Air Quality Monitoring in Beijing and Validation of Satellite Retrieval Products

P. Wang, Y. Liu, H. Yu, Z. Cai, J. Bai, G. Wang, X. Xia, X. Zong, X. Meng, J. Xia, M. Min, J. Tang

LAGEO, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029

AMFIC Annual Meeting, 16-17 October 2008, Beijing

Progress on WP2.3 & 3

Contents Validation of Satellite Retrieved Ozone Products Air quality monitoring by MaxDOAS through Chin

a-Belgium cooperation Aerosol Optical Depth derived from CIMEL-318 su

nphotometer Review of the Air Quality in Beijing during the 2008

Olympic Games Assessment of air quality ensuring measures from

satellite data during Beijing Olympic Games Summary

1, Validation of Satellite Retrieved Ozone Products

GOME （ Liu X. 2005 ） VS GPSO3/IAP & Vaisala ozone sondes(ECC)

List of ozone sonde stations in China:

<GOME-Ozonesonde>/<Ozonesonde>1 SDAccuracyRandom error3 standard error of mean

GOME （ Liu X. 2005 ） VS GPSO3/IAP & Vaisala ozone sondes(ECC)

GOME:

-50 -40 -30 -20 -10 0 10 20 30 40 500

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10

15

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25

30

35

403

8

11

13

15

15

17

17

17

17

17171717

17

17

N pairs

[%]

Alti

tude

[km

]高

度

Lhasa拉萨

-50 -40 -30 -20 -10 0 10 20 30 40 500

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10

15

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25

30

35

40 Xining西宁

[%]

Alti

tude

[km

]高

度

7

12

12

12

14

14

14

15

1515

15

15

15

15

15

N pairs (b)(a)

-50 -40 -30 -20 -10 0 10 20 30 40 500

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35

2

10

14

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N pairs

[%]

Alti

ttude

[km

]高

度

Beijing北京

(c)

Elevation = 3650m Elevation = 2296m

GPSO3Large discrepancy are mainly caused by Ozone multi layers structures in spring

Cai et al.,2008 ， submitted to J. App. Meteo.

Comparison of tropospheric column ozone (TCO) between G

OME retrievals and ozonesonde observations.

MIPAS VS GPSO3/IAP

0 20 40 60 80 100 120 140 160

10

15

20

25

30

35

Ozone Partial Pressure [nb]

Alti

tud

e [k

m]

-50 -40 -30 -20 -10 0 10 20 30 40 50

14

14

28

32

33

34

34

32

24

7

[%]

MIPASOzonesonde

MIPAS 1 STDOzonesonde 1 STD

(MIPAS-Sonde)/Sonde

1 STD3 SEM

Comparison of vertical ozone distribution and relative difference between MIPAS (black) and ozone sonde (green) from Beijing.

GOMOS VS GPSO3/IAP

0 20 40 60 80 100 120 140 16010

15

20

25

30

35

Ozone Partial Pressure [nb]

Alti

tud

e [k

m]

-50 -40 -30 -20 -10 0 10 20 30 40 50

[%]

GOMOSOzonesonde

GOMOS 1 STDOzonesonde 1 STD

(GOMOS-Sonde)/Sonde1 STD3 SEM

Comparison of vertical ozone distribution and relative difference between GOMOS (black) and ozone sonde (green) from Beijing.

GOMOS & MIPAS VS GPSO3-IAP

Yi Liu, et al. 2008

Three instruments show very good consistency in representing a sub peak value

of ozone in the upper troposphere and lower stratosphere (UTLS).

2, Air Quality Monitoring by Max-DOAS

Cooperation with Belgium BIRA team (Michel Van Roozendael, Paul Simon, Noel Parmentier, Gaia Pinardi,

Caroline FAYT, Christian Hermans)

A MaxDOAS was setup in the Institute of Atmospheric Physics since June, 2008, before the Beijing Olympic Games

The Objective of the instrument is to measure column amount of NO2, SO2, O3, etc.

The data can be employed to assess the effect of the ensuring measures of air quality for Beijing Olympic Games.

The data can be used to validate the satellite products such as OMI and Scimachy data.

Preliminary Results:

44% decrease of NO2 column density was found from the MaxDOAS measurement during the vehicle restriction period, based on the MaxDOAS measurements, compared to the prior period.

