ABSTRACT
Carbon-monoxide (CO), Hydrogen sulphide (H2S) and sulphurdioxide (SO2) concentrations were
determined in the morning, afternoon and evening hours at the Sabon-Gari Market, Zaria and
Aliyu Mustapha Social Centre, Ahmadu Bello University Zaria, using an automatic gas sampling
system. The concentrations of these gases have been attributed to the burning of solid and fossil
fuels and bacterial decomposition of organic matter from dump sites and gutters. The distribution
of the gaseous pollutants showed either a platykurtic (flat) or leptokurtic (peaked) distribution.
Analysis of variance using Friedman test showed no significant difference at (P<0.05) within the
study sites. Hierarchical cluster analysis carried out showed more agglomeration between site B
and D during the morning and afternoon hours respectively and between site A and D for the
evening hour for all the Sites at location1 while at location 2, their is more agglomeration
between site A and C during the morning hour and site A and B for afternoon and evening hours
respectively. The concentration of Cd, Cr, Fe, Ni and Pb were determined in the street dust of
the Sabon – Gari market Zaria using AAS. The concentration of these metals are within the
range of 0.40 – 1.45μgg-1, 16.92 – 33.82μgg-1, 240 – 315.61μgg-1, 3.05 – 6.04 μgg-1 and 25.79 –
121.35μgg-1 respectively. This indicated the order of relative abundance as Fe> Pb> Cr> Ni> Cd
for all the sites. Correlation analysis between metals indicated significant positive correlation at
(P<0.05) for Pb and Cd and at (P < 0.01) for Cd and Cr, Pb and Cr, Fe and Cr and Fe and Ni.
Metal pollution in street dust are of anthropogenic origin mainly vehicular, generator and other
gasoline powered equipment emissions.
Â
TABLE OF CONTENTS
Declaration- – – – – – – – – – ii
Certification- – – – – – – – – – iii
Dedication- – – – – – – – – – iv
Acknowledgment- – – – – – – – – v
Abstract- – – – – – – – – – vii
Table of Contents- – – – – – – – – viii
List of Tables- – – – – – – – – – xii
List of Figures- – – – – – – – xv
List of Appendix- – – – – – – – – xvi
CHAPTER ONE
INTRODUCTION
1.1 Background of the Study- – – – – – – 1
1.2 Air pollution – – – – – – – – 2
1.3 Ambient Air Quality – – – – – – – 3
1.4 Effects of Air Pollution on Animals – – – – – – 4
1.5 Other Effects of Air pollution – – – – – – – 5
1.6 indoor Air Pollution – – – – – – – 5
1.7 Sources of Indoor Air pollution – – – – – – – 6
1.8 Effects of indoor Air pollution – – – – – – 6
1.9 Street Dust – – – – – – – – – – – 7
1.10 Heavy Metals – – – – – – – – – – 8
1.11 Toxic Effects of Heavy Metals – – – – – – – 11
1.12 Justification – – – – – – – – – – – 12
1.13 Aim and Objectives of the Research – – – – – – 13
ix
CHAPTER TWO
LITERATURE REVIEW
2.1 Carbon Monoxide (CO) – – – – – – – 14
2.2 Hydrogen Sulphide (H2S)- – – – – – – 16
2.3 Sulphur Dioxide (SO2) — – – – – – – 18
2.4 Cadmium (Cd) – – – – – – – – 19
2.5 Chromium (Cr) – – – – – – – 20
2.6 Iron (Fe) – – – – – – – – – 21
2.7 Nickel (Ni) – – – – – – – – 21
2.8 Lead (Pb) – – – – – – – – – 22
CHAPTER THREE
3.0 MATERIALS AND METHODS – – – – – 24
3.1 The Study Area — – – – – – – 24
3.2 List of Reagents – – – – – – – – – 27
3.3 Preparation of Solutions – — – – – – 27
3.3.1 Stock Solution – – – – – – – – 27
3.3.2 Standard Working Solution – – – – – – 28
3.4 Sample Collection – – – – – – – 28
3.4.1 Gas Samples – – – – – – – – 28
3.4.2 Street Dust Samples – – – – – – – 28
3.5 Sample Treatment – – – – – – – 29
3.5.1 Gas Sample Treatment – – – – – – 29
3.5.2 Street dust Sample Treatment – – – – – – 29
x
3.6 Determination of physicochemical parameters of Street Dust – – 29
3.6.1 Determination of pH – – – – – – – – – 29
3.6.2 Determination of Organic Matter – – – – – – 29
3.6.3 Particle Size Distribution – – – – – – 31
3.6.4 Determination of Phosphate (PO4
3-) – – – – – – 32
3.6.5 Determination of Chloride (Cl-) – – – – – – 32
3.6.6 Determination of Mineral Nitrogen (NH4
+- n; NO3
— n) – – – 33
3.7 Instrumentation – – – – – – – 34
3.7.1 Crowcon-Gasman – – – – – – – 34
