The Status of Acid Deposition in Malaysia Based on Malaysian
Meteorological Department (MMD) Data Analysis from 1994 – 2008
Maznorizan Mohamad, Siniarovina Urban, Siva Shangari & Toh Ying Ying
Abstract
It was first started in 1976 with only two stations located in Tanah Rata and Petaling Jaya, and today
the Malaysian Meteorological Department (MMD) of Air Pollution Network comprises a total of 23
stations well distributed over Peninsular, Sabah and Sarawak continuously monitor the acidity level
over most areas in the country. Acid deposition which is one form of atmospheric pollution occurs
when emissions from sources undergo complex chemical reaction in the atmosphere and fall to the
earth as wet deposition or dry deposition. Two of the main sources of acid deposition are natural and
anthropogenic emissions. Natural sources include volcano emissions, forest fires, ocean, dust storm
and microbial processes, while anthropogenic refers to industrial and transportation emissions, and
other man-made pollutants.
In the atmosphere, oxides of sulphur and nitrogen collectively referred to as SO X and NOX
experienced
a chemical transformation through photochemical processes and chemical reactions
which results in the production of sulphuric (H2SO4) and nitric (HNO3) acids as the end products.
The current status of Acid Deposition in Malaysia is determined and analyzed based on the data
collected by the MMD from 1994-2008.
A comprehensive assessment of Acid Deposition over
Peninsular, Sabah and Sarawak which is based on the Time Series Data Analysis for Annual pH
(1994-2008) is presented in this paper. In addition, the trend analysis which referred to the annual
rainwater pH distribution Maps for Peninsular, Sabah and Sarawak are
also discussed
and
concluded according to different regions.
1. Introduction
Atmospheric pollution occurs when substances are present at concentrations
sufficiently above normal ambient levels to produce a measurable effect on humans,
animals, plants or materials. These substances may come from natural or man-made
sources and may exist in the form of gases, liquids or solid particles. The major manmade sources are from transportation, power generation plants, burning of biomass,
and industrial processes. Once released into the atmosphere, pollutants may then be
transported, diluted and physically and chemically transformed.
For many years, the Malaysian Meteorological Department has been
monitoring the chemical composition of the atmosphere in several locations in
1
Malaysia. The first background air pollution station was established at Tanah Rata,
Cameron Highlands more that 33 years ago. The continuous and meticulous
collection of data over the years by a team of dedicated staff has led to the evolution
of one of the best sets of air quality data available in the country dating back to the
seventies. Its applications are wide-ranging catering to a wide spectrum of users.
The assessments of the field data have also been crucial in ensuring a rational and
scientific approach to resolving national and regional environmental problems
associated with weather, climate and atmospheric pollution including acid deposition
issues.
2. Sources of Acid Deposition
Acid deposition occurs when emissions from combustion of fossil fuels and
other industrial processes undergo complex chemical reactions in the atmosphere
and fall to the earth as wet deposition or dry deposition.
„Acid Rain‟ is a broad term referring to the wet and dry deposition from the
atmosphere containing higher than normal amounts of acidic components. Both the
depositions are collectively known as acid deposition and it brings harmful effects on
plants, aquatic animals, infrastructures and also to humans.
Two of the main sources of acid deposition are natural and anthropogenic
emissions. Natural sources include volcano emissions, forest fires, ocean, dust
storm and microbial processes, while anthropogenic refers to industrial and
transportation emissions, and other man-made pollutants. Coal power plants are one
of the most polluting. The air pollutants are air-borne substances which can be
carried hundreds of kilometres in the atmosphere before they are converted to acids
and deposited.
Various oxides of sulphur and nitrogen collectively referred to as SOX and
NOX are produced and released to the atmosphere in the course of electric power
generation, industrial processes, transportation and other human activities. In the
atmosphere, a chemical transformation of the SOX and NOX occurs through
photochemical processes and chemical reactions which results in the production of
sulphuric (H2SO4) and nitric (HNO3) acids as the end products. When SOX and NOX
are released into the atmosphere by smokestacks, fuel combustion, or natural
causes, they mix with water vapour at unusual proportions to cause acid deposition.
