Characterization of carbonaceous aerosol particles emitted by solid fuel combustion in rural areas

Air pollution from waste combustion poses serious environmental and public health risks. In Hungary, illegal waste burning in residential stoves remains a significant yet underreported emission source. This study characterizes aerosols in a rapidly expanding rural settlement near Budapest (Solymár), where traffic, biomass burning, and suspected waste combustion are significant contributors to local air pollution. During a 6-week intensive winter campaign in 2025, real-time particle number concentrations, size distributions, and black carbon (BC) levels were measured using an Optical Particle Counter (Grimm 1.109) and a Portable Aethalometer (AE42). Complementary PM_2.5 samples were collected on quartz filters over 24-h intervals and analyzed using thermo-optical methods to quantify organic (OC) and elemental carbon (EC) fractions. Video surveillance supported source interpretation. By separating traffic- and biomass-related aerosol contributions with the Aethalometer model and comparing them with EC and OC time series, we evaluated the suitability of EC and OC as source-specific markers and identified potential illegal waste-burning events. Extreme episodic pollution was observed, with 1-min PM_2.5 concentrations reaching 212 μg/m³ and BC peaking at 23.8 μg/m³, far exceeding background levels at a nearby suburban station. Optimizing marker correlations yielded Ångström exponents of αFF = 1.15 and αBB = 2.2, the latter likely elevated by episodic waste-burning contributions. This interpretation is supported by concurrent increases in refractory EC2 fractions during periods deviating from typical biomass-burning patterns. These findings enhance emission inventories and support the development of targeted mitigation strategies, while ongoing work expands marker databases to improve source apportionment.