Indoor distribution and personal exposure of cooking-generated PM2.5 in rural residences of China:A multizone model study

The fine particulate matter(PM2.5)emitted during cooking is a significant contributor to household air pollution in rural China,resulting in millions of premature deaths annually.Since cooking is an internal pollution source,the indoor concentration of cooking-generated PM2.5 can vary among different rooms in multizone rural residences.This study provides a comprehensive understanding of indoor PM2.5 from cooking in rural residences by utilizing on-site investigations to gather information on cooking behavior and dwelling layout in three Chinese villages,and subsequently simulating indoor spatiotemporal concentrations of cooking-generated PM2.5 using a multizone model.Our findings indicate that the type of zone significantly influences the zonal concentration of PM2.5,with the highest concentrations found in kitchens(i.e.,13.9 to 188.0μg/m3)and lowest in non-adjacent zones to the kitchen(i.e.,0.01 to 7.5μg/m3)among all the modeled conditions.More importantly,the study also assesses the resulting personal exposures for occupants with different time-spent patterns,revealing that the main cook at home and preferring to stay in the adjacent rooms to the kitchen are at the highest risk for personal exposure.The highest personal exposure levels of cooking-generated PM2.5 are 28.5±30.1μg/m3,which is 34 times that of occupants who stay away from the kitchen.The study provides a deeper scientific insight into the indoor spatial distribution and personal exposure to cooking-generated PM2.5 in rural residences,which is crucial for developing effective interventions to mitigate the detrimental health impacts of household air pollution in rural areas.

Characterization of personal exposure concentration of fine particles for adults and children exposed to high ambient concentrations in Beijing, China

In China, the health risk from overexposure to particles is becoming an important public health concern. To investigate daily exposure characteristics to PM 2.5 with high ambient concentration in urban area, a personal exposure study was conducted for school children, and office workers in Beijing, China. For all participants （N = 114）, the mean personal 24-hr exposure concentration was 102.5, 14.7, 0.093, 0.528, 0.934, 0.174 and 0.703 μg/m 3 for PM 2.5 , black carbon, Mn, Al, Ca, Pb, and Fe. Children’s exposure concentrations of PM 2.5 were 4–5 times higher than those in related studies. The ambient concentration of PM 2.5 （128.5 μg/m 3 ） was significantly higher than the personal exposure concentration （P 0.05）, and exceed the reference concentration （25 μg/m 3 ） of WHO air quality guideline. Good correlation relationships and significant differences were identified between ambient concentration and personal exposure concentration. The relationships indicate that the ambient concentration is the main factor influencing personal exposure concentration, but is not a good indicator of personal exposure concentration. Outdoor activities （commute mode, exposure to heating, workday or weekend travel） influenced personal exposure concentrations significantly, but the magnitude of the influence from indoor activities （exposure to cooking） was masked by the high ambient concentrations.

Protection Performance Evaluationof the Respirators and PersonalExposure Measurement in aBelgian Viscose Rayon Factory

This paper presents the evaluation results of protective performance of the respirators (full face supplied-fresh air respirators and half-mask active charcoal filter) and personal exposure measurement (Infacepiece sampling) in a Belgian viscose rayon factory. With in-facepiece sampling technique and personal sampling method, we measured the CS2 concentrations inside and outside of the different respirators. We found two kinds of the respirators have significant effect on decreasing the CS2 exposure level for the subject, especially for the spinners. Full face supplied-fresh air respirator have good protective effect for the spinners and have limit protection for the high exposure job although the PF value is more than 10. It still need to improve more. In-facepiece sampling for all the subjects exposed to CS2 in the factory found most subjects have exposed to low CS2 concentration, most exposure levels were under the control range, but sulfuror are high exposure, the exposure level is higher than ACGIH TLV value.

Personal PM_(2.5)-bound PAH exposure and lung function in healthy office workers:A pilot study in Beijing and Baoding,China

The effect of short-term exposure to polycyclic aromatic hydrocarbons(PAHs)on the respiratory system among healthy residents is unclear.Beijing and Baoding are typical polluted cities in China,and there is little research on PAH exposure and its health effects at the individual level.Fourteen healthy female office workers were recruited in urban Beijing and Baoding,China,in 2019.The personal exposure to fine particulate matter(PM_(2.5))-bound PAHs and lung function were seasonally monitored.The relationships between PAH exposure and lung function were determined by a generalized mixed linear model.Subjects were exposed to high levels of PAH,in which the benzo[a]pyrene(BaP)level(1.26 ng/m^(3))was over than Chinese national indoor standard(1 ng/m^(3)).All PAHs concentration was higher in winter than that in summer and autumn.Only benz[a]anthracene(BaA)and chrysene(Chr)exposure showed weak relations with decreased lung function,i.e.,a 0.58% and 0.73% decrease in peak expiratory flow at lag 2 day,respectively(p<0.05).PAHs may not be suitable exposure indicators for short-term change in lung function.Our findings highlight the importance of reducing PAH pollution for public respiratory health protection in heavy-polluted cities of China.This pilot study also provides experience on personal PAH assessment such as estimation of the number of repeated measurements required,which is helpful to determine the relationship between PAH exposure and health effect.

Prediction of Perceived Air Quality for Personalized Ventilation Systems

The characteristics of the air jet from the outlet of a personalized ventilation system were related to the perceived air quality and ventilation rate. The perceived air quality was expressed as percentage of dissatisfied people for a system supplying isothermal fresh air. The relationship was verified using a thermal manikin with a breathing function in a climate chamber sitting by a desk equipped with a personalized venti- lation system. A trace gas was introduced into the climate chamber and fully mixed. The personal exposure effectiveness (εp) is based on concentrations of trace gas in the chamber and in the manikin nose which is affected more by the distance between the movable outlet and the occupant’s breathing zone than by the personalized air flowrate and does not change much for the personalized air flowrate higher than 10 L/s when the distance is fixed. Some predicted dissatisfied values for a personalized ventilation system com- pared with those acquired in human subject experiments have an absolute difference of less than 3%.

Investigation of exhaled pollutant distribution in the breathing microenvironment in a displacement ventilated room with indoor air stability conditions

This study experimentally studied the dispersion of exhaled pollutant in the breathing microenvironment(BM)in a room equipped with a displacement ventilation(DV)system and indoor air stability conditions(i.e.,stable and unstable conditions).The vertical temperature differences and the carbon dioxide(CO_(2))concentration in the BM were measured.Results show that when DV is combined with the stable condition(DS),pollutant tends to accumulate in the BM,leading to a high pollutant concentration in this region.Whereas,when DV is combined with the unstable condition(DU),pollutant diffuses to a relatively wider area beyond the BM,thus the pollutant concentration in the BM is substantially reduced.Moreover,increasing the flow rate can reduce the pollutant concentration in the BM of the DS but yields little difference of the DU.In addition,personal exposure intensity increases with time,and the DS has a relatively higher increase rate than DU.The results suggest that indoor air stability will affect the performance of DV systems.DS will lead to a higher health risk for people when they stay in the indoor environment with pollutant sources,and DU is recommended for minimizing pollutant level in the BM in order to reduce the pollutant concentration and providing better air environments for the occupants.