Modifying effects of green space on the relationships between air pollution and ischemic cerebrovascular event recurrence in Tianjin, China.

This study aimed to explore how air pollution and green space influence ICE recurrence and whether they might interact with each other. A case-cross design was used in this study, which was carried out in Tianjin, China. A total of 8306 patients with recurrent ICE were collected from 2019 to 2020. The maximum effects of PM2.5, PM10, SO2, NO2, CO were 1.012 (95%CI: 1.004, 1.019), 1.010 (95%CI: 1.004, 1.016), 1.035 (95%CI: 0.982, 1.091), 1.067 (95%CI: 1.043, 1.091) and 1.012 (95%CI: 1.004, 1.021) , respectively, and the risk was higher in males and in the 50-60 age group. In the stratification of greening, it was found that air pollution except O3 had the highest risk of ICE recurrence for those with lower green space. Our study found that air pollution (except O3) can increase the risk of ICE recurrence, and this risk can be reduced by increasing green space.

Source apportionment of heavy metals in PM2.5 samples and effects of heavy metals on hypertension among schoolchildren in Tianjin.

The prevalence of hypertension in children has increased significantly in recent years in China. The aim of this study was to provide scientific support to control ambient heavy metals (HMs) pollution and prevent childhood hypertension. In this study, ambient HMs in PM2.5 were collected, and 1339 students from Tianjin were randomly selected. Positive matrix factorization (PMF) was used to identify and determine the sources of HMs pollution. The generalized linear model, Bayesian kernel machine regression (BKMR) and the quantile g-computation method were used to analyze the relationships between exposure to HMs and the risk of childhood hypertension. The results showed that HMs in PM2.5 mainly came from four sources: soil dust, coal combustion, incineration of municipal waste and the metallurgical industry. The positive relationships between As, Se and Pb exposures and childhood hypertension risk were found. Coal combustion and incineration of municipal waste were important sources of HMs in the occurrence of childhood hypertension. Based on these accomplishments, this study could provide guidelines for the government and individuals to alleviate the damaging effects of HMs in PM2.5. The government must implement policies to control prime sources of HMs pollution.

Effects of air pollution and green spaces on impaired lung function in children: a case-control study.

The occurrences of impaired lung function during childhood could substantially influence the health states of the respiratory system in adults. So, the effects of air pollution and green spaces on impaired lung function in children were investigated in this study. The lung function of each student was tested every year from 2015 to 2017 and the method of case-control study was applied. 2087 students aged from 9 to 11 years old of primary schools in Tianjin were ultimately included in this study. The method of propensity score matching (PSM) was performed to minimize the confounding bias and the conditional logistic regression model was carried out to evaluate the effects of indoor and outdoor environmental risk factors on the occurrences of impaired lung function in children. For every interquartile range (IQR) increase in the mixture of six air pollutants at the lag1, lag2, and lag3 periods, the risks of getting impaired lung function were increased by 53.4%, 34.7%, and 16.9%, respectively. The protective effect of greenness at lag2 period (odds ratios (OR)) = 0.022 (95% confidence interval (CI): 0.008-0.035)) was stronger than that at lag1and lag3 periods, respectively. Separate and combined effects of most air pollutants at different lag periods exerted hazardous effects on the lung function of students. Exposure to greenness had protective effects on the lung health of children.

Health risks of PM2.5-bound polycyclic aromatic hydrocarbon (PAH) and heavy metals (PPAH&HM) during the replacement of central heating with urban natural gas in Tianjin, China.

To investigate the health effects of fine particulate matter (≤ 2.5 µm in aerodynamic diameter; PM2.5)-bound heavy metals and polycyclic aromatic hydrocarbons (PAHs) before and after the implementation of the Urban Natural Gas Heating Project (UNGHP), the lifetime cancer risks, hazard quotients (HQs) of heavy metals and PAHs were calculated. Seven kinds of heavy metals (Al, As, Cd, Cr, Mn, Ni and Se) and 12 kinds of PAHs including acenaphthylene (ANY), acenaphthene (ANA), fluoranthene (FLT), pyrene (PYR), chrysene (CHR), benz[a]anthracene (BaA), benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF), benzo[a]pyrene (BaP), dibenz[a,h]anthracene (DBA), benzo[ghi]perylene (BPE) and indeno[1,2,3-cd]pyrene (IPY) were analyzed and used for the health risk assessments. It was found that HQ of Mn fell from 1.09 in the coal-burning period to 0.72 in the gas-burning period in the suburban area. And lifetime cancer risks of PAHs fell from 35.7 × 10-6 in the coal-burning period to 17.22 × 10-6 in the gas-burning period in the urban area. It could be concluded that, during the gas-burning period, downward trends were observed for the lifetime cancer risks and HQs of most kinds of heavy metals and PAHs in all regions of Tianjin compared to those during the coal-burning period. The UNGHP was effective, and we should also take other measures to control the pollution.

