1. 中国酸雨沉降机制、输送态势及调控原理 第三课题 2005CB422203 In situ observation of dust involved photochemistry over southern China LIFE+ PhotoPaq conference 2014 16 April 2014 Wei Nie 1, Aijun Ding 1, Tao Wang 2, Christian George 3 1 Institute for Climate and Global Change Research/School of Atmospheric Sciences, Nanjing University 2 Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China 3 CNRS, UMR5256, IRCELYON, Institut de Recherches sur la Catalyse et l’Environnement de Lyon, Villeurbanne, F-69626, France

2. Background Health effect Dust aerosols Global climate change IPCC 2007 Atmospheric chemistry Ocean ecosystem LIFE+ PhotoPaq conference 2014 16 April 2014

3. Roles in photochemistry Light extinction (scattering and absorbing) Scavenge reactive gaseous Scavenge molecular clusters Direct uptake and decomposition oxidant, e.g. O 3 and OH LIFE+ PhotoPaq conference 2014 16 April 2014

4. Introduction to the campaign Roles of dust in new particle formation Roles of dusts in HONO chemistry Causes of the observed heterogeneous photochemistry Contents LIFE+ PhotoPaq conference 2014 16 April 2014

5. Introduction to the campaign Roles of dust in new particle formation Roles of dusts in HONO chemistry Causes of the observed heterogeneous photochemistry Contents LIFE+ PhotoPaq conference 2014 16 April 2014

6. Site location Mt Heng Mar to May 2009， 1269m a.s.l. LIFE+ PhotoPaq conference 2014 16 April 2014

7. Duration ： 2009. 3. 14 – 6. 1 Measurements ： Gaseous: SO 2, NO x, NO y, NH 3, HNO 3, HCl, CO, CO 2, VOCs, O 3 Aerosols: PM 2.5, PM 10, BC, B sp, WSIs, Size distribution, MOUDI, Filter samples Cloud and fog: pH, conductivity, WSIs, organic acids, heavy metals, HCHO, H 2 O 2 ， S(IV) ， PAHs Wet deposition: pH, conductivity, WSIs, organic acids, heavy metals Introduction to the campaign LIFE+ PhotoPaq conference 2014 16 April 2014

8. Overall results LIFE+ PhotoPaq conference 2014 16 April 2014

9. Overall results 1.CALIPSO measured vertical profiles of total attenuated backscatter and aerosol subtype on 25 April. 2.MODIS true-color imagery of eastern China on 24 and 25 April 2009. LIFE+ PhotoPaq conference 2014 16 April 2014

10. Introduction to the campaign Roles of dust in new particle formation Roles of dusts in HONO chemistry Causes of the observed heterogeneous photochemistry Contents LIFE+ PhotoPaq conference 2014 16 April 2014

11. New particle formation and growth Weak dust Strong dust NPF can co-exist with dusts, even under very heavy particle loadings! LIFE+ PhotoPaq conference 2014 16 April 2014

12. New particle formation and growth The formation rates and growth rates were significantly enhanced during dust episodes! Date J 15 (cm -3 S -1 ) GR(15-30) (nm h -1 ) GR(30-50) (nm h -1 ) Q (cm -3 s -1 ) PM 10 ** (μg m -3 ) 15-Mar0.264.3NA * 1.0e+06- *** 25-Mar0.175.6 1.1e+0656.3 7-Apr0.277.711.4 1.9e+0675.7 20-Apr0.156.1 1.0e+0682.0 22-Apr0.204.9 19.3 1.5e+06135.1 25-Apr0.45 7.2 12 2.8e+06668.6 26-Apr0.26 7.422.4 2.8e+06506.9 27-Apr0.316.111.9 1.7e+0675.3 4-May0.174.63.5 1.3e+0669.8 5-May0.296.45.8 1.8e+0654.6 LIFE+ PhotoPaq conference 2014 16 April 2014

13. NPF- possibly additional H 2 SO 4 Sulfuric acid proxy in DS episodes show different feature; Sulfate was formed corresponded to NPF in the daytime; Probably additional H 2 SO 4 was produced related to dust. LIFE+ PhotoPaq conference 2014 16 April 2014

14. NPF- possibly additional OVOCs Calculated VOCs was lower in DS episodes; Potentials of producing low-volatile organic vapors is also lower; Probably additional low-volatile organic vapors were produced related to dusts

15. Introduction to the campaign Roles of dust in new particle formation Roles of dusts in HONO chemistry Causes of the observe heterogeneous photochemistry Contents LIFE+ PhotoPaq conference 2014 16 April 2014

16. HONO production Nitrite formation was significantly enhanced in the daytime of dust episode! LIFE+ PhotoPaq conference 2014 16 April 2014

17. Possible related surface processes 1.Surface photolysis of HNO 3 (Zhou et al., 2003; Ramazan et al., 2004) 2.NO 2 photo-conversion on the soot surface (Aubin and Abbatt,2007) 3.Heterogonous photochemical process of NO 2 on the surface organic substance (George et al., 2005; Stemmler et al., 2006) 4.NO 2 photo-catalyic on the surface of TiO 2 (Gustafsson et al.,2006; Ndour et al., 2008) LIFE+ PhotoPaq conference 2014 16 April 2014

18. Samples Fine particles (µg/m 3 ) Coarse particles (µg/m 3 ) NO 2 - TiNO 3 - NO 2 - Ti * NO 3 - 25/04 daytime0.680.582.02.021.6118.2 26/04 daytime 1.50.421.04.491.1210.7 HONO formation LIFE+ PhotoPaq conference 2014 16 April 2014

19. Introduction to the campaign Roles of dust in new particle formation Roles of dusts in HONO chemistry Causes of the observed heterogeneous photochemistry Contents LIFE+ PhotoPaq conference 2014 16 April 2014

20. Possible causes- mixture with anthropogenic pollution LIFE+ PhotoPaq conference 2014 16 April 2014

21. Possible causes- mixture with anthropogenic pollution Anthropogenic pollutants, e.g. sulfate and BC were enhanced during DS; Evident secondary coating were formation on the surface of dust particles; Sufficient solar radiation and RH even during heavy dust storms. LIFE+ PhotoPaq conference 2014 16 April 2014

22. Summary and implication

23. In-situ observed evidence for dust promoted NPF and HONO production; Suggesting an un-expected roles of Asian dust in the global climate change via influencing the CCN budget; Indicating that aerosols have potentials to act as oxidant (catalyst) via direct and indirect pathways to enhance the atmospheric oxidation capacity, and thus impact the atmospheric chemistry in a more significant way. LIFE+ PhotoPaq conference 2014 16 April 2014

24. 中国酸雨沉降机制、输送态势及调控原理 第三课题 2005CB422203 谢谢！ Thanks！ LIFE+ PhotoPaq conference 2014 16 April 2014

25. HONO formation Dust episode Photochemical episode Nitrite (µg/m 3 ) 2.50.6 Nitrate (µg/m 3 ) 15.620.1 BC (µg/m 3 ) 3.23.5 Concentrations of nitrate and BC were higher in photochemical episodes than those in dust storm, excluding the possibility of first two processes. LIFE+ PhotoPaq conference 2014 16 April 2014