Size segregated PM and its chemical composition emitted from heated corn oil

Temperature-dependent particle number emission rates and emission characteristics during heating processes of edible oils

The goal of this research is to investigate the temperature-dependent emission rates of particle numbers and emission characteristics during oil heating. Seven regularly used edible oils were studied in a variety of tests to attain this objective. First, total particle number emission rates ranging from 10 nm to 1 μm were measured, followed by an examination within six size intervals from 0.3 μm to 10 μm. Following that, the impacts of oil volume and oil surface area on the emission rate were investigated, and multiple regression models were developed based on the results. The results showed that corn, sunflower and soybean oils had higher emission rates than other oils above 200 °C, with peak values of 8.22 × 109#/s, 8.19 × 109#/s and 8.17 × 109#/s, respectively. Additionally, peanut and rice oils were observed to emit the most particles larger than 0.3 μm, followed by medium-emission (rapeseed and olive oils) and low-emission oils (corn, sunflower and soybean oils). In most cases, oil temperature (T) has the most significant influence on the emission rate during the smoking stage, but its influence was not as pronounced in the moderate smoking stage. The models obtained are all statistically significant (P < 0.001), with R2 values greater than 0.9, and the classical assumption test concluded that regressions were in accordance with the classical assumptions regarding normality, multicollinearity, and heteroscedasticity. In general, low oil volume and large oil surface area were more recommended for cooking to mitigate UFPs emission.

Temperature-dependent particle mass emission rate during heating of edible oils and their regression models

Particulate matter emitted by heated cooking oil is hazardous to human health. To develop effective mitigation strategies, it is critical to know the amount of the emitted particles. The purpose of this research is to estimate the temperature-dependent particle mass emission rates of edible oils and to develop models for source strength based on the multiple linear regression method. First, this study examined seven commonly used oils by heating experiments. The emission rates of PM2.5 and PM10 were measured, and the effects of parameters such as oil volume and surface area on the emission rates were also analysed. Following that, the starting smoke points (Ts') and aggravating smoke points (Tss') of tested oils were determined. The results showed that oils with lower smoke points had greater emission rates. Notably, the experiments performed observed that peanut, rice, rapeseed and olive oil generated PM2.5 much faster at 240 °C (2.22, 1.50, 0.82 and 0.80 mg/s, respectively, at the highest emission conditions) than that of sunflower, soybean, and corn oil (0.15, 0.12 and 0.11 mg/s, respectively). The temperature, volume, and surface area of oils all had a significant impact on the particle mass emission rate, with oil temperature being the most influential. The regression models obtained were statistically significant (P < 0.001), with the majority of R² values greater than 0.85. Using sunflower, soybean and corn oils, which have higher smoke points and lower emission rates, and smaller pans for cooking is therefore recommended based on our research findings.

Effects of household cooking with clean energy on the risk for hypertension among women in Beijing

Outdoor air pollution and indoor burning of biomass fuel can cause high blood pressure. However, little is known about the effects of cooking with clean energy on hypertension. We thus explored whether cooking with clean energy is associated with the risk for hypertension. The study used baseline data from 12,349 women from a large population-based cohort study in Beijing, China. Information on cooking habits, health status, and other characteristics was collected by questionnaire and physical examination. Fasting blood samples were collected to measure total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and homocysteine (HCY). An index of cooking exposure was constructed. Log-binomial regression models were used to estimate the association between cooking exposure and risk for hypertension. The prevalence of hypertension was 26.7%. Any cooking exposure at all was associated with an increased risk for hypertension with an adjusted prevalence ratio (aPR) of 2.27 (95% confidence interval [CI]: 2.01, 2.57). The risk for hypertension increased with increases in cooking frequency, time spent cooking, and the cooking index, all showing a dose-effect relationship (P < 0.001). An increased risk for hypertension was associated with both cooking using mainly electricity (aPR: 1.75, 95% CI: 1.41, 2.17) and cooking using mainly natural gas (aPR: 2.30, 95% CI: 2.03, 2.60). The cooking index was positively correlated with plasma concentrations of TC, TG, LDL-C, and HCY and negatively correlated with HDL-C. Abnormal levels of all these biomarkers were associated with an increased prevalence of hypertension after adjustment for confounding factors. Cooking with clean energy, mainly cooking habit, may contribute to an increased risk for hypertension among female residents of Beijing. Abnormal metabolism of lipids or HCY may be an important mechanism involved in the development of cooking-related hypertension.

