Peak Journal of Physical and Environmental Science Research Vol.1(2), pp. 12-22, June, 2013
http://www.peakjournals.org/sub-journals-PJPESR.html
ISSN 2331-575X
©2013 Peak Journals
Full Length Research Paper
Acidic rain probability and solid aerosol concentration in the
atmosphere of Faisalabad (Pakistan)
Shahid M. A. K.1*, Awan M. S.1, Hussain K.2 and Sabir R1
Accepted 31 May, 2013
In the present study, an attempt has been made to study the impact of soilderived aerosols on the rain acidification using the data of high volume
sampler set up at different locations of the Faisalabad city. The solid
aerosol exhibits significant positive correlation with rain pH indicating the
alkaline behavior. The more the solid aerosols are present in the
atmosphere, the more the alkalinity of the rain water. It has also been found
statistically that the rainfall pH is a function of soil pH. Thus the rain water
at a particular place possesses all the fundamentals characteristic of the
nearby soil. The rainfall weighted pH value of last five years with respect to
ten Faisalabad stations randomly selected using standard techniques have
therefore been used along with the pH value as determined by various
other workers in different parts of the world and on that basis, International
Organization for Standardization (ISO) pH curves have been drawn and
utilized, and finally, the pH regionalization has been made. Thus on the
basis of this study, the entire Faisalabad city can be divided into three such
zones as follows; normal pH zone N, high pH zone H, and very high pH
zone VH. The implications of these findings were discussed in this paper.
Key words: High volume sampler, solid aerosols concentration, precipitation
gap, ISO pH curves, rainfall pH zoning remedial measures.
1Department
of Physics, G.C.
University,
Faisalabad,
Punjab,
Pakistan.
2Department of Physics, High Energy
Physics, Punjab University, Lahore,
Punjab, Pakistan.
*Corresponding
author.
E-mail:
[email protected]. Tel.: +92
302 6062879.
INTRODUCTION
The main aim of the present study was to examine the
behavior of soil derived aerosols towards rain
acidification whether they influence the rain pH, if so then
to what extent? If the atmosphere was kept free from
these aerosols by some techniques then what will be the
normal pH value in such an environment? Such a study
gave clue about the probable region of high acidic rain
potential and helps us in preparing the acidic rain zoning
in the country which was considered to be of great
importance to the government in planning heavy
installation and industries in such zones and if necessary
to take precautionary measures to protect human beings,
animals, agriculture, soil and structures from the harmful
effects of acidic rain.
During clouding and subsequent rain formation,
sufficient mixing actually takes place in the atmosphere
where by the soluble components of these soils; derived
aerosols, dissolved in the cloud column, influencing the
pH value of the rain water. The other observers took
some aero plain observation and noticed that the rain that
dropped immediately coming out from the clouds
possesses relatively low pH. But when they reach the
earth surface, the pH increases (Mudgal et al., 2002).
Therefore the environment through which the rain drops
travel plays an important role in deciding the rain
acidification at each location. In the tropics, the
atmosphere has high dust load almost throughout the
year except the costal belt. Therefore the dust was
considered to be an important factor in influencing the pH
rainfall. When clouds form, they contain millions of water
droplets in each cubic meter of air. Each of the cloud
droplet forms on a solid aerosol, so the amount of water
droplets in the clouds is the same as that of solid
aerosols at that time in the atmosphere; so the number of
solid aerosols and their physio-chemical characteristics
have different impacts on climate. Prevailing winds below
the compounds causes both wet and dry acidic
deposition over hundreds of miles. Scientists have
confirmed that acidic rain occurs when sulphur dioxide
(SO2) and nitrogen oxides react in the atmosphere with
Shahid et al.
water, oxygen and other chemicals to form various acidic
compounds (Weathers and Likens, 2006). Sunlight
increases the rate of these reactions through photolysis
and enhances the mild acidic rain chances. Acidic rain
occurs or not in a certain area is measured with pH
values of air and water samples. The lower the pH value,
the more the chances of acidic rain and converse. Pure
water has a pH value 7.0 and is neutral. Normal rain is
slightly acidic due to dissolvation of CO 2 from the
atmosphere. In year 2000, pH value of most of acidic
rains occurring in North America was measured at about
4.3. To check the acidic rain probability, pH value was
used as a yard stick (EPA, 2003).
Concepts of ISO pH curves
In order to identify and then locate precisely the regions
of high and low pH in rain water, the rainfall weighted pH
value of ten Faisalabad stations has been plotted along
with the pH value as determined by various other workers
in different part of the world and the ISO pH lines have
been drawn on their basis which demarcates the high
and low pH zone in Faisalabad separately. North west
Faisalabad experiences high pH values ranging from 8.0
to 9.0 while the south east belt represents regions of low
pH = 6 to 7 which may be considered as a potential
region of acidic rain occurrence. From these figures, one
can easily infer the region susceptible to acidic rain at
Faisalabad in the near future. The main reason behind
this is that northwest Faisalabad contains huge load of
soil oriented particulates in the atmosphere which are
predominantly alkaline in nature. It consists mainly of
carbonates and by-carbonates of calcium, magnesium,
sodium, potassium and cations, while the south east belt
because of its geographical and geological setting, does
not possesses such a high density of soil particulate in
the atmosphere. To confirm this, impact of suspended
particulate matter (SPM) on pH value has been studied
(Ang and li, 1984; Ayrault et al., 2010; Chen et al., 1986;
Freitas et al., 2010; Garcia et al., 2011; Hansen et al.,
2002; Hao et al., 2007; Hu and Buyanovsky, 2003).
