OBJECTIVEParticulate samples from the atmosphere in an electronic waste dismantling area were collected to investigate the levels and sources of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs).

METHODSParticulate samples including total suspended particulates (TSP) and particulate matter <2.5 μm diameter (PM(2.5)) were collected on selected non-rainy days in summer (Jul 10-12, 2006) and winter (Jan 11-13, 2007) from Fengjiang (FJ), an electronic waste (e-waste) dismantling area in eastern China, and an adjacent area Luqiao (LQ). The samples were analyzed by isotope dilution - high resolution gas chromatography / high resolution mass spectrometry (HRGC/HRMS).

RESULTSIn FJ, the mean PCDD/F concentrations (mean TEQ values) were 280.6 pg Nm(-3) (3.432 pg WHO-TEQ Nm(-3)) for the TSP samples and 223.3 pg Nm(-3) (3.180 pg WHO-TEQ Nm(-3)) for the PM(2.5) samples. The total PCDD/F concentrations and TEQs in the PM(2.5) samples were about 66.8%-108.0% of the TSP samples, indicating that the fine particles contained higher levels of PCDD/Fs than coarse particles. The PCDD/F levels in FJ were much higher than those detected in common urban areas around the world, suggesting that the study area was heavily polluted by PCDD/Fs. Furthermore, the total average daily PCDD/F intake in FJ was estimated at 62.11 pg WHO-TEQ kg(-1)·day(-1) for adults and 110.11 pg WHO-TEQ kg(-1)·day(-1) for children, which greatly exceeds the WHO (1998) tolerable daily intake of 1-4 pg of WHO-TEQ kg(-1)·day(-1).

CONCLUSIONThe PCDD/F homologues and congener profiles confirmed that the PCDD/Fs in FJ originated from crude e-waste recycling activities. The severe dioxin pollution present in FJ has also substantially influenced the adjacent area of LQ through atmospheric transport. Open burning of medical waste was another source of PCDD/Fs identified in LQ.

Air Pollutants ; chemistry ; Atmosphere ; Benzofurans ; chemistry ; China ; Dibenzofurans, Polychlorinated ; Electronic Waste ; Environmental Exposure ; Humans ; Inhalation Exposure ; Occupational Exposure ; Particulate Matter ; chemistry ; Polychlorinated Dibenzodioxins ; analogs & derivatives ; chemistry ; Refuse Disposal ; methods ; Seasons

OBJECTIVEThe objective of this study was to investigate the aspiratory resistance, filtration penetration and their influence factors of N95 filtering-facepiece respirators used widely in China.

METHODSThe total of 6 brands and 21 models of N95 filtering-facepiece respirators which are certified and big sales on the market. The aspiratory resistance and filtration efficiency filter penetration were measured while air pump ran from 10 L/min to 100 L/min using differential pressure gauge and the PortaCount, respectively.

RESULTSThe filtration penetrations for 2 of the 21 models were lower than 95%, and the qualified rate for all models was 90.47%. The filtration penetrations gradually decreased when ventilation flow of air pump increased. The negative correlation was observed between filtration penetration and ventilation flow (r(2) = 0.711, P < 0.05). The resistances of all 21 models of N95 respirators met the requirements of the national standard. The aspiratory resistance started to elevate with the increasing of ventilation flow, and a positive correlation between both (r(2) = 0.878, P < 0.05). Significant differences of filtration penetration and aspiratory resistance were observed among between different brands (P < 0.05) although no differences of filtration penetration existed among different models of one brand (P > 0.05). But the differences of the aspiratory resistance among different models of one brand were statistically significant (P < 0.05).

CONCLUSIONThe aspiratory resistances of all N95 filtering-facepiece respirators used in this study met the requirements of the national standard. And the qualified ratio of filtration penetration of all models was higher than 90%. The influencing factors of aspiratory resistance included materials, size and ventilation flow. And influencing factors for filtration penetration were materials and ventilation flow.

Air Pollutants, Occupational ; China ; Equipment Design ; Filtration ; instrumentation ; Masks ; standards ; Materials Testing ; Respiratory Protective Devices ; standards

Objective To analyze the basic characteristics and variation trend of death causes of permanent residents in Enshi City during 2013-2018, to assess the burden of different diseases, and to provide a scientific basis for formulating disease prevention and control strategies. Methods The death monitoring data of permanent residents in Enshi City, Hubei Province from 2013 to 2018 was collected. The crude mortality, standardized mortality, life expectancy, potential years of life loss (PYLL), standard potential years of life loss (SPYLL), average years of life lost (AYLL), and annual percentage change (APC) were calculated to describe the distribution and trend of death causes. Results The average annual crude death rate and standardized death rate of residents in Enshi City from 2013 to 2018 were 679.43 per 100 000 and 615.02 per 100 000, respectively. The top 5 causes of death were circulatory system diseases, respiratory system diseases, malignant tumors, injuries, and digestive system diseases, accounting for 91.2% of the total deaths. Analysis of life expectancy found that the average life expectancy of local residents from 2013 to 2018 was 78.02 years, and the value in the male group (75.57 years) was lower than that in the female group (80.78 years). Life loss analysis revealed that PYLL caused by various diseases was 171 620 person-years, SPYLL was 171 284.62 person-years, and AYLL was 15.03 years/person in Enshi City from 2013 to 2018. Among all the death causes, the top five in terms of life loss were injuries, malignant tumors, circulatory diseases, respiratory diseases and digestive diseases. Conclusion From 2013 to 2018, the death rate of residents in Enshi City was relatively higher compared with those in other cities in China, the average annual crude death rate was on the rise, and the average annual standardized death rate was on the decline, indicating a highly ageing region. Chronic diseases such as circulatory system diseases, malignant tumors, and respiratory diseases, as well as injuries were the main death causes and caused a heavy burden of diseases, which should be the focus of future prevention and control work. Considering the higher levels of death and life loss indicators of male residents than those of women, targeted prevention and control measures should be taken to narrow the gap between men and women and improve the overall life quality of the whole population.

