ABSTRACT
Indoor air pollution (IAP) kills 4 million people worldwide, particularly in
developing countries where many people rely heavily on biomass for energy.
Globally, 3 billion people use biomass fuel for cooking and heating. Burning
biomass emits carbon monoxide (CO) and other pollutants. Hence, IAP is the leading
cause of non-communicable diseases in the world. Women and children suffer most
of the burden of IAP because they are usually responsible for cooking.
In a rural, poor community in Adamawa State, northeastern Nigeria, I assessed risks
to human health from biomass burning. I used structured questionnaires to interview
heads-of-households about their household composition, cooking habits, cooking
fuel, and kitchen area. Using a CO data logger, I also measured CO emissions during
cooking for 16 households with indoor kitchens. The number of doors, windows, and
gaps were counted and measured to assess ventilation and subjectively categorized
into a ventilation index.
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My results showed that adult women (n =134) were mainly responsible for cooking
in the Bole community, and mean number of times residents cooked per day was
2.25 ± 0.55. The primary fuel source for all but four households was wood. Most
households had outdoor cooking areas (n = 101). Mean CO reading (111.9 ± 41.4
ppm) exceeded World Health Organization recommended safe levels. Ventilation
appeared to be important for reducing CO concentrations during cooking. This
research reinforces that indoor pollution from biomass burning poses a risk to the
human health and contributes to deforestation.
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TABLE OF CONTENTS
CERTIFICATION…………………………………………………………………………………………..ii
READERS’ APPROVAL………………………………………………………………………………..iii
DEDICATION……………………………………………………………………………………………….iv
ACKNOWLEDGEMENTS………………………………………………………………………………v
ABSTRACT………………………………………………………………………………………………….vi
LIST OF TABLES …………………………………………………………………………………………..x
LIST OF FIGURES…………………………………………………………………………………………xi
CHAPTER 1……………………………………………………………………………………………………1
INTRODUCTION …………………………………………………………………………………………..1
Biomass use………………………………………………………………………………………………….2
Health impacts related to IAP…………………………………………………………………………….3
Vulnerable populations…………………….…………………………………..……..4
Incomplete combustion and pollutants…………………………………………………5
Case of Nigeria ……………………………………………………………………………………………..10
HYPOTHESES …………………………………………………………………………………………….11
AIMS & OBJECTIVES ………………………………………………………………………………….11
CHAPTER 2 …………………………………………………………………………………………………12
MATERIALS & METHODS ………………………………………………………………………….13
Study Site ……………………………………………………………………………………………………..13
Sampling …………………………………………………………………………………………………….. 12
CHAPTER 3 …………………………………………………………………………………………………15
RESULTS ……………………………………………………………………………………………………15
CHAPTER 4 …………………………………………………………………………………………………25
DISCUSSION ………………………………………………………………………………………………25
CHAPTER 5………………………………………………………………….………28
CONCLUSION………………………………………………………………………28
REFERENCES………………………………………………………………………29
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LIST OF TABLES
Table 1. Different structures of cooking area encountered in Bole Community…….19
Table 2. Comparison of mean and maximum CO readings recorded with
ventilation index………………………………..……………………………………20
x
LIST OF FIGURES
Fig.1. The percentage of people relying on the different types of biomass fuels and
their regions……………………………………………………………………………3
Fig.2. Woman in Bole Community, Adamawa Northeastern Nigeria cooking with an
open fire stove………………………………………………………………..……….6
Fig.3. Process of incomplete combustion yields the poisonous gas, carbon
monoxide………………………………………………………………………………7
Fig.4. Map of Adamawa State in Nigeria, with a star indicating the general location of
Bole community within Adamawa.……………………………………………..……13
Fig.5. Outdoor area with thatched cover……………………………………………16
Fig.6. Outdoor cooking area without cover…………………………………….…….17
Fig.7. Indoor cooking area with aluminum roofing ……………………………..….17
Fig.8. Indoor cooking area with thatched roofing ……………………………….….18
Fig.9. Cooking period in minutes and levels of CO (ppm) measured during cooking in
Docochi HH4..………………………………………………………………………21
Fig.10. Cooking period in minutes and levels of CO (ppm) measured during cooking
in Docochi HH7…………………………………………………………………..….22
Fig.11. Cooking period in minutes and levels of CO (ppm) measured during cooking
in four different ward ………………………………………………………..………24
1
CHAPTER 1
INTRODUCTION
Global air quality is worsening every day due to both outdoor and indoor pollution.
