The influence of organic compounds on the development of precipitation acidity in maritime clouds
- ISSN: 1680-7324
- DOI: 10.5194/acp-4-1097-2004
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 nu- merical 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 inor- ganic case (CIC) and the inorganic+organic case (IOC) with respect to CCN compositions. The results indicate an in- crease in the droplet concentration for the IOC, and a delay in the development of precipitation. The pH spectral evolution was studied during both the de- velopment and precipitation stages. The influence of the dif- fusion of formic acid and its generation by oxidation of hy- drated formaldehyde in the aqueous phase result in a reduc- tion in the pH of precipitation in the range between 0.05 and 0.15pH units (from 1 to 3%) for the high ambient SO2 con- centration (20 ppb) and between 0.2–0.5pH units (from 4 to 10%) for the low ambient SO2 concentration (1 ppb) case.