[Role of Ammonia in Aerosol Liquid Water, pH, and Secondary Inorganic Aerosols Formation at an Ammonia-rich City in Changzhou].
Huan Jing Ke Xue
; 45(8): 4493-4501, 2024 Aug 08.
Article
en Zh
| MEDLINE
| ID: mdl-39168669
ABSTRACT
Ammonia ï¼NH3ï¼ is an important alkaline reactive nitrogen, which, as a precursor of fine particulate matter, raises public health issues. In this study, online NH3, SO2, NO2, PM2.5, and its water-soluble inorganic ions were detected to deduce the influence of NH3 on aerosol liquid water content ï¼AWCï¼ and aerosol pH, including the formation of water-soluble secondary ions in PM2.5 in winter in Changzhou, an ammonia-rich city in the Yangtze River Delta area in winter. The results showed that NH4+ mainly existed in the form of NH4NO3 and ï¼NH4ï¼2SO4, and the remaining NH4+ existed as NH4Cl. Owing to the NH3-NH4+ buffer system, the aerosol pH values were found at 4.2 ± 0.4, which was positively correlated with the NH3 content. The aerosol pH value variation narrowed with the increase in PM2.5 concentration and tended to be between 4 to 5. AWC increased exponentially with the increase in humidity and SNA content, among which NH4NO3, ï¼NH4ï¼2SO4, and NH4Cl contributed 58.5%, 18.4%, and 8.3%, respectively, due to their hygroscopicity. Aerosol pH, AWC, and NH3-NH4+ conversion promoted the gas-to-particle conversion of SO2 and NO2. In Changzhou, rich NH3-NH4+ were found to maintain relatively high pH values, push up AWC, and promote the heterogeneous reaction of SO2, whereas NO3- generation was dominated by a homogeneous reaction, which was accelerated by NH3. According to the simulation results, relatively noticeable changes in aerosol pH and AWC could be found by the reduction of up to 30% of NH3.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
Zh
Revista:
Huan Jing Ke Xue
Año:
2024
Tipo del documento:
Article
País de afiliación:
China
Pais de publicación:
China