Mass spectrometric analyses of the airborne fine particles in a megacity of Yangtze River delta (YRD), China

Transcription

1 Presented at Yale-NUIST AE Center Video Seminar Mass spectrometric analyses of the airborne fine particles in a megacity of Yangtze River delta (YRD), China 盖鑫磊 (Xinlei Ge) School of Environmental Science and Engineering Nanjing University of Information Science and Technology (NUIST) 1-1-9

2 Background PM chemistry Filter sampling and off-line analyses: Coarse time resolution (daily sample, etc.), thus very limited to capture the details of fast atmospheric processes, May introduce artifacts during sample storage and analyses Possible loss of semi-volatile species. Online analyses: Don t require sample preparation Real-time display fine time resolution Capture detailed mechanisms

3 Nitrate Equivalent Mass Concentration (µg m -3 ) Soot Particle-Aerosol Mass Spectrometer (SP-AMS) SO SO Ammonium. ug/m3 Nitrate. Sulphate 9. Organics 13. Chloride.1 SO 3 Mexico City /. S 7 HSO 3 H SO. 1 1 m/z (Daltons) 1. Quantitative composition 1 1 Real-time and online measurements of inorganic (sulfate, nitrate, chloride, ammonium) and organic species of PM 1 High chemical resolution (~ under W mode) Fine time resolution (a few mins or secs. each sample) Upgraded with a laser vaporizer able to detect Black carbon (BC) and associated refractory species. Size-resolved composition m/z 3 3. Elemental comp. (C n H m N p O z S w )

4 For field on-line measurement For chamber study For off-line analyses of liquid samples

5 Nitrate Equivalent Mass Concentration (µg m -3 ) How does an AMS work? Likely every min, an averaged mass spectrum (an ensemble of all fragments from all particle-phase species) is obtained The Mass spectrometry analysis is to sort out each species from the fragments (The Game of Puzzles!) chemical composition of the aerosols SO SO S 7 Ammonium. ug/m3 Nitrate. Sulphate 9. Organics 13. Chloride.1 SO 3 HSO 3 H SO Mexico City / Certain species has its unique, reproducible fragmentation pattern, which can be used to apportion the total signals.. m/z (Daltons) MS analysis Courtesy: Q.Zhang

6 Nitrate Equivalent Mass Concentration (µg m -3 ) How does an AMS work? Ammonium. ug/m3 Nitrate. Sulphate 9. Organics 13. Chloride.1 Inorganic species (sulfate, nitrate, chloride and ammonium )are easy to quantify SO SO SO 3 Mexico City / BUT organics can contain numerous species. S 7 HSO 3 H SO. m/z (Daltons) It is almost impossible to quantify each individual organics molecules (perhaps unnecessary); BUT we Still want to know the characteristics, sources of the organics (OA). They can contain very toxic compounds! Factor analysis (segregate the total ORG into a finite number of factors)

7 Lanzhou 1 (Summer). µg m -3 AMS field studies in China Oraganics Sulfate Nitrate Ammonium Chloride Black Carbon HOA COA BBOA CCOA SV-OOA LV-OOA 1% 1% 11% 7% 1% % Beijing 11 (Winter). µg m -3 Urban Urban downwind O/C Beijing 11 (Summer). µg m -3 Beijing (Summer) 3.1 µg m -3 O/C Beijing (Summer). µg m -3 No SP-AMS study O/C..39. O/C O/C O/C.1.3. O/C.13.1 O/C.11.7 O/C Changdao 11 (Spring) 7. µg m -3 Shanghai 1 (Summer) 9. µg m -3 Jiaxing 1 (Summer) 3.9 µg m -3 Jiaxing 1 (Winter) 1.9 µg m µg m -3 (Summer) BackGarden 33.1 µg m -3 (Winter) Kaiping. µg m -3 (Winter) Shenzhen 9 1. µg m -3 (Spring) Hongkong 11

8 Field campaigns in Nanjing 1 Summer 1 Winter (Nanjing Youth Olympic: ) Nanjing Meteorological Bureau (Spring Festival: ) NUIST Campus

9 空气进口 ( 窗户外 ) 气溶胶进口气溶胶进口 PM. 切割头 气溶胶进口 1 Summer Roof 二氧化硫分析仪 氮氧化物分析仪 臭氧分析仪 气粒综合采样口 干燥管 空气动力学粒径谱仪 干燥管 颗粒物热解析系统 纳米颗粒测量仪 中和器 扫描电迁移 - 率粒径谱仪 扫描电迁移率粒径谱仪 气溶胶质量分析仪 凝结核计数器 凝结核计数器 二氧化碳 甲烷 水蒸汽分析仪 高分辨率化学电离飞行时间质谱仪 高分辨率黑碳 - 气溶胶质谱仪 三波段光声黑碳光度计 云凝结核计数器 1 summer instruments (MOUDI, high-volume sampleer not shown)

10 Results and discussion 1. Overall characteristics 1 Summer Wind Speed (m s -1 ) Total PM 1 : 19.9 µg/m 3 31.% 17.3%.%.9% 9.% 1.%

11 1 Winter Prevailing eastern wind both in summer and winter Wind Speed (m S -1 ) % NO 3-3.% SO -.% organics 1.9% NH.3% BC.% Cl -

12 Mass Conc. (µg m -3 ) g /m3 Mass Conc. (µg m -3 ) g /m3 Mass Conc. (µg m -3 ) Mass Conc. (µg m -3 ) g /m3 Temperature ( o C) Temperature ( o C) Diurnal patterns Summer Hour of Day Nitrate (Laser off) Hour of Day BC (Laser on) Mass Cons. g /m Hour of Day Nitrate (Laser off) Diurnal Hour BC (Laser on) Winter 1 1 Nitrate variations were mainly governed by Temperature in Nanjing!!! Hour of Day Sulfate (Laser off) Hour of Day Sulfate (Laser off) Hour of Day Organics (laser off) Diurnal Hour Organics (Laser off) Hour of Day Diurnal Hour 1 1

