Trimethylamine as Precursor to Secondary Organic Aerosol Formation via Nitrate Radical Reaction in the Atmosphere

Abstract

Amines in fine particulate matter have been detected and quantified during ambient studies of winter inversions in Logan, UT, using aerosol mass spectrometry. Amine-related compounds account for 0.5-6 microg m(-3) of fine particulate mass during some wintertime periods. The amine contributions sometimes show a clear diurnal pattern, reaching peak concentrations during the middle of the nightwhile decreasing during the morning and afternoon. Smog chamber reactions show that the reaction of tertiary amines with nitrate radical can account for this behavior in the atmosphere. The lower bound reaction rate of trimethylamine and nitrate radical is estimated at 4.4 x 10(-16) cm3/molecules/s with a conversion rate to the aerosol phase of approximately 65%. This suggests that amines could be a contributor to secondary organic aerosol formation in areas where nitrate radical is a significant player in oxidation chemistry.

Enhanced trimethylamine-containing particles during fog events detected by single particle aerosol mass spectrometry in urban Guangzhou, China

“…In addition to the peak at mass-to-charge þ59 corresponding to the TMA, dominant peaks in the positive ion mass spectrum are potassium/organics (Dall'Osto et al, 2009a;Moffet et al, 2008). In this study, no evidence showed the presence of non-salt organic products of TMA in particles because no fragments of common secondary organic products for TMA such as trimethylamine-Noxide at m/z 76 [TMAOH] þ , dimethylnitramine at m/z À90 [CH 3 N 2 O 2 ] À and m/z À74 [CH 3 N 2 O] À were observed through the whole sampling period (Angelino et al, 2001;Silva et al, 2008). Fig.…”

“…Recent measurements by Silva et al (2008) showed that amines could account up to 20% of organic matter mass in fine aerosol during some wintertime periods in Utah, USA. Angelino et al (2001) reported that up to 80% of single particles contained amine signals during some episodes in Riverside, CA.…”

“…TMA can react with gas phase acid (e.g., sulfuric acid and nitric acid) in the atmosphere to form particulate salts through acidebase reactions (Kurtén et al, 2008;Murphy et al, 2007;Silva et al, 2008), and it is even more important than ammonia in enhancing atmospheric nucleation (Erupe et al, 2011;Kurtén et al, 2008;Smith et al, 2010). Through laboratory experiments and ambient observations using an aerosol time-of-flight mass spectrometer (ATOFMS), Rehbein et al (2011) demonstrated that cloud/fog processing could enhance gas-to-particle partitioning of TMA, which is highly dependent on aerosol water content, and that TMA prefers to accumulate in acidic particles.…”

“…Besides, TMA can also participate in the formation of secondary organic aerosol. Several studies have shown that gas-phase TMA could form non-salt organic aerosol products through reaction with oxidizing agents such as O 3 , OH, and NO 3 radical (Murphy et al, 2007;Silva et al, 2008). The relative importance of atmospheric behaviors of TMA in different regions is not yet clear.…”

Single particle analysis of amines in ambient aerosol in Shanghai

“…They can also undergo photooxidation and oxidation reactions with OH radicals, NO 3 radicals and O 3 in the ambient atmosphere to form non-volatile aerosol components. [13,[18][19][20] De Haan et al [21,22] observed that reactions between glyoxal and amines or amino acids can produce light-absorbing, nitrogen-containing imidazoles and oligomers. Particle phase amines have been extensively observed in many areas [9,17,[23][24][25] especially in ultrafine particles during nucleation [26][27][28] and particle growth [29] events.…”