In order to solve the problems of difficult test, high cost and long cycle in the development of large-scale airborne negative pressure isolation system, the simulation analysis of negative pressure response characteristics is carried out around various aviation conditions such as aircraft ascending, leveling and descending, especially rapid decompression, based on the computational fluid dynamics (CFD) method. The results showed that the isolation cabin could achieve -50 Pa pressure difference environment and form a certain pressure gradient. The exhaust air volume reached the maximum value in the early stage of the aircraft's ascent, and gradually decreased with the increase of altitude until it was level flying. In the process of aircraft descent, the exhaust fan could theoretically maintain a pressure difference far below -50 Pa without working; Under the special condition of rapid pressure loss, it was difficult to deal with the rapid change of low pressure only by the exhaust fan, so it was necessary to design safety valve and other anti-leakage measures in the isolation cabin structure. Therefore, the initial stage of aircraft ascent is the key stage for the adjustment and control of the negative pressure isolation system. By controlling the exhaust air volume and adjusting parameters, it can adapt to the change of low pressure under normal flight conditions, form a relatively stable negative pressure environment, and meet the needs of biological control, isolation and transport.
Aircraft ; Computer Simulation ; Aviation/instrumentation* ; Humans ; Hydrodynamics ; Air Pressure ; Equipment Design ; Pressure

Under the background of climate change, the escalating air pollution and extreme weather events have been identified as risk factors for chronic respiratory diseases (CRD), causing serious public health burden worldwide. This review aims to summarize the effects of changed atmospheric environment caused by climate change on CRD. Results indicated an increased risk of CRD (mainly COPD, asthma) associated with environmental factors, such as air pollutants, adverse meteorological conditions, extreme temperatures, sandstorms, wildfire, and atmospheric allergens. Furthermore, this association can be modified by factors such as socioeconomic status, adaptability, individual behavior, medical services. Potential pathophysiological mechanisms linking climate change and increased risk of CRD involved pulmonary inflammation, immune disorders, oxidative stress. Notably, the elderly, children, impoverished groups and people in regions with limited adaptability are more sensitive to respiratory health risks caused by climate change. This review provides a reference for understanding risk factors of CRD in the context of climate change, and calls for the necessity of adaptive strategies. Further interdisciplinary research and global collaboration are needed in the future to enhance adaptability and address climate health inequality.
Climate Change ; Humans ; Air Pollution/adverse effects* ; Risk Factors ; Respiratory Tract Diseases/etiology* ; Chronic Disease ; Air Pollutants/adverse effects* ; Environmental Exposure/adverse effects*

BACKGROUND: Hemorrhagic stroke (HS) is associated with significant disability and mortality. However, the relationship between meteorological factors and hemorrhagic stroke, as well as the potential moderating role of these factors, remains unclear. METHODS: Daily data on HS, air pollution, and meteorological conditions were collected from January 2015 to December 2021 in Ganzhou to analyze the relationship between meteorological factors and HS admissions. This analysis employed a time-stratified case-crossover design in conjunction with a distributional lag nonlinear model. Additionally, a bivariate response surface modelling was utilized to further investigate the interaction between meteorological factors and particulate matter. The study also stratified the analyses by gender and age. To investigate the potential impact of extreme weather conditions on HS, this study defined the 97.5th percentile as representing extremely high weather conditions, while the 2.5th percentile was classified as extremely low. RESULTS: In single-day lags, the risk of admissions for HS was significantly associated with extremely low temperature (lag 1-2 and lag 13-14), extremely low humidity (lag 1 and lag 9-12), and extremely high precipitation (lag 2-7). Females exhibited greater susceptibility to extremely low temperature than males within the single-day lag pattern in the subcomponent layer, with a maximum relative risk (RR) that was 7% higher. In the cumulative lag analysis, the risk of HS admissions was significantly associated with extremely high temperature (lag 0-8∼lag 0-14), extremely low humidity (lag 0-2∼lag 0-14), and extremely high precipitation (lag 0-4∼lag 0-14). Within the cumulative lag day structure of the subcomponent layer, both extremely low and extremely high temperature had a more pronounced effect on females and aged ≥65 years. The risk of HS admissions was positively associated with extremely high barometric pressure in the female subgroups (lag 0-1 and lag 0-2). The highest number of HS admissions occurred when high PM_2.5 concentrations coexisted with low precipitation. CONCLUSIONS Meteorological factors were significantly associated with the risk of hospital admissions for HS. Individuals who were female and aged ≥65 years were found to be more susceptible to these meteorological influences. Additionally, an interaction was observed between airborne particulate matter and meteorological factors. These findings contributed new evidence to the association between meteorological factors and HS.
China/epidemiology* ; Humans ; Female ; Male ; Aged ; Middle Aged ; Cross-Over Studies ; Hospitalization/statistics & numerical data* ; Adult ; Hemorrhagic Stroke/etiology* ; Meteorological Concepts ; Weather ; Particulate Matter/analysis* ; Air Pollution/adverse effects* ; Environmental Exposure/adverse effects* ; Aged, 80 and over ; Young Adult

