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Energy-efficient urban development leads to the compact design of apartments. Recirculating ventilation solutions are an attempt to minimize the space required for ventilation ducting, but more data on their performance are needed. Cooking is a major source of volatile organic compounds (VOCs) emissions. It is necessary to assess how well recirculating kitchen hoods perform in reducing the residents' exposure to cooking fumes compared to extracting hoods, and what airflow rates assure good removal efficiency. We have monitored the occupant exposure to several VOCs generated during the cooking of a model meal under different ventilation scenarios in a purpose-built test kitchen resembling the layout of a modern, open-space apartment. Time-resolved VOC emission profiles were measured using a proton transfer reaction time-of-flight mass spectrometer. The performance of activated carbon sorption-based filters for recirculating kitchen hoods in the removal of selected VOCs was also assessed. Alcohols, particularly ethanol, dominated emissions from cooking a typical Norwegian meal, but they also included acetaldehyde, acetone, carboxylic acids, and trimethylamine, among others. The use of recirculating kitchen hoods led to, on average, higher occupant exposure to VOCs compared to extracting kitchen hoods during and after cooking. This was in part due to the poor ethanol removal efficiency of the recirculating ventilation's air filters. [Display omitted] • PTR-ToF-MS used to monitor occupant's exposure to VOCs emitted during cooking. • Different kitchen ventilation conditions and configurations were tested. • Extracting kitchen ventilation outperforms recirculating solutions in VOCs removal. • VOCs emission from typical Norwegian cooking is dominated by ethanol. • Activated carbon filters have poor removal efficiency for ethanol. [ABSTRACT FROM AUTHOR]

Although indoor air pollution from the use of biomass fuels is a serious health problem in Senegal, little effort has been made in this country to evaluate indoor air quality impacts from biomass combustion with traditional stoves and indoor air quality improvements derived from the use of improved cookstoves. A cross-sectional study was conducted in a rural village of Senegal to determine indoor air pollution during cooking and non-cooking periods. PM 2.5 and CO concentration levels were determined, along with two far less studied pollutants in cookstove studies, ultrafine particles and black carbon, using portable monitors. A total of 22 households were selected, 12 using the traditional stove and 10 using a locally produced rocket stove. Rocket stoves, the most extended type of improved stove used in sub-Saharan Africa, contributed to a significant reduction of total fine and ultrafine (UFP) particles and carbon monoxide (CO) (75,4%, 30,5% and 54,3%, respectively, p < 0.05) with regard to the traditional stoves, but increased black carbon (BC) concentrations (36,1%, p < 0.05). This proves that the climate and health-relevant properties of stoves do not always scale together and highlights that both dimensions should be always considered. Findings evidence that, in addition to a switch in the emission source (i.e. cookstove and/or fuel), successful strategies focused on the improvement of household air quality in Senegal should contemplate ventilation practices and construction materials. [ABSTRACT FROM AUTHOR]

The lockdown measures caused by the COVID-19 pandemic substantially affected air quality in many cities through reduced emissions from a variety of sources, including traffic. The change in PM 2.5 and its chemical composition in downtown Toronto, Canada, including organic/inorganic composition and trace metals, were examined by comparing with a pre-lockdown period and respective periods in the three previous years. During the COVID-19 lockdown, the average traffic volume reduced by 58%, whereas PM 2.5 only decreased by 4% relative to the baselines. Major chemical components of PM 2.5 , such as organic aerosol and ammonium nitrate, showed significant seasonal changes between pre- and lockdown periods. The changes in local and regional PM 2.5 sources were assessed using hourly chemical composition measurements of PM 2.5. Major regional and secondary PM 2.5 sources exhibited no clear reductions during the lockdown period compared to pre-lockdown and the previous years. However, cooking emissions substantially dropped by approximately 61% due to the restrictions imposed on local businesses (i.e., restaurants) during the lockdown, and then gradually increased throughout the recovery periods. The reduction in non-tailpipe emissions, characterized by road dust and brake/tire dust, ranged from 37% to 61%, consistent with the changes in traffic volume and meteorology across seasons in 2020. Tailpipe emissions dropped by approximately 54% and exhibited even larger reductions during morning rush hours. The reduction of tailpipe emissions was statistically associated with the reduced number of trucks, highlighting that a small fraction of trucks contributes disproportionally to tailpipe emissions. This study provides insight into the potential for local benefits to arise from traffic intervention in traffic-dominated urban areas and supports the development of targeted strategies and regulations to effectively reduce local air pollution. [Display omitted] • Major regional and secondary PM 2.5 sources exhibited no clear reductions. • COVID-19 lockdown created air quality benefits by reducing traffic-related PM 2.5 • Reduction of tailpipe emissions was caused mainly by the reduced number of trucks. • Targeted strategies for heavy emitters are necessary to mitigate traffic emissions. • Cooking emissions dropped substantially due to the restriction on local businesses. [ABSTRACT FROM AUTHOR]

