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The cooking in residential settings generates high concentrations of particulate matter (PM), causing health risks to occupants. Kitchen range hoods are commonly installed in the Republic of Korea, but their frequency of use and efficiency are considerably low. This study examined the effect of a make-up air-supply system during cooking or even after cooking in combination with a range hood by measuring the indoor concentrations of ultrafine particles (UFPs) and PM2.5. Conducted in a full-scale test house, the study investigated the actual airflow of range hoods and evaluated how the make-up air-supply system affected particle removal and dispersion. The results showed that the addition of a make-up air supply system significantly increased airflow and reduced the spread of pollutants. When the range hood was operated after cooking, the particle removal efficiency was 96.9% and 74.6% for PM2.5 and UFPs, respectively. These findings strongly indicate that integrating a make-up air-supply system with range hoods can significantly improve indoor air quality in residential buildings. This method is more compatible with occupant behavior and has the potential to improve health outcomes. [ABSTRACT FROM AUTHOR]

In order to reduce the pressure of the central smoke shaft in high-rise apartments, a controllable baffle-hood was proposed to improve the smoke removal efficiency without increase the exhaust airflow rate in the kitchen. A series of baffle-type hoods with various locations and shape of panel were explored to evaluate the pollutant removal efficiency. The results showed that the baffle design reduces pollutant concentration by 8%–71% and lowers temperature by 0.8 °C–2.0 °C compared to conventional range hoods. A power function relationship was found between pollutant concentration and air velocity at cross-sectional of inlet. The panel is still a simple and useful technology in the home kitchen, if it can solve the convenience of cooking operations. HIGHLIGHTS: A series of baffle-type hoods by panels in home kitchen were proposed and their effects are obviously better than traditional one. The baffles are controllable and convenience for cooking operation. There is a power function relationship between pollutant concentration in kitchen space and air velocity at inlet section. [ABSTRACT FROM AUTHOR]

Range hoods are commonly used in residential kitchens to capture pollutants generated during cooking. Direct capture represents the true capture performance of the range hood as a local exhaust device. A better metric for evaluating range hood capture performance is direct capture efficiency (DCE), defined as the ratio of pollutant directly captured by the hood to the total pollutant emission from the source. This paper clarifies the dynamic functioning mechanism of direct capture and reflux capture, analyzes the dynamic characteristics of exhaust concentration, and deduces a simple method for DCE determination based on dynamic temporal separation, where DCE is the ratio of the peak concentration of direct capture (C1) to the peak concentration of total capture (C2). Experimental and simulation studies on dynamic exhaust concentration were conducted under different ventilation conditions, and the results were in good agreement. Then, the determination methods of C1 and C2, including the experimental methods, were further studied to calculate the DCE. The measured and simulated results for DCE based on dynamic temporal separation showed good consistency, with a deviation of less than 2.0%. Finally, the two spatial separation methods for determining DCE (mass flux ratio and virtual purification) proposed and verified in our previous study showed good agreement with the dynamic temporal separation method based on C1/C2 proposed here, with a maximum deviation of 2.0%. The determination method of DCE based on dynamic time separation, particularly the experimental method, is of great significance for evaluating the real capture performance of range hoods. [ABSTRACT FROM AUTHOR]

A key aspect of achieving acceptable indoor air quality is source control. Cooking has been recognized as a significant source of pollutants for health impacts (e.g., PM2.5 and NO2) as well as moisture and odour. A common method of controlling this pollutant source is by using a range (or cooker) hood that vents to outside. However, field and laboratory experiments have shown highly variable performance for these devices. We use the capture efficiency metric (the fraction of the pollutants that are exhausted to outside at steady state) to characterize the range hood performance. To address this issue and provide useful information for builders, contractors, designers and home occupants, a laboratory rating method for range hood capture efficiency has recently been developed by LBNL and ASTM. The test method uses standardized emitters to create a heated plume and seed it with tracer gas. The tracer gas measurements in the room, the range hood exhaust and in the ambient air are used to estimate capture efficiency. However, this test method only applies to wall-mounted range hoods. Some range hoods are not wall-mounted: island range hoods are designed to operate over a cooktop in the middle of a room rather than against a wall and downdraft hoods draw air from near the cooktop rather than overhead. This paper discusses the development of a new test apparatus for island and downdraft hoods and presents measured capture efficiency data from example hoods. The results of this work will be used in future revisions to the ASTM standard.