Emission characteristics of particulate matter, odors, and volatile organic compounds from the grilling of pork

Meat-grilling restaurants are considered to be residential emission sources of air pollutants. To investigate the emission characteristics of particulate matter (PM), odors, and volatile organic compounds (VOCs) from the grilling of meat, a grilling apparatus equipped with butane gas burners was used to grill pork belly and marinated pork ribs in a laboratory setting. When grilling the pork belly, the emission factor for PM with a diameter of 2.5 μm or below (PM_2.5) was 754 mg-PM·kg-meat^-1, accounting for 99% of total suspended particles (TSPs), while that of the marinated pork ribs was 137 mg-PM·kg-meat^-1 (96% of TSPs). Ammonia and acetaldehyde were the most common odors emitted during grilling at 43-88 mg·kg-meat^-1 and 22-30 mg·kg-meat^-1, respectively. Aldehydes were the most significant contributor to total odor intensity (36%-67%). Benzene, vinyl acetate, and hexene were the most abundant VOCs for the pork belly, while butane, vinyl acetate, and n-dodecane were the most abundant for the marinated ribs. Among the VOCs emitted from the pork grilling process, hexene, butane, and toluene were the dominant ozone precursors. The information obtained in this study is useful for furthering the understanding of the characteristics of air pollutants emitted from actual meat-grilling restaurants. Additionally, knowledge of the PM, odor, and VOC emission characteristics and their emission factors is useful for establishing management strategies for air pollutants from meat-grilling restaurants.

Evaluation of the effectiveness of a portable air cleaner in mitigating indoor human exposure to cooking-derived airborne particles

Gas cooking is an important source of airborne particulate matter (PM) indoors. Exposure to cooking-derived PM can lead to adverse human health impacts on non-smokers, especially in poorly-ventilated residential homes. Most of the previous studies on gas cooking emissions mainly focused on fine particles (PM_2.5) with little information on their size-fractionation. Moreover, studies dealing with mitigation of indoor human exposure to cooking-derived PM are currently sparse. Therefore, a systematic study was conducted to investigate the characteristics of PM_2.5 and size-fractionated PM derived from five commonly used cooking methods, namely, steaming, boiling, stir-frying, pan-frying and deep-frying in a poorly-ventilated domestic kitchen under controlled experimental conditions. Additionally, an indoor portable air cleaner was employed as a mitigation device to capture cooking-derived PM and improve indoor air quality (IAQ). Results revealed that the oil-based deep-frying cooking released the highest airborne particles which were about 170 folds higher compared to the baseline levels for PM_2.5 mass concentrations. The use of the air cleaner showed a statistically significant (p < 0.05) reduction in the indoor PM_2.5 levels. Moreover, PM_<0.25 (particles with diameter ≤ 250 nm) showed a very high mass concentration (378.2 μg/m³) during deep-frying, raising human health concern. A substantial reduction (~60-85%) in PM_<0.25 mass concentrations and their total respiratory deposition doses (RDD) in the human respiratory tract was observed while using the air cleaner during the five cooking methods. Furthermore, morphological characteristics and the relative abundance of trace elements in cooking-derived PM were also investigated. This study provides useful insights into the assessment and mitigation of indoor human exposure to cooking-derived PM.

