OBJECTIVEThe study was designed to compare the combustion products of coal gas, liquefied petroleum gas and natural gas in relation to indoor air pollution.

METHODSRegular pollutants including B(a)P were monitored and 1-hydroxy pyrene were tested in urine of the enrolled subjects. Radon concentrations and their changes in four seasons were also monitored in the city natural gas from its source plant and transfer stations to final users. To analyze organic components of coal gas, liquefied petroleum gas and natural gas, a high-flow sampling device specially designed was used to collect their combustion products, and semi-volatile organic compounds contained in the particles were detected by gas chromatograph-mass spectrograph (GC/MS).

RESULTSFindings in the study showed that the regular indoor air pollutants particles and CO were all above the standard in winter when heating facilities were operated in the city, but they were lowest in kitchens using natural gas; furthermore, although NO2 and CO2 were slightly higher in natural gas, B(a)P concentration was lower in this group and 1-hydroxy pyrene was lowest in urine of the subjects exposed to natural gas. Organic compounds were more complicated in coal gas and liquefied petroleum gas than in natural gas. The concentration of radon in natural gas accounted for less than 1% of its effective dose contributing to indoor air pollution in Beijing households.

CONCLUSIONCompared to traditional fuels, gases are deemed as clean ones, and natural gas is shown to be cleaner than the other two gases.

Air Pollution, Indoor ; analysis ; Carbon Dioxide ; analysis ; Coal ; Gas Chromatography-Mass Spectrometry ; Incineration ; Nitrogen Dioxide ; analysis ; Petroleum ; Radon ; analysis ; Volatilization

OBJECTIVETo evaluate the method for collecting NO2 in workplace air using a solid adsorbent and determining the concentration of NO2 by ion-exchange chromatography.

METHODSNO2 in workplace air was collected using sampling tubes filled with 13X molecular sieve soaked with triethanolamine, and the samples were desorbed with a certain concentration of triethanolamine solution to obtain NO2(-). NO2(-) was separated with an anion exchange chromatography column and quantified by a conductivity detector. The concentration of NO2 was determined based on the conversion coefficient of NO2 and NO2(-).

RESULTSDifferent concentrations of NO2 (standard gas) was collected using the sampling tubes at different time points, and the sampling efficiency and desorption efficiency could reach more than 90%. The penetrating capacity of sampling tubes was more than 1.1 mg. The comparative test shows that there was no significant difference between the new method and national standard method (solution absorption) (P > 0.05). The samples could be stored at room temperature for more than 16 days. The calibration curve plotted in the new method was linear in the range of 0.1∼20.0 µg/ml, with a correlation coefficient of 0.9998; the detection limit was 0.01 µg/ml; the minimum detectable concentration was 0.05 mg/m(3) (V0 = 3.0 L).

CONCLUSIONThis determination method meets the requirements of Guide for establishing occupational heath standards-Part 4 Determination methods of air chemicals in workplace (GBZ/T 210.4-2008) and shows obvious advantages for determination of NO2 in workplace air.

Air ; analysis ; Air Pollutants, Occupational ; analysis ; Chromatography, Ion Exchange ; methods ; Nitrogen Dioxide ; analysis ; Workplace

At present, the death cases of simple asphyxiant gas acute poisoning are increasing sharply. Common asphyxiant gases in death cases include nitrogen, helium, carbon dioxide, methane, propane, laughing gas, etc. Simple asphyxiant gas has no affinity for biological matrices and escapes quickly, which puts forward new requirements for autopsy procedures, selection and collection of samples, laboratory analysis and identification. This paper reviews the research and development process of death cases caused by simple asphyxiant gas acute poisoning and put forwards the collection and analysis strategy of the samples in such cases. The most valuable biological samples in such cases should be lung tissues associated with the airways, followed by brain tissue and cardiac blood. Gaseous samples from the esophageal cavity, tracheal cavity, pulmonary bronchi, gastric and cardiac areas are also recommended as valuable samples. In the case of postmortem examination, the gas should be injected into gas sample bag directly. Biological materials such as tissue and blood should be directly sealed in head-space vials and analyzed by using the headspace gas chromatography-mass spectrometry.
Carbon Dioxide/analysis* ; Autopsy ; Gas Chromatography-Mass Spectrometry ; Methane/analysis* ; Nitrogen