Much attention is directed to IAP presently, as it is considered a leading cause of
respiratory diseases that cause the premature deaths of 4 million people around the
world (WHO, 2016). Indoor air pollution is the emission of harmful substances in
living area. Sources of IAP include materials used in furnishings, semi-volatile, and
volatile compounds released by building materials, insecticides, and biomass fuels
(mainly cow dung, straws, crop residues, woods, and twigs) (Zhang & Smith, 2003).
The largest contributor of IAP in developing country is biomass burning. Biomass
burning is the combustion of living and dead vegetation (Cole, 2001). This process
emits pollutants, which gets trapped when people cook indoors hence promotes
respiratory diseases (WHO, 2016).
About 7.7% of global mortality is due to IAP (WHO, 2016). In middle- and lowincome countries, 10% of mortality is caused by indoor pollution. Whereas the same
risk factor is 0.2% in developed countries (WHO, 2016). IAP emitted from the
burning of biomass poses a greater risk to human health than any other source of
pollution. Hence, mortality and morbidity in developing countries are heavily
attributed to burning biomass fuel. The reason is some people, most especially
women in the developing countries use substandard stoves that produces smoke,
which gets trapped when used in areas with poor ventilation (Bruce, et al., 2015).
Chronic exposure to smoke lowers the body’s immunity and eventually lead to
respiratory diseases (Bruce, Perez-Padilla, & Albalak, 2000).
2
Although the health impact of IAP is well studied, there has been limited
intervention that will bring effective solutions based on these findings. Some of the
limitations are due to technology, behavior, and lack of infrastructure.
Biomass use
People use biomass as fuel for cooking and heating all over the world (Fig.1). More
than 2.4 billion of the global population relies on biomass fuel for cooking and
heating (WHO, 2016). In addition, most biomass users are in developing countries.
In Africa, 78% of household energy is from biomass fuel (WHO, 2012). Clean
source of energy is important, but poverty and inadequate power supply have made
clean energy beyond the reach of people living in developing countries. Therefore,
people are forced to look for cheap alternative sources of fuel, regardless of
consequences on human health (NPC & ICF, 2014).
In addition to Africa, Asian countries such China, India, and Nepal also have large
percentage of people using biomass fuel. In China, 80% of the rural population
derives 60%-80% of its domestic energy from biomass fuel (World Energy Outlook,
2006). In India and Nepal, 72% and 88% of their respective daily fuel use is derived
from biomass (Ranabhat, et al., 2015; Joon, et al., 2014)
3
Fig. 1. The percentage of people relying on the different types of biomass fuels and their
regions (Credit: UNPD, 2007; WHO, 2009).
Health impacts related to IAP
Exposure to pollutants emitted from biomass fuels cause respiratory diseases,
miscarriages, and some cancers. Globally, non-communicable diseases including
stroke, ischemic heart diseases, chronic obstructive pulmonary, lung cancer, and
acute lower respiratory diseases in children resulting from IAP, cause 4 million
premature deaths (WHO, 2016). For example, acute lower respiratory infections kill
over 2 million children every year (Bruce, Perez-Padilla, & Albalak, 2000). IAP is
also the third largest cause of deaths in the world aside from heart disease. In
addition, upper respiratory tract infections, which are common in children under 5
years; chronic pulmonary disorder; and lung cancer in women are all caused by
4
indoor pollution. Smoke exposure from wood also causes inflammation of the lungs
and fibrosis (Bruce, et al., 2000; WHO, 2012).
In Africa, an estimated 41,000 deaths from chronic obstructive pulmonary diseases
and 350,000 from acute lower respiratory infections due to IAP were recorded in
2000 (WHO, 2012). In addition, the risk of having pneumonia doubles in individuals
who are exposed to indoor pollution. Every year, 2 million children in developing
nations die from pneumonia and 900,000 of the deaths cases are caused by indoor
pollution (WHO, 2016).
IAP kills approximately 700,000 women every year in Africa every year (WHO,
2012). In some parts of China, women exposed to IAP have developed lung cancer,
even though they were not smokers (Smith, Mehta, & Maeusezahl-Feuz, 2004).
Indoor air pollution is responsible for 1.5% of deaths in China annually
(Baumgartner, et al., 2011).
