The Measurement And Gas/particle Partitioning Of Atmospheric Low Molecular Aliphatic Amines

Atmospheric low molecular aliphatic amines are widely exists in atmospheric gas and particle phase.The gas/particle partitioning of amines is an important part of the atmospheric behaviors of amines and a key intermediate step connecting emission and deposition.In this work,we improved the measurement methods of 9 low molecular aliphatic amines by ion chromatography.Amines in both gas phase and particle phase,along with fine particulate matter(PM_2.5)were measured.Taking the northern suburb of Nanjing as an example,the gas/particle partitioning of low molecular aliphatic amines was analyzed.In winter and summer,the total concentrations of amines were 97.36±72.17 and 111.97±42.43ng/m³,respectively.Gas phase amines concentrations were 70.26±57.72 and85.41±36.79ng/m³,which were higher in summer.Particle phase amines concentrations were29.62±23.17 and 26.72±11.52ng/m³,which were higher in winter.The concentrations of gas and particle phase amines showed different seasonal and diurnal variations,which were related to pollutants emissions,gas phase removal efficiencies and gas/particle conversions.The gas/particle distribution coefficients（?）of amines were 0.36±0.20 and 0.25±0.11 in winter and summer,respectively.Direct dissolution pathway may be the dominant pathway for MA while acid-base reaction pathway for DMA.Heterogeneous reactions may contribute to the partitioning of TMA.The gas/particle partitioning of amines may be affected by meteorological conditions,gaseous pollutants and aerosol ions.Fine particulate matter(PM_2.5)is an important component of particle phase,which has a great impact on human health.Particle phase amines were mainly enriched in PM_2.5,accounting for about 85%.The concentrations of amines in PM_2.5 were 38.67±15.52 and34.75±11.79 ng/m³ in winter and summer,respectively.The concentrations were higher in winter and nighttime.C1-C2 amines were the dominate amines in PM_2.5（61.50±17.31%）.The competitiveness of gaseous amines relative to NH₃ will enhance in summer.Amines in PM_2.5tend to present in the form of sulfate salts.According to PMF model analysis,the main sources of C1-C2 amines were residents living emissions（34.06%）;soil and plants emissions（26.07%）;marine,industrial and biomass burning emissions（21.80%）,as well as secondary reaction products and biomass burning emissions（18.07%）.