BACKGROUND: There is growing evidence that the occurrence and severity of respiratory diseases in children are related to the concentration of air pollutants. Nonetheless, evidence regarding the association between short-term exposure to air pollution and outpatient visits for respiratory diseases in children remains limited. Outpatients cover a wide range of disease severity, including both severe and mild cases, some of which may need to be transferred to inpatient treatment. This study aimed to quantitatively evaluate the impact of short-term ambient air pollution exposure on outpatient visits for respiratory conditions in children. METHODS: This study employed data of the Second People's Hospital of Yichang from January 1, 2016 to December 31, 2023, to conduct a time series analysis. The DLNM approach was integrated with a generalized additive model to examine the daily outpatient visits of pediatric patients with respiratory illnesses in hospital, alongside air pollution data obtained from monitoring stations. Adjustments were made for long-term trends, meteorological variables, and other influencing factors. RESULTS: A nonlinear association was identified between PM_2.5, PM₁₀, O₃, NO₂, SO₂, CO levels and the daily outpatient visits for respiratory diseases among children. All six pollutants exhibit a hysteresis impact, with varying durations ranging from 4 to 6 days. The risks associated with air pollutants differ across various categories of children's respiratory diseases; notably, O₃ and CO do not show statistical significance concerning the risk of chronic respiratory conditions. Furthermore, the results of infectious respiratory diseases were similar with those of respiratory diseases. CONCLUSIONS Our results indicated that short-term exposure to air pollutants may contribute to an increased incidence of outpatient visits for respiratory illnesses among children, and controlling air pollution is important to protect children's health.
Humans ; China/epidemiology* ; Air Pollutants/analysis* ; Respiratory Tract Diseases/chemically induced* ; Child ; Child, Preschool ; Environmental Exposure/adverse effects* ; Air Pollution/analysis* ; Infant ; Male ; Particulate Matter/adverse effects* ; Female ; Ambulatory Care/statistics & numerical data* ; Outpatients/statistics & numerical data* ; Adolescent ; Infant, Newborn

BACKGROUND: It is inaccurate to reflect the level of dust exposure through working years. Furthermore, identifying a predictive indicator for lung function decline is significant for coal miners. The study aimed to explored whether club cell secretory protein (CC16) levels can reflect early lung function changes. METHODS: The cumulative respiratory dust exposure (CDE) levels of 1,461 coal miners were retrospectively assessed by constructed a job-exposure matrix to replace working years. Important factors affecting lung function and CC16 were selected by establishing random forest models. Subsequently, the potential of CC16 to reflect lung injury was explored from multiple perspectives. First, restricted cubic spline (RCS) models were used to compare the trends of changes in lung function indicators and plasma CC16 levels after dust exposure. Then mediating analysis was performed to investigate the role of CC16 in the association between dust exposure and lung function decline. Finally, the association between baseline CC16 levels and follow-up lung function was explored. RESULTS: The median CDE were 35.13 mg/m³-years. RCS models revealed a rapid decline in forced vital capacity (FVC), forced expiratory volume in the first second (FEV₁), and their percentages of predicted values when CDE exceeded 25 mg/m³-years. The dust exposure level (<5 mg/m³-years) causing significant changes in CC16 was much lower than the level (25 mg/m³-years) that caused changes in lung function indicators. CC16 mediated 11.1% to 26.0% of dust-related lung function decline. Additionally, workers with low baseline CC16 levels experienced greater reductions in lung function in the future. CONCLUSIONS CC16 levels are more sensitive than lung indicators in reflecting early lung function injury and plays mediating role in lung function decline induced by dust exposure. Low baseline CC16 levels predict poor future lung function.
Uteroglobin/blood* ; Humans ; Dust/analysis* ; Occupational Exposure/analysis* ; Male ; Middle Aged ; Adult ; Retrospective Studies ; Lung Injury/chemically induced* ; Coal Mining ; Biomarkers/blood* ; China/epidemiology* ; Air Pollutants, Occupational ; Female