Comparison of PM2.5 emission rates and source profiles for traditional Chinese cooking styles

The number of restaurants is increasing rapidly in recent years, especially in urban cities with dense populations. Particulate matter emitted from commercial and residential cooking is a significant contributor to both indoor and outdoor aerosols. The PM_2.5 emission rates and source profiles are impacted by many factors (cooking method, food type, oil type, fuel type, additives, cooking styles, cooking temperature, source surface area, pan, and ventilation) discussed in previous studies. To determine which cooking activities are most influential on PM_2.5 emissions and work towards cleaner cooking, an experiment design based on multi-factor and level orthogonal tests was conducted in a laboratory that is specifically designed to resemble a professional restaurant kitchen. In this cooking test, four main parameters (the proportion of meat in ingredients, flavor, cooking technique, oil type) were chosen and five levels for each parameter were selected to build up 25 experimental dishes. Concentrations of PM_2.5 emission rates, organic carbon/elemental carbon (OC/EC), water-soluble ions, elements, and main organic species (PAHs, n-alkanes, alkanoic acids, fatty acids, dicarboxylic acids, polysaccharides, and sterols) were investigated across 25 cooking tests. The statistical significance of the data was analyzed by analysis of variance (ANOVA) with ranges calculated to determine the influence orders of the 4 parameters. The PM_2.5 emission rates of 25 experimental dishes ranged from 0.1 to 9.2 g/kg of ingredients. OC, EC, water-soluble ions (WSI), and elements accounted for 10.49-94.85%, 0-1.74%, 10.09-40.03%, and 0.04-3.93% of the total PM_2.5, respectively. Fatty acids, dicarboxylic acids, n-alkanes, alkanoic acids, and sterols were the most abundant organic species and accounted for 2.32-93.04%, 0.84-60.36%, 0-45.05%, and 0-25.42% of total PM_2.5, respectively. There was no significant difference between the 4 parameters on PM_2.5 emission rates, while a significant difference was found in WSI, elements, n-alkanes, and dicarboxylic acids according to ANOVA. Cooking technique was found to be the most influential factor for PM_2.5 source profiles, followed by the proportion of meat in ingredients and oil type which resulted in significant difference of 183.19, 185.14, and 115.08 g/kg of total PM_2.5 for dicarboxylic acids, n-alkanes, and WSI, respectively. Strong correlations were found among PM_2.5 and OC (r = 0.854), OC and sterols (r = 0.919), PAHs and n-alkanes (r = 0.850), alkanoic acids and fatty acids (r = 0.877), and many other species of PM_2.5.

Characteristics of cooking-generated PM10 and PM2.5 in residential buildings with different cooking and ventilation types

The fine particles (PM_2.5, PM₁₀) have worsened indoor air quality and have caused an adverse effect on health. While range hoods have been typically used to exhaust cooking-generated fine particles in residential buildings, it is difficult to remove the fine particles effectively. The present study analyzed the effect of cooking on indoor air quality through the on-site measurements of cooking-generated fine particles (PM_2.5 and PM₁₀) in 30 residential buildings. The results of the field measurement showed that the fine particles occurred during the cooking and the concentration exceeded the Korean indoor fine particle concentration standards for PM₁₀ and PM_2.5. The particle decay rate constant in field measurement was 1.27-21.83 h^-1. The emission rates were 0.39-20.45 mg/min. In addition, the fine particles were measured in the experimental building by varying the cooking methods and ventilation types. Four different cooking methods were selected including broiling fish, meat, frying egg, and meat. By operating the range, hood system and the natural ventilation, the dispersion of the fine particle concentration, the particle emission rate, decay rate constant, and the Living-Kitchen (L/K) Ratio change was evaluated quantitatively. Based on the obtained results, the maximum concentrations of the fine particles were measured when broiling fish. Moreover, the range hood system was not able to decrease the cooking-emitted particle concentration effectively during the cooking period. The cooking-emitted particles were removed rapidly when both natural ventilation and the range hood system were operated simultaneously, where the particle decay rate constant was approximately 9 h^-1. Furthermore, the selection of cooking type was the most important factor that can significantly have an impact on indoor particle concentrations. Cooking - generated particles; Range hood; Particle decay rate constant; Living-Kitchen (L/K); PM2.5; Emission rate.

