Sub micron aerosol variability and its ageing process at a high altitude site in India: Impact of meteorological conditions
| Autor: | Subrata Mukherjee, Sachin D. Ghude, G. S. Meena, Mohammad Yusuf Aslam, Anil Kumar Vasudevan, Chinmay Jena, Vyoma Singla, K. K. Dani, Pramod D. Safai, Govindan Pandithurai, P. Buchunde |
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| Rok vydání: | 2020 |
| Předmět: |
010504 meteorology & atmospheric sciences
Health Toxicology and Mutagenesis India 010501 environmental sciences Toxicology Atmospheric sciences 01 natural sciences chemistry.chemical_compound Altitude Mass concentration (chemistry) Relative humidity Tropospheric ozone Sulfate 0105 earth and related environmental sciences Aerosols Air Pollutants General Medicine Particulates Pollution Trace gas Aerosol chemistry Environmental science Particulate Matter Seasons Environmental Monitoring |
| Zdroj: | Environmental pollution (Barking, Essex : 1987). 265 |
| ISSN: | 1873-6424 |
| Popis: | The effect of relative humidity and temperature on the submicron aerosol variability and its ageing process was studied over a high altitude site, Mahabaleshwar in south-west India. The mass composition of non-refractory particulate matter of 1 μm (NR-PM1) size was obtained using Time of Flight Aerosol Chemical Speciation Monitor (ToF-ACSM) along with the measurements on a few trace gases during winter (December 2017–February 2018) and summer season (20th March - 5th May 2018). Sulfate exhibited strong dependence on the relative humidity (RH) as its mass fraction increased with the increase in RH. The Sulfate oxidation ratio (SOR) calculated during summer season also showed an increasing trend with RH indicating the influence of aqueous phase oxidation on sulfate fraction. On the other hand, OOA showed remarkable enhancement in its mass fraction with the increase in temperature along with the corresponding increase in f44 and tropospheric ozone. OOA, ozone and f44 ratio increased 14–34%, 8–26% and 25–43% respectively with the increase in temperature from 18 to 30 °C. This is indicative of the dominance of photochemical ageing processes during high temperature conditions. The extent of photochemical ageing was found to be higher during summer season (mean temperature ∼25.4 ± 2.6 °C) as compared to winter season (mean temperature ∼20.5 ± 2.6 °C). The nitrate diurnal was majorly governed by gas to particle partitioning process during winter season, whereas the summertime nitrate diurnal was influenced primarily by its formation rate. The non parametric wind regression analysis revealed that the mass concentration during winter was majorly contributed by distant sources from north east direction while during summer the local sources were more dominant. |
| Databáze: | OpenAIRE |
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