Residential cooking can be a significant indoor source of odour, pollutants and particulate matter. Conventionally, range hoods expel the air into the ambient. A number of studies have investigated their contaminant capture performance. However, for highly energy efficient houses the installation of extracting range hoods can pose certain challenges, e.g. high ventilation losses, additional thermal bridges and potential air leakage sites. Therefore, the use of recirculation range hoods has become standard for highly energy efficient housing with mechanical ventilation with heat recovery in Central Europe.Open questions remain regarding their capture and filtration efficiency as a function of filter age, especially for particles and odours. But also, the actual energy savings potential when using recirculating instead of extracting devices in a highly energy efficient housing had not been documented yet. This paper addresses these questions with a literature review and an energetic comparison.The review identified a good number of studies which have investigated the capture performance of extracting range hoods with a focus on pollutants resulting from gas combustion and/or the cooking generated particles. These studies show that capture efficiency, in particular for front burner use, can vary drastically for different designs and that particle capture does not necessarily match capture efficiency for gaseous contaminants. No scientific study investigating the performance of recirculating range hoods was found. Tests for consumer magazines as well as surveys indicate notably lower performance compared to extracting hoods. In summary one can say that performance tests are urgently needed to quantify the capture and filter efficiency for particles and (odorous) organic compounds as a function of filter age.

In high-rise buildings with large indoor and outdoor temperature difference, neglecting the effect of stack effect in smoke exhaust shafts may cause calculation error of the fluid network model. In this paper, the mathematical model of kitchen smoke exhaust system considering the influence of stack effect was put forward and it can be inserted different range hood sub-models. Compared with the results of six working conditions of the model without considering the stack effect, the error of the proposed model were reduced by 7.6%, 4.3%, 4.1%, 2.8%, 2.4%, and 2.1%. While the indoor and outdoor temperature difference varies from −5 °C to 49 °C, the effect of stack effect on the pressure in the flue and the flow rate for each user was studied for six operating rates s. The results show that under the combined effect of stack effect and flue resistance, the static pressure of the kitchen smoke exhaust system showed a low-high-low distribution, and the maximum static pressure in the flue moved toward the bottom with the increase of temperature difference. User flow rates exhibit a low-high-low-high distribution, with an increased flow rate in the bottom users and the largest flow rate in the top users.

Severely cold weather reduces the willingness of residents to open windows while cooking. This results in an insufficient replenishment of makeup air and a reduction in the range hood discharge capacity. For an effective trade-off between indoor air temperature maintenance and air quality aggravation in winter, a new makeup air supply method (ceiling makeup air) was proposed and established both experimentally and numerically. The improvements in the kitchen air environment during cooking were studied through experimental tests and CFD simulations, considering different makeup air arrangements. The results reveal that the ceiling makeup air scheme can significantly reduce the concentration of PM2.5 compared with the cracks makeup air scheme (wherein the kitchen window and door are closed). Moreover, it increased the indoor temperature by over 11.9 °C compared with the open window makeup air scheme. The average relative error between the experimental and simulated data was within 6.1%. Among the considered factors, the size of the air inlet had the largest impact. This was followed by the layout, size, and shape of the ceiling inlets. The ceiling makeup air scheme demonstrated the potential for improving residential kitchen air environments in severely cold regions. [ABSTRACT FROM AUTHOR]

Residential cooking can be a significant indoor source of odour, pollutants and particulate matter. Conventionally, range hoods expel the air into the ambient. A number of studies have investigated their contaminant capture performance. However, for highly energy efficient houses the installation of extracting range hoods can pose certain challenges, e.g. high ventilation losses, additional thermal bridges and potential air leakage sites. Therefore, the use of recirculation range hoods has become standard for highly energy efficient housing with mechanical ventilation with heat recovery in Central Europe.Open questions remain regarding their capture and filtration efficiency as a function of filter age, especially for particles and odours. But also, the actual energy savings potential when using recirculating instead of extracting devices in a highly energy efficient housing had not been documented yet. This paper addresses these questions with a literature review and an energetic comparison.The review identified a good number of studies which have investigated the capture performance of extracting range hoods with a focus on pollutants resulting from gas combustion and/or the cooking generated particles. These studies show that capture efficiency, in particular for front burner use, can vary drastically for different designs and that particle capture does not necessarily match capture efficiency for gaseous contaminants. No scientific study investigating the performance of recirculating range hoods was found. Tests for consumer magazines as well as surveys indicate notably lower performance compared to extracting hoods. In summary one can say that performance tests are urgently needed to quantify the capture and filter efficiency for particles and (odorous) organic compounds as a function of filter age.

