Open Journal of Air Pollution, 2018, 7, 298-308 
http://www.scirp.org/journal/ojap 
ISSN Online: 2169-2661 
ISSN Print: 2169-2653 
 
 
 
Analysis of Air Pollutants in Xiong’an New Area 
Based on MATLAB Grey Model 
Ying Xie*, Wenjun Wang, Baochang Li, Zhiwei Zhao, Lei He 
Baoding University, Baoding, China 
 
 
 
How  to  cite  this  paper:  Xie,  Y.,  Wang, 
W.J., Li, B.C., Zhao, Z.W. and He, L. (2018) 
Analysis of Air Pollutants in Xiong’an New 
Area  Based  on  MATLAB  Grey  Model. 
Open Journal of Air Pollution, 7, 298-308. 
https://doi.org/10.4236/ojap.2018.74015 
 
Received: October 17, 2018 
Accepted: December 22, 2018 
Published: December 25, 2018 
 
Copyright © 2018 by authors and   
Scientific Research Publishing Inc. 
This work is licensed under the Creative 
Commons Attribution International   
License (CC BY 4.0). 
http://creativecommons.org/licenses/by/4.0/   
Open Access
 
 
 
Abstract 
The purpose of this paper is to study the air pollutants in Xiong’an New Area 
based on MATLAB grey model [1]. From 2011 to 2016, the results of sulfur 
dioxide  (SO2),  nitrogen  dioxide  (NO2)  and  inhalable  particulate  matter 
(PM1O) detected at monitoring points in the three counties of Xiong’an were 
analyzed. According to the  national environmental air quality standard [2], 
the air quality in Xiong’an New Area was reasonably evaluated based on grey 
model in MATLAB. Judging from the weight of pollution factors in the mod-
el, sulfur dioxide (SO2) is the controlling factor of air quality in Xiong’an New 
Area, and the weight of nitrogen dioxide (NO2) gradually increases. The main 
sources of the three pollutants were obtained by comprehensive data analysis, 
and a grey model was established according to the mass concentration of the 
main air pollutants, and the grey forecasting model was tested. The experi-
mental results show that the model can be effectively applied to the forecast-
ing of ambient air quality. On this basis, the present situation of atmospheric 
environmental quality in Xiong’an New  Area  and suggestions for improve-
ment are obtained. 
 
Keywords 
Xiong’an New Area, Air Pollution, Grey Model, Forecasting, Suggestion 
1. Introduction 
On  April  1,  2017,  the  Central  Committee  of  the  Communist  Party  of  China 
(CPC)  and  the  State  Council  announced  their  decision  to  establish  Xiong’an 
New Area in Hebei Province. Xiong’an New Area is located in the hinterland of 
Beijing, Tianjin and Hebei, with obvious geographical advantages. It is another 
New Area of  national significance  after Shenzhen  Special Economic Zone and 
Pudong New Area in Shanghai. The key task of planning and building Xiong’an 
New Area is to relax the non-capital functions of Beijing, build a green and intel-
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DOI: 10.4236/ojap.2018.74015    Dec. 25, 2018 
 
