Analyzing the influence of temperature and seasonal variation on fine air pollution: Developing and validating a proxy for identifying cities with varying wood use levels

Source abstract

Introduction: Residential wood combustion (RWC) in cold climates like Chile emits particulate matter (PM2.5, PM10) and harmful pollutants, impacting population health. Despite health risks, RWC emissions are understudied, especially regarding seasonal variation and weather effects. This study evaluates a wood use proxy, PM2.5 seasonality, and temperature/humidity impacts on air pollution in Chilean cities. Methods: Data on PM2.5 and weather variables in Chile (2013–2021) were analyzed from validated air quality stations. Wood use was estimated using a proxy combining PM2.5 variability and winter temperature. Time series models explored PM2.5 patterns, seasonality, and associations with weather, validating wood use estimates against official data. Results: PM2.5 patterns, trends, and seasonal variability were modelled and cities with varying levels of wood use clearly identified, with cities with high wood use exceeding the WHO daily recommendations on half of the winter days. The temperature inflexion point (TIP) identified a city-specific point where PM2.5 substantially increased, facilitating the interpretation of PM2.5 variability across cities with varying wood use. Conclusion: Significant seasonal variation in PM2.5, potentially attributable to RWC, was observed, with temperature largely driving this variation. A novel wood use proxy was developed to classify cities, allowing for more precise and large-scale analysis of this complex association. The TIP was lower and the temperature’s impact on PM2.5 greater in cities with high wood use. Despite air quality plans, PM levels remain high, making the proxy useful for future research and informing authorities on the regulation and mitigation of woodsmoke-related PM to protect public health.