0

5

10

15

20

25

30

6-16 6-21 6-26 7-1 7-6 7-11 7-16 7-21 7-26 7-31 8-5 8-10 8-15 8-20

Date

NO 2 VCD (10

15

molec/cm

2 )

Future work:

More carefully assess the effect of the air quality ensuring measures during Beijing 2008 Olympic Games.

Validation of satellite products (OMI, Sciamachy data)

3, Aerosol Optical Depth derived from CIMEL-318 sunphotometer

2 Cimel-318 sunphotometers in AERONET provide the aerosol optical depth continuously in Beijing and Xianghe, 50 km far from Beijing at east.

3, Aerosol Optical Depth derived from CIMEL-318 sunphotometer

National stadium and swimming pools

3. Review of the Air Quality during the Beijing Olympic Games

During the Beijing Olympic Games, the main

air pollutants reduced by 50%. The air quality

met the standard everyday with 10 excellent

days. SO2, CO and NO2 concentrations are

similar to the developed mega-cities over the

World. PM is lower than third phase objective

value of air quality of WHO.

06-01 06-06 06-11 06-16 06-21 06-26 07-01 07-06 07-11 07-16 07-21 07-26 08-01 08-06 08-11 8-16 08-210

10

20

30

40

50

60

NO 2 V

erti

ca

l C

olu

mn

(1

01

5 mo

l/c

m2)

July 1 July 20

云识别软件界面（检测前） 云识别软件界面（检测后）

* 图像分辨率： 2272×1704,/24bit

* 图像视场：～ 183°，遮挡小* 采集频率： 1分钟间隔可调* 环境温度： 0°C~40°C

可见光全天空成像仪技术指标：可见光全天空成像仪技术指标：

Visible Total Sky Imager

Infrared Scanning Sky Imager

Many clear skies were recorded by TSI

3, Review of the Air Quality during the Beijing 2008 Olympic Games

In order to ensure good air quality for Beijing Olympic Games, a series of measures for improving air quality were carried out in Beijing and its surrounding areas. 300,000 high emission vehicles were prohibited on roads, 2,000,000 cars were restricted on roads by the policy “odd days for odd number cars, even days for even number cars”. A large number of plants and factories were temporarily closed or limited in producing capability, or works after meeting the emission standard.

Odd/even days for odd/even number cars1,500,000 cars involved

Air Quality Ensuring Measures for Beijing Olympic Games

Jul 1 Aug 1 Sep 1 Sep 20Sep 6Aug 8Jul 20 -- 17-- 24

End

High emission cars with yellow mark stop, 300,000 cars involved.

Government and company cars stop by 50% ， and 70% after July 1

Jun 23

Many high emission factories were closed, or limited in productivity.

backgrounds

3 years ago, a big project was implemented by

Beijing EPA. The project is known as “The

Transport and Transformation of Air Pollutants

in Beijing and its Surrounding Areas and the

Objective Study of Air Quality in Beijing”. The

objective of the project is to answer How to

control the air pollution during the Beijing

Olympic Games. A robust ensuring measures

of air quality was expected.

For the objectives, some basic scientific questions need to be answered.

How much pollution is transported from the surrounding industrial areas such as Tianjin, Tangshan, Shijiashuang cities?

What is the relationship between air pollution and meteorological conditions?

How is the secondary aerosols produced? How much does the secondary aerosols accounts for in total suspended particles in percentage?

Which key factors control the production of ozone? NO2 or VOCs?

Many top institutions and universities were invo

lved in the project. They are the Institute of Atm

ospheric Physics, Chinese Academy of Scienc

es, Peking University, Qinghua University, Chin

ese Academy of Environmental Sciences, etc.

Beijing Environment Protection Bureau was res

ponsible for the project.

Surface monitoring network with chemical anal

yzers, aircraft measurement, mobile measurem

ent, DOAS, lidar measurement, and satellite m

easurement, numerical simulation and predictio

n were integrated to study the air pollution in B

eijing.

Air quality monitoring by DOAS, MaxDOAS, Lidar

The O3, NO2, SO2 concentrations were measured

in Beijing and Xianghe from the beginning of

August to present continuously by two DOAS.  

