Distribution of respirable suspended particulate health and remedial measures in Joda-Barbil

South African Journal of Chemical Engineering,vol.18, no. 1, pp 18-29
18
Distribution of respirable suspended particulate
matter in ambient air and its impact on human
health and remedial measures in Joda-Barbil
region in Odisha
Kiran Kanti Panda1, Akhila Kumar Swar2, Rahas Bihari Panda3,B. C. Meikap4, 5
1
Health, Safety & Environment Division, Essar Steel India Limited, Bhubaneswar, Odisha, India
2
State Pollution Control Board, Odisha, Bhubaneswar, India
3
Department of Environmental Science, Fakir Mohan University, Balasore, Odisha, India
4
Department of Chemical Engineering, Indian Institute of Technology (IIT), Kharagpur, P.O. Kharagpur
Technology, West Bengal - 721302, India.
5
School of Engineering, University of KwaZulu-Natal, Durban, South Africa
Keywords: mining pollution, air pollution, suspended particulate matter, respirable particulate matter,
fugitive dust
Abstract—Indiscrete mining and transportation of Iron and Manganese ore by road clubbed with
operation of huge numbers of sponge iron plants, iron ore crushers and stone crushers in the JodaBarbil area of Odisha State, India has led to considerable deterioration of ambient air quality.
Therefore in order to ascertain the ambient air quality, monitoring was conducted at 08 locations
spread over a radial distance of 15 kms in all directions with Joda as the epi-centre for three seasons
namely summer, post monsoon and winter during 2008-09. Results of Bholabedha-Joda-Barbil
Region in Odisha, have been presented in this paper. The Suspended Particulate Matter (SPM , >10
micron) and Respirable Particulate Matter (RSPM, ≤10 micron) concentration have been found to
have exceeded the National Ambient Air Quality standards prescribed by Ministry of Environment
and Forest (MoEF), Government of India at most of the locations. Health data collected from the
District Health Department indicated that incidence of Pulmonary Tuberculosis amongst residents of
the study area has increased between 1999 and 2008 during which the iron ore mining and road
transportation was rampant. Therefore, an effective Air Pollution Management Plan was formulated
with an intention to substantially reduce the impact of dust pollution on the surrounding areas.
INTRODUCTION
India has an iron ore reserve of 14,630 million tonnes out of which Odisha itself accounts for a staggering 4761
million tonnes which accounts for 33% of the total reserve (as per the CPCB’s Comprehensive Industry
Document on iron ore mining. Owing to the huge iron ore reserves in Odisha and the rising demand of steel in
the international market, there has been a tremendous boom in the mining as well as metallurgical industries.
Joda-Barbil region of Odisha in India, has majority of the iron and manganese ore deposits which has resulted in
massive mining, establishment of numerous sponge iron plants and associated metallurgical units.
Correspondingly, the load on the road transportation through trucks and tippers has gone up many folds. All
these activities have resulted in adverse impacts on the air quality of the region. ( Tripathi et al, 2010; Panda and
Pradhan, 2011). Literature survey reveals that there are significant research in the area of suspended particulate
matter distribution in various industrial areas of India and China ( Zhou et al., 2007; Zhang et al., 2011; Zhiyuan
et al., 2011; Weijun et al., 2010; Badwar , 2005; Meikap et al. ,2002; Rajmohan et al., 2008 )
Effects of Particulate Matter on Human Health
The effects of inhaling particulate matter have been widely studied in humans and animals and include asthma,
lung cancer, cardiovascular issues and premature death. The size of the particle is a main determinant of where
in the respiratory tract the particle will come to rest when inhaled. Because of the size of the particle, they can
penetrate the deepest part of the lungs. Larger particles are generally filtered in the nose and throat and do not
cause problems, but particulate matter smaller than about 10 micrometers, referred to as Respirable Suspended
Particulate Matter or PM10, can settle in the bronchi and lungs and cause health problems. The 10 micrometer
size does not represent a strict boundary between respirable and non-respirable particles, but has been agreed
upon for monitoring of airborne particulate matter by most regulatory agencies. Similarly, particles smaller than
South African Journal of Chemical Engineering,vol.18, no. 1, pp 18-29
19
2.5 micrometers, PM2.5 tends to penetrate into the gas-exchange regions of the lung, and very small particles (<
100 nanometers) may pass through the lungs to affect other organs. In particular, a study published in the
Journal of the American Medical Association indicates that PM 2.5 leads to high plaque deposits in arteries,
causing vascular inflammation and atherosclerosis, a hardening of the arteries that reduces elasticity, which can
lead to heart attacks and other cardiovascular problems. Researchers suggest that even short-term exposure at
elevated concentrations could significantly contribute to heart disease (Pope et al., 2002; Brown et al., 1950;
Bradhawar et al., 2004; Boubel et. al, 1994; Turco and Davis, 1971).
