Spatiotemporal trends of wildfire distribution and smoke exposure metrics across selected provinces in Canada.

Abstract

Background: Wildfire activity in Canada has intensified remarkably in recent years, leading to a record-breaking 2023 season during which transboundary smoke dispersed and affected populations across North America and Europe. Beyond immediate fire-related hazards, wildfire smoke represents a severe environmental and public health threat. Increasing fire frequency, duration, and severity have been linked to climate change, land-use transformation, and prolonged drought.

Methodology: An ecological time-series analysis at the provincial level was used to examine spatiotemporal trends in wildfire distribution and PM₂.₅ metrics. Two primary data sources were integrated: wildfire activity indicators (area burned and number of fires) and air quality measurements (PM₂.₅ concentrations and high-risk air quality days). Data were aggregated at the provincial level for each calendar year, enabling temporal trend analysis and ecological correlation assessment. PM₂.₅ concentrations were used as a proxy for wildfire smoke exposure. R statistical software (version 4.4.1) was used for visualization and regression analysis.

Results: Temporal trend analysis revealed consistent increases in burned area across the provinces. Ontario demonstrated the largest proportional growth despite non-significant interannual differences. Heat-map visualization demonstrated significant spatial and temporal variability in wildfire burned areas. Quebec recorded the highest wildfire extent in 2023 (>4 million hectares), while British Columbia and Alberta each exceeded 1 million hectares. Ontario consistently exhibited lower burned areas compared to the other provinces.

Conclusion: The results from the study revealed that fire intensity, scale, and persistence play a more critical role in determining pollution exposure than the number of fire events alone. These findings highlight the complex interplay between climatic, environmental, and human influences in shaping wildfire dynamics and their public health implications across Canada.