2
Although both humans and nature cause this corrosive precipitation, anthropogenic
sources release approximately twice as much airborne acid.
There are two main mechanisms by which the atmosphere is cleansed of
these acids or acid-forming pollutants, it is by wet and dry deposition. Wet deposition
refers to the acidic rain, fog, mist and snow while dry deposition is combination of
airborne dry acidic particles. The wet deposition involves the uptake of the gas or
particle into a cloud droplet or raindrop and subsequent deposition of the raindrop on
the ground. If the uptake occurs inside the cloud the process is referred to as incloud scavenging (rainout) and if the uptake takes place as the raindrop falls from
the cloud base to the ground, the process is referred to as sub-cloud scavenging
(washout).
As for the dry deposition, it involves the gravitational setting (of particles) and
direct impaction on surface (applicable to both solid and liquid particles and gases).
The lighter particles can be lofted at a considerable distances by the wind and
spread out by turbulent diffusion before either coagulating or polymerizing into
particles, which are heavy enough to fall by gravity. Thus dry deposition permits the
removal of the acid forming pollutants directly on to the earth‟s surface in the
absence of precipitation. In other cases, these particles may become attached to
objects on the ground such as buildings, homes, cars, and trees and can be washed
from these surfaces by rainstorms, leading to increased runoff.
3. Sources of Acid Deposition in Malaysia and Measured by Various
Institutions to Reduce Emission
In general pollutant sources in the country can be categorized into mobile
sources and stationary sources. In 2007, the mobile sources which are the main
contributor to air pollution, released almost 2.17 million tonne of pollutants or 85.8%
of the total emission to the atmosphere (Compendium of Environment Statistics,
Malaysia 2008). Of these, the road transportation is the dominant source of acid
pollutants in this country. According to the Compendium of Environment Statistics
Malaysia 2008, motor vehicle population has increased from 14.8 million in 2005 to
16.8 million in 2007. Figure 1 shows the number of motor vehicles registered in
Malaysia since 2003 to 2007.
3
Number of Motor Vehicles Registered, Malaysia 2003-2007
18,000,000
16,000,000
14,000,000
12,000,000
10,000,000
8,000,000
6,000,000
4,000,000
2,000,000
0
2003
2004
2005
2006
2007
Figure 1: Number of motor vehicles registered in Malaysia (2003-2007)
Of the existing motor vehicle, most are petrol driven followed by diesel and
some on natural gas (NGV). Their principal pollutants are by-products of combustion
and secondary pollutants formed from photo-chemical reactions. It is estimated that
in 2007, about 4778 tonnes of carbon monoxide, 1077 tonnes of oxides of nitrogen,
67 tonnes of sulphur dioxide and 30 tonnes of particulate matter were emitted daily
into the atmosphere by mobile sources (Compendium of Environment Statistics,
Malaysia 2008). Due to the high concentration of motor vehicles in the urban areas,
the air quality of major towns has deteriorated. Emissions from aircrafts, rail, ships
and motorboats, also contribute to a certain degree to the pollution load. Figure 2
shows the total emission of pollutants to atmosphere by mobile source in the year
2007.
4
Metric Tonnes
Total Emission of Pollutants to Atmosphere from Mobile
Sources, Malaysia, 2007
2,000,000
1,800,000
1,743,917
1,600,000
1,400,000
1,200,000
1,000,000
800,000
600,000
393,407
400,000
200,000
24,504
11,005
0
CO
NO2
SO2
PM10
Source: Department of Environment, 2008
Figure 2: Total emission of pollutants to atmosphere from mobile sources, Malaysia,
2007
In 2007, the stationary sources, which are mainly industries and power plants,
had contributed around 12.3% of the total emission load to the atmosphere. Figure 3
shows the percentage of pollutants emitted to the atmosphere by the two types of
stationary sources. The chart for the industries sector show a large amount of oxides
of nitrogen were emitted to the atmosphere followed by sulphur dioxide, particulate
matter and carbon monoxide. As for the power plants, a large amount of emissions
were oxides of nitrogen, followed by sulphur dioxide, carbon monoxide and
particulate matter.
