scholarly journals Effect of Humidity on the Reactive Uptake of Ammonia and Dimethylamine by Nitrogen-Containing Secondary Organic Aerosol

Atmosphere ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1502
Author(s):  
Natalie R. Smith ◽  
Julia Montoya-Aguilera ◽  
Donald Dabdub ◽  
Sergey A. Nizkorodov
Keyword(s):  
Relative Humidity ◽  
Secondary Organic Aerosol ◽  
Condensation Reaction ◽  
Organic Aerosol ◽  
Uptake Coefficient ◽  
Acid Base Equilibrium ◽  
Amine Uptake ◽  
Reactive Uptake Coefficient ◽  
Uptake Coefficients ◽  
Toluene Photooxidation

This study investigated the uptake of ammonia (NH3) by secondary organic aerosol (SOA) particles generated via limonene photooxidation or ozonolysis as well as the uptake of dimethylamine (DMA) by limonene ozonolysis, α-cedrene photooxidation, or toluene photooxidation SOA in an environmental chamber between 0–50% relative humidity. In addition to the acid-base equilibrium uptake, NH3 and DMA can react with SOA carbonyl compounds converting them into nitrogen-containing organic compounds (NOCs). The effective reactive uptake coefficients for the formation of NOCs from ammonia were measured on the order of 10−5. The observed DMA reactive uptake coefficients ranged from 10−5 to 10−4. Typically, the reactive uptake coefficient decreased with increasing relative humidity. This is consistent with NOC formation by a condensation reaction between NH3 or DMA with SOA, which produces water as a product. Ammonia is more abundant in the atmosphere than amines. However, the larger observed reactive uptake coefficient suggests that amine uptake may also be a potential source of organic nitrogen in particulate matter.

scholarly journals Reactive uptake coefficients for heterogeneous reaction of N<sub>2</sub>O<sub>5</sub> with submicron aerosols of NaCl and natural sea salt

2004 ◽  
Vol 4 (5) ◽  
pp. 1381-1388 ◽  
Author(s):  
D. J. Stewart ◽  
P. T. Griffiths ◽  
R. A. Cox
Keyword(s):  
Relative Humidity ◽  
Flow Reactor ◽  
Heterogeneous Reaction ◽  
Sea Salt ◽  
Uptake Coefficient ◽  
A Value ◽  
Reactive Uptake Coefficient ◽  
Uptake Coefficients ◽  
Kinetics Of Uptake ◽  
Kinetics Of

Abstract. The kinetics of uptake of gaseous N2O5 on submicron aerosols containing NaCl and natural sea salt have been investigated in a flow reactor as a function of relative humidity (RH) in the range 30-80% at 295±2K and a total pressure of 1bar. The measured uptake coefficients, γ, were larger on the aerosols containing sea salt compared to those of pure NaCl, and in both cases increased with increasing RH. These observations are explained in terms of the variation in the size of the salt droplets, which leads to a limitation in the uptake rate into small particles. After correction for this effect the uptake coefficients are independent of relative humidity, and agree with those measured previously on larger droplets. A value of γ=0.025 is recommended for the reactive uptake coefficient for N2O5 on deliquesced sea salt droplets at 298K and RH>40%.

scholarly journals Reactive uptake coefficients for heterogeneous reaction of N<sub>2</sub>O<sub>5</sub> with submicron aerosols of NaCl and natural sea salt

2004 ◽  
Vol 4 (1) ◽  
pp. 569-590 ◽  
Author(s):  
D. J. Stewart ◽  
R. A. Cox
Keyword(s):  
Relative Humidity ◽  
Flow Reactor ◽  
Heterogeneous Reaction ◽  
Sea Salt ◽  
Uptake Coefficient ◽  
A Value ◽  
Reactive Uptake Coefficient ◽  
Uptake Coefficients ◽  
Kinetics Of Uptake ◽  
Kinetics Of

Abstract. The kinetics of uptake of gaseous N2O5 on submicron aerosols containing NaCl and natural sea salt has been investigated in a flow reactor as a function of relative humidity (RH) in the range 30-80% at 295+/-2 K and a total pressure of 1 bar. The measured uptake coefficients, γ, were larger on the aerosols containing sea salt compared to those of pure NaCl, and in both cases increased with increasing RH. These observations are explained in terms of the variation in water content and hence size of the salt droplets, which leads to a limitation in the uptake rate into small particles. After correction for this effect the uptake coefficients are independent of relative humidity, and agree with those measured previously on larger droplets. A value of γ=0.025 is recommended for the reactive uptake coefficient for N2O5 on deliquesced sea salt droplets at 298 K and RH>40%.

scholarly journals α-Pinene secondary organic aerosol yields increase at higher relative humidity and low NO<sub><i>x</i></sub> conditions

2016 ◽  
Author(s):  
Lisa Stirnweis ◽  
Claudia Marcolli ◽  
Josef Dommen ◽  
Peter Barmet ◽  
Carla Frege ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Relative Humidity ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Liquid Water Content ◽  
Strong Increase ◽  
Chemical Compositions ◽  
Scanning Mobility Particle Sizer ◽  
Equilibrium Partitioning ◽  
Phase Partitioning

