The role of Secondary inorganic aerosol in the Yangtze River Delta of China

Secondary Inorganic Aerosol in the Yangtze River Delta of China

Roeland Cornelis JANSEN

PhD defense presentation

Fudan University Handan Road 220, 200433, Shanghai China

November 30, 2014

Professor Jianmin CHEN

Outline:

1. Introduction:• Secondary Inorganic Aerosol and the Yangtze River Delta of China: Introduction and objectives of this study

2. Experimental part:• Methodology: Locations, used instruments and meteorological data• Results from 2 campaigns: The role and behavior of secondary inorganic aerosol during haze and fog in

Shanghai and in Hangzhou

3. Conclusions and suggestions for further work

4. Acknowledgment

5. Q&A

Introduction: The Yangtze River Delta of China

Millions of people

Millions of cars

Thousands of factories

Tons of emission

A lot of agriculture

…

NOx SO2 NH3

Tropospheric NO2 concentrations in east China mapped with the

ERS-2 research satellite during the Global Ozone Monitoring

Experiment (GOME). Reprinted from Huang et al., 2011.

Introduction: Emissions in Yangtze River Delta of China

Point sources in the Yangtze River Delta: left

power plants and right: industrial point sources

Reprinted from Li et al.,2011

Reprinted from Aneja et al., 2001

Formation, growth and removal of atmospheric aerosol

Samples are all sub-micrometer aerosol. Reprinted from

Jimenez et al., 2009.

Introduction: Secondary Inorganic Aerosol (SIA)

Precursor gasses NH3, SO2 , NOx and HCl react

(SO2 and NOx after oxidation) to form SIA:

2 NH3(g) + H2SO4(l) (NH4)2SO4(l)

NH3(g) + HNO3(g) NH4NO3(s or l)

NH3(g) + HCl(g) NH4Cl(s or l)

SIA makes up 30-70% of the total mass of submicron aerosol (PM1)

Reprinted from NOAA

Introduction: Atmospheric aerosol behavior

Hygroscopic properties

Scattering of radiation

Reprinted from Malm, 1999

Studies on SIA role and behavior

Hygroscopic properties

Reprinted from Tang, 1979

Scattering of radiation

Effects of hygroscopicity:• Increase in water content• Increase of particle size• More effective scattering• Cloud formation

Effects of scattering:• Decrease of visibility• Global cooling effect

Reprinted from Malm, 1999.

What is the behavior and role of SIA in the YRD?

Experimental part: 2 campaigns

Hangzhou, Zhejiang University Shanghai, Fudan University

December 2012April-May 2012

Instrument: Time Resolution:

Aerosol inorganic composition: MARGA 1 hourPM mass: R&P TEOM 1400a 1 hour

Thermo SHARP 5030 1 hour

Acidic trace gas + ammonia MARGA 1 hourO3 Thermo 49i continuousNOx Thermo 42i continuous

Visibility Belfort 5000/6000 continuous

RH, temperature, pressure, wind speed Metone continuousVaisala (Hydromet) continuous

Aerosol

Gas

Meteorological

Experimental part: Instruments

MARGA at site in Hangzhou.

Experimental part: MARGA worldwide ~50 publications since 2010

Aerosol: Gas:

Na+ NH3

K+ SO2

NH4+ HNO2

Mg2+ HNO3

Ca2+ HClNO3

-

Cl-

SO42-

hourly results, recovery ~90%

Validation of data:Winiwarter, 1989Wyers et al., 1993Khlystov et al, 1995Slanina et al, 2001Trebs et al., 2004

Antkowiak et al., 2009Hahlbusch et al., 2011 Makkonen et al., 2012

TOC

TN

VA

MS

Experimental part: Time series of RH and Visibility in Shanghai

Experimental part: Time series of SIA and precursor gasses

Experimental part: Correlations Visibility versus PM1 mass

Correlation of visibility vs. PM1 mass. Correlations of visibility vs. PM1 mass for different

RH values

Conclusion: The correlation between visibility and mass concentration of PM1 depends stronglyon the relative humidity

Experimental part: Rel. mass contribution of SIA

Shanghai PM1; December 2012, n=617

Classifying periods of air pollution

Visibility > 10 km.

Du et al., 2011; Xiao et al., 2011; Wu et al., 2005

Clear FogHaze

Visibility < 10 km.

RH < 90%

Time > 4 hr.

Visibility < 10 km.

RH > 90%

Time > 4 hr.

