Potential Enhancement in Atmospheric New Particle Formation by
Amine-Assisted Nitric Acid Condensation at Room Temperature
Abstract
Atmospheric aerosol plays a critical role in global climate and public
health. Recent laboratory experiments showed that new particle formation
is significantly enhanced by rapid condensation of nitric acid and
ammonia at low temperatures. Amines are derivatives of ammonia with a
significant presence in the atmosphere. For example, the wide
implementation of amine-based Post-Combustion Carbon Capture (PCCC)
units may significantly increase the ambient alkanolamine and polyamine
levels. Using thermodynamic simulations, the condensation of
alkylamines, alkanolamines and polyamines with nitric acid at various
temperatures was systematically evaluated. Alkylamines will condense
with nitric acid at temperatures comparable to that of ammonia. However,
with additional hydrogen bonding groups, alkanolamines and polyamines
may condense with nitric acid at room temperature, suggesting a new
potential pathway to remove these amines from the atmosphere. Our
results suggest the potentially critical role of amines in the
atmospheric new particle formation via condensation with nitric acid to
rapidly grow freshly nucleated clusters over their critical size at a
higher temperature than ammonia. The condensed amines and nitric acid
can also facilitate water uptake by aerosol particles at low relative
humidity, which may alter their subsequent atmospheric transformations.