Efficacy of 75% alcohol in pretreatment of the Andersen sampler in trapping maximum airborne microbes.

The present study was conducted to evaluate the effects of the pretreatment methods and sampling time on the sampling of airborne bacteria in hospitals. Methods for the pretreatment of Andersen samplers, namely, non-sterilized, 75% ethanol and autoclaving sampled for 5 min, 10 min and 15 min in the general ward and class 1000 clean operating department, respectively, were studied. Statistical analysis was used to compare the differences in sampling results of airborne bacteria under different pretreatment methods, sampling time and environmental conditions. In the first test, the sampling results of the airborne bacteria obtained by pretreatment of the sampler with 75% ethanol and without pre-treatment were not very different, and the sampling results showed a certain declining trend with the extension of the sampling time. In the second test, the pretreatment effect of autoclaving was significantly better than that of 75% ethanol, and the sampling time had no effect on the sampling results. After removing the influencing factors of the environment, the results were consistent with the results of the second test. It was observed that the Andersen samplers should not be pretreated with 75% ethanol before airborne microbes sampling. The pretreatment should be carried out by autoclaving, and the sampling time has little effect on the sampling results.

Interactive effect between temperature and fine particulate matter on chronic disease hospital admissions in the urban area of Tianjin, China.

This study focuses on effects of fine particulate matter (PM2.5) on chronic disease under different levels of temperature. We obtained type 2 diabetes, cerebral stroke and coronary heart disease hospital admissions (HAs) from five hospitals in urban Tianjin as well as the concentrations of PM2.5, nitrogen dioxide (NO2) and sulphur dioxide (SO2). We used distributed lag nonlinear models to explore nonlinear and lag effects of PM2.5. In single-pollutant models, PM2.5 was positively associated with type 2 diabetes, cerebral stroke and coronary heart disease HAs, with strongest effects at lag1, lag0 and lag06, respectively. The corresponding relative risk rates (RR%) were 1.836%, 2.083% and 6.428%. In co-pollutant models, the correlation between PM2.5 and HAs on high-temperature days was generally stronger than that on low-temperature days. This study indicated that PM2.5 can increase HA rates for these chronic diseases, and effects of PM2.5 on high-temperature days were stronger than that on low-temperature days.

How the constituents of fine particulate matter and ozone affect the lung function of children in Tianjin, China.

As the pollution of fine particulate matter (≤ 2.5 µg/m3 in aerodynamic diameter; PM2.5) and ozone (O3) is becoming more and more serious in developing countries, we, hereby, investigated the effects of PM2.5, constituents of PM2.5 and O3 on the lung function of children in Tianjin, China. The lung functions of 198 pupils from nine primary schools in Tianjin were examined (repeated five times) during the months of October to December in 2016, 2017 and 2018, respectively. And the mixed-effect models were used to evaluate the effects of air pollutants. A 10 µg/m3 increase in PM2.5 and O3-8h might lead to reductions of forced vital capacity (FVC) in 1.03% (- 1.87 to - 0.19%) and 21.09% (- 25.54 to - 16.58%), respectively, while a 10 ng/m3 increment in ANY might account for the 166.44% (- 221.32 to - 112.31%) decreases in FVC. PM2.5 and O3-8h might be more harmful to the lung functions of female students and participants with PS exposure at home. And the main sources of pollution resulting in the decrease in pulmonary function might be traffic pollution and coal combustion.

Study on Pollution Characterization and Source Apportionment of Daytime and Nighttime PM2.5 Samples in an Urban Residential Community in Different Weather Conditions.

