SP-AMS analyses on BCcontaining

Transcription

1 SP-AMS analyses on BCcontaining particles 盖鑫磊 南京信息工程大学 环境科学与工程学院 1--1

2 Its positive forcing is second only to CO

3 Organic coating on BC particles Gaseous pollutant (e.g. VOCs) Primary organic aerosol (POA) and BC Photooxidation SOA in yellow Mix of POA, secondary organic aerosol (SOA) and BC Photo-oxidation SOA in brown (SOA formation and aging) Courtesy: NUS, Alex Lee

4 Influences Cloud condensation nuclei activity Cloud droplet CCN activity Water uptake Ambient particles in Tokyo Aging Coating thickness Kuwata et. al., JGR, 9 Bare BC BC coated with hydrophobic compounds BC coated with hydrophilic compounds Courtesy: NUS, Alex Lee

5 Influences absorption enhancement Liuet. al., Nat. Comm., 15 Cappa et. al., Science, 1 Penget. al., PNAS, 1 Cui et. al., Sci. Total Environ., 1 包覆层引起的透镜效应, 可以增强吸光, 但是增强程度有较大争议, 主要与包覆物厚度 成分以及混合状态密切相关 Liu et. al., Nat. Geophys., 17 Courtesy: NUS, Alex Lee

6 Our special tool: Soot particle aerosol mass spectrometer (SP-AMS) Ensemble data: Chemical compositions (SO -, NO -, NH +, Cl -, organic, BC) Size distribution (- nm) For submicron aerosols (PM 1 ) Onasch et al., 1, Aerosol Sci. & Tech.,,

7 Soot particle aerosol mass spectrometer (SP-AMS) vs. HR-ToF-AMS From Sampling inlet Pure BC BC + coating Organic & inorganic SP-AMS (laser vaporizer) BC-containing particles only HR-ToF-AMS (thermal vaporizer) SOA coating: Detected by both instruments Courtesy: NUS, Alex Lee 7

8 Detection of BC-containing particles only Coating evaporation m/z Ensemble Mode R + SP-AMS laser vaporizer only configuration e - rbc core evaporation ( o C) Filament Onasch et al., 1, Aerosol Sci. Techno.,, Courtesy: NUS, Alex Lee

9 The vaporizer 9

10 A case in highly polluted environment -Beijing, winter 中科院大气所铁塔分部 AIR POLLUTION AND HUMAN HEALTH (APHH) 基金委中英合作重大项目

11 Instrumentation 11

12 Results -overview Inoragnics (µg m - ) OA factors (µg m - ) 5 (a) (b) Average Mass : 9. µg m - 59.%.% 1.%.5%.%.%.7% 1.5%.9% 1.% Avg. : 5. NH + SO - NO - 11/17 11/ 11/ 11/ 11/9 1/ 1/5 1/ 1/11 Date and time (UTC+) Cl - FOA BBOA OOA1 OOA rbc (µg m - ) Org (µg m - ) BC_SPAMS mass [µg/m ] Abs_PAX r =.9 Slope = 1.7?.17 1 BC_SP Mass [µg/m ] r =.9 Slope =.7?.15 1:1 line 1//1 1/1/1 11//1 11/1/1 1:1 line 1/1/11 1/1/1 1/11/ BC_SPAMS Mass [µg/m ] Inter-comparison 1

13 Results size distribution Fresh Plume 7 (a) D va (nm) (d) D va (nm) rbc*5 SO - * NO - * Org 5 Mass loading (µg m - ) rbc (µg m - ) (b) D va (nm) (e) D va (nm) SO _ (µg m - ) Org. (µg m - ) (c) D va (nm) (f) D va (nm) NO _ (µg m - ) Chl.(µg m - ) dm/dlog d va (µg m - ) dm/dlog d va (µg m - ) PToF size (nm) High RH period Significant size mode difference for coating vs rbc Probably not well formed core-shell structure PToF size (nm) 1

14 Results sources, processes % of total 1 (a) (b) (c) (d) O/C=.1, H/C=1.15 O/C=., H/C=1.5 O/C=.5, H/C=1. O/C=., H/C=1.5 FOA+rBC BBOA+rBC OOA1+rBC OOA+rBC C 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 1 1 m/z (amu) FOA (fossil fuel combustion traffic + coal) BBOA (biomass burning) OOA1 and OOA (secondary) Aqueous-phase and photochemical processes (f) SOA/rBC (e) 1.% %.7% OA-related rbc FOA BBOA OOA1 OOA 1.9% Hour of Day POA/rBC (c).% 15.% (d).% 1.% 15.% 5.% 5.% 5.% Foggy episode.%.1%.5%.5% 11.5% Primary episode 15.% 9.% 1.%.%.% 1