It was thus felt necessary to undertake a research study pertaining to the concentration of particulate matter in
ambient air over an area of 15 kms from Joda in the district of Keonjhar, Odisha., India. Air Pollution in respect
of concentration of Particulate Matter in ambient air of Joda-Barbil Region has been a major concern due to the
onset of unrestricted mining, metallurgical processes and associated transportation. This has resulted in adverse
impacts on more than 181000 of people residing in the study area. Thus an attempt was made with an objective
to evaluate the spatial distribution of particulate matter in the ambient air of the study area to correlate the same
with the incidence of pulmonary diseases and suggest an environmental management plan to control/reduce the
concentration of Particulate Matter in the ambient air of the study area.
MATERIALS AND METHODS
This research was carried out in the Residential and Rural areas of Joda–Barbil Region of Odisha located
between 21° 45’0” - 21° 21’ 0” latitude and 85° 10’ 0” - 85° 40’ 0” longitude of Survey of India Topo sheet
No.73 G/5, 73 G/9, 73 F/8 and 73 F/12 and is in the district of Keonjhar having an area of 8240 km2 . This area
is located in the northern part of Odisha and the location map of the study area in Keonjhar District of Odisha
State, India is depicted in Fig.1. (a) Index map of study area and Fig. 1(b) monitoring stations in various places
and direction in the study area. There are 45 Iron and Manganese ore mines operating in the state of Odisha and
out of these, 29 mines are located in Keonjhar district. This accounts for around 65% of the operating mines in
Odisha. 109 sponge iron plants are in operation in Odisha and out of which 12 are operating in the study area.
Considering the concentration of Iron and Manganese ore mines and Sponge Iron Plants in the study area, it can
be well construed that there is significant air pollution potential due to these activities. Besides, these there are
several stone and iron ore crushers operating in the study area. Air Quality Monitoring at eight stations was
conducted in the study area during three seasons namely Summer, Post Monsoon and Winter season of 20082009 with a frequency of twice in week. Selection of stations was based on topography, wind direction,
locations of mining and industrial activities, transportation network and habitation. Air quality parameters like
Suspended Particulate Matter (SPM) and Respirable Suspended Particulate Matter (RSPM) were measured
using High Volume Air Sampler (Make: Envirotech, Model: APM-460) maintaining an average flow rate of
more than 1.1m3/min, (Glass Fiber Filter Paper) and Electronic Balance adopting Gravimetric method. Sampling
was conducted on 24 hourly basis at each station during the study period. The concentrations of SPM and
RSPM were measured in μg/m3. Guidelines of Central Pollution Control Board, New Delhi on Air Quality
Monitoring-2003 were followed for undertaking the above monitoring. While conducting these monitoring,
detailed activities of the surrounding areas were recorded. For computing the results, standard statistical
techniques were adopted. Sample Analysis was performed by adopting standard analytical methods (APHA).
South African Journal of Chemical Engineering,vol.18, no. 1, pp 18-29
20
RESULTS AND DISCUSSION
(a)
(b)
Fig. 1 (a) Index map of study area in Odisha (b) Monitoring stations in various places and direction in the study
area
South African Journal of Chemical Engineering,vol.18, no. 1, pp 18-29
21
(a)
(b)
(c)
Fig. 2 Co-relation between SPM & RSPM at Bholabeda of Odisha during (a) summer-2008 (b) post monsoon2008 (c) winter -2008-2009.
South African Journal of Chemical Engineering,vol.18, no. 1, pp 18-29
(a)
(b)
Fig. 3 Wind rose for the period (a) October 2009 (b) March-May 2008
22
South African Journal of Chemical Engineering,vol.18, no. 1, pp 18-29
23
(b)
(b)
Fig.4 (a) Locations showing traffic density studies undertaken (b) correlation between traffic density, SPM and
RSPM
South African Journal of Chemical Engineering,vol.18, no. 1, pp 18-29
Fig. 5 Spatial distribution of RSPM in the study area
Fig.6 Distribution of TB patients within the project area from 2004-08
24
South African Journal of Chemical Engineering,vol.18, no. 1, pp 18-29
25
Fig. 7 Comparative analysis between RSPM and pulmonary disorders at Bhadrasahi vs. Bholabeda (Controlled
Study).
