3 years ago

Chemical composition and source-apportionment of sub-micron particles during wintertime over Northern India: New insights on influence of fog-processing

Chemical composition and source-apportionment of sub-micron particles during wintertime over Northern India: New insights on influence of fog-processing
A comprehensive study was carried out from central part of Indo-Gangetic Plain (IGP; at Kanpur) to understand abundance, temporal variability, processes (secondary formation and fog-processing) and source-apportionment of PM1-bound species (PM1: particulate matter of aerodynamic diameter ≤ 1.0 μm) during wintertime. A total of 50 PM1 samples were collected of which 33 samples represent submicron aerosol characteristics under non-foggy condition whereas 17 samples represent characteristics under thick foggy condition. PM1 mass concentration during non-foggy episodes varied from 24–393 (Avg.: 247) μg m−3, whereas during foggy condition it ranged from 42–243 (Avg.: 107) μg m−3. With respect to non-foggy condition, the foggy conditions were associated with higher contribution of PM1-bound organic matter (OM, by 23%). However, lower fractional contribution of SO4 2−, NO3 and NH4 + during foggy conditions is attributable to wet-scavenging owing to their high affinity to water. Significant influence of fog-processing on organic aerosols composition is also reflected by co-enhancement in OC/EC and WSOC/OC ratio during foggy condition. A reduction by 5% in mineral dust fraction under foggy condition is associated with a parallel decrease in PM1 mass concentration. However, mass fraction of elemental carbon (EC) looks quite similar (≈3% of PM1) but the mass absorption efficiency (MAE) of EC is higher by 30% during foggy episodes. Thus, it is evident from this study that fog-processing leads to quite significant enhancement in OM (23%) contribution (and MAE of EC) with nearly equal and parallel decrease in SO4 2−, NO3 and NH4 + and mineral dust fractions (totaling to 24%). Characteristic features of mineral dust remain similar under foggy and non-foggy conditions; inferred from similar ratios of Fe/Al (≈0.3), Ca/Al (0.35) and Mg/Al (0.22). Positive matrix factorization (PMF) resolves seven sources: biomass burning (19.4%), coal combustion (1.1%), vehicular emission (3%), industrial activities (6.1%), leather tanneries (4%), secondary transformations (46.2%) and mineral dust (20.2%).

Graphical abstract



In this study, fog-processing enhanced organic matter contribution by 23%, MAE of EC by 30% and WSON/TN by 20%.

Publisher URL: www.sciencedirect.com/science

DOI: S0269749117341994

You might also like
Never Miss Important Research

Researcher is an app designed by academics, for academics. Create a personalised feed in two minutes.
Choose from over 15,000 academics journals covering ten research areas then let Researcher deliver you papers tailored to your interests each day.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.