BACKGROUND: Previous studies have demonstrated that short-term exposure to ambient particulate matter elevates the risk of ischemic stroke in major urban areas of various countries. However, there is a notable gap in research focusing on remote areas inhabited by ethnic minorities and the cumulative effects of air pollutants. Our study conducted in the area aims to explore the potential association between ischemic stroke and air pollutants and contribute to improving health outcomes among the community. METHODS: This retrospective observational study was conducted at the Xing'an League People's Hospital in Inner Mongolia. The medical records of 4,288 patients admitted for IS between November 1, 2019, and October 31, 2020, were reviewed. Data on demographics (age and sex), air pollutants (PM₁₀, PM_2.5, NO₂, NO, CO, and O₃), and meteorological factors (daily average temperature, daily average wind speed, and daily average atmosphere pressure) were collected and analyzed. The statistical analysis included descriptive statistics, Poisson distribution analysis to evaluate the adverse effects of atmospheric pollutants on daily hospitalizations, and subgroup analysis to determine whether gender and age could modify the impact on hospitalizations. RESULTS: A substantial correlation was revealed in single-day lags model. The peak delayed effects of PM₁₀, PM_2.5, SO₂, and NO₂ were observed at lag8 (PM₁₀ (OR = 1.016, 95%CI 1.002, 1.030), PM_2.5 (OR = 1.027, 95%CI 1.007, 1.048), SO₂ (OR = 1.153, 95%CI 1.040, 279) and NO₂ (OR = 1.054, 95%CI 1.005, 1.105)) while males exhibited a consistent trend from lag0 to lag8 (PM₁₀ (OR = 1.035, 95%CI 1.018, 1.053), PM_2.5 (OR = 1.056, 95%CI 1.030, 1.082), SO₂ (OR = 1.220, 95%CI 1.072, 1.389), NO₂ (OR = 1.126, 95%CI 1.061, 1.120), CO (OR = 10.059, 95%CI 1.697, 59.638) and O₃ (OR = 0.972, 95%CI 0.946, 0.999)). When gender and age were considered, a positive impact was also observed after three days cumulative effect in males. CONCLUSIONS There is a significant cumulative effect of exposure to air pollution on IS hospital admissions, especially the males and patients under the age of 65. Our results also suggested that a notable association between CO and NO₂ in two-pollutant models.
Humans ; Male ; Female ; Air Pollution/analysis* ; China/epidemiology* ; Retrospective Studies ; Middle Aged ; Air Pollutants/analysis* ; Aged ; Particulate Matter/analysis* ; Hospitalization/statistics & numerical data* ; Adult ; Ischemic Stroke/chemically induced* ; Environmental Exposure/adverse effects* ; Aged, 80 and over

