南昌市粗颗粒气溶胶中水解氨基酸的浓度和组成特征

Concentration and composition characteristics of hydrolyzed amino acids in coarse aerosol in Nanchang

对南昌市5个不同采样区的粗颗粒气溶胶进行采集,测定并分析了粗颗粒气溶胶中水解氨基酸(HAA)的浓度、组成特征以及稳定氮同位素变化规律。结果表明,南昌市粗颗粒气溶胶中总水解氨基酸(THAA)摩尔浓度为0.2~4396.1 pmol/m^(3),平均摩尔浓度为429.8 pmol/m^(3),5个采样区中,森林地区THAA浓度相对最高。脯氨酸(Pro)、甘氨酸(Gly)、丙氨酸(Ala)、缬氨酸(Val)、亮氨酸(Leu)、谷氨酸(Glu)、异亮氨酸(Ile)是南昌市粗颗粒气溶胶中的主要HAA。降雨会影响粗颗粒气溶胶中HAA浓度变化,可导致Ala、Val、Leu、Ile、Glu、Gly等自然源HAA浓度增加。降雨期THAA稳定氮同位素比值(δ15 N)相比非降雨期呈现整体偏负的特征,说明降雨对自然源生物气溶胶的释放具有促进作用,导致THAA和自然源HAA单体浓度增加。

The coarse-grained aerosols from five different functional areas in Nanchang were collected,and the concentration,composition characteristics,variation law of stable nitrogen isotope of hydrolyzed amino acids(HAA)in coarse aerosol were measured and analyzed.The results showed that the molar concentration of total hydrolyzed amino acids(THAA)in aerosol coarse particles in Nanchang was 0.2-4396.1 pmol/m^(3),and the average molar concentration was 429.8 pmol/m^(3).Among the five sampling areas,the concentration of THAA in forest area was relatively high.The main HAA in coarse aerosol in Nanchang include proline(Pro),glycine(Gly),alanine(Ala),valine(Val),leucine(Leu),glutamic acid(Glu)and isoleucine(Ile).Rainfall would affect amino acid concentration in coarse-grained aerosol,rainfall could also increase the concentration of naturl sources HAA such as Ala,Val,Leu,Ile,Glu and Gly.Compared with the dry periods,the stable nitrogen isotope ratio of THAA in rainfall period(δ15 N)showed an overall negative characteristic.These results indicated that rainfall promoted the release of bioaerosols from natural sources,leading to the increase of THAA and HAA monomer concentrations.