Study of solid aerosols
The five year average concentration of suspended
particulate matter collected from different sites selected in
the
Faisalabad
atmosphere
reveals
the
high
concentration of suspended particulate matter in North
West Faisalabad while the density at the southern coastal
belt is lower, which gives us a clue that high rainfall pH
values are actually caused by the high concentration of
dust particulate in the atmosphere over north west
Faisalabad. The low values of suspended particulate
matter (SPM) concentration in the belt are mainly responsible for low pH values in the region because acidic
neutralizing capacity decreases there. This reflexes the
13
alkaline behavior of SPM. This state of affairs indicates
an increase in the pH values with the increase in the
concentration of suspended particulate in the atmosphere
thus confirming the alkaline behavior of SPM. It can be
seen that in a clean unpolluted atmosphere free from all
SPM, the pH value are in the acidic range; that is, pH =
5.57. Thus any increase in pH values over this value is
actually called by the soil derived particulates present in
the atmosphere over the region as a neutralized agent for
the rain acidification (Tables 1 and 2) (Harte, 1983; Ji and
Cheng, 1982; Lau and Charison, 1977; Li and Wang,
1984).
Soil pH and rain pH core relationship
The nature intensity frequency and precipitation
distribution influences the course of soil formation at a
place. Normally with increasing moisture, N and C
contents, Clay contents, aggregation, and saturation
capacity of exchangeable hydrogen tend to increase; on
the other hand, exchangeable basis and pH values show
a decrease with increasing moisture. The depth of
calcium carbonate, horizon in pedicel soils increases with
increasing moisture. Under tropical Asian condition, clay
contents have shown a decrease with an increase in
rainfall possibly because of decomposition of clay to form
secondary concentration. The windblown soil particles
representing the soil characteristic reach the atmosphere
and react with following rain drops whereby its soluble
components dissolve there in the rain water thus
influencing its pH values. Therefore the impact of the
nature of the soil towards the rain acidification is profound
and has been studied accordingly.
Precipitation gap
The nature of the first rainy showers after a precipitation
gap of a few months indicates longer periods for the
atmosphere to be filled by both the alkaline particulate on
one hand and the acidic components due to
anthropogenic emission on the other hand. Thus the
resultant nature of the atmosphere is found to be alkaline
or the alkaline balance in the atmosphere tilts in favour of
alkalinity. In pH zoning at Faisalabad, the atmosphere is
considered as a huge reservoir into which some gases
are dumped, thus considering the total input in the
atmosphere through anthropogenic, biogenic, agricultural
and other natural activities. The rainfall pH zoning at
Faisalabad has been made on the basis of the results
obtained in present study. Accordingly, Faisalabad can
be divided into three such zones:
1. Normal pH zone N. pH from 6 to 7.
2. High pH zone H. pH from 7 to 9.
3. Very High pH zone VH. pH > 9 and above.
Peak J. Phys. Environ. Sci. Res.
Table 1. Some physical parameters of collected solid aerosols.
Sample code
2K01
2K20
2K03
2K04
2K05
2K06
2K07
2K08
2K09
2K10
2K11
2K12
2K13
2K14
2K15
2K16
2K17
2K18
2K19
2K20
2K21
2K22
2K23
2K24
2K25
2K26
2K27
2K28
2K29
2K30
2K31
2K32
2K33
2K34
2K35
2K36
2K37
2K38
2K39
2K40
2K41
2K42
2K43
2K44
2K45
2K46
2K47
2K48
2K49
2K50
Color
Dull Yellow
Light Gray
Green Tinge
Green Tinge
Green Tinge
Green Tinge
Light Green
Light Green
Brown
Black Tinge
Black Tinge
Black Tinge
Black Tinge
Blakish Brown
Light Gray
Light Gray
Light Gray
Light Yellow
Dull Green
Dull Green
Black
Light Yellow
Light Gray
Light Green
Dull Green
Dull Green
Dull Green
Dull Green
Dull Green
Dull Green
Light Green
Light Green
Yellow Tinge
Brown
Black
Black
Black
Black
Black
Black
Muddy Gray
Muddy Gray
Muddy Gray
Shining Gray
Shining Gray
Dark Gray
Dark Gray
Dark Gray
Dark Gray
Balkish Gray
Sample code
2K51
2K52
2K53
2K54
2K55
2K56
2K57
2K58
2K59
2K60
2K61
2K62
2K63
2K64
2K65
2K66
2K67
2K68
2K69
2K70
2K71
2K72
2K73
2K74
2K75
2K76
2K77
2K78
2K79
2K80
2K81
2K82
2K83
2K84
2K85
2K86
2K87
2K88
2K89
2K90
2K91
2K92
2K93
2K94
2K95
2K96
2K97
2K98
2K99
2K100
Color
Balkish Gray
Balkish Gray
Balkish Gray
Black
Black
Black
Black
Black
Blakish Brown
Blakish Brown
Blakish Brown
Blakish Brown
Blakish Brown
Blakish Brown
Blakish Brown
Blakish Brown
Brownish Black
Brownish Black
Brownish Black
Black
Black
Black
Black
Black
Black
Blakish Brown
Blakish Brown
Blakish Brown
Gray
Gray
Gray
Yellow
Yellow
Yellow
Yellow
Light Gray
Light Gray
Light Gray
Light Gray
Gray Tinge
Gray Tinge
Dull Green
Light Gray
Light Yellow
Light Yellow
Light Yellow
Black
Blackish Brown
Brownish Brown
-------do-------
14
Shahid et al.
