Reply on RC1

Published: Feb. 25, 2024

Abstract. Nitrogen-containing organic compounds (NOCs) are abundant and important aerosol components, deeply involving in global nitrogen cycle. However, the sources formation processes of NOCs remain largely unknown, particularly city (Urumqi, China) farthest from ocean worldwide. Here, PM_2.5 collected Urumqi over a one-year period were characterized by ultrahigh-resolution mass spectrometry. The abundance CHON (mainly poor-O unsaturated aliphatic-like species) positive ion mode was higher warm than cold period, which attributed to contribution fresh biomass material combustion (e.g., forest fires) associated with amidation fatty acids rather oxidation processes. nitro-aromatic negative increased significantly tightly related old-age dry straws) wintertime Urumqi. For CHN compounds, we found that alkyl nitriles aromatic CNH showed periods, respectively. It further confirmed different impacts fresh- materials on NOC compositions. Our results clarify mechanisms emitted NOCs.

Language: Английский

Reply on RC2

Published: Feb. 25, 2024

Abstract. Nitrogen-containing organic compounds (NOCs) are abundant and important aerosol components, deeply involving in global nitrogen cycle. However, the sources formation processes of NOCs remain largely unknown, particularly city (Urumqi, China) farthest from ocean worldwide. Here, PM_2.5 collected Urumqi over a one-year period were characterized by ultrahigh-resolution mass spectrometry. The abundance CHON (mainly poor-O unsaturated aliphatic-like species) positive ion mode was higher warm than cold period, which attributed to contribution fresh biomass material combustion (e.g., forest fires) associated with amidation fatty acids rather oxidation processes. nitro-aromatic negative increased significantly tightly related old-age dry straws) wintertime Urumqi. For CHN compounds, we found that alkyl nitriles aromatic CNH showed periods, respectively. It further confirmed different impacts fresh- materials on NOC compositions. Our results clarify mechanisms emitted NOCs.

Language: Английский

Contrasting Molecular Characteristics and Formation Mechanisms of Biogenic and Anthropogenic Secondary Organic Aerosols at the Summit and Foot of Mt. Huang, East China

Published: Jan. 1, 2023

Secondary organic aerosol (SOA) exerts a considerable influence on atmospheric chemistry. However, little information about the vertical distribution of SOA in alpine setting is available, which limited simulation using chemical transport models. Here, total 15 biogenic and anthropogenic tracers were measured PM2.5 aerosols at both summit (1840 m a.s.l.) foot (480 Mt. Huang during winter 2020 to explore their formation mechanism. Most determined species (e.g., BSOA ASOA tracers, carbonaceous components, major inorganic ions) gaseous pollutants presented higher concentrations than those summit, suggesting relatively more significant effect emissions ground level. The ISORROPIA-II model showed that acidity increases as altitude decreases. Air mass trajectories, potential source contribution function (PSCF), correlation analysis with temperature revealed was mostly derived from local oxidation volatile compounds (VOCs), while mainly influenced by long-distance transport. robust correlations NH3, NO2, SO2) indicated could promote productions mountainous background atmosphere. Moreover, most correlated well levoglucosan all samples, biomass burning played an important role mountain troposphere. This work demonstrated daytime significantly valley breeze winter. Our results provide new insights into distributions provenance free troposphere over East China.

Language: Английский