Objective: To investigate and monitor the occupational hazards in the Teaching and Research Laboratory (hereinafter referred to as the place) of a university, so as to provide basis for the occupational health work in the university. Methods: November 2014, 46 places in a university were selected by stratified random sampling, and the occupational health risk factors were investigated. Results: Indoor temperature, humidity, sulfur dioxide, nitrogen dioxide, carbon monoxide and carbon dioxide were detected in 21 sites, xylene and hydrofluoric acid were detected in 6 sites, and colony count was detected in 18 sites, the power frequency electric field intensity was measured in 23 places, and the x-ray radiation dose was measured in 4 places. Noise was measured at 21 sites, with 7 sites exceeding the standards accounting for 33.3% (7/21) ; 21 sites were detected for illumination and 10 sites for nonconformity accounting for 47.6% (10/21) ; 10 sites for Microwave Radiation and 3 sites exceeding the standards accounting for 30% (3/10) ; and 25 sites were detected for outdoor air volume and air velocity, the percentage of unqualified was 72% (18/25) in 18 sites, among which the wind velocity was statistically significant in teaching, research and experimental sites (P=0.010) . Conclusion: The occupational hazards in the teaching and research places of a university should be paid attention to, and the engineering protection and personal protection should be strengthened in the experiment.
Air Pollution, Indoor/analysis* ; Humans ; Humidity ; Nitrogen Dioxide/analysis* ; Occupational Exposure ; Occupational Health ; Universities

BACKGROUND: Metabolic Dysfunction-associated Steatotic Liver Disease (MASLD) has become a global epidemic, and air pollution has been identified as a potential risk factor. This study aims to investigate the non-linear relationship between ambient air pollution and MASLD prevalence. METHOD: In this cross-sectional study, participants undergoing health checkups were assessed for three-year average air pollution exposure. MASLD diagnosis required hepatic steatosis with at least 1 out of 5 cardiometabolic criteria. A stepwise approach combining data visualization and regression modeling was used to determine the most appropriate link function between each of the six air pollutants and MASLD. A covariate-adjusted six-pollutant model was constructed accordingly. RESULTS: A total of 131,592 participants were included, with 40.6% met the criteria of MASLD. "Threshold link function," "interaction link function," and "restricted cubic spline (RCS) link functions" best-fitted associations between MASLD and PM_2.5, PM₁₀/CO, and O₃ /SO₂/NO₂, respectively. In the six-pollutant model, significant positive associations were observed when pollutant concentrations were over: 34.64 µg/m³ for PM_2.5, 57.93 µg/m³ for PM₁₀, 56 µg/m³ for O₃, below 643.6 µg/m³ for CO, and within 33 and 48 µg/m³ for NO₂. The six-pollutant model using these best-fitted link functions demonstrated superior model fitting compared to exposure-categorized model or linear link function model assuming proportionality of odds. CONCLUSION Non-linear associations were found between air pollutants and MASLD prevalence. PM_2.5, PM₁₀, O₃, CO, and NO₂ exhibited positive associations with MASLD in specific concentration ranges, highlighting the need to consider non-linear relationships in assessing the impact of air pollution on MASLD.
Humans ; Nitrogen Dioxide ; Cross-Sectional Studies ; Air Pollution/analysis* ; Air Pollutants/analysis* ; Particulate Matter/analysis* ; Liver Diseases ; Environmental Exposure/analysis*