3.7.2 Calibration – – – – – – – – 34
3.7.3 Operation – – – – – – – – – 35
3.7.4 Instrumental- – – – – – – – 37
3.8 Digestion of Sample – – – – – – – 37
3.9 Calibration Curve – – – – – – – – 37
CHAPTER FOUR
RESULTS AND DISCUSSIONS
4.1 Results – – – – – – – – 38
4.2.0 Discussion – – – – – – – – 49
4.2.1 GeneralDiscussion of Gaseous Pollutants – – 49
4.3 Location 1 (Sabon-Gari Market Zaria) – – – – – 50
4.3.1 Carbon-monoxide – – – – – – – 50
4.3.2 Hydrogen Sulphide – – – – – – – 51
4.3.3 Sulphur dioxide – – – – – – – 51
xi
4.4 Location 2 (Aliyu Mustapha Social Centre A.B.U. Zaria) – – 52
4.4.1 Carbon-monoxide – – – – – – – 52
4.4.2 Hydrogen Sulphide- – – – – – – – 53
4.4.3 Sulphur dioxide – – – – – – – 53
4.5 Statistical Analysis – – – – – – – 63
4.5.1 Descriptive Statistics – – – – – – – 63
4.5.2 Friedman Test – – – – – – – – 63
4.6 Location 1 (Sabon-Gari Market Zaria) – – – – 64
4.6.1 Carbon-monoxide – – – – – – – – 64
4.6.2 Hydrogen Sulphide – – – – – – – 66
4.6.3 Sulphur dioxoide – – – – – – – 68
4.7 Location 2 (Aliyu Mustapha Social centre A.B.U. Zaria ) – 69
4.7.1 Carbon-monoxide – – – – – – – – 69
4.7.2 Hydrogen Sulphide – – – – – – – 71
4.7.3 Sulphur dioxoide – – – – – – – 72
4.8 Cluster Analysis – – – – – – – 75
4.9 Discussion of Trace Metals – – – – 78
4.9.1 Physicochemical Parameters of Dust Sample – – – – 80
4.9.2 Heavy Metal Concentration in Street Dust – – – – 82
4.9.3 Mean Concentration of Metals in the Dust samples
Across the Sites.- – – – – – 83
4.9.4 Correlation between Heavy Concentration in Street
Dust Sample – – – – – 84
xii
CHAPTER FIVE
CONCLUSION AND RECOMMENDATIONS
5.1 Conclusion- – – – – – – – – 92
5.2 Recommendations – – – – – – – 93
References – – – – – – – – – 94
Appendices – – – – – – – – – 104
CHAPTER ONE
INTRODUCTION
1.1 Background of the study
In the earlier days, the impact of man’s activity on the earth’s environment was rather
little and nature could resist and compensate for it. At the end of the 19th century, environmental
problems arose due to the growing cities and industrialization.
Pollution of air and water channels in the bigger cities became severe. In the 20th century,
the increase in intensity of agricultural and cattle rearing, changes and growth in industrial
processing and in the nature of compounds used from natural and synthetic compounds made
environmental problems even greater. Nature could no longer resist and compensate for them.
Pollution is the undesirable changes in the physical, chemical or biological characteristics
of air, water or land that can harmfully affect the health, survival or activities of human or other
living organism (Albert, 1992). It is the existence of substances in the environment that prevents
the functioning of natural processes producing undesirable environmental and health effects due
to their chemical composition or quality.
The substances that cause pollution are referred to as pollutants, therefore pollutants can
be defined as substance not normally present or that are present in large concentration than
normal with harmful effects especially on living organism. In other words, pollution is the
undesirable modification of air, water or food by substance that are toxic or with diverse effects
on health, offensive though not necessarily harmful to health with the risk of damaging human
health, the well being, the artificial and the natural environment (Ross, 1972; John, 1983; Albert,
1992). It is an act of discharging accidentally or deliberately that in any way damages or
threatens the environment (Howard, 1985)
2
1.2 Air Pollution
Air pollution is a contamination of air by the discharge of harmful substance (Thursten et
al., 2006). A broader definition of air pollution is the presence in the atmosphere of
contaminants such as dust, fumes, gas, mist, odour, smoke or vapour in quantities and of such
characteristics and duration such as to be injurious to human, plant or animal life or to properly
or to interfere unreasonably with the comfortable enjoyment of life and property (Bishop, 2003).