Venting range hoods can control indoor air pollutants emitted during residential cooktop and oven cooking. To quantify their potential benefits, it is important to know how frequently and under what conditions range hoods are operated during cooking. We analyzed data from 54 single family houses and 17 low-income apartments in California in which cooking activities, range hood use, and fine particulate matter (PM2.5) were monitored for one week per home. Range hoods were used for 36% of cooking events in houses and 28% in apartments. The frequency of hood use increased with cooking frequency across homes. In both houses and apartments, the likelihood of hood use during a cooking event increased with the duration of cooktop burner use, but not with the duration of oven use. Actual hood use rates were higher in the homes of participants who self-reported more frequent use in a pre-study survey, but actual use was far lower than self-reported frequency. Residents in single family houses used range hoods more often when cooking caused a discernible increase in PM2.5. In apartments, residents used their range hood more often only when high concentrations of PM2.5 were generated during cooking.

Evidence on the potential risk factors of normocytic anemia, the most prevalent morphology subtype of anemia, was scarce to date. The purpose of this study is to investigate the association of cooking fuel use or daily cooking duration with normocytic anemia and further explore the modification effect of mechanical ventilation. Participants totaling 29,448 from the Henan Rural Cohort were included in this study. Normocytic anemia was defined by hemoglobin (based on the World Health Organization criteria) and mean corpuscular volume. Cooking-related data was collected by questionnaire, and the average daily cooking duration was calculated by the weekly cooking frequency and the cooking duration of each meal. Logistic regression models were employed to derive the combined and independent associations of cooking fuel type and daily cooking duration with normocytic anemia and the modification effect of ventilation. Compared with people who never cooked, both clean fuel and solid fuel users were significantly associated with increased prevalent normocytic anemia [OR (95% CI) = 1.196 (1.014, 1.411) and 1.335 (1.105, 1.614), respectively], and the effect estimates on normocytic anemia risk were 1.260 (1.043, 1.523), 1.320 (1.104, 1.578), and 1.310 (1.081, 1.587) in participants who daily cooked < 1 h/day, 1–2 h/day, and ≥ 2 h/day, respectively. These relationships were attenuated in subjects with mechanical ventilation (All P < 0.05). Cooking with solid fuel or for a long duration are independently associated with prevalent normocytic anemia in rural population, and mechanical ventilation could attenuate these associations. Future efforts to reduce the burden of anemia could target the universal use of ventilation and solid fuel use or cooking duration reduction. Clinical trial registration: The Henan Rural Cohort Study has been registered at Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699). Date of registration: 06 July, 2015. http://www.chictr.org.cn/showproj.aspx?proj=11375 [ABSTRACT FROM AUTHOR]

A key aspect of achieving acceptable indoor air quality is source control. Cooking has been recognized as a significant source of pollutants for health impacts (e.g., PM2.5 and NO2) as well as moisture and odour. A common method of controlling this pollutant source is by using a range (or cooker) hood that vents to outside. However, field and laboratory experiments have shown highly variable performance for these devices. We use the capture efficiency metric (the fraction of the pollutants that are exhausted to outside at steady state) to characterize the range hood performance. To address this issue and provide useful information for builders, contractors, designers and home occupants, a laboratory rating method for range hood capture efficiency has recently been developed by LBNL and ASTM. The test method uses standardized emitters to create a heated plume and seed it with tracer gas. The tracer gas measurements in the room, the range hood exhaust and in the ambient air are used to estimate capture efficiency. However, this test method only applies to wall-mounted range hoods. Some range hoods are not wall-mounted: island range hoods are designed to operate over a cooktop in the middle of a room rather than against a wall and downdraft hoods draw air from near the cooktop rather than overhead. This paper discusses the development of a new test apparatus for island and downdraft hoods and presents measured capture efficiency data from example hoods. The results of this work will be used in future revisions to the ASTM standard.