Objective: To investigate the association of mixed exposure to greenness and nitrogen dioxide(NO₂) and hypertension among the older adults aged 65 years and over in China. Methods: The study subjects were from the Chinese Longitudinal Healthy Longevity Survey from 2017 to 2018. A total of 15 423 older adults aged 65 years and over meeting the criteria were finally included in the study. A questionnaire survey was used to collect information on demographic characteristics, lifestyle habits and self-reported prevalence of hypertension. Blood pressure values were obtained through physical examination. The level of normalized difference vegetation index(NDVI) was measured by the Medium-resolution Imaging Spectral Radiator(MODIS) of the National Aeronautics and Space Administration(NASA). The concentration of NO₂ was from China's surface air pollutant data set. Meteorological data was from NASA MERRA-2. The exposure to NDVI and NO₂ for each study subject was calculated based on the area within a 1 km radius around their residence. The association between mixed exposure of NDVI and NO₂ as well as their interaction and hypertension in older adults was analyzed by using the multivariate logistic regression model. The restrictive cubic spline(RCS) function was used to explore the exposure-response relationship between greenness and NO₂ and the risk of hypertension in study subjects. Results: The mean age of 15 423 older adults were (85.6±11.6). Women accounted for 56.3%(8 685/15 423) and 55.6%(8 578/15 423) lived in urban areas. The mean time of residence was (60.9±28.5) years. 59.8% of participants were with hypertension. The mean NDVI level was 0.41±0.13, and the mean NO₂ concentration was (32.18±10.36) μg/cm³. The results of multivariate logistic regression analysis showed that NDVI was inversely and linearly associated with the hypertension in older adults, with the OR(95%CI) value of 0.959(0.928-0.992). Compared with the T₁ group of NDVI, the risk of hypertension was lower in the T₃ group, with the OR(95%CI) value of 0.852(0.769-0.944), and the trend test was statistically significant(P<0.05). Compared with the T₁ group of NO₂, the risk of hypertension was higher in the T₂ and T₃ groups, with OR(95%CI) values of 1.160(1.055-1.275) and 1.244(1.111-1.393), and the trend test was statistically significant (P<0.05). The result of the RCS showed that NDVI was inversely and linearly associated with hypertension in older adults. NO₂ was nonlinearly associated with hypertension in older adults. The interaction analysis showed that NDVI and NO₂ had a negative multiplicative interaction on the risk of hypertension, with OR(95%CI) value of 0.995(0.992-0.997). Conclusion: Exposure to greenness and NO₂ are associated with hypertension in older adults.
Aged ; Humans ; Female ; Nitrogen Dioxide ; Air Pollution ; Prevalence ; Hypertension/epidemiology* ; China/epidemiology* ; Particulate Matter/analysis*

Nitrogen dioxide (NO₂) is an important indoor air pollutant, with both outdoor and indoor sources contributing to indoor NO₂ exposure levels. Considering the association of high NO₂ exposure with adverse health effects, the Standards for indoor air quality (GB/T 18883-2022) have been revised to further restrict indoor NO₂ limit values. The 1-h average concentration limit value for NO₂ has been reduced from 0.24 mg/m³ to 200 μg/m³.This study analyzed the technical contents related to the determination of the limits of indoor NO₂ in Standards for Indoor Air Quality (GB/T 18883-2022), including source, exposure level, health effects, and the process and evidence basis for determining the limit value. It also proposed prospects for the direction for the implementation of the indoor NO₂ standard.
Humans ; Air Pollution, Indoor/adverse effects* ; Nitrogen Dioxide ; Air Pollutants/analysis* ; China ; Air Pollution/adverse effects*

Nitrogen dioxide (NO₂) is an important indoor air pollutant, with both outdoor and indoor sources contributing to indoor NO₂ exposure levels. Considering the association of high NO₂ exposure with adverse health effects, the Standards for indoor air quality (GB/T 18883-2022) have been revised to further restrict indoor NO₂ limit values. The 1-h average concentration limit value for NO₂ has been reduced from 0.24 mg/m³ to 200 μg/m³.This study analyzed the technical contents related to the determination of the limits of indoor NO₂ in Standards for Indoor Air Quality (GB/T 18883-2022), including source, exposure level, health effects, and the process and evidence basis for determining the limit value. It also proposed prospects for the direction for the implementation of the indoor NO₂ standard.
Humans ; Air Pollution, Indoor/adverse effects* ; Nitrogen Dioxide ; Air Pollutants/analysis* ; China ; Air Pollution/adverse effects*

OBJECTIVETo study the present situations of lung cancer in Wuhan and to explore the relationship between the potential years of life lost of lung cancer and air pollution, especially vehicle emissions.