People who have bronchitis due to tobacco smoking have similar symptoms to those
exposed to biomass smoke. A person exposed to IAP from solid-fuel burning equally
has a high risk of having lung cancer as those cigarette smokers. The level of
exposure to IAP in some developing countries is equivalent to smoking a pack of
cigarettes a day (Bruce, et al., 2000).
Vulnerable populations
Women and children get the most share of burden from indoor air pollution
(Baumgartner, et al., 2011). This is because women and their daughters often do the
5
cooking in the house (Fig. 2), which exposes them to smoke from burning biomass.
In Bengal, India, about 50% of women use biomass fuel to cook at least once a day,
and about 65% of the women spend two to three hours cooking every day
(Chakaraboty, Mondal, & Datta, 2004). The same study reported that 70% of women
cook in the same room in which they sleep. Women who cook with solid fuels (e.g.
biomass and charcoal) are three times more likely to acquire chronic respiratory
diseases than those who cook with gas and electricity (WHO, 2012). IAP increases
respiratory illness such as pneumonia, especially in young children under 5 years of
age (Fullerton, Bruce, & Gordon, 2008). More than 75% of children die every year
due to IAP in Africa (WHO, 2012).
Aside from women and young children, elderly people; pregnant women; fetuses;
infants; and people with anemia, cardiovascular, or pulmonary diseases are
particularly vulnerable and susceptible to the effects of pollutants emitted from
biomass combustion indoors. In one study, adults who are 45 years above were
diagnosed, and 20% of men and 10% of women were at risk having an obstructive or
restrictive lung disease. (Baumgartner, et al., 2011).
Incomplete combustion and pollutants
Although many pollutants are released when biomass is burned, carbon monoxide
(CO) and particulate matter are the key pollutants that are tested for and monitored
due to the level of indoor air pollution they cause and their potential health impacts
(WHO, 2012). Both are emitted as a result of incomplete combustion of solid fuels
such as wood.
6
Fig. 2. Woman in Bole Community, Adamawa Northeastern Nigeria cooking with an open
fire stove (Credit: Lynne R. Baker).
Incomplete combustion occurs when there is partial burning of wood due to
insufficient oxygen or low temperatures. Complete combustion of produces only
water and carbon dioxide as byproducts, but in the case of incomplete combustion,
CO is also released (Fig. 3). Other pollutants caused by incomplete combustion
include particulate matter, NO2, formaldehyde, acrolein, benzene, toluene, styrene,
and 1,3 butadiene (WHO, 2016).
7
Some of these pollutants are tiny and respirable, and hence why they can cause
respiratory diseases when inhaled. The severity of impact of these pollutants on
human health depends on three key factors: 1) level of exposure (Bruce, et al., 2015;
Smith et al., 2000; Chakaraboty et al., 2004; W.H.O., 2016.)2) amount of ventilation,
and 3) type of biomass used (Smith et al., 2000 and Ezzakati et al., 2000).
Particulate matter of 10 µg in diameter (PM10) and smaller are respirable and can
penetrate deep into the lungs, especially particulate matter less than 2.5µg (PM2.5)
(Ezzati & Kammen, 2002). Therefore, can cause lung diseases. Frequent exposure to
smoke from burning biomass is associated with lung diseases, such as acute lower
respiratory disease, lung fibrosis, chronic bronchitis, and lung cancer (WHO, 2016).
Fig. 3. Process of incomplete combustion yields the poisonous gas, carbon monoxide
8
The mean concentrations of PM2.5 measured in Nepal households when women are
cooking with biomassfuel was as high as 30,000 µg/m3. Thus, the reason why
chronic bronchitis is found to be the same for both men smokers and women nonsmokers (Ranabhat, et al., 2015) . This concentration far exceeded the permissible
maximum of no more than 3,000 µg PM2.5 over a 24-hour period, according to World
Health Organization (WHO) (WHO, 2016).In another study, children in a Navajo
community seen at Public Health Service Indian Hospital, who lived in households
that use biomass fuel were exposed to PM10 levels of 65µg and above. These
children thus have a seven-times greater risk of developing lung disease (Robin,
1996).
Carbon monoxide
Along with particulate matter, CO poses a notable threat to human health when it is
released indoors. CO is a tasteless gas that has no color or odor, and it is slightly
soluble in water. It has lower density than air and binds easily with blood
hemoglobin. CO has higher affinity for hemoglobin than oxygen (Cullis & Hirschler,
1989).