Table 2. pH and electrical conductivity of solid aerosol samples.
Code
2K01
2K20
2K03
2K04
2K05
2K06
2K07
2K08
2K09
2K10
2K11
2K12
2K13
2K14
2K15
2K16
2K17
2K18
2K19
2K20
2K21
2K22
2K23
2K24
2K25
2K26
2K27
2K28
2K29
2K30
2K31
2K32
2K33
2K34
2K35
2K36
2K37
2K38
2K39
2K40
2K41
2K42
2K43
2K44
2K45
2K46
2K47
2K48
2K49
2K50
pH for rain
water
8
8
8
7
7
8
8
8
7
7
7
7
8
7
8
10
9
7
9
10
10
7
8
8
8
7
7
7
7
8
9
8
8
8
8
8
8
9
9
9
9
7
7
9
8
8
9
9
8
8
For
SPM
6.7
6.7
6.8
7.1
6.9
6.6
6.8
6.1
6.8
6.8
6.9
5.2
6.1
6.0
7.2
9.0
6.1
3.5
6.5
6.9
7.8
6.5
6.9
6.1
7.5
6.2
7.0
8.0
8.0
6.9
6.2
6.2
7.3
6.9
6.2
6.5
7.2
6.9
7.1
6.8
8.2
6.9
6.9
6.5
7.8
6.9
6.5
3.5
6.2
7.2
Ec (ds/m)
Code
4.12
3.52
3.02
3.61
3.17
3.23
3.09
3.13
2.86
3.19
5.70
1.99
2.39
2.14
4.87
5.25
4.25
2.93
2.93
4.16
3.18
3.32
3.04
4.18
2.09
2.35
5.29
5.19
3.97
4.33
5.29
1.06
2.37
2.61
2.21
2.62
2.21
4.28
1.74
3.98
1.67
1.74
3.71
3.61
3.56
3.61
4.01
3.60
3.62
4.01
2K51
2K52
2K53
2K54
2K55
2K56
2K57
2K58
2K59
2K60
2K61
2K62
2K63
2K64
2K65
2K66
2K67
2K68
2K69
2K70
2K71
2K72
2K73
2K74
2K75
2K76
2K77
2K78
2K79
2K80
2K81
2K82
2K83
2K84
2K85
2K86
2K87
2K88
2K89
2K90
2K91
2K92
2K93
2K94
2K95
2K96
2K97
2K98
2K99
2K100
pH for rain
water
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
9
9
8
8
8
8
8
8
8
8
8
8
8
8
8
7
7
8
8
7
8
7
8
7
7
8
7
7
7
7
For SPM
Ec (ds/m)
6.0
6.2
5.2
6.8
7.5
5.9
6.7
6.0
6.9
6.4
6.7
6.7
6.9
6.8
6.2
6.8
6.6
7.0
6.8
6.7
6.9
7.0
6.5
7.1
7.5
7.2
6.5
6.2
6.9
7.3
6.2
6.9
7.2
8.1
6.2
6.5
7.1
6.5
6.2
7.07
7.2
6.8
7.5
7.07
6.2
6.2
6.5
7.0
7.2
7.6
2.84
2.71
1.24
2.62
2.51
2.04
2.04
3.91
3.56
3.57
3.59
3.59
3.55
2.84
1.06
2.37
1.08
3.59
3.58
3.54
1.40
1.14
1.59
1.14
2.56
2.59
2.59
2.58
7.09
3.71
1.79
3.12
2.21
1.62
3.51
11.7
13.3
5.00
9.50
11.50
9.30
9.90
7.30
9.90
6.60
6.30
11.40
7.00
5.4
14.3
15
Peak J. Phys. Environ. Sci. Res.
