Multi-pollutant contribution of wood heating to emissions, concentrations and population exposure during winter time down to the street levels

This study quantifies the impact of residential wood heating on winter air quality in France, including street-level analysis in Paris. It applies a multi-scale model to simulate regulated and emerging pollutants, such as organic matter (OM), black carbon (BC), and ultrafine particles (UFP), associated with health risks. Wood-burning emissions in Île-de-France and Paris were estimated using detailed local surveys, a new classification of appliances and emission factors accounting for condensable compounds. Over France, emissions were quantified from the EMEP top-down emission inventory, with post-estimated condensables. Wood burning is a major contributor to particulate pollution: in France, it accounts for 39.9% of PM_2.5, 72.4% of BC, and 76.7% of OM. In Paris, contributions are similar, except for BC (27.2% at street level), influenced by other sources, as road traffic. Contributions to UFP are lower, ranging from 7% in Parisian streets to 15.5% over France. Wood burning significantly contributes to outdoor population exposure in Paris (33% for PM_2.5, 20% for BC, and 70% for OM), with heating emissions mostly from auxiliary and comfort use (98%). Two 2030 scenarios were evaluated: business-as-usual (BAU) and a national emission-reduction objective. Under BAU, PM_2.5 emissions and concentrations decline by 32.6% and 13.4% over France, and by 18.1% and 14.2% in Paris. Concentration reductions are smaller than emission reductions because some PM_2.5 components (e.g. inorganics) are unaffected by wood-burning controls. The national objective scenario achieves larger impacts, typically 50%-70% greater than BAU, reducing PM_2.5 concentrations of about 22%-24% in urban and street environments. Environmental Implications Health risks of fine particles depend on their composition and size, with black carbon, organics, and ultrafine particles emerging as key indicators. Our results indicate that reducing residential wood heating is an effective policy lever to mitigate wintertime particulate pollution in urban areas. In Paris, a large share of emissions arises from auxiliary and comfort heating, suggesting that targeted measures addressing non-essential wood use could deliver substantial air-quality benefits. The transition to newer heating technologies should be carefully evaluated to ensure that improvements in mass-based air quality are not offset by increased ultrafine particle emissions, which are not covered by current regulations but may have important health implications.