13 % of total % of total 3. OA Mass spectra 1 Summer Organics (Laser off) rbc (Laser on) (W mode) Organics (no rbc) O/C =.7 H/C = 1. N/C =. OM/OC = 1..3% m/z (amu) 1 11 C x H y C x H y O 1 C x H y O H y O 1 C x H y N p C x H y O z N p MO z N p C x (rbc) % 9.% 1.%.7% 1.3% 1.9% Higher ON species than other places Presence of amino compounds 1 Winter Organics (no rbc) O/C =.31 H/C = 1. N/C =.1 OM/OC = 1..% 3.% C x H y C x H y O 1 C x H y O H y O 1 C x H y N p C x H y O z N p C x (rbc) % 1.% 7.%.1%.1% m/z (amu) Higher ON and BC in suburban site Likely Industrial emissions?

14 mass µg/m3 * % of total mass µg/m3 * % of total. Volatility PM spectra 1 Summer Total: 1.1 µg/m 3.7% laser off o C 1.7%.%.% 19.% m/z m/z (amu) O/C =.3 H/C = 1.9 N/C =.3 OM/OC = 1. C x H y C x H y O 1 C x H y O H y O 1 C x H y N p C x H y O z N p % Total:. µg/m % 1.%.9%.%.% laser on o C 1 1 O/C =.39 H/C = 1.3 N/C =.7 OM/OC = 1. C x H y C x H y O 1 C x H y O H y O 1 C x H y N p C x H y O z N p m/z m/z (amu) Significant amount of non-volatile organics remains in the particles under o C, not only rbc A portion of Nitrate and sulfate remains in the oc-denudered particles, indicating presence of other nitrate/sulfate salts.

15 H/C O/C H/C O/C Mass Fraction remained. Volatility OA behavior OA (Laser off) N/C Organics (laser off) TD temperature ( o C) TD Temperature ( o C) OA (Laser on).. On average, 1% of organics remains even under oc, and these non-volatile organics tend to be more oxidized N/C How does this relate to the Optical properties?? TD Temperature ( o C)

16 Mass Fraction Remained Mass Fraction Remained Mass Fraction Remained Mass Fraction remained Mass Fraction remained. Volatility Inorganics behavior 1. Nitrate (laser off).. Sulfate (laser off) TD temperature ( o C) TD temperature ( o C) 1. Ammonium (laser off) Chloride (Laser off) TD temperature ( o C) rbc (Laser on) TD temperature ( o C) TD temperature ( o C)

17 Organics Sulfate D va (nm) Nitrate Total BC (m/z 3). Size distribution 1 Summer Mass Conc. (µg/m 3 ) Hour of day

18 Mass Percent (%) Mass Percent (%) 1 Summer 1 Winter D va (nm) D va (nm)

19 Time (t)... Nitrate Equivalent Mass Concentration (µg Nitrate m -3 ) Equivalent Mass Concentration (µg m -3 ) Nitrate Equivalent Mass Concentration (µg m -3 ) Positive Matrix Factorization (PMF, 正矩阵因子分解 ) ORG t i = C t p MS p i E t i t = # of time steps = ts p1 ms p1 ts p ms p ts p3 ms p3 i = # of m/z 3. p = # of comp. Ammonium. ug/m3 3 ms Organics = c a ms a c. Nitrate b ms b c c ms. c Sulphate 9. m/z (i) Factor 1 Organics Factor 13. Factor 3. ts Chloride.1 x ms ts x ms ts x ms µg m Source apportionment m/z m/z m/z PMF Analysis S SO SO 7 SO 3 HSO 3 H SO Mexico City /. t ~ 1,s i ~ 3 m/z (Daltons) Courtesy: Q.Zhang 1

20 % of total 1 Summer 7.% 1 1 O/C =., H/C = 1.1, N/C =.9, OM/OC = 1. NOA Nitrogen-enriched 1.% OA NOA O/C =., H/C = 1.79, N/C =.9, OM/OC = 1.7 HOA Vehicle OA HOA OOA COA Morning Rush hour 1.7% 7.9% Evening Rush hour O/C =.1, H/C = 1.7, N/C =., OM/OC = 1.31 COA Local Cooking-related OA Lunchtime Dinnertime 1 O/C =., H/C = 1.3, N/C =.1, OM/OC = 1.9 OOA Oxygenated (secondary) OA m/z (amu)

21 % of total Mass Conc. (µg m -3 ) 1 Winter LSOA 1.% LVOOA 1.% SVOOA 1.% O/C =.1, H/C = 1.73, N/C =., OM/OC = 1.1 O/C =.33, H/C = 1.37, N/C =.3, OM/OC = 1.9 O/C =., H/C = 1.1, N/C =.3, OM/OC = 1. O/C =.33, H/C = 1., N/C =., OM/OC = 1. O/C =.9, H/C = 1.7, N/C =., OM/OC =. O/C =.7, H/C = 1.3, N/C =.3, OM/OC = m/z (amu) 9 HOA IOA COA LSOA LVOOA SVOOA Hour of Day COA 1.% IOA 1.% HOA.1% /1/1 3/3/1 3/13/1 3/3/1 Date and time (Beijing time)

22 Conclusions For the first time, we conducted the SP-AMS study in China and got lots of interesting results For the first time, we discovered the occurrence of fullerenes in the ambient particles, in China atmosphere. Only an overview, lots of in-depth analyses are needed

23 TO BE CONTINUED Thanks!