Some of these particles are directly emitted into the air from a variety of sources such as cars,
trucks, factories, construction sites, tilled fields and burning of woods.
Pollutants in the atmosphere may be of natural origin such as smoke, fumes, ash and
gases from volcanoes, forest fires, sand and dust from windstorms in arid regions, fog in humid
low-lying areas and natural terpene haze from pine trees in mountainous region long before
human induced or anthropogenic problems came on the scene (Howard, 1985). Pollutant sources
are varied and may be categorized into mobile (transportations), stationary combustion,
industrial process and solid waste disposal (US-EPA, 1975). Regulated air pollutants are of two
groups, the criteria and the hazardous air pollutants. Criteria pollutants include particulate matter,
Nitrogen oxides, sulphur oxides, carbon monoxide, ozone and lead while hazardous air
pollutants includes asbestos, beryllium, mercury, vinyl chloride, arsenic, radio nuclides, benzene
and coke oven emission. (Hermann,1991). Depending on their origin, pollutants are considered
either primary or secondary contaminants. Primary pollutants such as hydrogen sulphide,
hydrocarbon (HC) are emitted directly to the atmosphere in the form in which they were emitted.
Secondary pollutants such as ozone and peroxyacetylnitrate (PAN) are those in the atmosphere
by photochemical hydrolysis or oxidation reaction. (Lee, 1978; Howard,1985).
3
1.3 Ambient Air Quality
Ambient air is the outside air that is free to move, it is the open air around us. Ambient
air pollution is also referred to as tropospheric or ground level air pollution (Hill, 2004). Air
pollution was a major nuisance for many and a serious concern for some in the industrializing
cities of the 19th century, but concerted efforts to address ambient pollution only began in the 20th
century (Hassan et al.; 2003). There is considerable variation in exposure to air pollution
between and within urban centres, depending on geographical factors as well as the type of
activities undertaken in and around the urban centres (Hassan et al., 2003). Ambient air pollution
is usually worse in urban centres; however, overall exposure to air pollution (indoor and
ambient) is higher in rural areas because most biofuel users are rural (Colls, 2002). Air pollutants
are blown across state and national boarders sometimes in significant amounts (Colls, 2002).
Ambient air pollution has reached excessively high levels in many large cities in Asia, Africa
and Latin America (Hassan et al.; 2003). However, as a result of higher emission standard and
closer monitoring levels, certain types of air pollutants have declined in many developed
countries. On the other hand, the ambient air pollution levels are a growing problem in urban
cities in many developing countries. Several factors contribute to the worsening air pollution
level in developing country cities including rapid growth in urban population, increasing
industrialization and rising demand for energy and motor vehicles. Other factors such as poor
environmental regulation, less efficient technology of production, congested roads, age and poor
maintenance of vehicles; also add to the problem. (Starkman, 1975).
4
1.4 Effects of Air Pollution on Animals
Air pollution is a major environmental health problem affecting both developed and
developing countries (WHO, 2003). That air pollution causes ill health and death is well
documented (Starkman,1975). Recent estimates of the global burden of disease suggests that
approximately 5% of trachea, bronchus and lung cancer, 2% of cardio-respiratory mortality and
about 1% respiratory infections are attributed to outdoor air pollution (WHO, 2002; Ezzati et al.;
2002). Air pollution from outdoor sources, such as motor vehicles, industry and neighborhood
level, solid waste burning is associated with increased morbidity and mortality from respiratory
infection in children and adults (Hauser and Shy, 1972).
Air pollution is estimated to cause approximately two (2) million premature deaths
worldwide per year. More than half of this burden is borne by people in developing countries
(Cohen, 2007). Air pollution has both acute and chronic effects on human health. Health effects
range anywhere from minor irritation of eyes and the upper respiratory system to chronic
respiratory and heart disease. It has been shown to cause acute respiratory infections in children
and chronic bronchitis in adults. It has also been shown to worsen the condition of people with
pre-existing heart or lung disease (WHO, 2003). Individual reaction to air pollution depends on
the type of pollutants a person is exposed to, the degree of exposure and the individual’s health
status (Wikipedia, 2007). A person who exercises in outdoors on hot, smoggy days increases
their exposure to pollutants in the air (Wikipedia, 2007). The WHO estimated that 500,000
people die prematurely each year because of exposure to ambient concentrations of airborne
particulate matters (Colls, 2002).