Range hood is a local ventilation device applied widely in residential kitchen for maintaining healthy environment. This study firstly defines the direct capture efficiency (DCE) based on the two-zone model in a confined kitchen space. A mass flux ratio of the secondary captured pollutant to the entrained pollutant from the room zone is proposed for the determination of DCE, where the distribution coefficient is firstly solved, and then its sensitivity analysis on the DCE is carried out. To validate the mass flux ratio and concisely identify the DCE, a virtual purification method that artificially sets the escaped pollutant to zero, is further applied. Compared with the newly developed DCE, the existing indexes, such as contaminant removal efficiency (CRE), total capture efficiency (TCE), fail to differentiate the direct capture from the total capture. Finally, the effects of such factors as makeup airflow pattern, exhaust flow rate, cooking source temperature and the individual occupied/unoccupied on the DCE are fully studied. It is confirmed that different makeup airflow pattern results in distinguished airflow distribution, which makes a significant difference of more than 30% in DCE. Over 50% increase of DCE can be achieved when the exhaust flow rate is increased from 300 to 600 m3/h. About 30% decrease of DCE is observed with the increased cooking source temperature from 100 to 300 °C, and 10% increase of DCE is appeared in the individual occupied case. This reasonable definition and determination of DCE would help to improve the real capture performance of range hoods. [ABSTRACT FROM AUTHOR]

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]

As the number of enclosed residential buildings increases to minimize energy consumption, research on indoor air quality is becoming more important. Particulate matter (PM) generated during the cooking process in the kitchen, in particular, must be effectively removed because of rapid propagation to the room and harm to the human body. To remove this PM, residential exhaust hoods are being used. However, the pollutant collection efficiency of the hood is affected by the geometric shape of the hood frame and the environmental conditions. In this study, we investigated the effects of geometric frame shape (box, chimney, and canopy-type), installation height of hood, and heat-source temperature on the collection efficiency of the hood. Additionally, the effects of these characteristics on the human intake fraction of PM were investigated. Because of its frame geometry, the canopy-type hood had a larger average pressure difference in the inlet area than those of the other two types of hoods. Thus, the canopy-type hood has the most advantageous structure for collecting PM. For the canopy-type hood, the human intake fraction is 5.2 and 12.2 times lower than those for the box and chimney-types, respectively, when the installation height is 0.6 m. Consequently, the canopy-type hood was the most efficient for removal of PM and the most beneficial to the health of the occupant. This paper is valuable for installation of residential hood and configuration of automatic ventilation conditions in the kitchen, which mainly causes PM in indoor conditions. [ABSTRACT FROM AUTHOR]

Although solid fuel use for cooking is linked to an increased risk for depression, there is limited evidence on the effects of cooking duration and kitchen ventilation on these associations in rural areas. Among 29 903 participants from the Henan Rural Cohort, the independent and combined associations of cooking fuel type, cooking duration, and kitchen ventilation with depressive and anxiety symptoms were examined by logistic regression models and restricted cubic spline. The adjusted odds ratios (aORs) and 95% confidence intervals (CIs) of solid fuel use for depressive and anxiety symptoms were 1.237 (1.041, 1.469) and 1.384 (1.153, 1.662), respectively. Increased cooking duration was associated with an increased prevalence of depressive symptoms (aOR: 1.098, 95% CI: 1.033, 1.166) and anxiety symptoms (aOR: 1.074, 95% CI: 1.009, 1.144). Solid fuel use and long‐duration cooking associated with increased prevalence of depressive and anxiety symptoms were only observed in individuals without kitchen ventilation. Kitchen ventilation may attenuate the positive associations of solid fuel use and long‐duration cooking with the prevalence of depressive and anxiety symptoms, which suggested popularizing clean fuel and promoting kitchen ventilation may be effective strategies to improve mental health related to household air pollution sourced from solid fuel use and long‐duration cooking. [ABSTRACT FROM AUTHOR]

Results from medical research show that the use of domestic gas stoves could have a major impact on human health and well-being, especially if they used for heating. Approximately 0.289 m3 of natural gas is combusted daily in Hungarian kitchens. The users normally stand near the stove during its operation, which on average is 45 minutes long; therefore, they are directly affected by the combustion products. Nevertheless, uncertainties remain concerning the effects of the combustion products on humans; the nitrogen dioxide load could be the most problematic. Its nominal source strength is in a range of 12.0 - 21.0 ug/kJ, depending on the type of burner. In order to improve kitchen ventilation, a source model of domestic gas stoves has been developed that is based on measurement results, statistical data, and further technical assumptions.