In Japan, during the high economic growth period (1950-1960s), air pollution due to sulfur dioxide (SO₂) and dust derived from large-scale factories and power plants was apparent in many industrial districts, and it caused serious health problems such as the so-called "Yokkaichi Asthma." Many epidemiological studies have revealed the relationship between air pollution and respiratory diseases, and have provided scientific evidence for the regulatory control of air pollution. The concentration of SO₂ has markedly decreased since the 1970s, and its adverse health effects have improved. In contrast, increased automobile traffic has caused considerable traffic-related air pollution, including nitrogen oxides (NOx) and particulate matter (PM). Epidemiological studies in Chiba and Tokyo revealed that the prevalence and incidence of asthma were significantly higher among individuals living in roadside areas than among those living in other areas. Large-scale epidemiological studies conducted in urban districts have revealed an association between traffic-related air pollution and the onset of asthma in schoolchildren and persistence of asthmatic symptoms in preschool children. Thereafter, the concentrations of NOx and PM gradually decreased due to the control measures based on the Automobile NOx/PM Law enforced in 2001. Thus, epidemiological studies have contributed to a reduction in air pollution caused by automobile exhaust emissions. Recently, the adverse health effects of ambient fine PM (PM_2.5) and ozone (O₃) at ground level have become an international concern. Our epidemiological studies showed that short-term exposure to considerably low concentrations of PM_2.5 and O₃ was associated with a decrease in pulmonary function among asthmatic children and increased airway inflammation in healthy adolescents. The effects of exposure to PM_2.5 during pregnancy and early childhood on children's development have also been reported. These air pollutants consist of not only emissions from primary sources but also secondary formations in the atmosphere. They are affected by climate change and spread worldwide. Air quality control measures and climate change adaptation and mitigation strategies are synergistic, and will have co-benefits on human health. Therefore, global efforts are required to protect populations from the health risks posed by these air pollutants.
Japan/epidemiology* ; Humans ; Air Pollution/analysis* ; Air Pollutants/adverse effects* ; Particulate Matter/adverse effects* ; Asthma/chemically induced* ; Vehicle Emissions ; Epidemiologic Studies ; Environmental Exposure/adverse effects* ; Sulfur Dioxide/analysis*

BACKGROUND: Evidence on the combined effects of air pollutants and greenspace exposure on pulmonary tuberculosis (PTB) treatment is limited, particularly in developing countries with high levels of air pollution. OBJECTIVE: We aimed to examine the individual and combined effects of long-term exposure to air pollutants on PTB treatment outcomes while also investigating the potential modifying effect of greenspace. METHODS: This population-based study included 82,784 PTB cases notified in Zhejiang Province, China, from 2015 to 2019. The 24-month average concentrations of particulate matter with an aerodynamic diameter ≤2.5 µm (PM_2.5), ozone (O₃), nitrogen dioxide (NO₂), and sulfur dioxide (SO₂) before PTB diagnosis were estimated using a dataset derived from satellite-based machine learning models and monitoring stations. Greenspace exposure was assessed using the annual China Land Cover Dataset. We conducted analyses using time-varying Cox proportional hazards models and cumulative risk indices. RESULTS: In individual effect models, each 10 µg/m³ increase in PM_2.5, NO₂, O₃, and SO₂ concentrations was associated with hazard ratios for PTB treatment success of 0.95 (95% confidence interval (CI): 0.93-0.97), 0.92 (95% CI: 0.91-0.94), 0.98 (95% CI: 0.97-0.99), and 1.52 (95% CI: 1.49-1.56), respectively. In combined effect models, long-term exposure to the combination of air pollutants was negatively associated with PTB treatment success, with a joint hazard ratio (JHR) of 0.79 (95% CI: 0.63-0.96). Among the pollutants examined, O₃ contributed the most to the increased risks, followed by PM_2.5 and NO₂. Additionally, areas with moderate levels of greenspace showed a reduced risk (JHR = 0.81, 95% CI: 0.62-0.98) compared with the estimate from the third quantile model (JHR = 0.68, 95% CI: 0.52-0.83). CONCLUSIONS Combined air pollutants significantly impede successful PTB treatment outcomes, with O₃ and PM_2.5 accounting for nearly 75% of this detrimental effect. Moderate levels of greenspace can mitigate the adverse effects associated with combined air pollutants, leading to improved treatment success for patients with PTB.
Humans ; China/epidemiology* ; Air Pollutants/analysis* ; Tuberculosis, Pulmonary/drug therapy* ; Particulate Matter/adverse effects* ; Male ; Female ; Middle Aged ; Environmental Exposure/analysis* ; Ozone/adverse effects* ; Adult ; Sulfur Dioxide/adverse effects* ; Treatment Outcome ; Air Pollution/adverse effects* ; Aged ; Nitrogen Dioxide/adverse effects* ; Young Adult ; Adolescent