Cooking smoke exposure and respiratory symptoms among those responsible for household cooking: A study in Phitsanulok, Thailand

Cooking smoke affects the health of millions of people worldwide. In Thailand, however, information in regard to household cooking and the effects of cooking smoke is scarce. The objective of this descriptive study was to explore the risk factors and respiratory symptoms in household members responsible for household cooking. Participants from 1,134 rural households in Phitsanulok province, Thailand were randomly selected, using multistage sampling. Data on cooking activities and chronic respiratory problems, and symptoms identified in the past 30 days were collected using a modified questionnaire from the British Medical Research. Most of the participants were women aged over 40 years, who were responsible for food preparation in the household, and who usually cook with vegetable oil, using LPG gas, without a ventilation hood, according to the responses that we received, and our particular knowledge of household cooking facilities in rural areas in Thailand.

The most common chronic respiratory symptoms were runny nose (24.5% males, 21.8% females), dyspnea (26.1% females, 19.0% males) and chronic cough (9.2% females, 6.4% males). The most common respiratory symptoms experienced in the past 30 days were having a cold (28.3% females, 18.7% males), coughing (25.5% females, 21.1% ,males) and having sputum (13.0% females, 8.2% males). These symptoms were associated with tears while cooking, the number of hours present in the kitchen grilling food, and the number of stir-fried and deep-fried dishes prepared. This study demonstrated that cooking even with a clean fuel can quantitatively increase the risk of respiratory difficulties and symptoms. Since cooking is undertaken in every household in Thailand, this is a serious public health matter that demands more attention.

Investigating measurements of fine particle (PM2.5 ) emissions from the cooking of meals and mitigating exposure using a cooker hood

There is growing awareness that indoor exposure to particulate matter with diameter ≤ 2.5 μm (PM_2.5 ) is associated with an increased risk of adverse health effects. Cooking is a key indoor source of PM_2.5 and an activity conducted daily in most homes. Population scale models can predict occupant exposures to PM_2.5 , but these predictions are sensitive to the emission rates used. Reported emission rates are highly variable and are typically for the cooking of single ingredients and not full meals. Accordingly, there is a need to assess PM_2.5 emissions from the cooking of complete meals. Mean PM_2.5 emission rates and source strengths were measured for four complete meals. Temporal PM_2.5 concentrations and particle size distributions were recorded using an optical particle counter (OPC), and gravimetric sampling was used to determine calibration factors. Mean emission rates and source strengths varied between 0.54-3.7 mg/min and 15-68 mg, respectively, with 95% confidence. Using a cooker hood (apparent capture efficiency > 90%) and frying in non-stick pans were found to significantly reduce emissions. OPC calibration factors varied between 1.5 and 5.0 showing that a single value cannot be used for all meals and that gravimetric sampling is necessary when measuring PM_2.5 concentrations in kitchens.

Contributions of burner, pan, meat and salt to PM emission during grilling

Grilling ground beef meat was conducted in two locations at Nazarbayev University, Kazakhstan. The experiments were designed such that only particles from beef meat were isolated. A similar experimental protocol was applied at both locations. The average particle number and mass emission rates for grilling pure meat itself (excluding particles from pan and burner) were found to be 9.4 × 10¹²(SD = 7.2 × 10¹² particle min^-1 and 7.6 × 10 (SD = 6.3 × 10) mg.min^-1, respectively. The PM emissions (number and mass) from the burner were found to be negligible compared to the pan and meat emissions. Ultrafine particle (UFP) concentrations from the heated pan itself were comparable to those of grilled meat. However, the particle mass concentrations from the pan itself were negligible. Approximately an hour of continuous heating resulted in zero emissions from the pan.

Investigating the impact of different sport trainings on particulate matter resuspension in a sport center using well-characterized reference instruments and a low-cost monitor

The present study investigated the exposure of teenagers, adults, and students to PM₁, PM_2.5, PM₄, PM₁₀, particle number concentration at two sport facilities of Nazarbayev University including Gymnastics Hall and Multi-purpose Hall. Measurements were conducted during variety of sport training sessions including soccer, basketball, volleyball, Mixed Martial Arts (MMA), boxing, table tennis, etc. A low-cost instrument, Dylos was employed to compare its performance against two TSI instruments. In overall, the Dylos showed acceptable peaks when the source of particle resuspension was present. However, no correlation was observed between Dylos data and Dusttrak fine and coarse particle data. The average PM_2,5 and PM₁₀ concentrations were found to be below the WHO limits. The number of participants during the training sessions and sports involving balls including basketball, soccer and volleyball were the two factors responsible for the observed increased particle resuspension.