When CO enters the body, it forms carboxyhemoglobin (COHb) with blood
hemoglobin, which reduces the oxygen-carrying capacity and causes hypoplasia- dis
order that leads to underdevelopment or incomplete development of a tissue or organ.
Hypoplasia can in turn lead to brain and heart disorders depending on the level of CO
poisoning (Prockop & Chichkova, 2007). Frequent use of wood without completely
burning it can cause acute or chronic CO poisoning (Prockop & Chichkova, 2007).
9
Safe level of carbon monoxide for 15minutes, 1hour and 8 and per day is 81.1ppm,
28.4 ppm, 8.11ppm and 5.68ppm respectively (WHO, 2000). However, levels of 20-
50 ppm and higher are measured during cooking with biomass, thereby increasing
the COHb levels between 1.2% and 2.5% (Bruce, Perez-Padilla, & Albalak, 2000).
Severity of COHb damage depends on the amount of exposure to carbon monoxide;
the alveoli ventilation, which is the exchange of gas between alveoli; the external
environment, and the duration of exposure. Carbon monoxide poisoning also causes
brain disturbances – any abnormality in the function or structure of the brain; heart
infections; headache; vomiting; nausea; and, at higher levels, fatal coma and death
(Prockop & Chichkova, 2007).
Carbon monoxide exposure that results to COHb levels of 5.1–8.2 % can slow down
thoughts and impair movement of the body. This include, reduced coordination,
tracking and driving ability, and impaired vigilance and detection of small
environmental changes (Benignus, 1994). In addition, COHb levels of 5-20% can
interfere with cognitive performance. COHb level of 2-13% in a fetus can cause
reduced birth weight (Bruce et al, 2000). These authors also reported that exposure to
biomass smoke during pregnancy can result in impaired lung formation in infants.
People who have heart diseases are very sensitive to CO. Elevated levels of COHb
causes atherosclerotic narrowing of coronary arteries. This restricts blood flow to the
myocardium, and prevents physiological compensation for lowered oxygen delivery.
Again, COHb levels of 2.5–3.0% shorten time of onset of exercise in patients with
angina pectoris (WHO, 2000).
10
Case of Nigeria
As the most populous nation in Africa, the West African country, Nigeria, has a large
number of people living in rural areas (NPC & ICF, 2014). In 2013, 37.9% urban
population and 83.3% of rural population in Nigeria relies on solid fuels for cooking
and heating (NPC & ICF, 2014). Fewer than 5% of Nigerians have access to clean
household fuel such as liquid gas electricity that does not emit pollutants (WHO,
2014). Many people who use solid fuels in the rural parts of Nigeria have little or no
knowledge of the health impacts of burning these fuels indoors. revealed that most
people who cook indoors with solid fuel use unvented stoves with no chimney (NPC
& ICF, 2014). These stoves lead to the emission of pollutants, such as particulate
matter and CO, because there is little or no ventilation.
Although there are many studies on biomass and indoor air pollution in developing
countries, this topic is critically important for Nigeria given the large rural Nigerian
population that relies on biomass for energy. In this study, I assessed the level of
indoor pollution in households in a rural dryland community of Adamawa State,
northeastern Nigeria, by measuring carbon monoxide levels in households with
indoor kitchens. I also investigated the amount ventilation of these indoor spaces,
household cooking habits, and who within these households was most affected by
IAP.
11
HYPOTHESES, AIMS AND OBJECTIVES
Null Hypotheses: Carbon monoxide levels do not exceed harmful levels in rural
households in Adamawa State, northeastern Nigeria.
Research Hypothesis: Carbon monoxide levels exceed harmful levels in rural
households in Adamawa State, northeastern Nigeria.
Aim:
To assess levels of exposure to indoor air pollution from biomass burning in rural
households in Bole community, Adamawa State, northeastern Nigeria.
Objectives:
• To identify the main sources of fuel used for cooking and heating in
households.
• To evaluate ventilation of household rooms where cooking activities occur.
• To measure carbon monoxide exposure in households.
• To compare levels of carbon monoxide (CO) measured with World Health
Organization’s CO exposure guidelines.
• To create local awareness about indoor air pollution.
• Based on the results, to recommend alternatives to whom? to biomass for
fuel
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