Objectives To investigate the effects of low level of ambient NO₂ on the death of cardiovascular and cerebrovascular diseases in Enshi city and to identify sensitive population, so as to provide a scientific basis for formulating health policies. Methods The data of air pollutants, meteorological factors and death of cardiovascular and cerebrovascular diseases in Enshi city from 2015 to 2018 were collected. The generalized additive model based on Poisson distribution was used to analyze the effects of low ambient NO₂ level on the death risk of cardiovascular and cerebrovascular diseases in Enshi city. A subgroup analysis was performed on age, gender, and season. Results The average concentrations of major gaseous air pollutants in Enshi city from 2015 to 2018 were NO₂ (21.40 μg/m³), SO₂ (9.68 μg/m³), CO (0.88 mg/m³), and O₃ (61.21 μg/m³), respectively, all of which did not exceed the national secondary standard. The results of single pollutant model analysis showed that each 1 μg/m3 increase in NO₂ concentration in lag0 day was associated with a 0.33% increase (95% CI: 0.06 - 0.72) (P>0.05) in mortality risk of cardiovascular and cerebrovascular diseases. In the female population, each 1 μg/m3 increase in NO2 concentration in lag01 day was associated with a 0.92% increase (95% CI: 0.26 - 1.56) (P<0.05) in mortality risk of cardiovascular and cerebrovascular diseases. In the cold season, each 1 μg/m3 increase in NO₂ concentration in lag0 day was associated with a 0.62% increase (95% CI: 0.12 - 1.12) (P<0.05) in mortality risk of cardiovascular and cerebrovascular diseases. The results of the two-pollutant model showed that after controlling other gaseous pollutants (SO₂, CO or O₃), the effect of NO₂ on the mortality risk of cardiovascular and cerebrovascular diseases in women and the whole population in cold season still existed. Conclusion The low ambient level of NO₂ in Enshi city was significantly associated with increased mortality risk of cardiovascular and cerebrovascular diseases in female population as well as in cold seasons in the whole population. Attention should be paid to the health protection of special populations in areas with low ambient pollution level of NO₂ in special seasons.

Programmed death factor-1 (PD-1) is a promising target molecule for clinical tumor immunotherapy in recent years. Recent studies suggest that PD-1 and related signaling pathways (PI3K/AKT, JAK/STAT3, p38MAPK, ERK, etc.) played a key regulatory role in the process of pulmonary fibrosis. Silicosis is a systemic disease caused by inhalation of free silicon dioxide dust, which is mainly characterized by extensive pulmonary nodular fibrosis and seriously endangers the health of patients. Dissecting the role of PD-1 in the pathogenesis of silicosis may be of great significance in the mechanism research and clinical diagnosis and treatment of silicosis. This paper reviews the regulation of PD-1 molecule on related signaling pathways and its role in pulmonary fibrosis, and looks forward to the potential application of these mechanistic studies in silicosis research.

Objective To investigate the residential radon concentration in typical areas of Hubei Province and assess the dose hazards of radon to human body. Methods According to geographical location, five cities including Wuhan, Enshi, Shiyan, Xianning and Daye were selected, and the stratified cluster sampling and monitoring were conducted in accordance with the residential building structure. From April to July, 2019, RSKS standard detectors were placed in the bedroom or living room of the tested families. After continuously sampling for three months, those detectors were returned back to the laboratory for test readings using Radosys system. Results A total of 651 detectors were deployed in 577 households of 70 communities, and 634 detectors were recovered. The recovery rate of detectors was 97.4%. The indoor residential radon concentration in Hubei Province showed a logarithmic normal distribution, with a median (25% quantile and 75% quantile) of 40.52 (29.13,64.74) Bq/m3 and an annual effective dose of 2.02 mSv. The indoor radon concentrations in Wuhan and Enshi were significantly higher than those in Shiyan, Xianning and Daye (P<0.05). The indoor radon concentrations in brick wood or civil structures were significantly higher than those in reinforced concrete structures (P<0.05), and indoor radon concentration in the first floor was significantly higher than those in other floors (P<0.05). The indoor radon concentrations after 2010 were significantly lower than those between 2001 and 2010 (P<0.05). Conclusion The number of households with indoor radon concentrations exceeding the national limit in newly-built buildings accounted for 10.1%; The indoor residential radon concentration levels of in Hubei Province were influenced by building structure, age and floor.