The result of AAQ sample analysis of 08 locations in all directions on a 24 hourly basis (Period of sampling:
2008-09 & 2009-10) is summarized in a typical Table 1 which contains the location of sampling stations,
distance in kilometer from Joda, concentration of SPM and RSPM and there correlations. Fig. 2 shows the corelation between SPM & RSPM at Bholabeda of Odisha during (a) summer-2008 (b) post monsoon-2008 (c)
winter -2008-2009.
Table 1 SPM & RSPM concentration at various locations
Name of the area and
sampling location
Direction with respect
to Joda
Approx Distance(km)
from Joda
Conc. Range of SPM
in μg/m3 (Min-Max)
Conc. Range of
RSPM in μg/m3 (MinMax)
Bholabeda( A0 )*
SE
8.0
149.59-194.30
51.50-76.06
Baneikala Colony(A1)
N
2.0
258.82-306.11
79.44-89.88
Soyabali Village(A2)
Bhadrasahi Village(A3)
Topadihi (A4)
Jalahari Village(A5)
Daduan village(A6)
Beleipada Village(A7)
N
7.0
276.56-386.12
116.58-170.14
NW
5.0
1594.68-2712.56
277.46-649.49
WSW
12.5
460.65-551.66
135.58-178.66
S
6.5
234.65-395.05
140.47-176.69
E
6.0
426.80-500.34
134.30-188.10
NE
4.5
933.50-1023.07
336.12-418.66
Regression analyses were carried out between Suspended Particulate Matter (SPM) and Respirable Suspended
Particulate Matter (RSPM) to find out the correlation co-efficient (R2), where x=SPM and y=RSPM and
graphical presentations have been depicted in figures 2(a), (b), (c). The correlation was found to be significant
because with the increase of concentration of SPM at any location, the RSPM concentration is also showing an
increasing trend. The wind rose diagrams for the period (a) October 2009 (b) March-May 2008 are shown in
Fig. 3. There were traffic density studies carried out in Dec.2008 and June.2009 at 3 locations namely
Bhadrasahi, Beleipada and Jalahari considering the proximity of habitation and extent of road transportation.
The locations showing traffic density studies undertaken and the correlation between traffic density, SPM and
RSPM shown in Fig. 4.
South African Journal of Chemical Engineering,vol.18, no. 1, pp 18-29
26
A 24 hourly traffic survey conducted at Bhadrasahi Chowk on 2nd and 3rd June’09 established that the traffic
density was as high as 22585 which constitute 12907 heavy vehicles (Bus, Tippers, Loaders, HYWA,
Poclainetc) , 4068 Medium Vehicles (Jeep, Cars, Auto Rickshaws) and 5610 Light Vehicles (2-wheelers).The
reason of such high density can be attributed to movement of vehicles in all three directions (ie. to Barbil
railway siding in Northern direction, Jurudi railway siding in southern direction and Beleipada in Eastern
direction) in order to transport materials primarily iron ore and fines. The ambient air quality monitoring data of
Bholabeda (controlled study) have been depicted in Table 2 and have been compared with the National
Ambient Air Quality Standards of Central Pollution Control Board, New Delhi, Government of India dated
02.04.1996 .The prescribed standards for 24 hourly monitoring are as follows: SPM concentration - 200 μg/m3
(Residential, Rural and other areas ) & RSPM (PM 10) concentration - 100 μg/m3 (Residential , Rural and other
areas) .