In the sensitive zones S-I and S-II, the prime acid
neutralizer; that is, NH2 and alkaline salts were found
deficient. Apart from this, the access anions over cations
have been observed in the regions which are of marine
origin and so if some industries are setup in such regions,
then they are liable to create acidic rain problems in the
region. The acidic rain probability may however be
completely ruled out in H zone because of the strong
resisting capacity offered by the soil derived aerosols to
completely neutralize any trace of substances present in
the atmosphere. N zone is also considered to be free
from acidic rains at present. But in the near future, if the
capacity of the alkaline particulates to neutralized acidic
components weakens due to changes in soil nature and
composition caused by the quality and quantity of rain
and further industrialization, it may then be turned into
sensitive zone S-II future study on the subject which will
however throw some more light on the subject (Mo et al.,
1984; National Environmental Protection Agency, 1983;
Shahid et al., 2012a, b; Stenseth, 2002).
The purpose of this study is to present the current
scientific understanding of the causes and effects of
acidic rain on the basis of solid aerosol connection by
studying the important parameters of air quality like color
of solid aerosols, their Ec and pH value, fall rate, latitude
effect, dispersion patterns, interlocking capability, soil and
rain pH value co-relationship along with weight
percentage of gaseous pollutants and probability of acidic
rain which were calculated. It is hoped that this study will
provide significant insight into understanding the sources
of solid aerosols, which can be used to design future
monitoring and control strategy on the basis of zoning
and pooling technique knowledge about pH and Ec of
rain water which will provide valuable information on the
prevailing state of atmospheric air pollution and its corelation with the acidic rain probability.
MATERIALS AND METHODS
Aerosol sampling was carried out at NIAB, Radiation
Physics lab covering almost all the aspects of rural urban
areas in its surrounding. The solid aerosols were
collected using high volume air sampler with flow rate of
3
0.8 m /m having efficiency of 99% on watt men EPM
2000 fiber glass filter for the period of 12 h. pH by pH
meter model no. 8520 (HANNA) with accuracy ± 0.01 and
Ec by Ec meter model LF 530 (WTW) USA with accuracy
± 0.01 respectively wind direction data was also collected
from NIAB weather station, using the method of Steel and
Torre (1981), regression equations were developed for
flow rate, latitude effects, wind direction effect and were
used for calculation purposes.
RESULTS AND DISCUSSION
Tables 1 and 2 give record of pH values, electrical
16
conductivity and concentration of solid aerosols. Table 2
shows that pH values of all the solid aerosols were
between 7 and 10 with a majority of them having values
of 8. This shows that most of the samples were of
alkaline nature which gives an indication that there are
less chances of acidic rain in Faisalabad environment for
the time being, but random increase in number of
vehicles and industrial unit may cause acidic rain in future
in the normal zone. Though one cannot rule out the
presence of flue gases such as NOx, HC, CO and SO2 in
Faisalabad environment which are of acidic nature but
unable to cause acidic rain due to calcite loading. These
tables also show that values of concentration of solid
3
aerosols were between 122 and 1180 µg/m against pH
values which were between 8 and 10. No relationship
between these two quantities was found, which is against
the other studies in which the low value of electrical
conductivity of most of the samples indicate that the
major contributor to the said aerosols is soil derived
minerals. The anthropogenic content of samples appears
to be a minor contributor. Low values of electrical
conductivity also indicate clean environment, showing
non solubility of the pollutants in water. Electrical conductivity is more favorable through solids and stagnant fluids,
less responsible in liquids and gases along with clean
and fresh environment.
Molecule in the atmosphere are continuously moving
and colliding with each other according to kinetic theory
of gases. The atmosphere is also continuously
illuminated during day time resulting in the absorption of
energy by atmospheric molecules causing photochemical reaction; such reaction play an important role in
determining the atmospheric composition and fate of
many chemical species including solid aerosols that
contribute to air pollution. Aerosols are small enough to
remain suspended in the atmosphere for longer period of
time. Due to their large surface area, they have great
capacities to absorb and concentrate chemicals on their
surfaces and provide media for chemical reactions to
occur. Virtually all rain in nature was acidic. The ―acidic
rain‖ refers to the addition of SO2 (fuel consumption) and
NOx (vehicle use) (Table 10).
Contamination of rain water by high concentration of
atmospheric pollutants especially solid aerosols is of
great concern on both regional and global scales. In this
study, physio-chemical compositions of solid aerosols
and chemical composition of rain water provides an
understanding of pollutant source type and rain water
chemistry, and enhances the understanding of local,
regional and global information on the prevailing state of
atmospheric environment of that particular area, region or
country. In this study, an attempt has been made to study
some physio-chemical parameters of solid aerosols like
pH value, Ec along with latitude and wind direction effects
coupled with nucleation model and to develop its corelation with rain water for better understanding of the
probability of acidic rain occurrence in the region.
Shahid et al.
17
Figure 1. Formation of pollutant web and atmospheric neutrality.
Tagging this study with our previous studies already
published in well reputed journals, possible justifications
has been given to supplement the said understanding
and experimental findings of this study. Acidic rain
probability was calculated using simple mathematical
expressions, on the basis of pH value.
And on the basis of color
It was observed that flow rate is directly proportional to
temperature and inversely proportional to relative
humidity. Expansion and contraction of zone of pollution
was observed during hot and cold days; days and nights.
This confirms that the change in climatology directly
affects the shape and size of pollution zone. In other
words, we may say that by increasing or decreasing the
pollutant concentration, the climatology and acidic rain
probability was controlled.