METHODSData gathered between 1986 and 1995 in Wuhan city, including air pollution and tobacco production and data on lung cancer between 1991 and 2000 were collected extensively. Simple Correlation and Grey Relational Analysis were used to analyze the relationship of them.

RESULTSThere was a ascending tendency in variance of oxides of nitrogen (NOx). The degree of grey incidence (DGI) between the concentration of air pollutants and the male's or female's potential years of life lost of lung cancer (PYLL) were calculated respectively. In males, the values of DGI were 0.6702, 0.7071, 0.6199 on sulfur dioxide (SO2), NOx, total suspensions (TSP) respectively. In females,the values of DGI were 0.6188, 0.8555, 0.5842 according to the same order as listed above. Significant positive correlation was found between the concentration of NOx and with lung cancer in both males and females by spearman correlation test (rmale = 0.63523, P = 0.0484; rfemale = 0.76396, P = 0.0101).

CONCLUSIONWith the fast growing speed of the quantity of vehicles, pollution of vehicle emission-caused air pollution posed an important risk factor for lung cancer, despite the fact that tobacco smoking still played the leading role.

Air Pollution ; adverse effects ; China ; Female ; Humans ; Lung Neoplasms ; mortality ; Male ; Nitrogen Oxides ; analysis ; Sulfur Dioxide ; analysis ; Vehicle Emissions ; analysis

Objective: To assess the association between short-term exposure level of nitrogen dioxide and the hospitalization risk of heart failure. Methods: Based on China-PEACE Retrospective Heart Failure Study, 117 364 hospitalized patients with heart failure were recruited from 92 hospitals in 62 cities throughout China between January 1, 2015 and December 31, 2015. The daily exposure level of nitrogen dioxide, temperature, and humidity in the same cities during the same period were also collected. We applied the generalized additive model and Bayesian hierarchical model to quantify the lagged effect and cumulative effect of short-term (0-3 days) exposure to ambient nitrogen dioxide on the hospitalization risk of heart failure. We further conducted stratified analyses by age, region, and season to identify any difference in the associations between short-term nitrogen dioxide exposure and heart failure among subgroups. Results: The mean age for participants in the analysis was (70.32±12.22) years. The median, minimum and maximum of daily nitrogen dioxide concentration in 62 cities from January 1, 2015 to December 31, 2015 was 26.4 μg/m³, 2.33 μg/m³ and 150.25 μg/m³, respectively. The exposure level of nitrogen dioxide at the same day was associated with the hospitalization risk of heart failure (OR=1.022, 95%CI: 1.012, 1.031). Significant effects were also observed in the moving average concentrations from lag 0-1 to lag 0-3 day (OR=1.020, 95%CI: 1.009, 1.030; OR=1.016, 95%CI: 1.004, 1.028; OR=1.013, 95%CI: 1.001, 1.026). Moreover, all of the associations between short-term exposure to nitrogen dioxide and the risk of heart failure hospitalization were statistically significant, with no significant difference in all subgroups stratified by age, region, and season. Conclusion: A higher level of short-term exposure to nitrogen dioxide could trigger more hospitalizations with heart failure.
Aged ; Aged, 80 and over ; Air Pollutants/analysis* ; Air Pollution/analysis* ; Bayes Theorem ; China/epidemiology* ; Environmental Exposure/analysis* ; Heart Failure/epidemiology* ; Hospitalization ; Humans ; Middle Aged ; Nitrogen Dioxide/analysis* ; Particulate Matter/analysis* ; Retrospective Studies ; Sulfur Dioxide/analysis*