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Background: Exposure to wood smoke is associated with negative respiratory health outcomes such as airway infections and development of chronic obstructive pulmonary disease (COPD). Previous controlled exposure studies in humans with bronchoscopy sampling have shown wood smoke-induced bronchial cytotoxicity and impaired macrophage phagocytosis. The present study investigated whether an early and transient acute inflammatory response, as reflected in bronchial mucosal biopsies and lavage fluids, could be detected 6 h after wood smoke exposure.

Methods: On two separate occasions, fourteen healthy participants were exposed, in a double-blind, randomised crossover design, for 2 h to filtered air and diluted wood smoke generated from incomplete wood log combustion with a mean particulate matter concentration of 409 ± 43 µg/m3. Bronchoscopy with endobronchial mucosal biopsies, bronchial wash (BW) and bronchoalveolar lavage (BAL) was performed 6 h post-exposure. Biopsies were immunohistochemically stained, and lavage fluids analysed for soluble mediators.

Results: In bronchial mucosal biopsies, nuclear translocation of the transcription factors aryl hydrocarbon receptor (AhR) and phosphorylated c-jun (p-c-jun) was significantly reduced within the bronchial epithelium after wood smoke exposure compared to filtered air. There was no endothelial adhesion molecule-mediated recruitment of neutrophils or other inflammatory cells into the bronchial mucosa.

Conclusions: Exposure to wood smoke from incomplete wood log combustion suppressed nuclear translocation of transcription factors and the expected inflammatory response in endobronchial mucosal biopsies at 6 h post-exposure. This contrasts to the strong proinflammatory effects of other air pollutants such as ozone and diesel exhaust. Together with previous findings of increased cytotoxicity and impaired airway macrophage phagocytosis in humans, this response may be in line with compromised immune defence and increased susceptibility to airway infections, chronic bronchitis and COPD observed in populations exposed to high levels of indoor air pollution from wood smoke.

Coffee processing generates significant amounts of wastewater rich in organic compounds and sometimes also pesticides. This poses environmental challenges for producing regions. This study aimed to assist coffee producers by providing local waste management solutions by examining the adsorption efficiency of hydrochars and biochars derived from coffee pulps (CP) and coffee husks (CH) in removing polyphenols and pesticides from coffee processing wastewater (CPWW). These materials were tested for the adsorption of selected polyphenols and pesticides from CPWW. Hydrochars exhibited high removal efficiencies for polyphenols (up to 100 %), primarily via hydrogen bonding, while biochars effectively adsorbed hydrophobic pesticides (removal efficiencies up to ∼75 %) through hydrophobic interactions. Adsorption data fitted the Freundlich isotherm, indicating multilayer adsorption, and kinetic analyses suggested complex mechanisms involving both physisorption and chemisorption. These findings demonstrate the potential of coffee waste-derived chars to serve as sustainable adsorbents for mitigating pollution from CPWW, offering a promising local waste management strategy in coffee-producing countries.

This study investigates the emission characteristics of 38 polycyclic aromatic hydrocarbons (PAHs), representing four classes. These emissions were generated from ten cookstove-fuel combinations, involving four cookstoves and five biomass fuels of different types. Particle-phase PAHs, including parent PAHs (p-PAHs), alkylated PAHs (a-PAHs), oxygenated PAHs (O-PAHs), and polycyclic aromatic nitrogen heterocycle (PANH), were analyzed using gas chromatography–high resolution mass spectrometry (GC–HRMS) to determine emission factors (EFs) and compound profiles. Compared to the traditional three-stone fire, both the improved and the advanced cookstoves (i.e., applying staged combustion and pelletized fuels), generated substantially lower total PAH EFs, ranging from 20,391 µg/kg for the three-stone fire to 944 µg/kg for the advanced stove. All PAH classes followed the same trend, mainly influenced by cookstove technology and combustion efficiency, except for PANH, that showed a slightly different trend. In addition, EFs differed considerably by PAH class, each with distinct and varying compound distribution patterns. Toxicity potential was assessed using benzo[a]pyrene equivalents (BaPeq). While the three-stone fire showed the highest toxicity on a fuel-mass basis, the advanced cookstoves showed higher toxicity per unit particulate matter ' 1 µm (PM1) mass; thus, low PM1 and PAH emissions do not necessarily correspond to low relative toxicity. The findings highlight the importance of both cookstove design and fuel type in determining PAH emission factors, compound distribution, and understanding the health and environmental impacts of biomass cookstove applications and guiding the selection of cookstoves and sustainable fuels, towards cleaner alternatives.

