Preprints
https://doi.org/10.5194/egusphere-2023-317
https://doi.org/10.5194/egusphere-2023-317
28 Feb 2023
 | 28 Feb 2023

Numerical simulation and evaluation of global ultrafine particle concentrations at the Earth's surface

Matthias Kohl, Jos Lelieveld, Sourangsu Chowdhury, Sebastian Ehrhart, Disha Sharma, Yafang Cheng, Sachchida Nand Tripathi, Mathew Sebastian, Govindan Pandithurai, Hongli Wang, and Andrea Pozzer

Abstract. A new global dataset of annual averaged ultrafine particle (UFP) concentrations at the Earth's surface has been developed through numerical simulations using the ECHAM/MESSy Atmospheric Chemistry model (EMAC). Size distributions of emitted particles from the contributing source sectors have been derived based on literature reports. The model results of UFP concentrations are evaluated using particle size distribution and particle number concentration measurements from available datasets and the literature. While we obtain reasonable agreement between the model results and observations (logarithmic scale correlation of r = 0.76 for non-remote, polluted regions), the highest values of observed, street-level UFP concentrations are systematically underestimated, whereas in rural environments close to urban areas the model generally overestimates observed UFP concentrations. As the relatively coarse global model does not resolve concentration gradients in urban centres and industrial UFP hotspots, high-resolution data of anthropogenic emissions is used to account for such differences in each model grid box, obtaining UFP concentrations with unprecedented 0.1° x 0.1° horizontal resolution at the Earth's surface. This observation-guided downscaling further improves the agreement with observations, leading to an increase of the logarithmic scale correlation between observed and simulated UFP concentrations to r = 0.84 in polluted environments (and 0.95 in all regions), a decrease of the root mean squared logarithmic error (from 0.57 to 0.43), and removes discrepancies associated with air quality and population density gradients within the model grid boxes. Model results are made publicly available for studies on public health and other impacts of atmospheric UFPs, and for intercomparison with other regional and global models and datasets.

Matthias Kohl et al.

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-317', Anonymous Referee #1, 09 May 2023
    • AC1: 'Reply on RC1', Matthias Kohl, 03 Jul 2023
  • RC2: 'Comment on egusphere-2023-317', Anonymous Referee #2, 12 May 2023
    • AC2: 'Reply on RC2', Matthias Kohl, 03 Jul 2023

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-317', Anonymous Referee #1, 09 May 2023
    • AC1: 'Reply on RC1', Matthias Kohl, 03 Jul 2023
  • RC2: 'Comment on egusphere-2023-317', Anonymous Referee #2, 12 May 2023
    • AC2: 'Reply on RC2', Matthias Kohl, 03 Jul 2023

Matthias Kohl et al.

Matthias Kohl et al.

Viewed

Total article views: 938 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
646 272 20 938 15 14
  • HTML: 646
  • PDF: 272
  • XML: 20
  • Total: 938
  • BibTeX: 15
  • EndNote: 14
Views and downloads (calculated since 28 Feb 2023)
Cumulative views and downloads (calculated since 28 Feb 2023)

Viewed (geographical distribution)

Total article views: 956 (including HTML, PDF, and XML) Thereof 956 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 01 Oct 2023
Download
Short summary
Knowledge on atmospheric ultrafine particles (UFP) with a diameter smaller than 100 nm is crucial for public health and the hydrological cycle. We present a new global dataset of UFP concentrations at the Earth's surface derived with a comprehensive chemistry climate model, and evaluated with ground-based observations. The evaluation results are combined with high-resolution primary emissions to downscale UFP concentrations to an unprecedented horizontal resolution of 0.1° x 0.1°.