Effective exhaust hoods can mitigate the indoor air quality impacts of pollutant emissions from residential cooking. This study reports capture efficiencies (CE) measured for cooking generated particles for scripted cooking procedures in a 121-m3 chamber with kitchenette. CEs also were measured for burner produced CO2 during cooking and separately for pots and pans containing water. The study used four exhaust hoods previously tested by Delp and Singer (Environ. Sci. Technol., 2012, 46, 6167-6173). For pan-frying a hamburger over medium heat on the back burner, CEs for particles were similar to those for burner produced CO2 and mostly above 80percent. For stir-frying green beans in a wok (high heat, front burner), CEs for burner CO2 during cooking varied by hood and airflow: CEs were 34-38percent for low (51?68 L s-1) and 54?72percent for high (109?138 L s-1) settings. CEs for 0.3?2.0 ?m particles during front burner stir-frying were 3?11percent on low and 16?70percent on high settings. Results indicate that CEs measured for burner CO2 are not predictive of CEs of cooking-generated particles under all conditions, but they may be suitable to identify devices with CEs above 80percent both for burner combustion products and for cooking-related particles.

A large amount of ultrafine particles are produced while cooking that seriously endanger human health. This paper uses a computational fluid dynamics model to simulate interior space airflow in an oil-heating process with three exhaust hood positions. Based on the obtained airflow velocity and temperature distributions, combined with the drift flux model, we were able to predict the ultrafine particle distribution with three particle diameters. The results show that exhaust hood positions influence the effect of the air supplement, but do not significantly reduce the concentration of ultrafine particles. When the exhaust hood is placed facing the window, the air supplement improves the capture efficiency but exacerbates the diffusion of ultrafine particles. When placed away from the window and in a corner, the distribution of ultrafine particles in the kitchen is basically the same, but due to the air supplement, the temperature around the personnel at the corner position is effectively reduced. The results also show that the distribution of ultrafine particles can be attributed to the airflow velocity approaching the hood, and warmer supplementary air will cause them to diffuse easily into the surrounding environment. By comparing the particle distributions at 0.01, 0.05, and 0.1 µm particle diameter, it is found that the effect of particle dynamics on the diffusion of ultrafine particles is relatively slight in a limited space. When supplementary air comes from the door, the kitchen's airflow pattern produces some effect as the displacement ventilation. Although the supplementary air from different hood positions have similar effects on the airflow characteristics in the cooking zone, they have different effects on the diffusion of ultrafine particles to the surrounding environment. [ABSTRACT FROM AUTHOR]

Background: The food truck industry has rapidly expanded in the United States and kitchen environments can contain harmful contaminants from cooking emissions. The objective of this study was to examine the levels of aldehydes, polycyclic aromatic hydrocarbons (PAHs), and Particulate Matter (PM)2.5 generated from cooking process in food trucks. Methods : Area sampling was performed twice at two participating food trucks during work shifts. Nine aldehydes and eighteeen PAHs were analyzed according to the relevant standard methods while PM2.5 was measured with a real time monitor. Ventilation performance of the food truck exhaust hoods was also investigated using a thermal anemometer. Findings : Formaldehyde was the only aldehyde detected in all samples with a concentration range of 7.16 to 53.68 µg/m3. No PAHs were detected above the limit of quantification. Average PM2.5 concentrations ranged from 0.65 to 7.03 mg/m3. Food Trucks 1 and 2 have an average exhaust flow rate of 211 and 215 L/s per linear meter of hood, respectively. Conclusions/Application to practice : Overall, Food Truck 2 had consistently higher levels of aldehydes and PM2.5 with comparable ventilation performance as Food Truck 1. The higher exposure levels of Food Truck 2 could possibly be attributed to a larger volume of food orders and the heavy duty cooking equipment with an exhaust flow rate below the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) recommendations. Although more investigations need to be performed, the findings could be used to raise awareness of food truck workers and health practitioners to reduce potential exposure risks. [ABSTRACT FROM AUTHOR]