15 winter SP data Dp/Dc Core MMD (µm) BC mass (µg m - ) /11/1 1/11/1 1/11/1 1/11/1 1/11/1 /11/1 /11/1 /11/1 /11/1 /11/1 /11/1 /1/1 /1/1 /1/1 /1/1 dat II III E sca E sca E sca E sca D c (µm) D c (µm) D c (µm) I IV 9.1 D c (µm)

16 SP-AMS SP SP-AMS is not able to separate traffic and coal PAH could be from both coal and biomass burning But the SP mode 1 is clearly not likely to be coal/biomass burning II III E sca 1.1 I IV 9.1 D c (µm)

17 Results coating and aging Mass Fraction(%) (a) CP OSc Mass Fraction(%) (b) DP OSc (c) O/C.1.15 CP DP FE PE rbc Mass loading (µg m - ) 1 (d) CP DP FE PE 17

18 A case in very clean environment -Nam Co, Tibet, spring-summer 1

19 Results-size distribution, mixing state (a) dm/dlogd va (µg m - ) 5 1 Org. SO - NO - rbc D va (nm) D va (nm) (b) Org. (µg m - ) 9 7 D va (nm) 5 (c) NO - (µg m - ) 9 7 D va (nm) (d) SO - (µg m - ) 1 1 Similar size mode (only a small fraction of rbc) Well internally mixed likely Core-shell structure

20 Results-Sources, formation processes Pre-monsoon Monsoon (a) (b) O/C =.51, H/C = 1., N/C =.11, OM/OC = 1. 5 O/C =., H/C = 1.1, N/C =., OM/OC = 1.75 TBBOA RBOOA (e) (f) % 1.5% 9.% 1.%.%.5% 1.7%.5% r =.9 (TBBOA vs. C H O + )... C H O + % of total (c) (d) 5 O/C =.9, H/C = 1., N/C =.7, OM/OC =. O/C =.1, H/C = 1.5, N/C =.5, OM/OC = 1.9 SVOOA C x H y Cx H y O 1 Cx H y O H y O 1 Cx H y N p Cx H y O z N p m/z (amu) LVOOA 1 Mass Conc.(µg m - ) (g) (h) r =.95 (LVOOA vs. SO - ) r =.97 (SVOOA vs. NO - ) / /7 /11 /15 /19 / /7 Data and Time (UTC+) SO NO

21 Results-Sources, formation processes (i) RH(%) (j) NO - /rbc (k) 1... (l) O (ppb) T( o C) LVOOA/rBC TBBOA/rBC RBOOA/rBCSVOOA/rBC Hour of Day RBC SO - /rbc NO SO Diurnal variations indicate: Photochemical production of sulfate/lv-ooa Thermodynamic dissociation of nitrate/sv-ooa The rbccoating is predominately secondary species,and mainly produced from photochemical oxidation reactions 1

22 Results-Coating and aging Mass Fraction (a) Pre-monsoon (b) Monsoon OS c 伦敦 :Liuet. al., Nat. Comm., 15 1 (c). (d) OS c. -. Less BB Sig. BB Neg. BB -. Less BB Sig. BB Neg. BB 洛杉矶 :Leeet. al., ACPD, 17 Thick coating doesn t necessarily corresponds to heavy aging BBOA can thickly coat on BC, but it is relatively fresh Urban environment

23 Results-light absorption enhancement rbc MAAP /rbc AMS (E abs ).5 Sized by conc. of.5... rbc-containing particles TBBOA/OA Indirect semi-quantatitiveestimation of the lower bound of E abs due to lensing effect (brown carbon effect not included) 1 1 Up to % BBOA contributed significantly We will revisit Tibet next year with our Optical instrument and Thermodenuder for a more quantatitive measurement.

24 Next Thermodenuder Ambient = Abs Abs Parameterization (A quantitative and predictive algorithm that can be used in models) SP-AMS HR-AMS PAX 17 Beijing summer for 1 days Supported by a new NSFC project: More measurements in Nanjing Beijing Tibet

25 Acknowledgements 兰州大学黄建平研究组 ( 史晋森 ) 中科院寒旱所徐建中研究员中科院青藏所纳木错综合站美国加州大学戴维斯分校张琦教授 中科院大气所孙业乐研究组英国曼彻斯特大学 Hugh Coe 组 博士生 : 汪俊峰 吴杨周 申付振 5