Table 2 Bholabedha (in SE direction from Joda), distance from Joda 8.0 km. (controlled study)
Min
Max
Mean
SD
SUMMER
MARCH-MAY
SPM (μg/m3)
194.3
188.38
179.43
190.02
180.42
174.49
177.46
171.23
182.14
175.60
166.35
174.34
169.84
183.48
172.33
164.23
184.90
192.62
169.36
168.42
184.64
171.63
177.63
169.70
164.23
194.30
177.62
8.48
SEASON
RSPM
(μg/m3)
62.5
59.82
57.2
60.28
58.44
59.12
57.86
52.7
62.04
59.47
51.5
58.36
55.3
60.3
59.16
52.26
62.62
65.91
58.66
58.6
62.67
59.96
59.38
56.32
51.50
65.91
58.77
3.41
POST
OCT-NOV
SPM (μg/m3)
156.63
174.65
149.59
152.48
168.50
152.97
162.84
156.62
158.44
168.40
156.48
162.72
174.70
159.61
155.30
161.80
MONSOON
RSPM
(μg/m3)
52.56
66.80
55.58
57.42
59.28
58.32
60.08
59.54
58.63
61.55
59.93
61.45
65.77
60.45
53.24
60.42
149.59
174.70
160.80
7.63
52.56
66.80
59.44
3.76
WINTER
DEC-FEB SPM
(μg/m3)
167.54
172.67
169.48
167.47
182.48
178.56
172.76
170.24
163.68
177.53
174.52
170.26
188.39
175.36
168.48
170.07
171.15
182.34
172.12
175.54
176.78
177.60
172.34
174.65
163.68
188.39
173.83
5.56
SEASON
RSPM
(μg/m3)
63.26
66.90
64.53
62.45
71.66
70.29
63.36
65.51
54.48
68.29
67.14
66.60
76.06
70.82
69.63
67.35
68.11
73.28
71.54
69.59
70.66
71.26
68.96
68.82
62.45
76.06
68.40
3.34
The isopleth of RSPM concentration have been drawn for the study area based on the result of Ambient Air
Quality Monitoring to clearly visualize the pollution level at different locations covering residential area,
industrial area, mining area and road corridors as shown in Fig. 5. It is interesting to note that the area falling
under the North West quadrant is more polluted as compared to the rest of the area and dangerous for human
health.
Various stations used for monitoring work Station –A0 (Bholabeda): Controlled Study in SW
direction
The SPM concentrations found in the range between 149.59 μg/m3 and 194.30 μg/m3 and RSPM between 51.50
μg/m3 and 76.06 μg/m3. Which indicate that the concentrations are the lowest as compared to other locations as
the location is located around two kms away from the main road having excessive truck transportation and has
been surrounded by hills and greenery. The village road is a kuccha road which results in insignificant fugitive
emission.
South African Journal of Chemical Engineering,vol.18, no. 1, pp 18-29
27
Station –A1 (Baneikala) in North direction
The SPM concentrations found in the range between 258.82 μg/m3 and 306.11 μg/m3 and RSPM concentrations
range from 79.44 μg /m3 to 89.88 μg /m3. The concentrations of SPM & RSPM are comparatively low as
because the TISCO colony has thick plantation and all the roads are black topped. The nearest stack emission
source is the Ferro Alloys Plant of Tata Steel situated at distance of approx. 3 kms, the air pollution control
equipment of which are the wet scrubber type Gas Cleaning Plants that operate for more than 98% of the
operation time with an efficiency of more than 95% .The only contributor of SPM and RPM is the line source
emission due to vehicular movement on NH-215 situated at a distance of around 100 m from the monitoring
station.
Station –A2 (Soyabali) in North direction
The SPM and RSPM concentrations found in the range of 276.56 μg /m3 to 386.12 μg /m3 and 116.58 μg /m3 to
170.14 μg /m3 respectively. The reasonably higher concentrations of SPM & RSPM can be attributed to the
operation of an Iron Ore mine by Jindal Steel and Power Ltd. at a distance of around 2.5 kms in East direction
and a sponge Iron plant which is being operated by M/s Sumrit Sponge Iron Ltd. at a distance of around 1.2 kms
in west direction.
Station –A3 (Bhadrasahi) in NW direction
The SPM and RSPM concentrations found are exceedingly high at these stations which are. in the range of
1594.68 μg /m3 and 2712.56 μg /m3 for SPM and 277.46 μg /m3 649.49 μg /m3 for RSPM respectively. The
higher concentrations are possibly because of the fact that Bhadrasahi Chawk is a junction of roads leading to
Joda, Barbil and Koida and experience movement of highest numbers of vehicles in the study area. The road
condition was found to be completely worn out during the period of the study. In addition, the trucks are
transporting iron ore fines without cover resulting in spillage of fines and thus the fugitive emission due to
vehicular movements on the accumulated spilled out dust on the road surface. This not only makes the fines
finer but also helps in making them air borne for a pretty long period.