5
1.5 Other Effects of Air Pollution
Plants and animals are harmed by air pollution. Acid rain kills trees and can harm
animals, fish and other wild life. (Gardiner, 2006). Some gases that can harm aquatic fresh water
life are gasses such as chlorine, ammonia and methane (Thurston, 2006). Ammonia even at
dilute concentration is highly toxic to aquatic animals and for this reason is classified as
dangerous for the environment (Wikipedia, 2007). Damage to vegetation by air pollution is of
many kinds. Sulphur dioxide may damage field crops such as alfalfa and trees such as pines
especially during the growing season. Both hydrogen fluoride and Nitrogen dioxide in high
concentration have been shown to be harmful to citrus trees and ornamental plants (Thurston,
2006). Oxides of Nitrogen can injure vegetation at certain concentrations. Effects include
bleaching or killing plant tissue, causing leaves to fall and reducing growth rate. (Nyasula and
Mottola,1987).
1.6 Indoor Air Pollution
Indoor air pollution is the presence of chemical or biological contaminants in the air of
confined environments, which are not naturally present in high quantities in the external air of
the ecological system (Labowitz et al., 1984). Many people spend large portion of time indoor as
much as 80 – 90% of their lives. We work, study, eat, drink and sleep in enclosed environment
where air circulation may be resisted. Therefore, more people suffer from the effect of indoor
than outdoor pollution. Pollution exposure at home and work is greater than the outdoors. It has
been estimated that indoor air pollutant levels are 25 – 62% greater than outside levels and can
pose serious health problems. (Benson et al.,1972).
6
1.7 Sources of Indoor Air Pollution
There are many sources of indoor pollution which include tobacco smoke, vapour from
building materials, paints, floors and furniture. Others include maintenance and clearing products
(detergents, pesticides), Heating, Air conditioning devices and Cooking apparatus (coal, gas,
etc). Also, smoke from nearby houses, burning of household wastes, forest use or kerosene lamps
(Smith and Liu, 1993; Ayodele et al.; 2007a & b).
1.8 Effects of Indoor Air Pollution
Indoor air pollution from kitchen or household fires is a silent killer in poor countries
causing more death (Geneva, 2004). Impoverished families had little choice but to favour fires
fueled by cheap and readily available fuels like wood, coal or animal dung. Yet inhaling the
smoke produced by those fires is equivalent to consuming two packets of cigarettes a day (WHO,
2004). Women, who spend hours in the home tending the fires, pay the highest price along with
young children who suffer from chronic bronchitis or pneumonia (Albalak, 1997). WHO has
estimated that about two thousand, five hundred people in the world are exposed to excess level
of indoor pollution due to burning biomass and coal indoors in ovens that are poorly designed
and lacking proper chimneys? Some millions of additional deaths each year are blamed on rural
indoor pollution through suspended particulate matter and another four hundred and fifty
thousand deaths are attributed to urban indoor air pollution. These figures are over and above the
five hundred thousand excess death world wide due to concentrations of suspended particulate
matter and sulphur dioxide (WHO, 1972). There are many health problems potentially linked to
indoor air pollution; for instance, studies in China reported that coal smoke was a strong risk
7
factor for lung cancer among non-smoking women while another study in Japan has related lung
cancer to the past use of biofuel in cooking (Deckoning et al., 1985).
In the Gambia children under the age of five carried on their mother’s back during
cooking, has a six times higher risk of acute respiratory infections – a substantially higher risks
factor than their parent smoked. The source of health problems associated with indoor air
pollution include acute and chronic respiratory infections, tuberculosis, pneumonia, asthma, eye
diseases (cataract), lower birth rate, high infant mortality rate, malignancies of the digestive tract
and lungs, dermal and mucosa irritation (Dawson, 1983). However, these can be attributed to
short and long term effects. The extent to which the harm is affected depends on total exposure
and concentration of the air pollution (World Resources Institute WRI, 1998). Apart from the
enormous detrimental health effects, environmental impacts cannot be over looked. Demands for
traditional fuel also place significant pressures on local forests and woodlands, contributing to
deforestation, soil erosion and desertification. Frequently, the need for wood is so great that
afforestation attempts of badly degraded regions proves impossible because even young trees are
rapidly harvested for cooking fuel or charcoal production. The severely affected regions, the
poorest fuel sources, animal manures, grasses, crops residues, roots and shrubs are also
harvested. This increasingly common practice in parts of Africa and South Asia lead to a
spiraling loss of soil fertility as natural fertilizers is not returned to the ground. (Donna,1999).
