Indoor PM from residential coal combustion: Levels, chemical composition, and toxicity.

Indoor air quality is crucial for human health due to the significant time people spend at home, and it is mainly affected by internal sources such as solid fuel combustion for heating. This study investigated the indoor air quality and health implications associated with residential coal burning covering gaseous pollutants (CO, CO2 and total volatile organic compounds), particulate matter, and toxicity. The PM10 chemical composition was obtained by ICP-MS/OES (elements), ion chromatography (water-soluble ions) and thermal-optical analysis (organic and elemental carbon). During coal combustion, PM10 levels were higher (up to 8.8 times) than background levels and the indoor-to-outdoor ratios were, on average, greater than unity, confirming the existence of a significant indoor source. The chemical characterisation of PM10 revealed increased concentrations of organic carbon and elemental carbon during coal combustion as well as arsenic, cadmium and lead. Carcinogenic risks associated with exposure to arsenic exceeded safety thresholds. Indoor air quality fluctuated during the study, with varying toxicity levels assessed using the Aliivibrio fischeri bioluminescence inhibition assay. These findings underscore the importance of mitigating indoor air pollution associated with coal burning and highlight the potential health risks from long-term exposure. Effective interventions are needed to improve indoor air quality and reduce health risks in coal-burning households.

Toxicological and Mutagenic Effects of Particulate Matter from Domestic Activities.

People spend most of their time indoors, particularly in their houses where daily activities are carried out, enhancing particulate matter (PM) emissions with consequent adverse health impacts. This study intended to appraise the toxicological and mutagenic responses of particulate matter with a diameter less than 10 µm (PM10) released from cooking and ironing activities under different conditions. The cytotoxicity of the PM10 total organic extracts was tested in A549 cells using the WST-8 and the lactate dehydrogenase (LDH) assays, while the interference in cell cycle dynamics and reactive oxygen species (ROS) production was analysed by flow cytometry. The S. typhimurium TA98 and TA100 Ames tester strains with and without metabolic activation were employed to determine the mutagenic potential of the PM10-bound polycyclic aromatic hydrocarbons (PAHs). PM10 organic extracts decreased the metabolic activity of A549 cells; however, no effects in the LDH release were observed. An increase in ROS levels was registered only for cells treated with PM10 at IC20 from steam ironing, in low ventilation conditions, while cell cycle dynamics was only affected by exposure to PM10 at IC20 from frying horse mackerel and grilling boneless pork strips. No mutagenic effects were observed for all the PM10-bound PAHs samples.

In vitro toxicity of particulate matter emissions from residential pellet combustion.

Particulate matter emissions (PM10) from the combustion, in a residential stove, of two commercial brands of certified (ENplus A1) pellets, a non-certified brand and laboratory made pellets of acacia were tested for their ability to induce ecotoxic, cytotoxic, and mutagenic responses in unicellular organisms and a human cell line. Ecotoxicity was evaluated through the Vibrio fischeri bioluminescence inhibition assay. Moreover, cytotoxicity was assessed at two time points (24- and 48-hr) through two complementary techniques in order to evaluate the cellular metabolic activity and membrane integrity of human lung epithelial cells A549. The Ames test using two Salmonella typhimurium strains (TA100 and TA98) was employed to assess the mutagenic potential of the polycyclic aromatic hydrocarbon fraction extracted from the PM10 samples. Results obtained with the bioluminescent bacteria indicated that only particles from the combustion of acacia pellets were toxic. All samples induced impairment on the A549 cells metabolic activity, while no significant release of lactate dehydrogenase was recorded. PM10 emissions from acacia pellets were the most cytotoxic, while samples from both certified pellets evoked significant cytotoxicity at lower doses. Cytotoxicity time-dependency was only observed for PM10 from the combustion of acacia pellets and one of the brands of certified pellets. Mutagenic activity was not detected in both S. typhimurium strains. This study emphasises the role of the raw material for pellet manufacturing on the toxicological profile of PM emissions. Alternative raw materials should be deeply investigated before their use in pelletisation and combustion in residential appliances.

In vitro toxicity of indoor and outdoor PM10 from residential wood combustion.

Particulate matter with aerodynamic diameter < 10 µm (PM10) was collected, indoors and outdoors, when wood burning appliances (open fireplace and woodstove) were in operation. The PM10 ecotoxicity was assessed with the Vibrio fischeri bioluminescence inhibition assay, while the cytotoxicity was evaluated by the WST-8 and lactate dehydrogenase (LDH) release assays using A549 cells. Extracts of PM10-bound polycyclic aromatic hydrocarbons (PAH) were tested for their mutagenicity through the TA98 and TA100 Ames test. The bioluminescent inhibition assay revealed that indoor particles released from the fireplace were the most toxic. Indoors, the reduction in A549 cell metabolic activity was over two times higher for the fireplace in comparison with the woodstove (32 ± 3.2% and 72 ± 7.6% at the highest dose, respectively). Indoor particles from the fireplace were found to induce greater cytotoxicity than the corresponding outdoor samples. Combined WST-8 and LDH results suggest that PM10 exposure induce apoptotic cell death pathway in which the cell membrane integrity is maintained. Indoor and outdoor samples lacked direct and indirect mutagenic activity in any of the tester strains. For indoor-generated PM10, organic carbon and PAH were significantly correlated with cell viability and bioluminescence reduction, suggesting a role of organic compounds in toxicity.