Regression equation used
Y  142.765  0.0595X 
2
With R = 0.099, where Y = TSPM (Rate) and X =
distance from the source of TSPM. Fall rate was
calculated using the relation fall rate= 21.63 wt/ A
2
(Tons/Km /month) Where wt = Total weight of the TSPM
2
2
(g/cm ), A = surface area of the deposited dish (cm )
*Concentration is inverse square law follower.
N-W high concentration maximum load of TSPM is from
Sheikhupura to Jhang while S-E Low concentration
minimum load of TSPM is from Sahiwal/Okara to
Sheikhupura, which is due to geographical and geological
setup of the selected environment (Figure 1).
Several contradictory questions about atmospheric
nucleation and acidic rain probability about the
substances that contribute in the prediction of acidic rain
probability and size along with composition of cloud
clusters have not been resolved fully yet. Generally, an
increase in the concentration of dislocations will raise
interfacial energy between the ice embryo and the
nucleating particles hence decrease its nucleability. A
simple theoretical model proposed by Vonnegut (1947)
was used to answer the above questions. Most of the
phase contributing in the atmospheric pollution have
large values of lattice misfit and are poor nuclei
particularly quartz, calcite, and albite identified in this
study. They remain suspended in the atmosphere for
long period of time depending upon their size and hence
contribute positively toward atmospheric pollution and ice
nucleation (acidic rain) (Table 6) through nucleation,
condensation and coagulation processes (Waheed et al.,
2006; Ghauri et al., 2007; WorldBank, 2006; Thakre and
Joshi, 2001; Singh et al., 2001).
From the present study, it was quite clear now, that soil
Peak J. Phys. Environ. Sci. Res.
Table 3. Acidic rain probabilities in different zones.
Zone
N Zone
H Zone
VH Zone
pH value
7-8
8-9
9 and above
Probability
percentage (%)
49.42
41.86
8.72
Table 4. Acidic rain probability on the basis of
solid aerosol color.
Color
Light color (Acidic)
Dark color (Basic)
Probability (%)
20
80
Key: N, normal; H, high; VH, very high.
Table 5. Latitude effect on the concentration of particulate matter.
Serial No
2K01
2K02
2K03
2K04
2K05
Latitude (m)
3
6
9
12
15
2
Fall rate (Tons/km /month)
125
105
89
72
55
derived aerosols which are basic in nature, consisting
mainly of calcium Ca, Mg, Na, K, Cations, in the form of
carbonates, bicarbonates, phosphate and silicates play
an important role in controlling the rain acidification at a
place. Out of these pH is affected more by calcium rather
than sodium, potassium and magnesium; cations as the
calcite in the dust readily react with the acids in the rain
water. Quartz, carbonates, field spares, clay minerals and
fly ash are most important constituents of the natural dust
which are sufficiently available in the tropical soils and
from there they find their way to the atmosphere lifted up
by winds. North West Faisalabad is the only region in the
country with maximum industrial cum transportational
pollutant burden where the probability of acidic rain in
near future may not be ruled out, though the pH trends
are decreasing there too but very slowly. The rest of the
Faisalabad city is susceptible to acidic rain having pH
zones between 6 and 7, and overall probability of
occurrence of acidic rain at Faisalabad was estimated at
20%. The pH regionalization of Faisalabad on the basis
of these results is therefore of great importance; it is
specially so for developing countries like Pakistan where
the large industries are set up very frequently in different
parts of the city without any prior knowledge and
sensitivity of the acidification (Tables 3 - 9).
The wide variations in pH may be attributed to the
18
relative contributions in the solid aerosol scavenged by
cloud and rain drops. The pH is not sufficient to
characterize the acidity of precipitation, but rather its acid
base components must be considered. Generally, the
cloud droplets are initially acidic due to the formation of
HNO3. High pH values of more than 8, and as was noted
by us in the majority of the samples from Faisalabad
environment, may be due to the alkaline species
dominant over the acidic species, and pH values less
than 8 of industrial areas show converse behavior.
Moreover, the solid aerosols are highly hydrophobic and
are present in the Faisalabad atmosphere in high
concentration; they can enter the rain drops via variety of
—
scavenging process. Acidic SO4 present in drops is
neutralized by minerals such as CaCO3, NaHCO3 or
Na2CO3 to form CaSO4 or NaHSO4 and the excess
carbonates, dissociated in the solutions cause the rain
drops to be more alkaline. More than 70% samples had
shown low electrical conductivities which may be due to
the rain, fallen through the washed atmosphere. The data
was also compared with the measured electrical
conductivity on the basis of anion and equivalence and
was found to be in good agreement with the other
national and international studies (Wang et al., 1981,
1983; Wang, 1986; Yu et al., 1985; Yu, 1985; Zhao,
1984).