5
Power Plant
Industries
SO2
27%
PM10
12%
CO
10%
SO2
37%
NOx
51%
PM10
3%
CO
9%
NOx
51%
Figure 3: Percentage emission of pollutants to the atmosphere from stationary
sources through Industries and power plants
Today Malaysia has 25 thermal power plants (13 owned by TNB and 12
owned by independent power producers) and 8 hydro-based power plants. Although
the number of power plants had increase over the years but adequate measures
have been taken to minimize air pollution and maintain it below the Malaysian Air
Quality Standard. Tenaga Nasional Berhad (TNB) as the national power provider
comes into role that seeks the compliance to the ISO 14000 series standards which
has strict enforcements on environmental issues.
Open burning activities are another significant contribution to the air pollution
in the country. The Environmental Quality (Amendment) Act 1998, prohibits open
burning which includes any fire, combustion and smouldering in open air. However
some domestic refuse is still being disposed by open burning on the premises by
irresponsible owners. Burning of agricultural wastes and land clearing for different
land use which normally carried out during dry periods frequently aggravates the
haze problem. In 2005 and 2006 during the southwest monsoon season (June to
August), the government had banned open burning except for cremations, religious
rites and barbeques to combat the thick haze problem at that time. Although the
open burning produces striking pollution events but its contribution to formation of
acid rain precursors is slightly less significant as compared to the transportation and
power plants.
Malaysia is continuing its efforts to manage air quality issues and to mitigate
acidic deposition. Much effort is needed to update emission inventories, run an air
quality model operationally, and participate in an international cooperation such as
6
East Asia Acid Deposition Monitoring Network (EANET) activities. Malaysia
participated as part of the EANET network that comprises 13 countries from ASEAN,
China, Japan, Korea, Mongolia and Russia, with the aim of preventing or reducing
adverse impact on the environment caused by acid deposition. Such information will
be essential to determine the status and potential risks resulting from present and
future changes in acid deposition.
4. The Malaysian Acid Deposition Monitoring Network
The Malaysian Meteorological Department (MMD) of Air Pollution Network
comprises a total of 23 stations well distributed over Peninsular, Sabah and Sarawak
(Figure 4). This network was first established in 1976 with only two stations, namely
Petaling Jaya and Tanah Rata but gradually over the years the network extended to
cover more areas in the country. Most of the stations are located some distance from
urban centres, thus ensuring that only ambient conditions are monitored. The MMD
is one of the agencies that is continuously monitoring the acidity status of the
country. In the beginning, all of MMD‟s 23 air pollution monitoring stations are
equipped with the APS (Acid Precipitation Samplers). In 2008 MMD replaced the
APS in its stations with the Wet Only Rainwater sampler. The names, location
(latitude and longitude) and elevation of these sites are listed in Table 1.
Figure 4: A Location Map of the Air Pollution Monitoring Network
7
Most of the Air Pollution stations are co-located with meteorological stations
so that simultaneous and continuous observation of both meteorological and air
pollution parameters can be carried out. This would ensure that a comprehensive
data set comprising of both air quality and meteorological data would be available for
assessment of any air pollution event.
The station in Danum Valley, Sabah which is classified as one of the WMO
Baseline Global Atmosphere Watch (GAW) sites started operating in 2006 primarily
to measures chemical composition and selected physical characteristics of the
atmosphere in the tropics to improve the understanding of processes in an equatorial
rainforest.
Table 1: Names, Locations and Elevations of Station
Latitude (N)
Longitude (E)
Deg.
Min.
Deg.
Min.