Cooking activities in a domestic kitchen: Chemical and toxicological profiling of emissions.

To obtain emission factors and cooking-related chemical signatures, a monitoring campaign was carried out in a modern kitchen where different dishes of the Latin cuisine were prepared. Particulate matter (PM10, PM2.5 and PM1) and total volatile organic compounds (TVOCs) were continuously measured. Passive tubes for carbonyls and a high volume PM10 sampler were simultaneously used. PM10 filters were analysed for organic and elemental carbon and for multiple organic compounds, including polyaromatic hydrocarbons (PAHs). The toxic potential of PM10 was evaluated using a bioluminescence inhibition bioassay. Acrolein was never detected, while formaldehyde and acetaldehyde levels were comparable to those in the background air. The protection limit for TVOCs was always exceeded. Fine particles comprised more than 86% of the PM10 mass concentrations. PM10 emission rates ranged from 124 to 369 µg min-1. Relatively low PAH concentrations were obtained. PM10 encompassed alcohols, acids, plasticisers, alkyl esters, sterols, sugars, polyols, glyceridic compounds, phenolics, among others. Total concentrations were 1.9-5.3 times higher during cooking than in the background air but, for some compounds, differences of tens or hundreds of times were registered. PM10 from grilled pork was found to contribute to non-negligible cancer risks and to be very toxic, while samples from other dishes were categorised as toxic.

Loadings, chemical patterns and risks of inhalable road dust particles in an Atlantic city in the north of Portugal.

Road dust resuspension has a significant contribution to the atmospheric particulate matter levels in urban areas, but loadings, emission factors, and chemical source profiles vary geographically, hampering the accuracy of emission inventories and source contribution estimates. Given the dearth of studies on the variability of road dust, in the present study, an in-situ resuspension chamber was used to collect PM10 samples from seven representative streets in Viana do Castelo, the northernmost coastal city in Portugal. PM10 samples were analysed for organic and elemental carbon by a thermo-optical technique, elemental composition by ICP-MS and ICP-AES, and organic constituents by GC-MS. Emission factors were estimated to be, on average, 340 and 41.2 mg veh-1 km-1 for cobbled and asphalt pavements, respectively. Organic carbon accounted for 5.56 ± 1.24% of the PM10 mass. Very low concentrations of PAHs and their alkylated congeners were detected, denoting a slight predominance of petrogenic compounds. Si, Al, Fe, Ca and K were the most abundant elements. The calculation of various geochemical indices (enrichment factor, geoaccumulation index, pollution index and potential ecological risk) showed that road dust was extremely enriched and contaminated by elements from tyre and brake wear (e.g. Sb, Sn, Cu, Bi and Zn), while lithophile elements showed no enrichment. For As, the geochemical and pollution indices reached their maximum in the street most influenced by agricultural activities. Sb, Cd, Cu and As can pose a very high ecological risk. Sb can be regarded as the pollutant of highest concern, since it represented 57% of the total ecological risk. Hazard indices higher than 1 for some anthropogenic elements indicate that non-carcinogenic effects may occur. Except for a street with more severe braking, the total carcinogenic risks can be considered insignificant.

Mineralogical, chemical and leaching characteristics of ashes from residential biomass combustion.

Four types of pellets and three agro-fuels were chemically characterised and burned in a pellet stove. To assess the influence of the material composing the firebox and the combustion efficiency of distinct biomass heating devices in the composition of the bottom ashes, three of the pellets were also burned in a conventional woodstove and in a fireplace. Ashes were analysed for their C, H and N contents by an elemental analyser, whilst major and trace elements were quantified by inductively coupled plasma atomic-emission spectrometry and inductively coupled plasma mass spectrometry, respectively. The mineralogy of ashes was determined by X-ray powder diffraction. The European standard test was applied to samples to determine the leaching potential of major, minor and trace elements. The contents of major and trace elements in the different types of biomass presented enormous variations, which are reflected in dissimilar mineralogical and chemical compositions of the respective ashes. The leachable potential of several elements of environmental concern present in oxy-anionic form at the alkaline pH of biomass ashes were generally high in all samples. Concentrations of some elements in the leachates were in the range of values with classification of "hazardous materials" by the European legislation in what respects the acceptance of these wastes at landfills. Pellets made up of wood wastes and containing preservatives (chromated copper arsenate and ammoniacal copper arsenate) are of concern. Due to lower combustion efficiencies, the leachable potential for most of the trace elements in ashes from the woodstove, and especially from the fireplace, was lower than that of the pellet stove.