Air quality monitoring by DOAS, MaxDOAS, Lidar

• Instrument ： LEOSPERE Lidar ALS-300

• Site ： Xianghe• Date ： 2006-08 upto no

w• Mode ： Continuously

Detecting parameters ：Aerosol vertical distribution and ABL and cloud height

4. Assessment of air quality ensuring measures from satellite data during

Beijing Olympic Games

AURA-OMI data

从 OMI 卫星遥感数据可以很方面地获得整个华北地区的 NO2 含量的区域分布图象，直观看出 NO2 污染状况。

NO2 的卫星遥感图象为利用“好运北京”体育赛事期间北京市采取机动车限行措施的有利条件，对机动车尾气排放对空气质量的影响进行评估提供了很好的数据基础。

The NO2 column density decreased by 49% during the Beijing Olympic Games, and by 38% during the Paralymics due to the Air Quality Assurance Measures.

NO2 column density at the same period of 2005 ～ 2007

NO2 column density during the Beijing Olympic Games

Analysis method

In order to assess the effect of the Air Quality Ensuring Measures, 3 methods were taken:

（ 1 ） calculate the change of 2008 through the comparison with the same period of 2005-2007

（ 2 ） find the difference between Beijing and Tianjin in 2008 during the Olympic Games

（ 3 ） find the difference of NO2 density between the Olympic Games and the period prior to the Games from the MaxDOAS measurements

The remarkable decreasing tendency of NO2 column density was found during June to August of 2008 in Beijing. This tendency was proven by surface MaxDOAS measurement.

06-01 06-06 06-11 06-16 06-21 06-26 07-01 07-06 07-11 07-16 07-21 07-26 08-01 08-06 08-11 8-16 08-210

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50

60

NO

2 V

ert

ica

l Co

lum

n(1

01

5 m

ol/c

m2)

July 1 July 20

Analysis

Comparison of the 10-day average of NO2 column density in 2008 with that during 2005-2007. 49.4% reduction was found during the Olmypic Games. And 38% during the paralymics.

6 月上 / 中 / 下旬 7 月上 / 中 / 下旬 8 月上 / 中 / 下旬

0

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10

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30

1 2 3 4 5 6 7 8 9

NO2

Vert

ical

Col

umn

Dens

ity

(1015

mol

ec/c

m2 )Bei j i ng 2005-2007Bei j i ng 2008

Comparison with Tianjin

Comparison of NO2 column density in Beijing with that in Tianjin

6 月上 / 中 / 下旬 7 月上 / 中 / 下旬 8 月上 / 中 / 下旬

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1 2 3 4 5 6 7 8 9

NO2

Vert

ical

Col

umn

Dens

ity

(1015

mol

ec/c

m2 )

Ti anj i n 2008Bei j i ng 2008

Compared with Tianjin, 48.7% reduction

was found in July, and 31.2% reduction

in August, While during the same perio

d of 2005-2007, the difference is very s

mall, only 0.3%.

MaxDOAS measurement

44% decrease of NO2 column density was found from the MaxDOAS measurement, compared to the pre-air quality control measures.

Site ： Institute of Atmospheric Physics, CAS

0

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25

30

6-16 6-21 6-26 7-1 7-6 7-11 7-16 7-21 7-26 7-31 8-5 8-10 8-15 8-20

Date

NO 2 VCD (10

15

molec/cm

2 )

5. Summary

MIPAS and GOMOS ozone profiles were validated by ozone sonde in Beijing, Lhasa, Xi’ning, China. 2 papers submitted to Journal of Applied Meteorology and the Proceeding of the Symposium of Dragon Program.

A MaxDOAS was setup in Beijing since June 2008. 44% decease of NO2 column density was found from the MaxDOAS measurement during the air quality ensuring period.

5. Summary (cont’d)

Long term aerosol optical depth was recorded with AERONET sunpotometers

Air quality ensuring measures and air quality situation during the Beijing Olympic Games were reviewed. 10 excellent skies were recorded.

The effect of the ensuring measures was assessed from the OMI data. The NO2 column density decreased by 49% during the Beijing Olympic Games, and by 38% during the Paralymics. One paper submitted to Science Bulletin (H. Yu, P. Wang, etc., 2008).

Thanks for your attention ！