Elevation
(m MSL)
06
06
06
05
05
04
04
05
04
03
03
03
02
03
02
02
01
01
03
05
05
04
04
29
12
10
18
21
34
28
23
13
58
47
06
16
03
27
01
38
29
12
18
56
16
58
100
100
102
100
100
101
101
103
100
102
103
101
102
103
103
103
103
110
113
115
116
117
117
16
24
17
16
24
06
22
06
42
21
13
39
15
05
50
19
40
20
02
15
03
53
50
22
4
5
3
1
246
1545
5
7
60
15
46
9
33
44
88
38
22
3
29
2
17
426
Station
Chuping
Alor Setar
Kota Bharu
Bayan Lepas
Perai
Bukit Kledang
Tanah Rata
Kuala Terengganu
Sitiawan
Batu Embun
Kuantan
Petaling Jaya
Melaka
Muadzam Shah
Mersing
Kluang
Senai
Kuching
Bintulu
Labuan
Kota Kinabalu
Tawau
Lembah Danum
8
5. Assessment of Acid Deposition
Is pH a good indicator of atmospheric acidification? pH is defined as the negative logarithm
of the hydrogen ion concentration. This definition of pH was introduced in 1909 by the
Danish biochemist, Soren Peter Lauritz Sorensen. It is expressed mathematically as:
pH = - log [H+], where [H+] is hydrogen ion concentration in mol/L
The pH unit measures the degree of acidity or basicity of a solution. The pH value ranges
from 0 to 14. The lower the pH of a solution the greater the concentration of hydrogen ions.
Neutrality or equality of hydrogen and hydroxyl ions occurs at pH 7 which is the pH of
chemically pure water. Values above 7 exhibit basic properties. Values below 7 exhibit acidic
properties. Because the scale is not linear but logarithmic, a change of a pH unit represents
a ten-fold change in hydrogen ion concentration. Thus pH 4 is ten times more acidic than pH
5 and 100 times more acidic that pH 6, and so on.
“Clean” or unpolluted rain has a slightly acidic pH of 5.6, because of carbon monoxide and
water in the air react together to form carbonic acid, a weak acid.
With reference to the Time Series Data Analysis for the Annual pH (19942008) as shown in Figure 6, the northern region of Peninsular received acidic rainfall
with pH ranging from 4.4 to 5.5, with Perai as the most acidic area, followed by
Bayan Lepas and Alor Setar, and Chuping being the least acidic. However, since
2005, the acidity values in this northern region showed an improving trend.
In the east coast region, the most acidic period was generally recorded
between the year 2000-2005, with the rainfall pH values ranging from 4.6 to 5.0.
Nevertheless from 2006 onwards, the acidity values started to improve, that is
becoming less acidic for most places in the east coast states.
As for central part of Peninsular, Petaling Jaya indicated as being the most
acidic area with pH value of rainfall ranging from 4.2 to 4.6, followed by Sitiawan and
Bukit Kledang. The least acidic rainfall was recorded at Tanah Rata.
In addition to that, the pH values of between 4.2 to 5.1 were recorded for
southern region of Peninsular, with Senai recording the most acidic rainfall with the
pH values ranging from 4.2 to 4.5. Melaka, Kluang and Mersing had recorded less
9
acidic rainfall with pH values ranging from 4.4 to 5.1. Since the last 3 years from
2006 to 2008, Kluang was showing a significant deteriorating acidic trend, while
Senai and Mersing showed quite consistent values of acidity with pH values ranging
between 4.5 to 4.7.
For the state of Sarawak, the pH values range from 5.0 to 5.6 throughout the
year from 1994 to 2008, and these values were quite consistent in the year of
2000s especially in Bintulu. In Kuching, the year to year variation of acidity values
was quite significant, being quite acidic from the late 90s until 2005, when it started
to improve slightly from 2006 to 2008.
In Sabah, the pH values range from 4.8 to 5.9. In general, the pH distribution
wasn‟t showing any distinct pattern throughout those years (1994- 2008), except that
the lowest pH value of 4.8 was recorded in the late 90s in Kota Kinabalu and early
2000s in Labuan. The areas in Tawau, Labuan and Kota Kinabalu were showing
non-consistent pH values for the past 14 years.