The current study investigated the emission, distribution, and removal of cooking-emitted particles in the simulated residential module of the Well Living Lab. Cooking experiments were conducted following a standardized protocol under different interventions. Cooking experiments consisted of frying bacon that emitted 2.35 × 103 (2.22 × 103) μg/min of PM 2.5. Interventions studied included: Ventilation; a combination of Ventilation and Stove Hood; combination of Ventilation and Portable Air Cleaners; Air Flush; and combination of Air Flush, Stove Hood, and Bathroom Exhaust. The impact of door configuration was also assessed. Particulate Matter (PM 2.5) and CO 2 sensors were distributed in all spaces. A method based on CO 2 traced decay was used to characterize airflow. Particle removal rate and integrated PM 2.5 concentration were used to compare the capability of different interventions in removing PM 2.5 and reducing particle exposure. The combination of Ventilation and Stove Hood and the combination of Air Flush, Stove Hood, and Bathroom Exhaust showed the best performance in reducing the integrated PM 2.5 concentration of cooking-emitted particles. Particle Removal Rate showed that cooking-emitted PM 2.5 were most effectively removed by the combination of Ventilation and Portable Air Cleaners. Air Flush was not a very effective method in removing cooking-emitted particles even with the 2.5 times increase of the supply flow rate (4 h−1 in the residential module). Closing bedroom and/or bathroom doors changed particle distribution and increased PM 2.5 concentration in the kitchen and living room. • Adding a stove hood performed the best in reducing PM 2.5 concentration. • Ventilation and PACs combined was most effective in removing cooking-emitted PM2.5. • Air Flush was not effective in removing cooking-emitted particles. • Frying bacon emits 2.35 × 10 3 (2.22 × 10 3) μg/min of PM 2.5. [ABSTRACT FROM AUTHOR]

The mass, chemical composition and toxicological properties of fine particulates (PM 2.5) emitted from cooking activities in three Hong Kong based restaurants and two simulated cooking experiments were characterized. Extracts from the PM 2.5 samples elicited significant biological activities [cell viability, generation of reactive oxygen species (ROS), DNA damage and inflammation effect (TNF-α)] in a dose-dependent manner. The composition of PAHs, oxygenated PAHs (OPAHs) and azaarenes (AZAs) mixtures differed between samples. The concentration ranges of the Σ30PAHs, Σ17OPAHs and Σ4AZAs and Σ7Carbonyls in the samples were 9627–23,452 pg m−3, 503–3700 pg m−3, 33–263 pg m−3 and 158 – 5328 ng m−3, respectively. Cell viability caused by extracts from the samples was positively correlated to the concentration of benzo[a]anthracene, indeno[1,2,3-cd]pyrene and 1,4-naphthoquinone in the PM 2.5 extracts. Cellular ROS production (upon exposure to extracts) was positively correlated with the concentrations of PM 2.5 , decaldehyde, acridine, Σ17OPAHs and 7 individual OPAHs. TNF-α showed significant positive correlations with the concentrations of most chemical species (elemental carbon, 16 individual PAHs including benzo[a]pyrene, Σ30PAHs, SO 4 2−, Ca2+, Ca, Na, K, Ti, Cr, Mn, Fe, Cu and Zn). The concentrations of Al, Ti, Mn, Σ30PAHs and 8 individual PAHs including benzo[a]pyrene in the samples were positively correlated with DNA damage caused by extracts from the samples. This study demonstrates that inhalation of PM 2.5 emitted from cooking could result in adverse human health effects. [Display omitted] • Cooking PM 2.5 emissions elicited significant bioreactivity in dose-dependent manner. • Cantonese cooking style emitted highest PM 2.5 and chemical species concentrations. • Positive significant correlations showed between PM 2.5 /OPAHs and ROS. • Majority of high molecular weight PAHs showed strong correlations with TNF-α. • Benzo[a]pyrene demonstrated significant positive correlation against DNA damage. [ABSTRACT FROM AUTHOR]