Y. Xie et al. 
 
ligent new city and create a beautiful ecological environment. Like other regions 
in  Beijing,  Tianjin  and  Hebei,  the  three  counties  in  Xiong’an  New  Area  have 
long been plagued by environmental pollution, especially atmospheric pollutants 
[3] [4] [5] [6]. 
The pollutants in the atmosphere are mainly composed of chemical pollutants 
and particulates, etc. In order to protect and improve the living environment of 
human beings, many domestic scholars have investigated the air pollution in ci-
ties. The main pollutants in the atmosphere are atmospheric particulates, sulfur 
dioxide and nitrogen oxides [7] [8] [9] [10] [11]. According to the situation of 
urban air pollution, many experts consider and evaluate it from these three as-
pects. At present, grey system theory has become an important forecasting me-
thod, including decision-making, evaluation, planning and control, system anal-
ysis and  modeling. (Grey system theory is based on the concept  of associative 
space,  smooth  discrete  function  and  other  concepts  to  define  gray  derivatives 
and gray differential equations, and then use discrete data columns to build dy-
namic models in the form of differential equations, since this is the basic model 
of the intrinsic gray system, and the model is approximate Non-unique, so this 
model is a gray model, which is denoted as GM (Grey Model), that is, the gray 
model  is  generated  by  using  discrete  random  numbers  to  become  random, 
which is significantly weakened and more regular. A model of the equation form 
facilitates the study and description of its changing process.) In particular, it has 
a unique analysis and model building method, short time series of statistical data 
and incomplete information systems [12] [13] [14]. Many researchers in China 
have established a grey system, and many doctors and researchers have applied 
the grey system to research [15] [16] [17] [18] [19]. 
There are few applications of the grey theoretical model in atmospheric envi-
ronment prediction. Using the powerful matrix function of MATLAB, there are 
not  many  gray  GM  (1,1)  model  algorithms.  (The  gray  model  is  generally  ex-
pressed  as  GM(n,x)  model,  which  means  that  the  x  variables  are  modeled  by 
n-order  differential  equations.)  Based  on  the  MATLAB  grey  GM  (1,1)  model, 
this paper theoretically predicts the concentration of atmospheric pollutants in 
Xiong’an New District. 
2. Weighted Grey Relational Analysis Model of Urban Air 
Pollution Index 
Taking Xiong’an New Area as an example, the monitoring data of sulfur dioxide 
(SO2), nitrogen dioxide (NO2) and inhalable particulate matter (PM10) were mo-
nitored at monitoring points in the three counties of Xiong’an from 2011 to 2016 
[20] [21] [22]. According to the national environmental air quality standard, a 
weighted grey correlation analysis model is used to make a reasonable compre-
hensive evaluation of the air quality in Xiong’an New Area. 
2.1. Climatic Characteristics of Xiong’an New Area 
Xiong’an New Area includes Xiongxian, Rongcheng and Anxin counties in He-
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DOI: 10.4236/ojap.2018.74015 
 
Y. Xie et al. 
 
DOI: 10.4236/ojap.2018.74015 
 
 
bei Province and some surrounding areas. Located in the hinterland of Beijing, 
Tianjin and Baoding, it has a temperate continental monsoon climate with dis-
tinct seasons, drought and windy spring, hot and rainy summer, cool autumn, 
cold and less-snow winter. The average annual temperature is 11.7˚C, the high-
est monthly (July) average temperature is 26˚C, and the lowest monthly (Janu-
ary) average temperature is −4.9˚C with the annual sunlight of 2685 hours and 
an average annual rainfall of 551.5 mm, accounting for 80% from June to Sep-
tember, and a frost-free period of 191 days a year. 
2.2. Sources and Analysis Methods of Major Air Pollutants 
This paper analyzes the air pollution from the three factors of civil heating, dust 
raising and industrial pollution in Xiong’an New Area [23] [24]. 
Analysis of civil heating factors: the civil heating season leads to a decrease in 
air quality and a higher concentration of sulfur dioxide. Coal burning directly 
leads  to  an  increase  in  pollutant  concentration.  Civil  heating  is  an  important 
factor  affecting  air  quality.  The  level  of  economic  development  in  Xiong’an 
County  is  relatively  low,  with  coal-fired  heating  in  rural  areas  and  coal-fired 
heating in some county residents [25]. 
Analysis of the factors of floating dust: Xiong’an New Area is a city with little 
rain in the north, and the concentration of inhalable particulate matters in the 
air is higher than that in coastal cities, thus affecting the air quality in Xiong’an 
New Area. 
Analysis of industrial  pollution factors: The three counties of  Xiong’an take 
plastic  packaging, 
leather  shoes  and  non-ferrous  metal 
processing industries as the main pillar enterprises, and the development of the 
enterprises has also brought serious air pollution to the local area [26] [27]. 
latex  products, 
Refer  to  Table  1  for  the  sources  and  analysis  methods  of  the  major  atmos-
pheric pollutants sulfur dioxide, nitrogen dioxide and inhalable particulate mat-
ters PM10. 
2.3. Monitoring Results of Concentration of Mainair Pollutants 
The continuous monitoring data of air pollution monitoring in Xiong’an New 
Area (from the real-time air quality publishing platform of Hebei Environmental 
Monitoring Center Stationadopts the Dongyu 1000 series air quality automatic 
 