Annual pH-Alor Setar
2006
2007
2008
2007
2008
2005
2004
2003
2002
2004
2002
2003
2001
1999
2000
1998
1996
1997
1995
6
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
1994
pH
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
2001
Annual pH-Bayan Lepas
6
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
1994
pH
2000
Year
Annual pH-Perai
Year
2005
2006
Year
1999
1998
1997
1996
1995
1994
6
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
pH
6
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
1994
pH
Annual pH-Chuping
Year
10
Year
6
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
2005
2004
2003
2002
2001
2008
Annual pH-Bukit Kledang
2008
Year
2007
6
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
2007
Annual pH-Muadzam Shah
2006
Year
2006
2005
2004
2003
Year
2002
2000
1999
1998
Year
2001
2000
1999
1998
Annual pH-Tanah Rata
1997
1996
pH
Annual pH-Kuantan
1997
1996
1995
1994
2008
2007
2006
2005
2003
2004
2002
2001
2000
1998
1999
1997
1996
1995
1994
pH
6
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
1995
6
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
pH
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
pH
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
pH
pH
6
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
1994
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
pH
Annual pH-Kota Bharu
Annual pH-Kuala Terengganu
6
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
Year
Annual pH-Batu Embun
6
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
Year
11
Year
2006
2007
2008
2008
2003
2004
2002
2007
6
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
2006
Annual pH-Bintulu
2005
Year
2005
2004
2003
Year
2002
Year
2001
2000
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
Year
2001
2000
1999
Annual pH-Mersing
1998
1999
1997
1996
1995
1994
pH
Annual pH-Melaka
1998
Annual pH-Kuching
1997
1996
1995
1994
6
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
pH
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
pH
6
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
1995
6
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
pH
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
pH
2008
2007
2006
2004
2005
2003
2001
2002
2000
1999
1997
1998
1996
1995
1994
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
pH
pH
6
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
1994
2008
2007
2006
2005
2003
2004
2002
2001
2000
1998
1999
1997
1996
1995
1994
pH
Annual pH-Sitiawan
Annual pH-Petaling Jaya
6
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
Year
Annual pH-Kluang
6
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
Year
Annual pH-Senai
6
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
Year
12
Annual pH-Labuan
Year
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
6
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
1994
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
pH
6
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
1994
pH
Annual pH-Kota Kinabalu
Year
2008
2007
2006
2005
2003
2004
2002
2001
2000
1998
1999
1997
1996
1995
6
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
1994
pH
Annual pH-Tawau
Year
Figure 6: The Time Series Analysis for the Annual pH (1994-2008)
The annual rainwater pH distribution map for the year 1994 to 2008 is shown
in Figure 7, where in the 90s, the acidity situation in Sabah and Sarawak were
generally recorded as least acidic with pH values in the range of 5.2 - 5.6.
Nevertheless, in Peninsular the situation varied between least acidic (5.2 -5.6) to
moderate acidic (4.4 – 4.8) with some areas in southern part of Johore and Klang
Valley experiencing highly acidic rainfall with pH less than 4.4. The acidity situation
deteriorated in the early and middle of 2000s especially in the central part of
Peninsular, Penang and Johore where significant areas in southern Johore and
Klang Valley had recorded highly acidic rainfall (less than 4.4). In Sabah and
Sarawak, the acidity situation has deteriorated slightly as compared with the 1994 1999 situations where pH values then ranged between 5.2 – 5.6, compared to 4.8 –
5.2 in the 2000s. These were probably due to rapid development and population
growth in these two states.
13
The trend analysis in Peninsular which is based on the analysis done from the
year 1994-2008 can be divided into two categories: i) the East Coast of Peninsular,
where it received rainfall with pH values ranged between 4.8 – 5.6, which considered
to be between least to moderate acidic. The acidity level was even lower in the mid
and late 90s where the areas over the northern part of Kelantan and Terengganu
reported pH values in the range of 5.2 – 5.6. ii) the west coast states inclusive of
Penang, Perak, Klang Valley and Johore which experienced slightly higher level of
acidity as indicated by rainfall pH ranging from 4.4 to 4.8,
with some parts in the
Klang Valley and southern Johore receiving rainfall with pH values less than 4.4,
which can be considered as highly acidic. These particular areas are within the zone
of rapid growth of development and urbanization where high population density and
heavy industries probably have contributed to the high acidity level which peaked
between year 2000-2005.
