On-site measurement and simulation of indoor particulate matter distributed in a single room with stratified flow field

A large amount of heat and particles generated from cooking have a negative impact on occupants’ thermal comfort as well as the indoor environment in the kitchen and adjacent rooms. Although heat generation rate and emission strength of particles are largely affected by oil temperature and cooking duration, there is a lack of quantification on the impact of the indoor environment during the whole cooking process. This study applies a computational fluid dynamics method to simulate air temperature, velocity and particle distribution in a kitchen and indoor environment during a 10-min and after 2-min cooking process with constant make-up air organization from window opening in a Chinese-style residential kitchen. User-defined function was defined for dynamic oil temperature and emission rate based on experimental results from previous studies and was interpreted in FLUENT for transient simulation within 12 min. Results indicate that heat spread remarkably after 30 s of oil heating. Air temperature experienced an increase of about 10.0°C around the occupant during the whole cooking process. For particle distribution, a large variation in the kitchen was observed after 4 min. Particle concentration in an indoor environment was increased dramatically after 6 min. Further studies on the transmission mechanism of heat and particles from the kitchen space to an adjacent room under different cooking scenarios are needed for the design and control of kitchen ventilation.

Section: Introductionmentioning

confidence: 99%

Investigation on the indoor environment during a whole cooking process under constant make-up air organization in a Chinese-style residential kitchen

Liu

et al. 2023

“…Long-term exposure to high concentrations of PM 2.5 can cause various respiratory and cardiovascular diseases, and even increase the risk of early death. [4][5][6][7] Outdoor PM concentrations can significantly affect indoor air quality. 8 While previous studies have demonstrated an inverse relationship between PM and NAI, uncertainty regarding this relationship exists in urban residential areas where motor vehicles act as a common source of PM and NAI.…”

Section: Introductionmentioning

confidence: 99%

Spatiotemporal distribution of negative air ion and PM_2.5 in urban residential areas

Wang

Xia

Zhu

et al. 2022

Urban environments are characterised by high pollution levels, which adversely affect the physiology, psychology and behaviour of the urban residents. In this study, on-site measurements and air quality evaluations were performed in urban residential areas. The negative air ion (NAI) concentration, fine particulate matter (PM2.5) concentration, temperature and relative humidity were measured in different seasons. Both PM2.5 and the NAI concentrations changed significantly with seasons. The PM2.5 concentration was the highest in winter, intermediate in autumn and the lowest in summer, while the NAI concentration showed an opposite trend. The overall changes in NAI and PM2.5 concentrations showed a trend of double peaks and double valleys, and there was a substantial difference between rainy days versus sunny days. The NAI concentration was positively correlated with temperature and relative humidity, and the influence of relative humidity on NAI was greater than that of temperature. There were notable spatial differences in the intensity of impact by different pollution sources. Based on these results, suggestions were made for optimising the layout of residential buildings and the rationalisation of traffic networks, with the aim of increasing NAI concentrations and reducing PM2.5 concentrations. This would help reduce the pollution levels in urban residential areas.

“…Compared to the outdoor environment, the indoor one is characterized by small space, high tightness and a large coupling effect. Lin et al 10 combined on-site measurement and model simulation to characterize the spatial distribution of indoor PM in a single room with stratified flow fields. Research shows that indoor air might contain many microorganisms and particulate matters that are easy to adsorb virus droplets and cause infections.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of indoor human-induced particle resuspension under different ventilation conditions

Sun

Zheng

et al. 2022

This study performed a series of experiments to study the characteristics of human-induced particle resuspension under different ventilation conditions. Four modes of supplied airspeed were evaluated: no wind, low wind (2.742 m/s), medium wind (3.849 m/s) and high wind (4.422 m/s). Results show that the steady-state particle concentration can be approximated as a linear function of the airspeed. Human walking and ventilation conditions can have a significant and coupling role in particle behaviours. In particular, human walking provides initial energy for resuspension by disturbing the local fields, and thus increases the resuspension, especially for large particles of 5–10 μm in size. The wind has two competitive effects, that is, supplying energy to keep particles suspended and pushing the particles downward, and the latter becomes dominant when the airspeed was too high. Consequently, intermediate airspeeds can intensify the effect of human walking, and introduce higher peaks of particle concentration in the human-walking stages. As for the particle number density, similar conclusions can be drawn that the effect of ventilation conditions is more pronounced on small particles less than 1 μm while that of human walking is on large particles. This work lays a foundation for revealing the particle resuspension mechanism.