Abstract To investigate the PM 2.5 emission in the direct exposed area from Chinese family cooking, eleven kinds of Chinese ordinary family cooking dishes were designed including frying, quick-frying, stewing, deep-frying, boiling and steaming according to the results of questionnaire survey. The results showed that the intensity sequence for PM 2.5 emissions decreased as follows in general: deep-frying (0.709–2.731 mg/m3) > stir-frying (0.700–0.958 mg/m3) > stewing (~0.573 mg/m3) > quick-frying (0.140–0.433 mg/m3) > boiling (0.004–0.247 mg/m3) > steaming (0.011–0.088 mg/m3), most of them exceeded the national indoor air standard. The average concentration of PM 2.5 in the direct respiratory zone from family cooking was determined to be 0.599 mg/m3, which was about 8 times higher than the national indoor air standard of China and lower than that from commercial restaurants. The annual PM 2.5 inhalation exposure in the direct exposed area from family cooking for male and female was 346.30 mg/year and 309.59 mg/year, respectively. Although the annual PM 2.5 inhalation exposure of male operators in general ordinary family cooking was about 11.8% higher than that of females, the pregnant women, children and the elderly are not encouraged to prepare ordinary family cooking for a long time due to their sensitive to PM 2.5 emission. Selecting ventilator with high wind speed can reduce PM 2.5 emission more than 65% when compared to medium wind speed. Improvement of ventilator wind speed is considered to be an effect way to reduce PM 2.5 emission for cooking. Graphical abstract Unlabelled Image Highlights • PM 2.5 emission in respiratory zone from Chinese family cooking • The effect of cooking dishes and cooking style on PM 2.5 emission • The annual PM 2.5 inhalation exposure is evaluated for Chinese family cooking. [ABSTRACT FROM AUTHOR]

Abstract: Diabetes is related to exposure to polycyclic aromatic hydrocarbons (PAHs), inflammation in the body, and housing characters. However, associations of urinary monohydroxy‐PAHs (OH‐PAHs) or fractional exhaled nitric oxide (FeNO) with diabetes risk in relation to housing characters are unclear. In this study, 2645 individuals were drawn from the baseline survey of the Wuhan‐Zhuhai Cohort Study. Associations of diabetes with urinary OH‐PAHs or FeNO among cooking participants were estimated using logistic regression models. Among women with self‐cooking meals, urinary OH‐PAH levels were positively associated with diabetes risk (P < .05); the cooking women with high FeNO (≥25 ppb) had a 59% increase in the risk of diabetes (OR: 1.59, 95% CI: 1.06, 2.38), compared with those with low FeNO (<25 ppb). The cooking women with use of kitchen exhaust fans/hoods had a 52% decrease in the risk of diabetes (OR: 0.48, 95% CI: 0.27, 0.84), compared with those with nonuse of kitchen exhaust fans/hoods. The results indicated that the cooking women had an elevated risk of diabetes, which may be partly explained by an increase in the PAH body burden and higher inflammatory responses. Use of kitchen exhaust fan/hood can be associated with a lower risk of diabetes. [ABSTRACT FROM AUTHOR]

In kitchen environment, an efficient kitchen hood is especially demanded to ensure the provision of a healthy, comfortable and energy efficient working environment. The most accurate kitchen ventilation design method should be based on the heat gain of the appliances. In this paper the calculation equations of convection plumes, above kitchen appliances, were investigated. The heat source of cooking appliances is assumed to be a point heat source, and the temperature and velocity distributions are assumed to match the Gaussian distribution. In the kitchen environment, at the extraction point, the convection flow of the transitional region has not yet fully developed. Thus, the derived general plume equation is inaccurate for the transitional region. Nevertheless, when the position of the virtual origin is individual adjusted in a practical application, the results are reasonably accurate. The calculation experience formulas of the virtual origin position of air flow rate are worked out. [ABSTRACT FROM AUTHOR]