In another study tagged with this study, it was found
that in most of the samples, identified phases occur as
patches rather than single grain, so heterogeneity and
aggregation of the Faisalabad environment was a
dominating factor. One possible explanation is that
oxidation processes have converted the sulphides of
identified phases into a soluble hydrous sulphate which
was confirmed by the sulphate mineral as gypsum
detected in clay minerals by XRPD technique. The other
possible explanation is that to produce aggregates, there
must be some mechanism that groups particles to gather
into clusters and also some means by which they are
firmly bound so that the structural form persists. Clay
minerals, oxides of iron and manganese, along with
colloidal organic matter are important cementing
materials, as colloidal particulate matter are charged
bodies, dipole water molecules attach themselves firmly
as water molecules also carry positive and negative
charges due to evaporation of water molecules from
particulate matter, length of each linkage becomes
shorter and shorter, making cemented bonds stronger
and stronger, due to this conjunction aggregates are
formed (Figures 2 - 4).
Rocks and minerals or near equilibrium in the
atmosphere adjust to the greatly reduced temperature
and pressure in the environment; this re-adjustment or
changes due to abnormal variation in temperature and
pressure are called weathering. Rusting of metals,
cracking of side walls and lost mortar between bricks are
the few examples of weathering process. Major chemical
weathering reactions due to abundance of water, oxygen
Shahid et al.
19
Table 6. Fall rate (Tons/km2/month)/ wind direction.
Distance (m)
3
6
9
12
15
N-W
174
148
128
106
85
S-E
78
64
52
38
25
N-E
126
108
94
72
55
S-W
105
102
86
72
54
Table 7. Comparison of cell dimensions of ice nuclei and minerals identified in suspended particulate matter.
Identified phase
ICE
QUARTZ
ILLITE
CHOLIRIDTE
CALCITE
GYPSUM
TALC
ALBITE
Crystal system
HEXAGONAL
HEXAGONAL
MONOCLINIC
MONOCLINIC
HEXAGONAL
MONOCLINIC
MONOCLINIC
TRICLINIC
o
a (A )
4.490
4.913
5.190
5.320
4.989
5.680
5.287
8.144
o
c (A )
7.338
5.450
20.160
14.290
17.062
6.510
18.964
7.160
Basal Misfit % age
----9.2
15.4
18.3
10.9
16.3
17.5
81.0
Prism Misfit % age
----17.8
95.1
56.1
71.7
18.8
88.0
41.7
Figure 2. Anatomy of solid aerosol.
and carbon dioxide accounts far hydration, oxidation and
carbonation reaction. These reactions result in distraction
of existence mineral and synthesis new minerals. Sodium
chloride exits as the natural mineral halite. Sodium and
chlorine exist in the crystals as ions that attract each
other at the crystal faces; the sodium and chlorine ions
respectively attract the negative and positive poles of
water molecules. Adsorption of water molecules
dislodges the sodium and chlorine from the crystal and
greatly increases their solubility; in this way mineral
dissolved in water are washed out, which accounts for
the general absence of halite in the hummed regions,
which is similar in the case with other missing minerals.
There are two major groups of clay minerals; the silicate
clays which include illite, montmoriclonite, vermiculite and
kaolinite and the oxide clays which include primarily iron
and aluminum oxides. The complexity of weathering
system makes identification of their specific origins
impossible.
The nature of the weathering environment plays an
important role in determining when a given mineral will be
from. Illite formation is common in the temperature
Peak J. Phys. Environ. Sci. Res.
20
Figure 3. Structure formation for solid aerosol.
Figure 4. Digital scans of solid aerosols collected from sites of scientific interest showing colloidal formation .
regions where weathering environment has not been
intense. Alteration of mica minerals by the partial loss of
structural potassium and hydration is a common mode of
Illite formation. Montmoriclonite formation requires an
abundant supply of magnesium and a neutral or only
slightly acidic environment (pH value of most of the
samples lies in alkaline phase). In the temperature
regions, Illite can be altered into Montmoriclonite.
Ca
Mg
K
Na
+
+
+
+
2H2O
Ca++ +
2H2O
++
H2O
H2O
Adsorbed Phase
Mg
+
K
Na
+
+
++
+
Solution Phase
2OH -
+
2H -
2OH
-
+
2H -
OH
-
+
H-
OH
-
+
H-
Adsorbed Phase
PH Value
7
5.5
6 ------ 7
H Saturation
15%
50%
-------------
Base Saturation
85%
50%
50%
The table was developed using the above expression.
Taking CEC approximately as 13 hydrolyses
exchangeable bases as source of OH for the soil
solution. The exchangeable bases are hydrated, but have
been shown not to be hydrated for simplicity of illustration
(Habib et al., 2004; Mehta et al., 2009; Faiz and Gautam,
2004). Another possible justification is that due to the
presence of fly ash, road dust and pollens present in the
Faisalabad environment which are synthesized by micro
Shahid et al.
Table 8. Concentration on the basis of concepts of
ISO curves verses rain pH.
Concentration
30
50
70
90
110
21
Table 9. Soil and rain pH comparative study.
Soil pH
4.4
5.0
5.6
6.2
6.5
Rain pH
5.5
5.8
6.3
6.8
6.0
Rain pH
6.0
6.4
6.8
7.2
8.0
r=0.587+/- 0.232
r=0.683+/- 0.129
Table 10. Weight percentage of gaseous pollutants.
