The influence of organic compounds on the development of precipitation acidity in maritime clouds Centro de Ciencias de la Atmósfera, UNAM, 04510 Mexico City, Mexico
Abstract. In order to estimate the anthropogenic influence of gas and aerosol
emissions from the Petroleum Industry in maritime zones with clouds of small
vertical extent, a numerical 1-D Eulerian cloud-chemical model with detailed
microphysics (Alfonso and Raga, 2002) is used to simulate the influence of
water soluble organic compounds (WSOC) and organic+inorganic gas emissions
on cloud development. Following Mircea et al. (2002), we tested the
sensitivity of the cloud and precipitation development in the classical
inorganic case (CIC) and the inorganic+organic case (IOC) with respect to
CCN compositions. The results indicate an increase in the droplet
concentration for the IOC, and a delay in the development of precipitation.
The pH spectral evolution was studied during both the development and
precipitation stages. The influence of the diffusion of formic acid and its
generation by oxidation of hydrated formaldehyde in the aqueous phase result
in a reduction in the pH of precipitation in the range between 0.05 and 0.15 pH
units (from 1 to 3%) for the high ambient SO2 concentration (20
ppb) and between 0.2-0.5 pH units (from 4 to 10%) for the low ambient
SO2 concentration (1 ppb) case.
Citation: Alfonso, L. and Raga, G. B.: The influence of organic compounds on the development of precipitation acidity in maritime clouds, Atmos. Chem. Phys., 4, 1097-1111, doi:10.5194/acp-4-1097-2004, 2004.