Estimates of Black Carbon and Size-Resolved Particle Number Emission Factors from Residential Wood Burning Based on Ambient Monitoring and Model Simulations

Abstract

In this paper we derive typical emission factors for coarse particulate matter (PM₁₀), oxides of nitrogen (NO_x), black carbon (BC), and number particle size distributions based on a combination of measurements and air quality dispersion modeling. The advantage of this approach is that the emission factors represent integrated emissions from several vehicle types and different types of wood stoves. Normally it is very difficult to estimate the total emissions in cities on the basis of laboratory measurements on single vehicles or stoves because of the large variability in conditions. The measurements were made in Temuco, Chile, between April 18 and June 15, 2005 at two sites. The first one was located in a residential area relatively far from major roads. The second site was located in a busy street in downtown Temuco where wood consumption is low. The measurements support the assumption that the monitoring sites represent the impact of different emission sources, namely traffic and residential wood combustion (RWC). Fitting model results to the available measurements, emission factors were obtained for PM₁₀ (RWC = 2160 ± 100 mg/kg; traffic = 610 ± 51 mg/vehkm), NO_x (RWC = 800 ± 100 mg/kg; traffic = 4400 ± 100 mg/veh-km), BC (RWC = 74 ± 6 mg/kg; traffic = 60 ± 3 mg/veh-km) and particle number (N) with size distribution between 25 and 600 nm (N_25–600) (RWC = 8.9 ± 1 × 10¹⁴ pt/kg; traffic = 6.7 ± 0.5 × 10¹⁴ pt/veh-km). The obtained emission factors are comparable to results reported in the literature. The size distribution of the N emission factors for traffic was shown to be different than for RWC. The main difference is that although traffic emissions show a bimodal size distribution with a main mode below 30 nm and a secondary one around 100 nm, RWC emissions show the main mode slightly below 100 nm and a smaller nucleation mode below 50 nm.