 years.
• In the 2009 epidemic season, 14 African countries implementing enhanced surveillance, reported 88 199 suspected cases, including 5352 deaths, the largest number since a 1996 epidemic.
• Several vaccines are available to control the disease: a meningococcal A conjugate vaccine, C conjugate vaccines, tetravalent A, C, Y and W135 conjugate vaccines and meningococcal polysaccharide vaccines.

WHO suspected cases of Meningitis across the Meningitis Belt 

The disease, Meningitis, is transmittable through contact, such as sharing of utensils or kissing.  The time for the disease to manifest itself is 2-14 days after contraction.  The disease has been impacting young people under 20 years of age in Senegal and is often difficult to diagnose, especially in young children where it may be viewed as flu, because aches and pains are often associated with the flu.  In addition, spinal fluid must be extracted from potential patients to confirm Meningitis.  Many people in Senegal have been vaccinated for the Group A serotype, but in fact it is the strain of W-135 which is on the rise in Senegal.   The poor health care system in Africa, where doctors are not available to treat patients means that there is still 10-20% fatalities with the disease.

The question is why is occurs in these various intervals and what is the role of the environment.  Quite often religious pilgrimages to Mecca or Touba (in Senegal) where lots of people are together from different backgrounds will be associated with Meningitis outbreaks.   It is believed that  some portion of the population is carrying the bacteria in their throat at any given time.  The question is what triggers the outbreaks.


From an environmental point of view, dry air and winds from the north have been reported to be linked to Meningitis outbreaks.  However, in my opinion, dust is the most likely environmental cause related to Meningitis.  I say this because:  (1) large dust storms force people inside making transmission more likely; (2) Coarse or giant particles are likely to destroy tissue in the Nose and NasoPharynx making one more susceptible to Meningitis; (3) The dust may carry other pathogens (bacteria, virus, fungus) which can make one more susceptible to Meningitis.

Upper Respiratory system and Nasopharynx

In Senegal, we have seen an uptick in the number of suspected cases of Meningitis since 2010 with approximately 1400 suspected cases being identified during this time.  The majority of these cases are Sero-type W135 and more than 80% are occurring for people under 20 years of age.  In 2012 for example, there was a suspected 894 cases, but we have also found that dust concentrations were considerable higher in 2012 relative to 2013 or 2014.  With the help of the Ministry of Environment and dust models were are going back trying to reproduce the dust events during these two years and the results are very promising and will be submitted to peer review for publication.


2. The seasonal impact of dust on Asthma

At present, there are no studies in Sub-Saharan African which have linked dust to Asthma.  PM2.5 is a serious source of the problem for Asthma and based on both measurements and modeling.   I believe that is has a 2 period of the year when it is problematic.  The first period is during the winter/spring where heavy dust storms come into the region and air quality if poor for everyone.  The second time is from May through September where the dust from the Sahara rises above the Monsoon layer but slowly falls out as it is transported towards the Caribbean.  

While both periods are dangerous, it is the second one that is less obvious to the average person.  The dust is suspended at 2000-5000 feet above the ground and not in your face but you have to look up to the sky.   When dust is overhead, the sky looks milky white.

Dust Storm over Dakar, Senegal on July 1, 2010

However if you were flying above this dust, it takes on a different look.  It looks brown and you know that you hit JACKPOT --- Dust from the Sahara.

Flying over Sahara Dust between Cape Verde and Senegal.

Based on our analysis of data from the lab for atmospheric physics in Dakar, the dust size for summer dust events is 1-2 microns, which means that it is a hazard to the lower respiratory system...and especially those with Asthma.

One of my very good friends in Senegal is Mariama.  I have know her and her family members for more than a decade.  She has a daughter named Adja who will be 3 soon and is just so lively.

Mariama and Adja 

Me and Adja 

Mariama has Asthma and she tells me that Adja is a good candidate for Asthma unless she has an operation to address some issues as it relates to her upper respiratory system.  She working to gather the funds for the operation.    Just a few days (June 10) after visiting Mariama's family a dust event from the Sahara arrives over Dakar.

June 10 Saharan dust event over Senegal

I called Mariama because I left my Philly's hat there (gotta keep the Sun off my head).

