Characteristics and mixing state of amine-containing particles at a rural site in the Pearl River Delta, China

Abstract

Abstract. Particulate amines play an important role for the particle acidity and 43 hygroscopicity and also contribute to secondary organic aerosol mass. We investigated 44 the sources and mixing states of particulate amines using a single-particle aerosol 45 mass spectrometer (SPAMS) during summer and winter 2014 at a rural site in the 46 Pearl River Delta, China. Amine-containing particles accounted for 12.8 % and 9.2 % 47 of the total detected individual particles in summer and winter, respectively. only 6.7 % of the total amine-containing particles were found to be mixed with 57 ammonium, while in winter this percentage increased to 55 %. The ammonium-poor 58 state of amine-containing particles in summer may have been caused by the 59 displacement of particle-phase ammonium by amine uptake, which was more efficient 60 in summer at higher ambient RH (72 ± 13 %) than in winter (63 ± 11 %). In 61 ECOC-type amine-containing particles, the time series of the amine peak area and the 62 sum of the nitrate and sulfate peak areas were similar in both summer and winter, 63 suggesting the formation of aminium sulfate and nitrate salts. The particle acidity of 64 ECOC-type amine-containing particles was represented by the relative acidity ratio 65 (R a ), which was defined as the ratio of the total sulfate and nitrate peak areas to the 66 ammonium peak area. The R a decreased from 348 ± 335 and 28 ± 14 to 10 ± 5 and 9 ± 67 2 in summer and winter, respectively, after including amines along with the 68 ammonium in the acidity calculation, suggesting that it is reasonable to consider 69 amines when estimating particle acidity.

Size‐Resolved Mixing States and Sources of Amine‐Containing Particles in the East China Sea

“…The fraction of amine‐containing particles is comparable to those reported in previous studies in rural and urban areas. In a rural site in the Pearl River Delta (Heshan), amine‐containing particles accounted for 11.1% and 9.4% of the total detected individual particles in summer and winter, respectively (Cheng et al, 2018). In an urban area in southwestern China (Chongqing), 8.3% and 12.7% of the total particles were amine‐containing particles in summer and winter, respectively (Chen et al, 2019).…”

“…The TMA‐containing particles peaked at 0.5 to 0.6 μm on clear days and shifted to larger sizes with a peak at 0.6 μm during fog events (Zhang et al, 2012). Cheng et al (2018) reported that amine‐containing particles peaked in the size range of 0.5 to 0.7 μm in both summer and winter. In southwestern China, DEA‐containing particles were reported to peak at 0.6 μm (Chen et al, 2019).…”

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

“…Amines are widely present in rainwater, fog, gas and particle phases ( Ge et al, 2011b ), and they can be emitted from a variety of natural (e.g., marine environment and vegetation) and anthropogenic (e.g., biomass burning, animal husbandry, vehicle exhaust, and industrial processes) sources ( Ge et al, 2011a ; Murphy et al, 2007 ). Laboratory experiments and theoretical calculations have demonstrated that amines are more alkaline than ammonia, although the gaseous concentration of amine is one or two orders of magnitude lower than ammonia ( Cheng et al, 2018 ; Ge et al, 2011a ; Sorooshian et al, 2008 ). The concentration of amines is only 14%–23 % of ammonium, but it has been thought to be a key basic compound even in aerosol particles containing ammonium ( Sorooshian et al, 2008 ).…”

“…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.…”