Abstract. Secondary organic aerosol (SOA) yields from the photooxidation of α-pinene were investigated in smog chamber (SC) experiments at low (23–29 %) and high (60–69 %) relative humidity (RH), various NOx/VOC ratios (0.04–3.8) and with different aerosol seed chemical compositions (acidic to neutralized sulfate-containing or hydrophobic organic). A combination of a scanning mobility particle sizer and an Aerodyne high resolution time-of-flight aerosol mass spectrometer was used to determine SOA mass concentration and chemical composition. We present wall-loss-corrected yields as a function of absorptive masses combining organics and the bound liquid water content. High RH increased SOA yields by up to six times (1.5–6.4) compared to low RH. The yields at low NOx/VOC ratios were in general higher compared to yields at high NOx/VOC ratios. This NOx dependence follows the same trend as seen in previous studies for α-pinene SOA. A novel approach of data evaluation using volatility distributions derived from experimental data served as basis for thermodynamic phase partitioning calculations of model mixtures in this study. These calculations predict liquid-liquid phase separation into organic-rich and electrolyte phases. At low NOx conditions, equilibrium partitioning between the gas and liquid phases can explain most of the increase in SOA yields at high RH. This is indicated by the model results, when in addition to the α-pinene photooxidation products described in the literature, more fragmented and oxidized organic compounds are added to the model mixtures. This increase is driven by both the increase in the absorptive mass due to the additional particulate water and the solution non-ideality described by the activity coefficients. In contrast, at high NOx, equilibrium partitioning alone could not explain the strong increase in the yields with increased RH. This suggests that other processes including the reactive uptake of semi-volatile species into the liquid phase may occur and be enhanced at higher RH, especially for compounds formed under high NOx conditions such as carbonyls.

scholarly journals Light absorption by secondary organic aerosol fromα-pinene: Effects of oxidants, seed aerosol acidity, and relative humidity

2013 ◽  
Vol 118 (20) ◽  
pp. 11,741-11,749 ◽  
Author(s):  
Chen Song ◽  
Madhu Gyawali ◽  
Rahul A. Zaveri ◽  
John E. Shilling ◽  
W. Patrick Arnott
Keyword(s):  
Relative Humidity ◽  
Light Absorption ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Aerosol Acidity ◽  
Seed Aerosol

scholarly journals Sensitivities of the absorptive partitioning model of secondary organic aerosol formation to the inclusion of water

2008 ◽  
Vol 8 (6) ◽  
pp. 20311-20348 ◽  
Author(s):  
M. Barley ◽  
D. O. Topping ◽  
G. McFiggans ◽  
M. E. Jenkin
Keyword(s):  
Relative Humidity ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Organic Component ◽  
Condensed Phases ◽  
Aerosol Formation ◽  
Ambient Relative Humidity ◽  
Highly Sensitive ◽  
Volatile Organic ◽  
Secondary Organic Aerosol Formation

Abstract. Depending on the assumptions about the participation of water in absorptive partitioning, the prediction of the distribution of semi-volatile organic component between the gaseous and condensed phases is shown to be highly sensitive to the ambient relative humidity and the formulation of the partitioning model used. Further sensitivities to the assumed pre-existing particulate loading and to parameterised organic component non-ideality are explored and shown to contribute significantly to the variation in predicted secondary organic particulate loading.

scholarly journals Uptake of HO<sub>2</sub> radicals on Arizona test dust surface

2013 ◽  
Vol 13 (4) ◽  
pp. 8873-8900 ◽  
Author(s):  
Y. Bedjanian ◽  
M. N. Romanias ◽  
A. El Zein
Keyword(s):  
Relative Humidity ◽  
Flow Reactor ◽  
Uptake Coefficient ◽  
Gaseous Species ◽  
Local Conditions ◽  
Uv Irradiance ◽  
Reactive Uptake Coefficient ◽  
Kinetics Of ◽  
Geometric Surface ◽  
Dust Surface

Abstract. The interaction of HO2 radicals with solid films of Arizona Test Dust (ATD) was studied using a low pressure flow reactor (1–9 Torr) combined with a modulated molecular beam mass spectrometer for monitoring of the gaseous species involved. The reactive uptake coefficient of HO2 was measured from the kinetics of HO2 consumption on Pyrex rods coated with ATD as a function of HO2 concentration ((0.35–3.30) × 1012 molecule cm−3), relative humidity (RH = 0.02–94%), temperature (T = 275–320 K) and UV irradiance intensity (JNO2 = 0–0.012 s−1). The initial uptake coefficient was found to be independent of concentration of HO2, temperature and irradiation conditions, and to decrease with increasing relative humidity: γ0 = 1.2/(18.7 + RH1.1) (calculated using geometric surface area, with 30% estimated conservative uncertainty). An upper limit of 5% was found for the H2O2 forming pathway of the HO2 reaction with ATD surface. The results of the measurements indicate that HO2 loss on dust aerosol may be a non negligible sink for HOx species in the troposphere with the effect depending on specific local conditions.

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