Daytime and nighttime PM2.5 samples were collected from an urban community in Tianjin. The major chemical components in PM2.5, including metal elements, polycyclic aromatic hydrocarbons and inorganic water-soluble ions, were monitored. A positive matrix factorization (PMF) model was used to apportion the potential sources of PM2.5 under different weather conditions. When the Air Quality Index (AQI) was below 200, the concentrations of BaA, BbF, BkF, Na and NO3- during the nighttime were higher than those during the daytime. PMF analysis indicated that secondary aerosols (37.3%), biomass burning (26.7%) and coal combustion (26.0%) were important sources of PM2.5 in the urban residential community when the AQI was greater than 200. When the AQI was less than 200 in the urban residential community, the main sources of PM2.5 in the urban residential community were secondary aerosols (50.7%) and fossil fuel combustion (47.2%). The pollution status of PM2.5 in the residential community of the urban area was serious, and the source apportionments of the PM2.5 samples in the urban area were different under different weather conditions.

Health benefits on cardiocerebrovascular disease of reducing exposure to ambient fine particulate matter in Tianjin, China.

With the development of the industrialization level in China, high concentrations of fine particulate matter (≤ 2.5 µg/m3 in aerodynamic diameter (PM2.5)) could have a great impact on the health of the population. Our study is to quantify the health benefits on cardiocerebrovascular disease of reducing exposure to PM2.5 in Tianjin, China. We obtained the data on cardiovascular disease (CVD), ischemic heart disease (IHD), and cerebrovascular disease (CD) mortalities to quantify the association between CVD, CD, and IHD mortalities and PM2.5 and calculate health and economic benefits when the annual average concentration of PM2.5 was reduced to National Ambient Air Quality Standard (NAAQS) and World Health Organization (WHO) guidelines by using our concentration response (C-R) functions. There were 435.22 (95% CI 253.86 to 616.57) all-cause, 130.22 (95% CI 66.34 to194.09) IHD, and 204.07 (95% CI 111.66 to 296.47) CD deaths attributed to PM2.5 and the economic benefits obtained by preventing all-cause, IHD, and CD mortalities were equivalent to be 2.79%, 0.83%, and 1.31% of Baodi's GDP in Tianjin in 2017, respectively. PM2.5 concentration was positive with all-cause, IHD, and CD mortalities in rural, suburban, and urban area of Tianjin, China. Meanwhile, the number of avoidable deaths and economic cost of reducing PM2.5 concentrations to NAAQS and WHO guidelines was highest in the rural area.

Pollution Characterization and Source Apportionment of Day and Night PM2.5 Samples in Urban and Suburban Communities of Tianjin (China).

Day and night PM2.5 samples were collected from two typical urban and suburban communities in Tianjin. The major chemical components in PM2.5, including the metal elements, polycyclic aromatic hydrocarbons (PAHs), and inorganic water-soluble ions, were monitored. A positive matrix factorization (PMF) model was used to apportion the potential sources of PM2.5 at the two sites in the daytime and nighttime. The results indicated that the PM2.5 concentration was higher in the suburban area than in the urban area during the daytime in winter. The daytime and nighttime PAHs concentrations at both sites were both generally higher in winter than in summer. The concentrations of some of the metal elements were higher in summer than in winter. Regional differences and day and night differences in the metals and water-soluble ions commonly existed. The PMF analysis indicated that coal combustion and transportation-related sources were the predominant sources in the urban and suburban areas in the daytime in winter, and secondary aerosols were the most important source for the suburban area in the nighttime in winter. There were more pollution sources of PM2.5 during the daytime in summer, especially in the suburban area. In the nighttime in summer, the pollution sources of PM2.5 in the urban and suburbs areas were basically the same, but the source apportionment was quite different.

Let-7a inhibits migration of melanoma cells via down-regulation of HMGA2 expression.

This study aimed to investigate the effects of exosomes derived from BM-MSCs transduced with let-7a on B16f10 cells and BM-MSCs. BM-MSCs were transduced with let-7a and the exosomes of them were isolated for further culture of B16f10 cells and BM-MSCs. The migration of B16f10 cells were detected by transwell, proliferation of B16f10 cells and BM-MSCs was examined by MTT method, HMGA2 expression was measured by western blot. In addition, the let-7a secreted level in exosomes and IGF level were measured by RT-PCR and ELISA respectively. Our results showed that the level of let-7a in exosomes derived from Let-7a-transducted BM-MSCs was increased after treated by exosomes. HMGA2 in B16f10 cells was down-regulated and cell survival rate of BM-MSCs was decreased. However, neither cell survival rate of B16f10 cells nor IGF-1 secreted by B16f10 cells in different groups had significant differences. In conclusion, Let-7a contained in exosomes can inhibit the migration of Melanoma cells and inhibit the proliferation of BM-MSCs.