With the increasement of worldwide population, high-rise buildings of multi-dwelling units have been widely used as a residential building, especially in China, United States and India etc. At present, most of cooking exhaust shafts in high-rise residential building takes the form of central exhaust system. However, the mal-distribution of exhaust flow in central exhaust system often leads to oil fumes reflux and odor migration, which decreasing the performance of kitchen hoods. This study is conducted in a 32-storey residential building which employed central exhaust system. Static pressure and velocity distribution were investigated in central exhaust shaft with uniform cross section. In addition, Computational Fluid Dynamics was adopted to analyze flow characteristics and validated by comparing the simulation results with experimental data. The emphasis of this study lies in the effects of temperature differences and equally spaced operating rates of kitchen hoods on flow characteristics in central exhaust shaft. The results showed that when the temperature difference varies from −12 °C to 30 °C, the locations of maximum static pressure gradually moved downwards and presented a low-high-low distribution. The maximum occurred in the middle-low storeys under different operating rates. This paper is valuable for HVAC engineers to improve the design of central cooking exhaust shafts in high-rise residential buildings, and solve the mal-distribution problems of exhaust flow in central exhaust systems. [ABSTRACT FROM AUTHOR]

This paper investigates the situation of residential kitchen ventilation and individual exposure in China and attempts to reduce the exposure through organizing local make-up airflow. Measurements were conducted in a kitchen chamber to reproduce the real exposure to the cooking-generated particles under the mode of natural make-up airflow surveyed. Measurements results show that an individual cooking in a kitchen could be exposed to a concentration of airborne particles at ∼10 mg/m3 within a simplified cooking process of oil heating, in the case of an experimental kitchen chamber with an open window or closed window/door. Local make-up airflow through upward make-up air supply or downward make-up air supply was further investigated to determine the effectiveness for reduction of the exposure level. When the air-supply velocity at the outlet of the upward make-up air supply or downward make-up air supply mode was well defined, the individual exposure level could be reduced by 2–3 orders of magnitude, as compared to the baseline case when all the make-up air was from open window. Intake fraction of cooking-generated particles could be as low as ∼10−5 and ∼10−6 under the two modes. This finding has illustrated that well-organized local make-up airflow could largely reduce an individual’s exposure to the cooking-generated particles in Chinese residential kitchen. [ABSTRACT FROM AUTHOR]

Pollutants generated from cooking process are detrimental to occupant's health. For conventional residential kitchen in hot summer and cold winter region of China, range hood is installed to exhaust oil fume and other pollutants. In typical kitchen, air is supplied through the insect screen. However, this kind of air supply and exhaust system is not capable of providing air distribution for good indoor air quality in kitchen. In order to solve this problem, the combined scheme with air supply through slot air curtain and air exhaust through range hood is proposed, which is termed as the push-pull ventilation system. Both numerical simulation and field test were carried out to investigate the air velocity, temperature and pollutant distributions. Orthogonal study was performed during numerical simulation. Air curtain velocity (A), air curtain angle (B, C, D, E) and exhaust velocity (F) were chosen as six factors during the L 25 (5 6 ) orthogonal test. The average CO 2 concentration of the 25 cases in breathing region was compared. It is shown that by using the range hood alone, oil fume generated by cooking cannot be effectively exhausted out of the kitchen. With application of the push-pull ventilation system, the air temperature can be reduced during the summer scenario, which may improve occupant thermal comfort. Meanwhile, the pollutant concentration can be reduced with the improved air distribution. Moreover, the sequence for effect of influencing factors on the pollutant concentration distribution is A>B>C>E>D>F. This proposal provides a scientific support to reduce the indoor pollutant concentration in kitchen. [ABSTRACT FROM AUTHOR]

