Abstract
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.
Highlights
Ammonia (NH3) is the most abundant basic gas in the atmosphere and constitutes the majority of total reactive nitrogen [1]
We focused on the incorporation of organic N into aerosol particles for evidence of NH3 and DMA reactions with secondary organic aerosol (SOA) and considered the effects of relative humidity (RH) on this process
We find that increasing RH led to increased reactive uptake for highly viscous SOA, but for less viscous SOA, increasing RH instead suppressed amine uptake
Summary
Ammonia (NH3) is the most abundant basic gas in the atmosphere and constitutes the majority of total reactive nitrogen [1]. In the U.S and worldwide, the largest sources of NH3 emissions are agricultural and farming practices (~85% of total US NH3 emissions, 80–90% of global anthropogenic NH3 emissions) such as commercial fertilizer application and animal waste [4,5,6,7]. Due to the significant impact NH3 has on the environment, there have been several studies investigating how it influences the formation and aging of atmospheric fine particulate matter (PM2.5) [11,12,13]. Fine particulate matter consists of approximately 25–50% inorganic compounds and 40–65% organic compounds by mass [15,16]. Inorganic aerosols have been proven to adversely impact human health [17,18], decrease visibility [19], and affect the atmospheric radiative balance [20,21]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
