OPEN ACCESS

Articles online

Evidence of Organonitrate Formation at a High Altitude Site, Mahabaleshwar, during the Pre-monsoon Season

Category: Aerosol and Atmospheric Chemistry

Article In Press
DOI: 10.4209/aaqr.2018.03.0110
PDF | Supplemental material

Export Citation:  RIS | BibTeX

Vyoma Singla, Subrata Mukherjee , Govindan Pandithurai, Kundan K. Dani, Pramod D. Safai

  • Indian Institute of Tropical Meteorology, Pune 411 008, India

Highlights

Source apportionment of nitrate is done by sophisticated PMF technique.
Organo nitrate contributed 37.80 % to the total nitrate functionality.
NOx ratio for NIA factor was found to be 1.28.
NOx ratio of OOA-2 (~6.06) indicated isoprene oxidation as a major source of ON.


Abstract

The presence of organonitrate and organosulfate was found at Mahabaleshwar, a high altitude site, during the pre-monsoon season of 2016. A Time of Flight Aerosol Chemical Speciation Monitor (ToF-ACSM) was used to measure the organic and inorganic components of non-refractory particulate matter (NR-PM1) aerosol. Positive Matrix Factorization (PMF) was performed on the (i) organics mass spectra of the aerosol (PMFOA), (ii) organics mass spectra merged with inorganics (PMFOA+IOA) and (iii) integrated mass spectra of organics with NO+ and NO2+ ions (PMFOA+NOx) to derive the chemical information on organonitrate and organosulfate. The results of PMFOA were used as a reference for validating the factors obtained through the PMFOA+IOA and PMFOA+NOx results. The analysis of PMFOA resolved four PMF factors: hydrocarbon-like OA (HOA); biomass burning OA (BBOA); oxygenated OA-1 (OOA-1) and OOA-2. The analysis of PMFOA+IOA identified two additional inorganic factors: sulfate organic aerosol (OA) and nitrate OA. Sulfate OA and nitrate OA contributed 36% and 6%, respectively, to the total aerosol mass. Although both originated as secondary organic aerosol, they displayed different diurnal profiles. The results of PMFOA+NOx were used for the quantification and apportionment of nitrate aerosol in two forms, organic nitrate and inorganic nitrate, which contributed 38% and 62%, respectively, to the total nitrate aerosol mass. The diurnal variation in organic nitrate highlights photochemical oxidation and nocturnal oxidation by the nitrate radical as the two major sources. This source apportionment study using a combined (organic and inorganic) dataset provides new source factors and improves our understanding about the sources and chemical nature of submicron aerosols in the atmosphere. However, uncertainties in the quantification of organosulfate remain a limitation.

Keywords

Tof-ACSM PMF Organonitrate Organosulfate NIA


Related Article

Aerosol Emissions from Long-Lasting Smoldering of Boreal Peatlands: Chemical Composition, Markers, and Microstructure

Olga B. Popovicheva , Guenter Engling , I-Ting Ku, Mikhail A. Timofeev, Natalia K. Shonija
Accepted Manuscripts
DOI: 10.4209/aaqr.2018.08.0302
PDF

Characteristics of Air Pollutants and Greenhouse Gases at a Regional Background Station in Southwestern China

Linjun Cheng, Dongsheng Ji , Jun He, Liang Li, Li Du, Yang Cui, Hongliang Zhang, Luxi Zhou, Zhiqing Li, Yingxing Zhou, Chengyuan Miao, Zhengyu Gong, Yuesi Wang
Accepted Manuscripts
DOI: 10.4209/aaqr.2018.11.0397
PDF

Aerosol Pollution Characterization before Chinese New Year in Zhengzhou in 2014

Xiuli Wei , Huaqiao Gui, Jianguo Liu, Jie Zhang, Schwab James, Minguang Gao
Accepted Manuscripts
DOI: 10.4209/aaqr.2018.06.0226
PDF

Aerial Observation of Atmospheric Nanoparticles on Fukue Island, Japan

Kwangyul Lee, Indra Chandra, Takafumi Seto, Yayoi Inomata , Masahiko Hayashi, Akinori Takami, Ayako Yoshino, Yoshio Otani
;