Table 1. Sources and Analysis methods of various pollutants. 
Name of pollutant 
Analytical method 
source 
Sulfur dioxide (SO2) 
Sulfur dioxide (SO2) formaldehyde absorption para 
rosaniline spectrophotometry; Mercury tetrachloride 
parafuchsin spectrophotometry; UV fluorescence 
method; 
Inhalable particulate matter  Gravimetric analysis 
Nitrogen dioxide (NO2) 
Saltzman analysis method Chemiluminescence   
method 
GB/T 15262-94 
GB 8970-88 
GB6921-86 
GB/T 15436-95 
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Y. Xie et al. 
 
monitoring  system.  The  main  air  pollutants  are  O3,  PM2.5,  PM10,  SO2,  NO2, 
CO, etc., and the main pollutants which have serious impact on air quality are 
selected for analysis and research. The data in this paper are based on the annual 
average of air pollutants SO2, NO2 and PM10 (as shown in Table 2) from 2011 to 
2016. 
2.4. Comprehensive Evaluation of Atmospheric Environmental 
Quality 
The  evaluation  criteria  are  listed  in  the National Air Quality Standard of the 
People’s Republic of China (GB 3095-1996) and revised in 2000 (refer to Table 
3). 
Weighting  is  determined  by  considering  population  factors  and  weight  dis-
tribution  position.  According  to  the  contribution  rate  of  evaluation  factors  of 
each evaluation unit, the weight coefficient of each evaluation factor of the unit 
to be evaluated can be determined. 
The formula is as follows: 
α = ∑
i
x s
i
i
x s
i
i
                                                    (1) 
iα—The weight coefficient of pollutant I; 
is —Standard arithmetic mean of i pollutant concentration; 
ix —The actual concentration value of pollutant i. 
According to the formula, the weight of Xiong’an New Area in 2011-2016 is 
calculated (refer to Table 4). 
Table 4 gives the values of the annual pollution weight factor ai. The weight 
calculation results show that SO2 and PM10 are the main pollutants affecting the 
air quality in Xiong’an New Area. The main pollutants each year are SO2 (2011), 
PM10 (2012), PM10 (2013) and SO2 (2014-2016). In recent years, air pollution in 
Xiong’an New Area has gradually changed from PM10 to SO2, but there is still a 
long way to go to reduce the impact of PM10 on the environment. 
2.5. Evaluation Results of Weighted Grey Correlation 
r
=
n
∑
i
1
=
(
x
i
−
x
)(
y
i
−
y
)
n
∑
i
1
=
(
x
i
−
x
2
)
⋅
n
∑
i
1
=
(
y
i
−
y
2
)
                                            (2) 
xi, yi represent the actual value, the sequence of the fitted value, 
x ,  y   represent the actual value and the average of the fitted values. 
According to the above calculation method, the annual air quality calculation 
results are shown in Table 5. 
The r1, r2 and r3 in Table 5 are the correlation coefficients of the theoretical 
data of SO2, NO2 and PM10 and the measured data. 
Through the comprehensive analysis of Table 4 and Table 5, it is concluded 
that the air quality in Xiong’an New Area from 2011 to 2012 belongs to the III   
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DOI: 10.4236/ojap.2018.74015 
 
Y. Xie et al. 
Table 2. Monitoring results of air pollutants in Xiong’an New Area. 
 
Year 
2011 
2012 
2013 
2014 
2015 
2016 
SO2 (mg/m3) 
NO2 (mg/m3) 
PM10 (mg/m3) 
0.134 
0.137 
0.084 
0.079 
0.077 
0.063 
0.033 
0.039 
0.036 
0.025 
0.022 
0.032 
0.109 
0.107 
0.098 
0.109 
0.097 
0.087 
 