Background: The use of alternative and renewable fuels in the transport sector is growing rapidly due to increasing demand for sustainable energy solutions, however implying an increased risk for human exposure to emissions from these new fuels.

Methods: In this study, we examined the effects on BEAS-2B cells of particulate matter (PM) emissions, derived from the use of petroleum diesel (SD10) and rapeseed methyl ester (RME100) in a truck engine. We assessed several endpoints, including the induction of apoptotic and necrotic cell death, reactive oxygen species generation inside cells, inflammatory response, and cell cycle alterations.

Results: The characteristics of the exhaust PM varied between the two fuels, where the RME100-derived PM contained lower levels of polycyclic aromatic hydrocarbons and elemental carbon compared to SD10. Toxicological analyses revealed that PM from RME100 induced weaker oxidative stress and cell death responses than SD10. However, unlike SD10, RME100 PM caused a notable arrest in the S-G2/M phase of the cell cycle.

Conclusions: In summary, fuel type clearly influenced the characteristics of PM emissions from a heavy-duty diesel engine, which in turn affected the particles’ biological activity. Overall, RME100 exhaust PM exhibited lower toxicity compared to petroleum diesel PM in the BEAS-2B cell model.

Around one-fourth of the global population lacks access to clean fuels and technologies for cooking, most of them living in low- and middle-income countries. Reliance on rudimentary and inefficient biomass cookstoves results in high pollutant concentrations that adversely affect the health of those exposed to indoor air pollution, the environment, and the climate. In this study, we systematically reviewed the literature on aerosol and particle properties from biomass cookstoves of relevance to health, climate and the environment. We identified 187 articles reporting aerosol characterization (i.e. particulate mass or number concentrations, or particle size distributions). Of these, 82 presented detailed particle characterization (e.g. chemical composition), thus selected for further analysis. Articles were classified based on the reported particle properties and the study type and location, which allowed mapping research efforts to date and identifying major knowledge gaps. Most reviewed studies (39 articles) on particle properties reported particulate organic and elemental carbon composition. Despite considerable variability, the EC/TC ratio generally varied in the range of 0.1-0.4 for all cookstove technologies, indicating that organic carbon is the dominating PM fraction in biomass cookstove emissions. Findings from this systematic review highlight the need for further studies on particle properties from biomass cookstoves that use a multidimensional approach simultaneously combining several properties and different cookstove-fuel combinations. We also assessed the policy landscape, including the three main global policies concerning biomass cookstove emissions, and evaluated whether those policies included the state of the knowledge on particle properties and their adverse effects on human health, climate, and the environment. We finally identify key aspects that future policies should integrate, and critical knowledge gaps that must be filled to advance the overall development of the field. Notable was that field studies consistently report particle emission factors (PM_2.5) higher than the ones determined under laboratory conditions, for example, an average of 8.9 g/kg_fuel (field) compared to 5.2 g/kg_fuel (lab) for traditional cookstoves and 4.0 g/kg_fuel (field) compared to 1.3 g/kg_fuel (lab) for advanced cookstoves. Cookstove manufacturers, practitioners, policymakers, and society in general will benefit from a solid knowledge base regarding particle properties from biomass cookstoves and their related adverse effects on human health, climate, and the environment.

Globally, 3 billion people rely on solid biomass fuel for their everyday cooking, most often using inefficient cooking practices, leading to high exposure levels of household air pollution. This is subsequently associated with negative health and climate impact. Further, the inefficient use of biomass fuels applies pressure on natural forests, resulting in deforestation, loss of biodiversity, and soil degradation. Improved cookstove technologies and biomass fuels are being promoted to mitigate these issues. However, limited knowledge exists about how the interaction between stove technology and new fuels affects the physical and chemical properties of particulate emissions. In this study, the emission performance of four cookstove technologies in combination with five fuels was evaluated in a laboratory setup, applying a modified water boiling test with a hood dilution system for flue gas sampling. Filter sampling was applied to determine the emissions of fine particulate matter (PM₁) and for subsequent analysis of polycyclic aromatic compounds (PAC), organic- and elemental carbon, and inorganic composition. Particle mass size distribution was determined by using a 13-stage low-pressure cascade impactor. Online instruments were used to determine gaseous emissions (e.g., CO, CH₄, and BTX) as well as particle number size distribution. The results show that both the stove design and fuel properties influence the total emissions as well as the physiochemical PM characteristics. It was further seen that the impact of fuel on the PM properties did not translate linearly among the different stove technologies. This implies that each stove should be tested with various fuels to determine both the total emissions and fuel suitability.

