Quantifying the impacts of Canadian wildfires on regional air pollution networks

Teague McCracken; Pei Chen; Andrew Metcalf; Chao Fan

doi:10.1016/j.scitotenv.2024.172461

Quantifying the impacts of Canadian wildfires on regional air pollution networks

Sci Total Environ. 2024 Jun 10:928:172461. doi: 10.1016/j.scitotenv.2024.172461. Epub 2024 Apr 12.

Authors

Teague McCracken¹, Pei Chen², Andrew Metcalf³, Chao Fan⁴

Affiliations

¹ School of Civil and Environmental Engineering, Clemson University, 455 Bracket Hall, Clemson, SC 29631, USA. Electronic address: teaguem@clemson.edu.
² Department of Computer Science and Engineering, Texas A&M University, L.F. Peterson Building, College Station, TX 77843, USA. Electronic address: chenpei@tamu.edu.
³ School of Civil and Environmental Engineering, Clemson University, 455 Bracket Hall, Clemson, SC 29631, USA. Electronic address: ametcal@clemson.edu.
⁴ School of Civil and Environmental Engineering, Clemson University, 455 Bracket Hall, Clemson, SC 29631, USA. Electronic address: cfan@clemson.edu.

PMID: 38615767
DOI: 10.1016/j.scitotenv.2024.172461

Abstract

Wildfire smoke greatly impacts regional atmospheric systems, causing changes in the behavior of pollution. However, the impacts of wildfire smoke on pollution behavior are not easily quantifiable due to the complex nature of atmospheric systems. Air pollution correlation networks have been used to quantify air pollution behavior during ambient conditions. However, it is unknown how extreme pollution events impact these networks. Therefore, we propose a multidimensional air pollution correlation network framework to quantify the impacts of wildfires on air pollution behavior. The impacts are quantified by comparing two time periods, one during the 2023 Canadian wildfires and one during normal conditions with two complex network types for each period. In this study, the value network represents PM_2.5 concentrations and the rate network represents the rate of change of PM_2.5 concentrations. Wildfires' impacts on air pollution behavior are captured by structural changes in the networks. The wildfires caused a discontinuous phase transition during percolation in both network types which represents non-random organization of the most significant spatiotemporal correlations. Additionally, wildfires caused changes to the connectivity of stations leading to more interconnected networks with different influential stations. During the wildfire period, highly polluted areas are more likely to form connections in the network, quantified by an 86 % and 19 % increase in the connectivity of the value and rate networks respectively compared to the normal period. In this study, we create novel understandings of the impacts of wildfires on air pollution correlation networks, show how our method can create important insights into air pollution patterns, and discuss potential applications of our methodologies. This study aims to enhance capabilities for wildfire smoke exposure mitigation and response strategies.

Keywords: Air pollution; Network theory; Particulate pollution; United States; Wildfires.