A1
A2
A3
CO
63.73
64.67
64.87
HC
27.65
26.83
27.22
organisms gain positively and negatively charged groups
which have interlocked the identified phases into patches.
The oval and irregular shapes of the majority of the
samples also support our justification (confirmation of
presence of fibrous material) (Zhao et al., 1985a, b; Zhao
et al., 1986).
Conclusion
Chemical composition of rain water with respect to pH
value was carried out over a span of five years (2005 20011) at Faisalabad which gave the first hand
information of the region towards the knowledge of rain
water chemistry. Alkaline nature of rain water confirms
positive correlation with calcite as neutralizing agent. The
study of chemical composition of rain water to check the
acidic rain probability was carried out for Faisalabad
which represents the first attempt in the region to the
knowledge of rain water chemistry. This study suggest
that rain water is mostly of alkaline nature having good
co-relationship with Ca, Mg, K and Na which reveals that
the acidity of the atmospheric pollution is being
neutralized by soil derived components; other source
have relatively minor contributions. So it was concluded
that acidic rain and its harmful effects on ecology and
human beings can be reduced by reducing solid aerosol
pollution and enhancing soil contents especially calcite,
through eliminating recycling processes in residential
areas, installing industries beyond the city limits, and
focusing on green belts through plantation, as plants are
the natural pollution killers, filters and purifiers.
Recommendations
No doubt, the probability of acidic rain was ruled out for
NOx
6.05
5.92
5.50
SO2
2.57
2.60
2.40
the time being but it is the need of the hour that
awareness must be generated among the masses about
acidic rain and its hazardous effects on plant kingdom,
animal kingdom, human kingdom, soil and water along
with construction materials. This would definitely
pressurize the government to take effective steps to
control acidic rain chances in future for the time being.
The following 4 points strategy should be recommended
in this regard:
1. Use of scrubbers (SO2 remover) and catalytic
converters NOx reducer at smokestacks and exhaust
pipes.
2. Use of alternative cost effective energy sources like
CNG, LPG, hydro power, nuclear energy, geothermal
energy, etc.
3. Restoration of environment damage through liming
process (addition of lime stone to make it neutral).
4. Be environment friendly and play your individual role
by efficient and safer use of house hold appliances,
proper insulation, using public transport and taking active
part in plantation campaigns.
ACKNOWLEDGEMENTS
The authors feel great zeal of pleasure to thank the
Director NIBGE, Director NIAB Faisalabad, Punjab,
Pakistan for providing the laboratory facilities and to Dr.
Rana Muhammad Ajmal along with his technical team in
HI-TECH Lab and In-charge Metrological Cell
Department of crop Physiology, University of Agriculture
Faisalabad, Punjab, Pakistan, for providing us the SEM
and TEM along with other related facilities. Also for their
technical assistance when and where needed. Their
valuable suggestions, in time encouragements, healthy
Peak J. Phys. Environ. Sci. Res.
discussion and positive criticism in getting this work
completed with utmost ease and perfection.
REFERENCES
Ang M, li H (1984). ―Observationand preliminary analysis of acid rain in
1981 in Hangzhou, Nanning, Nanjing and Hefei‖. J. Environ. Sci.
5:52-54.
Ayrault S, Senhou A, Moskura M, Gaudry A (2010). Atmospheric trace
element concentrations in total suspended particles near Paris,
France. Atmos. Env. 44:3700-3707.
Chen S, Luo Q, Xu Y, Yan H, Zhao D, Zhang X (1986). ―Study of the
effects of acid precipitation on corrosion rate of metal materials‖.
Atmos. Environ. Acid Rain 1:39-44 (in Chinese).
EPA (2003). Acid Rain Progress Report: 2003 (EPA-430-R-03-011).
U.S. Environmental Protection Agency, Clean Air Markets Division,
Washington, DC: EPA.
Faiz A, Gautam S (2004). Technical and policy options for reducing
emissions from 2-stroke engine vehicles in Asia. Int. J. Veh. Des.
34(1):1–11.
Freitas MC, Pacheco AMG, Verburg TG, Wolterbeek HT (2010). Effect
of particulate matter, atmospheric gases, temperature, and humidity
on respiratory and circulatory diseases' trends in Lisbon, Portugal.
Environ. Monit. Assess. 162:113-121.
Garcia VC, Gego E, Lin S, Pantea C, Rappazzo K, Wootten A, Rao ST
(2011). An evaluation of transported pollution and respiratory related
hospital admissions in the state of New York. Atmos. Poll. Res. 2:915.
Ghauri B, Lodhi A, Mansha M (2007). Development of Baseline (Air
Quality) Data in Pakistan. Environ. Monit. Assess. 127:237-252.
Habib G, Venkataraman C, Shrivastava M, Banerjee R, Stehr JW,
Dickerson RR (2004). New methodology for estimating bio-fuel
consumption for cooking: Atmospheric emissions of black carbon and
sulfur dioxide from India. Global Biogeochemical Cycles, 18,
GB3007.