Emission of volatile organic compounds and production of secondary organic aerosol from stir-frying spices

Cooking is an important source of volatile organic compounds (VOCs) and a potential source of secondary organic aerosol (SOA) both indoors and outdoors. In this study, VOC emissions from heating corn oil and stir-frying spices (i.e. garlic, ginger, myrcia and zanthoxylum piperitum (Sichuan pepper)) were characterized using an on-line membrane inlet vacuum ultraviolet single-photon ionization time-of-flight mass spectrometer (VUV-SPI-TOFMS). VOC emissions from heating corn oil were dominated by aldehydes, which were enhanced by factors of one order of magnitude when stir-frying spices. Stir-frying any of the spices studied generated large amounts of methylpyrrole (m/z 81). In addition, stir-frying garlic produced abundant dihydrohydroxymaltol (m/z 144) and diallyldisulfide (DADS) (m/z 146), while stir-frying ginger, myrcia and zanthoxylum piperitum produced abundant monoterpenes (m/z 136) and terpenoids (m/z 152, 154). SOA formed from emissions of stir-frying spices through reactions with excess ozone in a flow reactor as well as primary organic aerosol (POA) emissions were characterized using a scanning mobility particle sizer (SMPS) and a high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS). Stir-frying garlic and ginger generated similar POA concentrations to those from heating corn oil while stir-frying myrcia and zanthoxylum piperitum generated double the amount of emissions. No SOA was observed from stir-frying garlic and ginger. The rates of SOA production from stir-frying myrcia and zanthoxylum piperitum were 1.8μgmin^-1g_spice^-1 and 8.7μgmin^-1g_spice^-1, equivalent to 13.4% and 53.1% of their own POA emission rates, respectively. Therefore, the contribution of stir-frying spices to ambient organic aerosol levels is likely dominated by POA. The rates of total terpene emission from stir-frying myrcia and zanthoxylum piperitum were estimated to be 5.1μgmin^-1g_spice^-1 and 24.9μgmin^-1g_spice^-1, respectively. Our results suggest that stir-frying spices could be an important source of terpenes in indoor environments in Hong Kong, at least during cooking.

Review of factors impacting emission/concentration of cooking generated particulate matter

Studies have shown that exposure to particulate matter (PM) emitted while cooking is related to adverse human health effects. The level of PM emissions during cooking varies with several factors. This study reviewed controlled studies available in the cooking PM emissions literature, and found that cooking method, type and quality of the energy (heating) source, burner size, cooking pan, cooking oil, food, additives, source surface area, cooking temperature, ventilation and position of the cooking pan on the stove are influential factors affecting cooking PM emission rates and resulting concentrations. Opportunities to reduce indoor PM concentrations during cooking are proposed. Minor changes in cooking habits and manner might result in a substantial reduction in the cook's exposure to the cooking PM. Finally, the need for additional studies is discussed.

Quantifying trace elements in the emitted particulate matter during cooking and health risk assessment

Particulate matter (PM) measurements were conducted during heating corn oil, heating corn oil mixed with the table salt and heating low fat ground beef meat using a PTFE-coated aluminum pan on an electric stove with low ventilation. The main objectives of this study were to measure the size segregated mass concentrations, emission rates, and fluxes of 24 trace elements emitted during heating cooking oil or oil with salt and cooking meat. Health risk assessments were performed based on the resulting exposure to trace elements from such cooking activities. The most abundant elements (significantly different from zero) were Ba (24.4 ug m^-3) during grilling meat and Ti during heating oil with salt (24.4 ug m^-3). The health assessment indicates that the cooking with an electric stove with poor ventilation leading to chronic exposures may pose the risk of significant adverse health effects. Carcinogenic risk exceeded the acceptable level (target cancer risk 1 × 10^-6, US EPA 2015) by four orders of magnitude, while non-carcinogenic risk exceeded the safe level (target HQ = 1, US EPA 2015) by a factor of 5-20. Cr and Co were the primary contributors to the highest carcinogenic and non-carcinogenic risks, respectively.