Characterization of urban amine-containing particles in Southwestern China: seasonal variation, source, and processing

Abstract

<p><strong>Abstract.</strong> Amine-containing particles were characterized in an urban area of Chongqing during both summer and winter using a single particle aerosol mass spectrometer (SPAMS). Among the collected ambient particles, 12.7 % were amine-containing in winter and 8.3 % in summer. Amines were observed to internally mix with elemental carbon (EC), organic carbon (OC), sulfate, and nitrate. Diethylamine (DEA) was the most abundant in both number and peak area among amine-containing particles. Wintertime amine-containing particles were mainly from the northwest direction where a forest park was located; in summer, they were from the northwest and southwest (traffic hub) directions. These origins suggest that vegetation and traffic were the primary sources of particulate amines. The average relative peak area of DEA depended strongly on humidity, indicating that the enhancement of DEA was possibly due to increasing aerosol water content and aerosol acidity. Using an adaptive resonance theory neural network (ART-2a) algorithm, four major types of amine-containing particles were clustered including amine-organic-carbon (A-OC), A-OCEC, DEA-OC, and A-OCEC-aged. The identified particle types imply that amine was uptaken by particles produced from traffic and biomass burning. Knowledge gained in this study is helpful to understand the atmospheric processing, origin, and sources of amine-containing particles in the urban area of Chongqing.</p>

Characteristics and sources of amine-containing particles in the urban atmosphere of Liaocheng, a seriously polluted city in North China during the COVID-19 outbreak

“…1 ). The average fraction (22.0 %) of amine-containing particles in Liaocheng was higher than that reported in urban background site in Switzerland (16.5 %) and some megacities in China such as Chongqing (12.7 %) and Guangzhou (0.8 %) ( Chen et al, 2019 ; Healy et al, 2015 ; Lian et al, 2020b ). In addition, Healy et al (2015) reported that the higher concentration of amines in the rural site than that in the urban and industrial sites was primarily due to the enhanced anthropogenic emissions of amines from agriculture activity and animal husbandry.…”

“…However, the partitioning of amines from the gaseous phase to the particle phase is mainly via direct dissolution under relatively high RH conditions ( Liu et al, 2018 ). Several field observations have demonstrated that the high RH condition is favorable for the gas-to-particle partitioning of amines ( Chen et al, 2019 ; Zhang et al, 2012 ). The DEA-containing particles were the most abundant amine-containing particles in the whole sampling period.…”

“…The SPAMS data were analyzed using the COCO V3.0 toolkit in Matlab 2014b (Math Work Inc., Natick, MA, USA). According to previous studies ( Chen et al, 2019 ; Cheng et al, 2018 ; Huang et al, 2012 ; Lian et al, 2020b ; Qin et al, 2012 ; Zhang et al, 2012 ), amine-containing particles were identified by querying m/z 59 (CH 3 ) 3 N + (TMA), 74 (C 2 H 5 ) 2 NH 2 + (DEA), 86 [(C 2 H 5 ) 2 NCH 2 + or C 3 H 7 NHC 2 H 4 + ] (DEA, DPA or TEA, defined as TEA in this study) ( Angelino et al, 2001 ), 101 (C 2 H 5 ) 3 N + (TEA), 102 (C 3 H 7 ) 2 NH 2 + (DPA), and 143 (C 3 H 7 ) 3 N + (TPA) ( Table S1 ). In this study, amine-containing particles were identified if the relative peak area of the marker ions listed above is higher than 1 %.…”

“…In recent years, single particle aerosol mass spectrometer (SPAMS) and aerosol time-of-flight mass spectrometry (ATOFMS) have been widely employed to study the chemical compositions, mixing states, and formation processes of amine-containing particles at a high time resolution ( Chen et al, 2019 ; Cheng et al, 2018 ; Healy et al, 2015 ; Lian et al, 2020b ; Qin et al, 2012 ). The gas-to-particle partitioning of amine is influenced by many factors, such as aerosol liquid water content (ALWC), particulate acidity, and atmospheric oxidation capacity, as well as meteorological conditions including relative humidity (RH) and temperature ( Chen et al, 2019 ; Cheng et al, 2018 ). Previous studies in southern China found that high RH condition was favorable for the enhancement of amine-containing particles ( Chen et al, 2019 ; Cheng et al, 2018 ; Zhang et al, 2012 ).…”

“…The gas-to-particle partitioning of amine is influenced by many factors, such as aerosol liquid water content (ALWC), particulate acidity, and atmospheric oxidation capacity, as well as meteorological conditions including relative humidity (RH) and temperature ( Chen et al, 2019 ; Cheng et al, 2018 ). Previous studies in southern China found that high RH condition was favorable for the enhancement of amine-containing particles ( Chen et al, 2019 ; Cheng et al, 2018 ; Zhang et al, 2012 ). Huang et al (2012) reported the higher counts of amine-containing particles during winter than that during summer, due to the lower temperature and higher RH conditions during winter.…”