Hansen J, Ruedy R, Sato M, Lo K (2002). ―Global Warming Continues
Science‖, 295, pp. 275.
Hao YC, Guo ZG, Yang ZS, Fang M, Feng JL (2007). Seasonal
variations and sources of various elements in the atmospheric
aerosols in Qingdao, China. Atmos. Res. 85:27-37.
Harte J (1983). ―An investigation of acid precipitation in Qinghai
Province, China‖. Atmos. Environ. 17:403-408.
Hu Q, Buyanovsky G (2003). ―Climate effects on corn yield in Missouri‖.
J. Appl. Meteorol. 42:1626-1635.
Ji B, Cheng Z (1982). ―Acid rain pollution in China. J. Environ. Prot.
12:24-27.
Lau NC, Charison RJ (1977). ―On the discrepancy between background
atmospheric ammonia gas measurement and the existence of acid
sulfates as a dominant atmospheric aerosol.‖ Atmospheric 11:475478.
Li H, Wang M (1984). ―Some preliminary studies of acid precipitation in
China. acata Meteorologica Sinica‖. 42:332-339.
Mehta B, Venkataraman C, Bhushan M, Tripathi SN (2009).
Identification of sources affecting fog formation using receptor
modeling approaches and inventory estimates of sectoral emissions.
Atmos. Env. 43(6):1288-1295.
Mo T, Deng J, Zhao K (1984). ―Study of precipitation chemical
composition in Shita Mountain of Fujian. ActaMeterologicaSinica.
9:211-215.
22
Mudgal R, Upadhyay R, Taneja A (2002). Composition of rain water in
Agra city; a semi-arid area in India. Indian J. Radio Space Phys.
31:49-55.
National Environmental Protection Agency (1983). ―Methods of
environmental monitoring and chemical analysis. P. 196 (inChinese,
unpublished).
Shahid MAK, Hussain K, Awan MS (2012a). Seasonal variations and
characterization of solid aerosols related to Faisalabad (Pakistan)
Environment. J. Basic Appl. Sci. 8(2):572-580.
Shahid MAK, Hussain K, Awan MS (2012b). Physico-chemical analysis
of solid aerosols generated from different industries of Faisalabad. J.
Basic Appl. Sci. 8(2):498-507.
Singh SP, Khare P, Satsangi S, Lakhani A, Maharaj K, Srivastava SS
(2001). Rainwater composition at a regional representative site of a
semi-arid region of India. Water Air and Soil Pollut. 127:93-108.
Steel RG, Torrie IH (1981). Introduction and procedures of statistics.
Stenseth NC (2002). Ecological effects of climate fluctuations. Science
297:1292-1296.
Thakre R, Joshi (2001). Analysis of wet precipitation of air pollutants in
Mumbai, India. Env. Monit. Assess. 71:269-278.
Waheed S, Rahman A, Khalid N, Ahmad S (2006). Assessment of Air
Quality of Two Metropolitan Cities in Pakistan: Elemental Analysis
Using INAA and AAS. Radiochim. Acta. 94:161-166.
Wang A, Huang Y, Ma C, Wang Q, Yang S, Liu H, Li M, Liu J (1981).
―Chemical characteristics of airborne particles in Beijing area‖.
ActaScientiac Circumstantial.pp.220-232.
Wang H (1986). ―Considerations of atmospheric environment protection
in the period of the 7th, Five year plan in China‖. Atmos. Environ.
Acid Rain 1:1-5.
Wang P, Jiang L, Liu Z, Zu Y, Ni T (1983). ―Measurement of
precipitation acidity and heavy metal content in Lanzhou‖. J. Environ.
Sci. 4:61-62 ( in Chinese).
Weathers KC, Likens GE (2006). Acid rain. 4th Ed. Philadelphia,
Environmental and Occupational Medicine. Lippincott-Raven Publ. In:
W. N. Rom (ed.), pp. 1549–1561.
World Bank (2006). Pakistan Strategic Country Environmental
Assessment. The World Bank.
Yu S, Yu Z, Ma G, Liu H, Shu J, Zu Z (1985). ―An investigation on the
causes of death of pinewoods in Sichuan province‖. J. Environ. Sci.
6:63-66.
Yu Z (1985). ―Geographical Distribution of acid rain in China Jingji
Ribao (Economic Daily), 29July.
Zhao D (1984).―Some aspects of air pollution and its control in China‖.
Environ. Sci. in China, 4, pp. 7-10 (in Chinese).
Zhao D, Xiong J, Xu Y (1985a). ―Chemical characteristics of acid rain in
China Environ. Chem. Special Issue (March). Pp. 137-146.
Zhao D, Xiong J, Xu Y (1985b). ―Acid rain in China. Its formation and
effects. Presented at the China U.S Workshop on Air Pollution
Ecology Effects‖. November. Nanjing. China (in English).
Zhao D, Xiong J, Xu Y, Fan Z, Tong Y (1986). ―Study of acid rain
formation in southwestern China. Atmos. Environ. Acid Rain.1:41-48
(in Chinese).