Mitigation of Secondary Organic Aerosol Formation from Log Wood Burning Emissions by Catalytic Removal of Aromatic Hydrocarbons

Toward Clean Residential Energy: Challenges and Priorities in Research

Solid fuels used for cooking, heating, and lighting are major emission sources of many air pollutants, specifically PM_2.5 and black carbon, resulting in adverse environmental and health impacts. At the same time, the transition from using residential solid fuels toward using cleaner energy sources can result in significant health benefits. Here, we briefly review recent research progress on the emissions of air pollutants from the residential sector and the impacts of emissions on ambient and indoor air quality, population exposure, and health consequences. The major challenges and future research priorities are identified and discussed.

Radical chemistry in oxidation flow reactors for atmospheric chemistry research

We summarize the studies on the chemistry in oxidation flow reactor and discuss its atmospheric relevance.

Developmental Study of Soot-Oxidation Catalysts for Fireplaces: The Effect of Binder and Preparation Techniques on Catalyst Texture and Activity

An awareness of increasing climate and health problems has driven the development of new functional and affordable soot-oxidation catalysts for stationary sources, such as fireplaces. In this study, Al(OH)3, water glass and acidic aluminium phosphate binder materials were mixed with soot-oxidation catalysts. The effect of the binder on the performance of the Ag/La-Al2O3 catalyst was examined, while the Pt/La-Al2O3 catalyst bound with Al(OH)3 was used as a reference. Soot was oxidised above 340 °C on the Ag/La-Al2O3 catalyst, but at 310 °C with same catalyst bound with Al(OH)3. The addition of water glass decreased the catalytic performance because large silver crystals and agglomeration resulted in a blockage of the support material’s pores. Pt/La-Al2O3 bound with Al(OH)3 was ineffective in a fireplace environment. We believe that AgOx is the active form of silver in the catalyst. Hence, Ag/La-Al2O3 was shown to be compatible with the Al(OH)3 binder as an effective catalyst for fireplace soot oxidation.

A Simple Method to Determine Cytotoxicity of Water-Soluble Organic Compounds and Solid Particles from Biomass Combustion in Lung Cells in Vitro

Adverse health effects of condensable organic compounds (COC) and potential secondary organic aerosols from wood combustion emissions are difficult to determine. Hence, available information is usually limited to a small number of specific applications. Therefore, we introduced a simple, fast, and economic method where water-soluble COC (WSCOC) and WSCOC together with water-soluble primary solid particles (WSpSP) from wood combustion were sampled and subsequently exposed to cultured human lung cells. Comparing the cell viability of H187 human epithelial lung cells from five combustion devices, operated at different combustion conditions, no, or only a minor, cytotoxicity of WSCOC is found for stationary conditions in a grate boiler, a log wood boiler, and a pellet boiler. All combustion conditions in a log wood stove and unfavorable conditions in the other devices induce, however, significant cytotoxicity (median lethal concentration LC₅₀ 5-17 mg/L). Furthermore, a significant correlation between CO and cytotoxicity was found ( R² ∼ 0.8) suggesting that the simply measurable gas phase compound CO can be used as a first indicator for the potential harmfulness of wood combustion emissions. Samples containing WSCOC plus WSpSP show no additional cytotoxicity compared to samples with COC only, indicating that WSCOC exhibit much higher cytotoxicity than WSpSP.

Effect of Stove Technology and Combustion Conditions on Gas and Particulate Emissions from Residential Biomass Combustion

We have systematically examined the gas and particle phase emissions from seven wood combustion devices. Among total carbon mass emitted (excluding CO₂), CO emissions were dominant, together with nonmethane volatile organic compounds (NMVOCs) (10-40%). Automated devices emitted 1-3 orders of magnitude lower CH₄ (0.002-0.60 g kg^-1 of wood) and NMVOCs (0.01-1 g kg^-1 of wood) compared to batch-operated devices (CH₄: 0.25-2.80 g kg^-1 of wood; NMVOCs: 2.5-19 g kg^-1 of wood). 60-90% of the total NMVOCs were emitted in the starting phase of batch-operated devices, except for the first load cycles. Partial-load conditions or deviations from the normal recommended operating conditions, such as use of wet wood/wheat pellets, oxygen rich or deficit conditions, significantly enhanced the emissions. NMVOCs were largely dominated by small carboxylic acids and alcohols, and furans. Despite the large variability in NMVOCs emission strengths, the relative contribution of different classes showed large similarities among different devices and combustion phases. We show that specific improper operating conditions may even for advanced technology not result in the emission reduction of secondary organic aerosol (SOA) forming compounds and thus not reduce the impact of wood combustion on climate and health.