Experimental part: Identifying haze periods

Experimental part: Meteorological conditions

Clear Haze Fog

Number of hours 354 114 48

T (°C) 20.9±6.1 20.8±3.8 18.4±3.2

RH (%) 61.3±16.9 73.9±11.4 93.1±1.9

Pressure (hPa) 1005±5.6 1002.7±3.6 1001.7±4.7

Wind Speed (m/s) 1.4±0.8 1.3±0.7 0.8±0.5

Visibility (km) 21.2±10.4 6.6±2.0 3.3±0.8

PM2.5 (μg/m3) 67±38 118±41 105±27

Clear Haze Fog

Number of hours 483 94 40

T (°C) 5.9±3.9 7.0±3.9 7.4±1.5

RH (%) 58.9±14.7 69.8±15.1 93.6±3.3

Pressure (hPa) 1024±3.7 1022±4.5 1019±1.7

Wind Speed (m/s) 2.4±1.1 2.6±1.1 2.2±0.9

Visibility (km) 25.6±11.2 7.2±1.9 5.4±2.1

PM1 (μg/m3) 31±17 62±26 24±9

Shanghai PM1; December 2012, n=617Hangzhou PM2.5; April-May 2012, n=516

69

229

clear

haze

fog

78

157

clear

haze

fog

%

%%%%

%

Conclusion: The visibility during fog is lowest while the mass concentration on PM is not, thisshows the importance of the RH value on visibility

24 6231

67118 105

Experimental part: SIA mass contribution to PM

Shanghai

PM1

Hangzhou

PM2.5

Conclusion: The SIA in aerosol changes slightly between clear, haze and fogwith nitrate being the most obvious change.

Clear Haze Fog

Relative mass contribution of major inorganic species to PM mass

during clear, haze and fog

Experimental part: SIA mass contribution to PM

Shanghai PM1; December 2012, n=617Hangzhou PM2.5; April-May 2012, n=516

Experimental part: Molar equivalent ratio SIA

Reprinted from Pathak et al., 2009

Equi-molar balance: [NH4+] / 2[SO4

2-] + [NO3-] 2 NH3 + H2SO4 (NH4)2SO4

NH3 + HNO3 NH4NO3

Conclusion: PM1 particles in Shanghai (in Dec. ‘12) are slightly alkaline. In the balance there is no significant difference between clear, haze and fog weather periods.

Nitrate to sulfate molar ratio

[NO3-]/[SO4

2-] as function of

ammonium to sulfate ratio

[NH4+]/[SO4

2-].

Relation between molar

concentrations of [NO3-] and

[NH4+] – [SO4

2-].

Hangzhou PM2.5 Shanghai PM 1

Experimental part: Molar ratios of SIA

Reprinted from Pathak et al., 2009 (PM2.5)

Conclusion: Nitrate formation starts after sulfate formation and there is no significantdifference between clear, haze and fog weather periods.

Conclusion: Nitrate formation happens mainly by SIA formation Beside sulfate and nitrate, ammonium is bound to species like chloride and bisulfate

Experimental part: NOAA HYSPLIT 4

500 and 1000 meter were used,

which represent the average

mixed layer height in Shanghai

(Huang et al., 2012a; Yang et al.,

2006; Kong et al., 2014).

NH3 emission sources are

Yangzhou (NW of Shanghai),

Nantong (NNW of Shanghai) and

Jiaxing (SW of Shanghai)

Huang et al., 2011.

To investigate the role of Secondary Inorganic Aerosol in the Yangtze River Delta 2 campaigns were conducted.

Visibility and PM mass/SIA mass are correlated, yet depend strongly on RH.

Mass concentrations of PM and SIA increase similarly during haze, and nitrate surpasses sulfate

Nitrate formation starts after sulfate formation and the concentrations we measured come from SIA formation (not N2O5 hydration).

Ammonium is also bound to species as Cl- and HSO4- shown by

the relation of excess ammonium vs. nitrate.

NOx and SO2 are local while NH3 is transported to the site

Summary and conclusions

Suggestions for further work

Haze and Fog studies are necessary to demonstrate the sources of air pollution in Urban China.

Expand the measurements, include organics and trace metals.

The role of nitrate seems interesting and needs further investigation.

The use of fertilizer seems inevitable, hence SO2 and NOx emissions may be decreasing. Monitor both gasses for long term to follow the governments actions.

Organize more summer schools and seminars.

2 SCI publications in 2014

Jansen et al., 2014. Advances in Atmospheric Sciences Nov. 2014, Vol. 31, Issue 6, pp 1427-1434 IF: 1.459

Roeland Cornelis Jansen, Jianmin Chen, and Yunjie Hu. Advances in Meteorology, Vol. 2014, Article ID 534675. IF: 1.348

Acknowledgement

Professor: Chen JianminProfessors: Zhang Shicheng, Wang LinTeachers: Kong Lingdong, Wu. , Zhang YiStudents: Shi Yang, Hu Yunjie, Li Chunlin, Leng Chunping

National Natural Science Foundation of China (No. 21190053 and 21177025), Shanghai Science and Technology Commission of Shanghai Municipality (No. 12DJ1400100, 13XD1400700) and Priority fields for Ph.D. Programs Foundation of Ministry of Education of China (No.20110071130003).

Secondary Inorganic Aerosol in the Yangtze River Delta of China

Roeland Cornelis JANSEN

Q&A