BACKGROUND: Indoor air quality (IAQ) is an important determinant of human health. In Japan, IAQ guidelines have been established for 13 chemicals since 1997. Regarding ethylbenzene (EB), a previous guideline value of 3800 µg/m³ was established in 2000. However, the Ministry of Health, Labour, and Welfare decided to revise the value because of the publication of new hazard information after the establishment of the previous guideline value and the establishment of their respective IAQ guidelines by foreign organizations based on the new hazard information. This study conducted a detailed hazard assessment on EB and derived hazard assessment values to provide a toxicologically valid basis for revising the IAQ guideline value. METHODS: As it was defined that the IAQ guidelines would not exert adverse health effects on humans even if they inhaled the chemicals from indoor air over a lifetime, we investigated the general toxicity, developmental and reproductive toxicity, genotoxicity, and carcinogenicity of EB based on reliable hazard information cited in published assessment documents by domestic, foreign, or international risk assessment organizations. All the collected hazard information was examined, and we originally judged the no-observed adverse effect level and the lowest observed adverse effect level of each toxicity study. We then selected the most appropriate key study, an endpoint, and a point of departure and derived the hazard assessment values for each toxicity category. Finally, we selected a representative hazard assessment value for EB from the minimum hazard assessment value among general toxicity, developmental and reproductive toxicity, and carcinogenicity. RESULTS: Among the three toxicity categories, the minimum hazard assessment value was obtained from general toxicity, which was 0.0858 ppm (370 µg/m³) based on the loss of the outer hair cells in the organ of Corti in the cochlea observed in a 13-week repeated-dose inhalation toxicity study using rats. CONCLUSIONS It would be appropriate to adopt 0.0858 ppm (370 µg/m³) as a representative hazard assessment value to provide a basis for revising the IAQ guideline value for EB.
Japan ; Air Pollution, Indoor/adverse effects* ; Risk Assessment ; Humans ; Benzene Derivatives/toxicity* ; Guidelines as Topic ; Animals ; Air Pollutants/toxicity*

BACKGROUND: Previous evidence showed that ambient air pollution and cardiovascular mortality are related. However, there is a lack of evidence towards the modification effect of long-term lifestyle on the association between short-term ambient air pollution and death from cardiovascular events. METHOD: A total of 14,609 death from major adverse cardiovascular events (MACE) were identified among the China Kadoorie Biobank participants from 2013 to 2018. Ambient air pollution exposure including particulate matter 2.5 (PM_2.5), SO₂, NO₂, CO, and O₃ from the same period were obtained from space-time model reconstructions based on remote sensing data. Case-crossover design and conditional logistic regression was applied to estimate the effect of short-term exposure to air pollutants on MACE mortality. RESULTS: We found MACE mortality was significantly associated with PM_2.5 (relative percent increase 2.91% per 10 µg/m³ increase, 95% CI 1.32-4.53), NO₂ (5.37% per 10 µg/m³ increase, 95% CI 1.56-9.33), SO₂ (6.82% per 10 µg/m³ increase, 95% CI 2.99-10.80), and CO (2.24% per 0.1 mg/m³ increase, 95% CI 1.02-3.48). Stratified analyses indicated that drinking was associated with elevated risk of MACE mortality with NO₂ and SO₂ exposure; physical inactivity was associated with higher risk of death from MACE when exposed to PM_2.5; and people who had balanced diet had lower risk of MACE mortality when exposed to CO and NO₂. CONCLUSIONS The study results showed that short-term exposure to ambient PM_2.5, NO₂, SO₂, and CO would aggravate the risk of cardiovascular mortality, yet healthy lifestyle conduct might mitigate such negative impact to some extent.
Humans ; Cardiovascular Diseases/epidemiology* ; China/epidemiology* ; Male ; Female ; Air Pollution/adverse effects* ; Middle Aged ; Air Pollutants/analysis* ; Particulate Matter/analysis* ; Environmental Exposure/adverse effects* ; Life Style ; Aged ; Adult ; Risk Factors ; Cross-Over Studies ; East Asian People