1.9 Street Dust
Dust kicked up by vehicles traveling on roads may make up 33% of air pollution. Street
dust consists of deposition of vehicle exhausts and industrial exhausts, tire and brake wears, dust
from paved roads or potholes, and dust from construction sites. Street dust represents a
8
significant source contributing to the generation and release of particulate matter into the
atmosphere. Control of street dust is a significant challenge in urban areas, and also in other
spheres with high levels of vehicular traffic upon unsealed roads such as mines and garbage
dumps. The component and quantity of street dusts is an environmental pollution indicator in big
cities as a source of outdoor air pollutant. (Yeung et al.,2003; Sezgin et al., 2004). The urban
environment is composed of varying concentrations of trace elements from a vast array of
anthropogenic sources (Hodel and Chang, 2004) as well as from natural geochemical processes
(Shakourn and El-Talib, 1995). Street dust particles can be grouped into: Elements
geochemically associated in nature as related to resuspension of soil particles as their main
source are building construction, renovation and weathering of building materials, Elements of
anthropogenic origin, that is, traffic, petrol and diesel operated generating machines, coal
combustion or domestic heating and Elements related to industrial activity in an area. (Loredo et
al., 2003).
Street dust, particles deposited on road, originates from the interaction of solid, liquid and
gaseous materials produced from different sources (Banerjee, 2003).
1.10 Heavy Metals
Heavy metals are natural constituents in nature, usually occurring in low concentration under
normal conditions. Anthropogenic activities can cause elevated levels of these metals in various
parts of the ecosystem. Environmental pollution by heavy metals may occur via various diffuse
and point sources. Heavy metal scattering by traffic is an example of diffuse spread, while the
emission of heavy metals by industrial establishments like metal smelters and iron works
represents point sources. Traffic activities on roads can contribute to elevated levels of heavy
9
metals in these environments through fossil fuel combustion, wear and tear of many parts of the
automobile, in addition to natural sources, as they might exist in the rocks of the surrounding
areas.
Heavy metals have been widely used in other research projects and therefore comparative
data are readily available. Many studies have examined the contribution of individual
components of the urban hydrological cycle to the transport and storage of heavy metals
(Lees, 1994; Xanthopolous and Hahn, 1993; Morrison et al., 1988; Gibson and Farmer, 1984;
Hamilton et al., 1984). Heavy metals may come from many different sources in urbanized areas,
including vehicle emissions, industrial discharges and other activities (Harrison et al., 1981).
Atmospheric pollution is one of the major sources of heavy metal contamination. Heavy metals
can accumulate in topsoil from atmospheric deposition by sedimentation, impaction and
interception. Top-soils and roadside dusts in urban area are indicators of heavy metal
contamination from atmospheric deposition. It has been noted that roadside soils near heavy
traffic are polluted by Pb and other metals (Wong and Mak, 1997).
Heavy metal pollutant in urban street dust has become a growing concern in recent years. In
Nigeria, Street dust is one major way through which heavy metals may find their way into soils
and subsequently living tissues of plants and human beings. In monitoring urban pollution, there
is need to consider the materials that cause the occurrence of pollutants. Chemical and biological
indicators are of interest when they provide information on the concentration and accumulation
in the ecosystem.
A range of metals and chemical compounds found in the street dust environment are harmful.
Pollutants can attack specific sites or organs of the body and disease can develop as a
consequence to such exposure (Archer and Barratt, 1976; Ayodele and Gaya, 1998). Although
10
there have been considerable number of studies on the concentration of heavy metals in street
dust, the vast majority have been carried out in developed countries with long histories of
industrialization (Jaradat and Momani, 1999). Very few studies have been carried out in
developing countries like Nigeria. Little interest has been focused on the contamination of street
dust by other heavy metals in Nigeria. Such data on pollutant metal concentration of street dust
in such areas are extremely scarce.
Humans and other living organisms are exposed to a variety of heavy metals that are released
into the environment. The uptake of these metals occurs through three main routes: dermal
absorption, inhalation and ingestion of contaminated dusts and soils, It has been noted that
children of age 1-8 are of specific concern for this pathway via their hands or mouths (Watt et
al., 1993).