Table 3. Grading standards for atmospheric environmental quality. 
Pollutant 
Sample time 
SO2 
NO2 
PM10 
Annual mean 
Annual mean 
Annual mean 
 
Table 4. Weight calculation results. 
Year 
2011 
2012 
2013 
2014 
2015 
2016 
SO2 
0.489 
0.520 
0.400 
0.452 
0.449 
0.427 
Limit concentration (mg/m3) 
Ⅰ level standard  Ⅱ level standard  Ⅲ level standard 
0.04 
0.04 
0.02 
NO2 
0.133 
0.133 
0.191 
0.167 
0.131 
0.185 
0.10 
0.08 
0.06 
0.15 
0.08 
0.10 
Weight coefficient 
PM10 
0.378 
0.347 
0.409 
0.381 
0.420 
0.387 
Primary pollutant 
SO2 
PM10 
PM10 
SO2 
SO2 
SO2 
 
Table 5. Results of comprehensive evaluation in recent years. 
Year 
2011 
2012 
2013 
2014 
2015 
2016 
r1 
0.528 
0.433 
0.529 
0.137 
0.422 
0.467 
Correlation degree 
r2 
0.650 
0.502 
0.810 
0.623 
0.846 
0.816 
r3 
0.815 
0.347 
0.538 
0.090 
0.457 
0.439 
Quality level 
Ⅲ level 
Ⅲ level 
Ⅱ level 
Ⅱ level 
Ⅱ level 
Ⅱ level 
 
level, that is, light pollution. From 2013 to 2016, the urban ambient air quality 
was  2 and the air was good. This indicates that the  ambient air quality in the 
New Area is gradually improving. This good air quality benefits from the posi-
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DOI: 10.4236/ojap.2018.74015 
 
Y. Xie et al. 
 
tive  measures  taken  by  the  State  Environmental  Protection  Administration  in 
recent  years.  The  advantage  of  grey  correlation  analysis  is  that  it  can  sort  the 
quality of analysis environment. According to the order from high to low, the air 
quality is the best in 2014, and the situation is worse from 2011 to 2016. 
2.6. Evaluate According to the Season and Heating Cycle 
Each  year  is  divided  into  heating  period  and  non-heating  period.  The 
non-heating  period  is  from  March  15  to  November  15  of  each  year,  and  the 
heating  period  is  from  November  15  to  March  15.  The  evaluation  results  are 
shown in Table 6. 
Table  6  shows  that  the  air  quality  in  Xiong’an  New  Area  is  good  during 
non-heating period, with PM10 as the main pollutant. The air quality is relatively 
poor during the heating period, and the main pollutant is sulfur dioxide. It can 
be seen that Xiong’an New Area is a coal-polluted city and needs to further con-
trol coal pollution. 
3. Forecast of Air Pollution in Xiong’an New Area Based on 
Grey Model 
3.1. Assumptions of Model 
Other pollutants in the atmosphere within a reasonable range are ignored; 
Ignoring the error of data in the process of detecting pollutants; 
Assuming  no  major  natural  disasters  such  as  earthquakes,  sandstorms  and 
floods, the city’s natural environment will remain stable. 
Assuming that no major industrial accident will occur in the past two years. 
3.2. Establishment of Grey Forecasting Model 
In order to ensure the consistency of the model parameter rate, the grey fore-
casting system theory was used to select data from August 2016 to March 2017, 
and  the  mass  concentrations  of  PM10,  NO2  and  SO2  were  selected  within  6 
months. According to the previous analysis results, three grey forecasting mod-
els of PM10, NO2 and SO2 in Xiong’an New Area are established respectively. The 
grey forecasting model is as follows: 
5822.23exp
2823.35exp
)
1
ˆ
1
χ + = −
(
k
ˆ
1
χ + = −
(
k
ˆ
1
χ + = −
(
k
)
1
822.67exp
)
1
(
(
(
0.0376
−
k
0.0177
−
k
0.0736
−
k
)
)
)
+
6277.38
                      (1) 
+
4545.56
                      (2) 
+
678.34
                        (3) 
(1) grey forecasting models of PM10. 
(2) grey forecasting models of NO2. 
(3) grey forecasting models of SO2. 
3.3. Test of Forecast Results 
According to the formula of grey forecasting model, the mass concentration of 
SO2 in the atmosphere in Xiong’an New Area from August 2016 to March 2017   
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DOI: 10.4236/ojap.2018.74015 
 