Station –A4 (Topadihi) in WSW direction
The concentration ranges are 460.65 μg /m3 and 551.66 μg /m3 for SPM and 135.58 μg /m3 and 178.66 μg /m3
for RSPM. The high dust concentrations are due to the proximity of the village (station) to NH-215 and road
transportation thereof. In addition, there are many industries and iron ore mines namely Deepak Steel & Power
Ltd., HIMA Ispat Ltd., R.P.Sao Iron Ore Mine and Shree Metallik Ltd. etc. present within a radius of 3 kms.
Station –A5 (Jalahari) in South direction
The concentrations of SPM and RSPM at this station varied between 234.65 μg /m3 and 395.05 μg /m3 for SPM
and 140.47 μg /m3 and 176.69 μg /m3 for RSPM . The higher concentrations can be attributed to the kuchha road
, that caters to the transportation of iron ore from nearby Kalinga Mining Corporation’s mine that is located at a
distance of about 8 mtrs from the sampling location in the North direction. Asphalted State highway connecting
Joda with Palashpanga and on which majority of the iron ore trucks ply,is at a distance of around 600mtrs in the
East direction . Essel Mining at Jiling is located at a distance of approx. 2 kms in the SE direction
Station –A6 (Daduan) in East direction
The concentrations of SPM & RSPM at this station ranged from 426.80 μg /m3 to 500.34 μg /m3 and 134.30 μg
/m3 to 188.10 μg /m3 respectively .Figures indicate that the concentration levels are higher than the prescribed
standards and can be attributed to kuchha Panchayat road passing through the village The road on which iron
ore dumpers ply is at distance of around 300mtrs in the East direction .The Tata Sponge Iron Ltd. is also situated
at a distance of around 3 kms in the North direction and M/s B.C.Deo mine is at a distance of about 1.5 kms in
Southern side.
South African Journal of Chemical Engineering,vol.18, no. 1, pp 18-29
28
Station –A7 (Beleipada) in North-East direction
The concentrations of SPM & RSPM were found to be in the range of 933.50 μg /m3 to 1023.07 μg /m3 for SPM
and 336.12 μg /m3 to 418.66 μg /m3 for RSPM. The higher concentrations are attributable to very heavy traffic
on NH-215 which is at distance of about 500 mtrs in the WNW direction and proximity to Tata Sponge Iron
Ltd., which is located at a distance of around 2 kms in the NE direction. In addition, Balita Iron Ore Mine is at a
distance of 2 kms in NW direction. Male and Female ratio as Industrial Workers is 1:0.22 as per Census 2001.
However from the data depicted in the Fig. 6 as compared to year 2004, there has been a rise of incidence of
pulmonary TB patients amongst both male as well as female workers. Fig. 6 shows the distribution of TB
patients within the project area from 2004-08. Fig. 7 depicts that the incidence of pulmonary disorders increases
with the increase in the concentration of RSPM.
CONCLUSIONS
Rapid industrialization in the developing country like India is inevitable and all these activities generally lead to
localized environmental problems in the region which needs to be properly addressed. The Government of India
as well as the State Government have been taking many air pollution control measures including formulation of
new or revision of the existing policies/legislations, criteria for setting emission standards for industries,
guidelines for sitting of industries , Environmental Impact Assessment, Environmental Audits, Adoption of
improved Pollution Control Technologies and Awareness Creation etc. To improve the air quality of the area
more specifically through reduction of point source emission and fugitive emission it is essential to install and
proper operation of highly efficient pollution control devices like electrostatic precipitator , gas cleaning plant ,
pulse jet bag filters, cyclone separators etc. in industries. Installation of dry fog systems in mines and mineral
processing units, effective monitoring of the operational efficiency of pollution control equipment and up
gradation from time to time, provision of high rise stacks for better dispersion of the particulate matter thereby
resulting in equitable distribution of particulate pollutants over a significantly larger area through dilution effect
should be ensured. The overburden of mines should be suitably moistened before being unloaded on the
overburden dump to avoid generation of fugitive dust and subsequently the dump slope should be covered with
sweet soil and coir mats for stabilization through bio-reclamation. Reduction of particulate matter in line source
emissions viz, fugitive emissions due to transportation of raw materials by road by adopting the measures: like
preference for rail transportation by enhancing the capacity of rail corridor, covering the dallah of trucks
carrying raw materials with tarpaulin to avert spillage, widening and black topping/ concreting the roads used
for transportation and the tailpiece of the silencer pipe of transporting vehicle should not be directed towards the
road which creates re-suspension of road dust, but it should be horizontal/ parallel to road surface to avoid
generation of fugitive dust from the roads dust, provision of green belt to arrest fugitive emissions, source
apportionment studies for pollution source inventories for future planning and monitoring, strict implementation
of the regulatory mechanism by the statutory authority vis-a-vis AAQ monitoring as per the guidelines of the
Central Pollution Control Board, capacity building for monitoring of P.M 2.5, provision of suitable Personal
Protective Equipment to concerned workers, pulmonary function tests for the people exposed to dusty
atmosphere and conduct detailed health study of people residing in the vicinity of mining areas and industries to
create a baseline and to establish correlation between air pollution and its impact on human health.
