2013年与2016年青岛采暖期间新粒子生成及活化为云凝结核能力的对比研究

A Comparative Study on the Generation and Activation of New Particles in Qingdao Area During the Heating Period in 2013 and 2016

于2013和2016年的采暖期间对青岛郊区的大气颗粒物数浓度(NCN)、粒径分布和云凝结核数浓度(NCCN)进行观测。对比发现:NCN在2016年比2013年下降了48%,这可能与污染物减排措施的加强相关。在过饱和度(SS)为0.4%和0.6%时,2016年的NCCN比2013年下降了25%和36%。然而,在SS为0.2%时,2016年的NCCN比2013年增加了6%。在大于100 nm颗粒物数浓度下降的条件下,低饱和度NCCN反而增加,表明大粒径颗粒物活化能力的增强抵消了其浓度减少对云凝结核数浓度的影响。对于不同过饱和度下云凝结核活化率,2016年比2013年上升了91%(0.2%SS)、29%(0.4%SS)和13%(0.6%SS)。两年观测期间,新粒子生成(NPF)事件的发生频率相近。新粒子生成速率(FR)在2016年((4.0±2.0)cm^-3·s^-1)高于2013年((2.2±0.8)cm^-3·s^-1),可能是2016年的颗粒物凝结汇的降低导致的。新粒子对NCCN的贡献和新粒子增长为云凝结核后的活化效率在2016年均低于2013年,说明减排措施的加强会降低新粒子对CCN的贡献。

The atmospheric aerosol particles number concentration(NCN),particle number size distributions and the concentrations of cloud condensation nuclei(NCCN)were observed in the suburb of Qingdao during the heating period in 2013 and 2016,respectively.The NCN measured during 2016 decreased by 48%compared with that in 2013,which may be related to the strengthening of pollutant emission reduction measures.The averaged NCCN in 2016 was 25% smaller than that of 2013 at supersaturation(SS)of 0.4% while the averaged NCCN during 2016 decreased 36% at SS of 0.6%.However,the averaged NCCN in 2016 increased 6% at SS of 0.2%.The averaged NCCN increased at lower SS with decreasing of the number concentrations of>100 nm particles(N>100 nm),implying that the activation ability of large than 100 nm particles is enhanced and then offsets the influence of the decrease of N>100 nm on the concentrations of CCN.The activation rates(AR)in 2016 were 91%,29%and 13%larger than that of 2013 at SS of 0.2%,0.4%and 0.6%,respectively.In order to explore the influence of new particle formation(NPF)events on the NCCN,a comparative analysis of NPF events during the two-year observation periods was conducted.The study found that the averaged formation rate(FR)of new particles in 2016((4.0±2.0)cm^-3·s^-1)was larger than that in 2013(2.2±0.8cm^-3·s^-1)and the averaged condensation sink(CS)in 2016 was smaller than that in 2013.Therefore,the lower CS may be the cause of the increased FR in 2016.The D pg max,survival probability(SP),the contribution of NPF events to the NCCN and the AR of newly particles in 2016 were lower than that of 2013,which indicated that the strengthening of emission reduction measures reduced the contribution of NPF events to CCN.