Y. Xie et al. 
 
DOI: 10.4236/ojap.2018.74015 
 
 
Table 6. Comprehensive evaluation results for the whole year. 
Year 
Term 
2011 
Heating period 
2012  Non-heating period 
 
Heating period 
2013  Non-heating period 
 
Heating period 
2014  Non-heating period 
 
Heating period 
2015  Non-heating period 
 
Heating period 
2016  Non-heating period 
Pollutant concentration (mg/m3) 
Ⅰ level 
Ⅱ level 
Ⅲ level 
Quality level 
Primary 
pollutant 
0.373 
0.642 
0.519 
0.607 
0.466 
0.679 
0.552 
0.483 
0.452 
0.694 
0.515 
0.801 
0.610 
0.776 
0.557 
0.645 
0.775 
0.801 
0.543 
0.820 
0.584 
0.701 
0.675 
0.416 
0.766 
0.392 
0.834 
0.416 
0.792 
0.453 
III level 
II level 
III level 
II level 
II level 
I level 
III level 
II level 
III level 
II level 
SO2 
PM10 
SO2 
PM10 
SO2 
PM10 
SO2 
PM10 
SO2 
PM10 
 
is calculated. (See Figure 1) The forecasted value of the grey model is taken as 
the input value, and the actual value is the output value. Iterate input and output 
values. The maximum number of cycles is set to 5000 and the initial step size is 
0.0001 m. 
The data processing shows that the experimental data and the theoretical data 
are basically fitted. 
According to the formula of the grey forecasting model, PM10, NO2 and SO2 
pollution in Xiong’an New  Area (See Figure 2) will be obtained in the  next 6 
months, and the forecasting results of the grey forecasting model will be tested. 
The accuracy of the model was verified by residual error test and posterior error 
test. The results of the remaining tests are shown in Table 7. 
4. Conclusion 
Through the study of the air environmental quality in Xiong’an New Area from 
2011 to 2016, it is found that the air environmental quality in the New District 
has  greatly  improved  in  the  past  six  years,  and  the  air  environmental  quality 
reached the III level in 2011 and 2012. Since 2013, the environmental quality has 
been  maintained  at  II  level,  meeting  the  national  requirements.  However,  the 
environmental quality is still in a state of constant repetition and it is necessary 
to continue efforts. Secondly, the grey correlation method is used to comprehen-
sively analyze the air environmental quality in Xiong’an New Area. The results 
are  in  line  with  the  actual  situation  and  reach  the  expected  evaluation  results 
[28] [29] [30]. The grey correlation method is applicable to the comprehensive 
evaluation of Xiong’an New Area’s air environment. 
5. Suggests 
“Green environmental protection, standards first” If Xiong’an New Area wants 
to  realize  the  development  vision  of  green  ecology  and  livability,  it  must   
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Y. Xie et al. 
 
 forecast result
results of testing
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6
8
10
12
14
16
18
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240
220
200
180
160
140
120
100
80
60
 
Figure 1. Forecasting of SO2 Concentration in Xiong’an New Area from August 2016 to 
March 2017. 
 
Test points
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6
8
10
12
14
16
18
20
22
Test  points
 
Figure 2. Forecasting of SO2 mass concentration in Xiong’an New Area. 
 
Table 7. The results of residual error test and posterior error test. 
Time 
2016.08 
2016.10 
2016.12 
2017.02 
Monitoring value 
Forecasted value 
Residual error 
Relative error (%) 
SO2 
86.53 
100.61 
189.53 
237.36 
305 
61.0388 
121.1906 
139.7011 
185.6357 
−18.88676 
14.10033 
17.14607 
10.16509 
18.43 
17.24 
7.79 
21.79 
Open Journal of Air Pollution 
 
DOI: 10.4236/ojap.2018.74015