Most trace elements especially the heavy metals remain in the soil nearly indefinitely. These
metals remain bound to organic matter unless they are remobilized mechanically as wind blown
dust (Turer et al., 2001). Human exposure to metals and their compounds in the environment is
through food, drinks and water. Other forms of uptake are via skin contact. (Ewers and
Schlipkőter, 1991a). However, over a period of time, adverse toxic effects may occur as a result
of long-term low-level exposure (Ewers and Schlipkőter, 1991). Motivations for controlling
heavy metal concentrations in gas streams are diverse. Some of them are dangerous to health or
to the environment (e.g. Hg, Cd, As, Pb, Cr), some may cause corrosion (e.g. Zn, Pb), some are
harmful in other ways (e.g. Arsenic may pollute catalysts). Within the European community the
13 elements of highest concern are As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sn, and Tl, the emissions
of which are regulated in waste incinerators. Some of these elements are actually necessary for
humans in minute amounts (Co, Cu, Cr, Mn, Ni) while others are carcinogenic or toxic,
11
affecting, among others, the central nervous system (Mn, Hg, Pb, As), the kidneys or liver (Hg,
Pb, Cd, Cu) or skin, bones, or teeth (Ni, Cd, Cu, Cr) (Banerjee A. 2003; Charlesworth et al.,2003
and Lu X et al., 2010). Heavy metal pollution can arise from many sources but most commonly
arises from the purification of metals, e.g., the smelting of copper and the preparation of nuclear
fuels. Electroplating is the primary source of chromium and cadmium through precipitation of
their compounds or by ion exchange into soils and muds, can be localize and lay dormant. Unlike
organic pollutants, heavy metals do not decay and thus pose a different kind of challenge for
remediation.
As an indicator of environmental pollution, the following metals were chosen for analysis:
cadmium (Cd), nickel (Ni), iron (Fe), chromium (Cr), and lead (Pb). Wood (1974) indicated that
these metals have known pollutant properties, are toxic and readily available to the environment.
The purpose of this paper is to assess the environmental impact of traffic by investigating the
distribution of heavy metal concentrations in street dust of major roads in the sabon-gari market,
zaria.
1.11 Toxic effects of heavy metals
Many heavy metals act as biological poisons even at parts of per billion (ppb) levels. The
toxic elements accumulated in organic matter in soils are taken up by growing plants (Alloway
and Ayres 1997). The metals are not toxic as the condensed free elements but are dangerous in
the forms of cations and when bonded to short chains of carbon atoms (Lees, 1994). Many
metals with important commercial uses are toxic and hence undesirable for indiscriminate release
into the environment (Bouce et al., 1990).
12
The uncontrolled input of heavy metals in soils is undesirable because once accumulated into
the soil, the metals are generally very difficult to remove (Walt et al., 1993). Subsequent
problems may be toxicity to the plant growing on the contaminated soils and uptake by the plants
resulting in high metal levels in plant tissues.
Generally, at the biochemical levels, the toxic effect caused by excess concentrations of
heavy metals include competition for sites with essential metabolites, replacement of essential
ions, reactions with SH groups, damage to cell membranes and reactions with the phosphate
groups (Alloway and Ayres, 1997).
1.12 Justification
This research is timely because:
 of the rising incidence of poor air quality which is a major nuisance for many and a
serious concern for some in the industrializing cities and confined environments
which concerted efforts to addressing it only began in the 20th Century (Hassan et. al.,
2003).
 Air pollution is a major environmental health problem affecting both developed and
developing countries; that air pollution causes ill health and death is well documented
(WHO, 2003).
 While air quality remains a principal environmental concern affecting the health and
quality of life of the residents and people in urban areas across the world, little or no
13
studies have been conducted on air quality in Zaria, thus the need to embark on such
studies.
1.13 Aim and Objectives
The aim of this research is to determine the presence and concentrations of some gaseous
pollutants in ambient air and some trace metals in street dust at the Sabon-Gari Market Zaria and
Aliyu Mustapha Social Centre, Ahmadu Bello University, Zaria, thus, serving as the base data
for gaseous pollution level in these locations in Zaria. This aim would be achieved through the
following objectives:
 To ascertain the presence and concentration of some gaseous pollutants such as CO, H2S
and SO2 at the Sabon-Gari Market Zaria and Aliyu Mustapha Social Centre, Ahmadu
Bello University Zaria.
 To determine how the concentration of these gases varies daily from morning through
afternoon to evening.
 To determine the levels of heavy metals such as Cr, Cd, Ni, Pb and Fe in street dust from
Sabon-gari market in Zaria.
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