Measurements of airborne particles in buildings with low-cost optical particle counters (OPCs) are often inaccurate and subject to uncertainties. This study introduces a methodology to improve the performance of low-cost OPCs in measuring indoor particles through machine learning. A two-month field measurement campaign was conducted in an occupied net-zero energy house. The studied OPCs (OPC–N2, Alphasense Ltd.) report size fractionated concentrations from 0.38 to 17.5 μm. Co-located reference instrumentation included a scanning mobility particle sizer (SMPS: 0.01–0.30 μm) and an optical particle sizer (OPS: 0.30–10 μm). The machine learning field calibration method applies Gaussian Process Regression (GPR) and includes two components: (1.) correction of the size-resolved OPC counting efficiency from 0.38 to 10 μm and (2.) prediction of volume size distributions (mass proxy) below the 0.38 μm detection limit of the OPC. The field calibration method is applicable to OPCs that report size fractionated concentrations. In (1.), a GPR function was used to correct the size-resolved counting efficiency of the OPCs between 0.38 and 10 μm using the OPS as reference. In (2.), a second GPR function was used to predict the volume size distribution below 0.38 μm using the SMPS/OPS as reference. This was done given the significant contribution of sub-0.38 μm particles to volume concentrations in the accumulation mode. The machine learning field calibration method resulted in a significant improvement in the accuracy of size-integrated volume concentrations (PV 2.5 , PV 10) reported by the OPCs as compared to the SMPS/OPS. Improvements were seen in the Pearson coefficient (before correction: 0.59–0.83; after correction: 0.98–0.99); coefficient of determination (before correction: 0.35–0.69; after correction: 0.97–0.98); and mean absolute percentage error (before correction: 35–69%; after correction: 19–25%). • Developed a new machine learning field calibration method for improving the performance of low-cost OPCs. • A two-month measurement campaign was conducted in a net-zero energy house to evaluate the calibration method. • Calibration method improves the accuracy with which OPCs report indoor particle volume size distributions. • Method is first to account for the volume contribution of the "missing" sub-0.38 μm particles not measured by OPCs. • A non-parametric, size-resolved approach to OPC calibration targets limitations in particle detection/sizing by OPCs. [ABSTRACT FROM AUTHOR]

Food cooking is a significant source of indoor volatile organic compounds (VOCs) that can pose serious adverse health effects. The use of liquefied petroleum gas (LPG), charcoal and wood as the cooking fuels for grilled or fried products can be a major source of the emitted pollutants inside industrial and commercial restaurants. This paper attempts to determine the inhalation exposure of VOCs generated by the food cooking process of barbecued and fried products in the kitchen area of a commercial barbecue restaurant. A broad range of VOCs was sampled and analyzed in a commercial barbecue restaurants' kitchen atmosphere for 30 days to investigate the exposure levels of the employee. The median concentration of carcinogenic VOCs were 6.11 μg/m3 for benzene, 3.51 μg/m3 for chloroform, 1.58 μg/m3 for styrene, 1.12 μg/m3 for ethylbenzene, 0.11 μg/m3 for tetrachloromethane and 0.06 μg/m3 for 1,2-dichloroethane. Sources of the quantified VOCs were mainly attributed to cooking styles and fuels, cleaning products and building materials. The carcinogenic potential of the indoor VOC exposure was between 3.4✕10−8 and 1.1✕10−5 that indicating a possible risk of lung cancer. • Indoor concentrations of 60 VOCs were analyzed in a barbecue restaurant. • Sources of the VOCs were attributed to cooking fuels and styles investigated by PCA. • An ILCR of 1.4✕10−5 was estimated for inhalation exposure to carcinogenic VOCs. [ABSTRACT FROM AUTHOR]