Background: Exposure to standard petrodiesel exhaust is linked to adverse health effects. Moreover, there is a mounting request to replace fossil-based fuels with renewable and sustainable alternatives and, therefore, rapeseed methyl ester (RME) and other biofuels have been introduced. However, recent toxicological research has indicated that biodiesel exhaust may also induce adverse health-related events.

Aim: To determine whether exposure to 100% RME biodiesel (BD100) exhaust would cause an acute airway neutrophilic recruitment in humans.

Methods: Fourteen healthy subjects underwent exposure to diluted BD100 exhaust and filtered air for 1-h, in a blinded, random fashion. Bronchoscopy with endobronchial mucosal biopsies, bronchial wash (BW) and bronchoalveolar lavage (BAL) was performed six hours after exposure. Differential cell counts and inflammatory markers were determined in the supernatant and biopsies were stained immunohistochemically.

Results: Compared with filtered air, BD100 exhaust exposure increased bronchial mucosal endothelial P-selectin adhesion molecule expression, as well as neutrophil, mast cell and CD68 + macrophage numbers. An increased influx of neutrophils and machrophages was also seen in BW.

Conclusion: Exposure to biodiesel exhaust was associated with an acute airway inflammation that appeared similar to preceding petrodiesel exposure studies. The present findings, together with the recently reported adverse cardiovascular effects after similar biodiesel exposure, indicate that biodiesel is not free of toxicity and may affect human health.

Most people in rural sub-Saharan Africa lack access to electricity and rely on traditional, inefficient, and polluting cooking solutions that have adverse impacts on both human health and the environment. Here, we propose a novel integrated agroforestry-bioenergy system that combines sustainable biomass production in sequential agroforestry systems with biomass-based cleaner cooking solutions and rural electricity production in small-scale combined heat and power plants and estimate the biophysical system outcomes. Despite conservative assumptions, we demonstrate that on-farm biomass production can cover the household’s fuelwood demand for cooking and still generate a surplus of woody biomass for electricity production via gasification. Agroforestry and biochar soil amendments should increase agricultural productivity and food security. In addition to enhanced energy security, the proposed system should also contribute to improving cooking conditions and health, enhancing soil fertility and food security, climate change mitigation, gender equality, and rural poverty reduction.

In urban areas, inhalation of fine particles from combustion sources such as diesel engines causes adverse health effects. For toxicity testing, a substantial amount of particulate matter (PM) is needed. Conventional sampling involves collection of PM onto substrates by filtration or inertial impaction. A major drawback to those methodologies is that the extraction process can modify the collected particles and alter their chemical composition. Moreover, prior to toxicity testing, PM samples need to be resuspended, which can alter the PM sample even further. Lastly, the choice of the resuspension medium may also impact the detected toxicological responses. In this study, we compared the toxicity profile of PM obtained from two alternative sampling systems, using in vitro toxicity assays. One system makes use of condensational growth before collection in water in an impinger – BioSampler (CG-BioSampler), and the other, a Dekati® Gravimetric Impactor (DGI), is based on inertial impaction. In addition, various methods for resuspension of DGI collected PM were compared. Tested endpoints included cytotoxicity, formation of cellular reactive oxygen species, and genotoxicity. The alternative collection and suspension methods affected different toxicological endpoints. The water/dimethyl sulfoxide mixture and cell culture medium resuspended particles, along with the CG-BioSampler sample, produced the strongest responses. The water resuspended sample from the DGI appeared least toxic. CG-BioSampler collected PM caused a clear increased response in apoptotic cell death. We conclude that the CG-BioSampler PM sampler is a promising alternative to inertial impaction sampling.