Mariama did not pick up and the next day that I spoke to her, she told me that she had an Asthma attack and could not speak.   When the dust event was over Dakar, the air became heavy and your skin had the feeling of dust on it, even though you could not see it.  We were monitoring from the lab and knew that it arrived.

In speaking to Dr. Toure at the local hospital she also believes that there is a double season for Asthma based on the patients coming in with acute respiratory problems.  The problem is that the country wide impact of dust and asthma are unknown but there is an effort to organize and collect relevant data.

3.  The mystery of the dust haze around Dakar. 

 Over the last 3 years we have noticed a haze over Dakar which we capture from the Ceilometer on the roof.  It was here is 2012, it was around when President Obama came to visit Senegal in 2013 and it is around it 2014.

Haze over Dakar looking downtown

We have tried to determine, where the dust is coming from, the sizes of the particles and why it is trapped near the ground based on the ceilometer.  

Our recent findings are:

1.  We now have high confidence that the dust is coming from Western Sahara and Morocco and coming down the coast and coming into Senegal.

2.  We now are confident that these are ultrafine particles of 0.1-0.3 microns in diameter.  

3. We do not know why these particles are trapped near the ground but they pose a health rise because they can penetrate deep into the lungs and possibly into human cells.  

My most recent visit to Senegal was probably the most fruitful, because I spoke to colleagues across various disciplines and we are developing a strategy for prediction, warning and treatment respiratory issues that arise from Saharan dust.  We know that millions of persons are being negatively impacted by Saharan Dust in West Africa.  It is time be part of the solution because the environmental cost is high:  Poor health and lower life expectancy.   We all deserve good health.  

Stay tuned

Incredible Dust storm enters Senegal Yesterday!!

Since Friday, we have been watching the possibility of a heavy dust event in Senegal as a warm thermal low moved from Algeria across Mali into Senegal.  The models that forecast dust storms were mainly in agreement with this heavy dust event coming into Senegal.  On Saturday, dust started to stream out of the country as seen on satellite.

Saturday afternoon June 21 Aqua Satellite image over Coastal Africa

This dust, while hazardous especially bad for the young and elderly and those with Asthma because the particle size is about 1-10 microns and can severely impact breathing capacity. The smaller sized particles will penetrate deep into the lungs.  

Sunday Morning, Visible satellite images continued to showed additional dust streaming off the coast of Africa.  You can notice that the Senegal River in the Eastern part of the country is becoming obscure.

Sunday morning June 22 Tera Satellite image over Coastal Africa

During the afternoon, even higher amounts of dust were seen coming off the coast suggesting that conditions were getting worse.  At this point the Senegal River in the East cannot be seen because of large amounts of dust.

Sunday Afternoon June 22 Aqua Satellite image over Coastal Africa

The European Space Agency satellite which can detect dust show very large quantities of dust moving over Senegal (in Magenta) and some of this dust was being lifted by a weather system.  

Sunday Afternoon June 22 at 4pm EUMETSAT Dust Images.  Dust is the Magenta color

As the dust entered into Senegal, this is a picture from my colleague Dr. Drame from Northern Senegal that was sent to him.  The dust has

Sunday Afternoon June 22 picture in Northern Senegal (Podor) during the dust event.

The dust reached the capital city of Dakar at approximately 8-10 PM last night and I am told dust is covering the city.  Waiting to hear the dust concentrations, but the aerosol optical thickness is 2.6 which is very high.  Our lidar measurements from the roof at the university show high dust concentrations from the ground  to 2 km (5000-6000 ft)

Dakar, Senegal Ceilometer intensity measurements for June 22-23.

My colleague Dr. Amadou Gaye has send me some pictures of the dust plume from the lab this morning.

Picture looking out towards the ocean from the lab.  Yes this is dust

The worst of the dust is over, as the plume is now out over the Atlantic but may still have an effect in the Caribbean as the winds will carry suspended particles there.

June 23 CIMSS 9AM Visible satellite of Dust leaving Senegal 

The health effects of this dust storm are unknown at present, but I have sent emails to my colleagues in Senegal, including some who work in the hospitals to alert them that there may be respiratory cases coming into the hospital.   The Ministry of environment I believe is also alerting the hospitals countrywide about the hazardous conditions.   The models continue to suggest poor air quality this week because of dust.  We will continue to forecast and monitor.