However starting from the year 2006, the situation began to improve with
nearly more than 50% of the areas recorded the pH values between 4.8 - 5.2, and
with slightly less than 50% of the areas recorded the pH values ranging from 4.4 –
4.8. In 2008, the situation was further improved when slightly more than 10% of the
areas in Peninsular, that is in the states of Perlis and Northern Kedah received
rainfall with pH values ranging from 5.2 – 5.6, and about more than 50% of the areas
reported pH values between 4.8 – 5.2, while the remaining 40% reported pH values
in the range of 4.4 to 4.8.
Compared to the rest of the states in Malaysia, Sabah recorded the least
acidic rainwater especially in the mid-90s, where some areas in eastern Sabah
recorded pH values of more than 5.6, but subsequently
from the year 2000
onwards, the rainwater in Sabah reported in the moderate acidity category with pH
values ranging from 4.8 - 5.2. As for the state of Sarawak, the acidity level has
improved slightly in the year 2008 as compared to the previous seven years. This
was especially true in the areas surrounding Kuching and Sri Aman where the pH
values were recorded between 5.2 – 5.6. The improvement of acidity level in these
areas contributed probably due to public cautions and government measures to
control and reduce the emission of acidic elements.
14
15
Note:
> 5.6 –
Clean
5.2 – 5.6 - Least Acidic
4.8 – 5.2 - Moderatae Acidic
4.4 – 4.8 - Acidic
< 4.4
– highly/Very Acidic
Figure 7: The Annual Rainwater pH Distribution (1994-2008)
6. Summary and Concluding Remarks
The rain acidity in Malaysia is not yet reaching the alarming level even though
the duration between year 2000-2005 was showing the acidity level in Peninsular at
its peak. Only 10 -20% of the areas recorded pH values of less than 4.4. The highly
acidic values recorded over areas in South Johore and Klang Valley are probably
due to the influence of highly developed and industrialized areas located in these two
localities. Nevertheless, from 2006 onwards the rainwater pH improved significantly
in Peninsular especially in the states of Perlis and Kedah as well as in Pahang and
Johore.
Areas in Sabah and Sarawak experienced an increasing acidity trend in the
early 2000s as compared to the 90s, but with the pH level of 4.8 – 5.2, it was still
less acidic if compared to the Peninsular. However in the 2008, the acidity trend
started to improve especially in the state of Sarawak.
As a conclusion, the rain acidity improving trend which can be observed in
the late 2000s is possibly due to the strict enforcement initiatives taken by the
government authority agencies and the industries to adopt for the green technology
as to minimize the release of the acidifying species into the atmosphere. Besides,
the public awareness for the cleaner environment as well as their participation in the
sustainable and environmentally friendly development are among the important
elements that contribute to this positive outcomes.
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Acknowledgement
The authors would like to thank Mdm. Leong Chow Peng (former MMD‟s Deputy
Director General) & Mdm. Siti Mariam Sumari (UiTM) for editing the article. Thanks
also due to the staff of Environmental Section, Department of Chemistry Malaysia for
performing the chemical analysis of the samples.
References
Malaysian Meteorological Service, 1988: Report on Rain Acidity Analysis Based on
Data from the National Acid Rain Monitoring Network.
Department of Statistics, Malaysia, 2008: Compendium of Environment Statistics
Annual Summary of Air Pollution Observations, (1994-2007)
EPA Information, March 2004
Acid Deposition Monitoring Network in East Asia (EANET): Periodic Report on the
Status of Acid Deposition in East Asia (Part I: Regional Assessement; Part II:
National Assessment)
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