This study was conducted to assess the current impact of natural gas appliances on air quality in California homes. Data were collected via telephone interviews and measurements inside and outside of 352 homes. Passive samplers measured time-resolved CO and time-integrated NOX, NO2, formaldehyde, and acetaldehyde over ~6-day periods in November 2011 - April 2012 and October 2012 - March 2013. The fraction of indoor NOX and NO2 attributable to indoor sources was estimated. NOX, NO2, and highest 1-h CO were higher in homes that cooked with gas and increased with amount of gas cooking. NOX and NO2 were higher in homes with cooktop pilot burners, relative to gas cooking without pilots. Homes with a pilot burner on a floor or wall furnace had higher kitchen and bedroom NOX and NO2 compared to homes without a furnace pilot. When scaled to account for varying home size and mixing volume, indoor-attributed bedroom and kitchen NOX and kitchen NO2 were not higher in homes with wall or floor furnace pilot burners, although bedroom NO2 was higher. In homes that cooked 4 h or more with gas, self-reported use of kitchen exhaust was associated with lower NOX, NO2, and highest 1-h CO. Gas appliances were not associated with higher concentrations of formaldehyde or acetaldehyde. [ABSTRACT FROM AUTHOR]

Concurrent supply and exhaust ventilation (CSEV) has been developed to effectively exhaust heat and contamination from the kitchen. The objective of this research was to investigate the performance variation of this system with respect to air flow rates. CSEV system can block the contaminated air from entering the inner space by supplying fresh air horizontally in the ceilings towards the hood where the overflowed contaminated gas tends to diffuse to inner part of the room. The system captures contaminated air in an area near the ceiling and this captured air is then exhausted through the ceiling outlet. For quantitative evaluation, heat and gas capture efficiencies were defined and calculated. Experiments were conducted to compute heat and gas capture efficiencies based on the temperature and SF6 concentration data that were measured at the exhaust locations. To find optimum operation conditions for a CSEV system, numerical analysis was carried out. The numerical results were in good agreement with the experimental values. Maximum differences between the two methods are 17% for hood system and 10% for CSEV. Both heat and gas capture efficiencies would increase as exhaust flow rate of the hood increases. However, the optimum supply flow rate of ceiling nozzle was found to be 100 m3/h for maximum efficiency. This optimum flow rate condition would improve removing heat and contamination from the kitchen for better indoor air quality. [ABSTRACT FROM AUTHOR]

The article focuses on a study conducted by the author related to effect of a draft generator on inclined air-curtain range hood in lateral, front and oblique directions. Topics discussed include the hood resisting front draft, impact of oblique and lateral drafts on the hood when draft velocity was increased, movement of oil mist with an increase in draft velocity, high containment ability of hood in front draft as compared to other two directions and flow visualization.

Effective exhaust hoods can mitigate the indoor air quality impacts of pollutant emissions from residential cooking. This study reports capture efficiencies ( CE) measured for cooking-generated particles for scripted cooking procedures in a 121-m3 chamber with kitchenette. CEs also were measured for burner produced CO2 during cooking and separately for pots and pans containing water. The study used four exhaust hoods previously tested by Delp and Singer ( Environ. Sci. Technol., 2012, 46, 6167-6173). For pan-frying a hamburger over medium heat on the back burner, CEs for particles were similar to those for burner produced CO2 and mostly above 80%. For stir-frying green beans in a wok (high heat, front burner), CEs for burner CO2 during cooking varied by hood and airflow: CEs were 34-38% for low (51-68 l/s) and 54-72% for high (109-138 l/s) settings. CEs for 0.3-2.0 μm particles during front burner stir-frying were 3-11% on low and 16-70% on high settings. Results indicate that CEs measured for burner CO2 are not predictive of CEs of cooking-generated particles under all conditions, but they may be suitable to identify devices with CEs above 80% both for burner combustion products and for cooking-related particles. [ABSTRACT FROM AUTHOR]

Objective: To investigate indoor factors affecting fractional exhaled nitric oxide (FeNO) in community residents. Methods: A total of 2404 adults (865 men, 1539 women, mean age 51.7 ± 13.3 years) were recruited to the study. Factors affecting FeNO were analyzed by multiple linear regression analysis. Results: Participants without a kitchen exhaust fan/hood had higher FeNO (GM: 10.21%, 95% CI: 4.18%-16.59%). Participants engaged in home cooking who used only liquefied petroleum gas had higher FeNO (GM: 5.75%, 95% CI: 0.10%- 11.73%) compared to those using natural gas for residential (home) cooking. Conclusion: Nonuse of a kitchen exhaust fan/hood and use of liquefied petroleum gas among persons engaged in home cooking were associated with higher FeNO levels. [ABSTRACT FROM AUTHOR]