Stromal cell-derived factor-1α as a novel biomarker for hyperlipidemia.

Stromal cell-derived factor-1 (SDF-1) is expressed in a wide variety of organs, such as heart, and plays a pivotal role in the mobilization of hematopoietic stem and progenitor cells in bone marrow. SDF-1α, a common subtype of SDF-1, may control hematopoiesis and angiogenesis, but its role in the pathogenesis of hyperlipidemia is unknown. The aim of this study was to determine the role of SDF-1α in the pathogenesis of hyperlipidemia. First, log-transformed SDF-1α serum levels (logSDF-1α) were significantly higher in male patients with borderline high lipid profile (BHLP; n=28; 2.15±0.08 ng/ml) compared to control subjects (n=37; 1.94±0.06 ng/ml; P<0.01). The logSDF-1α in male patients with high lipid profile (HLP; n=33; 1.95±0.08 ng/ml) were lower than BHLP patients (P<0.01). The logSDF-1α was positively associated with HDL-C only in female patients (n=125; r=0.379, P=0.016). These results suggest the different pathophysiology in male and female patients with hyperlipidemia. Moreover, flow cytometry analysis showed that expression of the SDF-1α receptor, CXC-chemokine receptor 4, was lower in peripheral blood mononuclear cells of patients with BHLP (n=10) and HLP (n=10), compared to control subjects (n=10; P<0.001). Lastly, peripheral blood leukocyte, neutrophil and lymphocyte counts were higher in BHLP patients (n=62; P<0.05). Taken together, we suggest SDF-1α as a biomarker of hyperlipidemia that may be helpful to uncover the pathogenesis of hyperlipidemia.

[Assessment of the air quality improment of cleaning and disinfection on central air-conditioning ventilation system].

OBJECTIVE: To assess the effect of air quality of cleaning and disinfection on central air-conditioning ventilation systems. METHOD: 102 air-conditioning ventilation systems in 46 public facilities were sampled and investigated based on Hygienic assessment criterion of cleaning and disinfection of public central air-conditioning systems. RESULTS: Median dust volume decreased from 41.8 g/m2 to 0.4 g/m2, and the percentage of pipes meeting the national standard for dust decreased from 17.3% (13/60) to 100% (62/62). In the dust, median aerobic bacterial count decreased from 14 cfu/cm2 to 1 cfu/cm2. Median aerobic fungus count decreased from 10 cfu/cm2 to 0 cfu/cm2. The percentage of pipes with bacterial and fungus counts meeting the national standard increased from 92.4% (171/185) and 82.2% (152/185) to 99.4% (165/166) and 100% (166/166), respectively. In the ventilation air, median aerobic bacterial count decreased from 756 cfu/m3 to 229 cfu/m3. Median aerobic fungus count decreased from 382 cfu/m3 to 120 cfu/m3. The percentage of pipes meeting the national standard for ventilation air increased from 33.3% (81/243) and 62.1% (151/243) to 79.8% (292/366) and 87.7% (242/276), respectively. But PM10 rose from 0.060 mg/m3 to 0.068 mg/m3, and the percentage of pipes meeting the national standard for PM10 increased from 74.2% (13/60) to 90.2% (46/51). CONCLUSION: The cleaning and disinfection of central air-conditioning ventilation systems could have a beneficial effect of air quality.

The health effects of odor emission from domestic renovation on household residents in Tianjin, China.

The health effects of odors emitted from the human environment have received some discussion in the literature. Little has been written, however, about the health effects of odor emissions from renovation. The authors therefore conducted a cross-sectional study with a simple randomized sampling design. The sample was selected from a building-and-construction registry that registered all building and domestic renovation applications in Tianjin, China. Information on demographics, physical symptoms, and health status was collected via personal interviews. Air samples were also collected from each household for chemical analysis. Data were analyzed with weighted logistic-regression models. A significant association was found between exposure to odor emission and unspecific physical symptoms. After potential confounders were adjusted for, it was found that people who had been exposed to moderate-to-strong odor emissions from renovations were about four times more likely to report experiencing unspecific discomfort than were people who had been exposed to weak odor emissions (odds ratio = 4.05; 95 percent confidence interval = 1.49-11.03). The results indicate that odor emissions from domestic renovation have a detrimental effect on human physical health. This effect seemed to be independent from that generated by chemicals. Implications and prevention strategies are discussed.