ACKNOWLEDGMENTS
The author is utterly indebted to the Department of Environmental Science of Fakir Mohan University,
Balasore, State Pollution Control Board, Odisha, Bhubaneswar and I.M.M.T(erstwhile RRL), Bhubaneswar,
Department of Health, Govt. of Odisha, M/s Utkal Polyclinic and Nursing Home, Bhubaneswar ,Digital
Cartography Services, Bhubaneswar , Dept. of Chemical Engineering, IIT Kharagpur and M/s S.S.Environics
India (Pvt.) Ltd, Bhubaneswar for their active co-operation in facilitating the research work.
REFERENCES
1.
2.
3.
Badhwar N, 2005. Guidelines for ambient air quality monitoring. Indian Journal of Air Pollution
Control, V(1):76--85
Boubel R W, Fox D L., Turner D B, Stein AC, 1994. Fundamental of air pollution, Academic Press,
USA, 3rd Edition, 106--110 & 203-222.
Bradhawar R C, Trivedi R C, Sen Gupta B, 2004. The air quality status and trends in India. Indian
Journal of Air Pollution Control, V(1) : 71-79.
South African Journal of Chemical Engineering,vol.18, no. 1, pp 18-29
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
29
Brown J H, Cooke K M, Key F G , Hatch T F, 1950. Influence of particle size upon the retention of
particulate matter in the human lungs. Journal of American Public Health Association , 40: 450--458.
Meikap B C, Kundu G, and Biswas M N, 2002. Scrubbing of fly-ash laden SO2 in a modified multistage bubble column scrubber.
American Institute of Chemical Engineers Journal, 48(8) : 2074- 2083.
Panda R B, Pradhan D, 2011. Assessment of air quality in Talcher Industrial Complex & its Health
Impact. International Journal of Environmental Science, I: 5-13.
Pope III C A, Richard T B, Michael J, Thun E E C, Daniel K, Kazuhiko I, George D T, 2002. Lung
Cancer, Cardiopulmonary mortality and long term exposure to fine particulate matter. Journal of the
American Medical Association, 287: 1132 -1141.
Raj Mohan B, Biswas S, Meikap B C ,2008. Removal of SO 2 from industrial effluents by a novel twin
fluid air assist atomized spray scrubber. Industrial & Engineering Chemistry Research, 47(20) : 7833-7840 .
Raj Mohan B, Biswas S, Meikap B C, 2008. Performance characteristics of the particulates scrubbing
in a counter-current spray-column, Separation and Purification Technology , 61: 96-102 .
State of Environment, 2006. State Pollution Control Board, Orissa, India
Tripathi A, Pal Raina, 2010. Air quality index at different sites of Moradabad City, India. Journal of
Pollution Research, 29(3), 471-476.
Turco, Davis, 1971. Detrimental effects of particulate matter on the pulmonary circulation. Journal of
the American Medical Association , 217: 81-82.
Weijun L, Longyi S, Zhishi W, Rongrong S, Shusheng Y, Uwa T, 2010. Size, composition, and mixing
state of individual aerosol particles in a South China coastal city. Journal of Environmental Sciences,
22(4), 561- 569.
Zhang, J., Zhiyun O, Hong M, Xiaoke W, 2011. Ambient air quality trends and driving factor analysis
in Beijing, 1983–2007. Journal of Environmental Sciences, 23(12), 2019-2028.
Zhiyuan R, Bing Z, Pu L, Cheng L, Lirong G, Minghui Z, 2011. Characteristics of air pollution by
polychlorinated dibenzo-p-dioxins and dibenzofurans in the typical industrial areas of Tangshan City,
China. Journal of Environmental Sciences, 23(2), 228 -35.
Zhou K, You-hua Y E, Qiang L, Ai-jun L, Shao-lin P, 2007. Evaluation of ambient air quality in
Guangzhou,China , Journal of Environmental Sciences, 19, 432—437.