Indoor air quality and sick-building syndrome at a metro station in Tianjin, China.

Metro systems play a crucial role in public transportation worldwide. Given that metro stations are unique built environments with a significant volume of daily commuters, ensuring a satisfactory air quality in these spaces becomes paramount. This study involved measurements of indoor air quality (IAQ), staff satisfaction, particulate matter (PM) chemical composition, and heavy metal health risks at a typical metro station in Tianjin over two seasons. Although the air exchange rate was sufficient to maintain a CO2 concentration less than 1000 ppm, the proportion of staff reporting no sick-building symptoms decreased from 83 % in spring to 25 % in winter. An average mass concentration of PM with an aerodynamic diameter smaller than 2.5 µm (PM2.5) of 68.0 ± 42.2 µg/m3 and an average PM1 mass concentration of 51.8 ± 33.3 µg/m3 were observed on the platform in winter. PM2.5 contained more metal in winter than in spring. PM2.5 in winter contained more metal in winter than in spring. With a lower relative humidity in winter, the coefficient of friction between railway wheels and rails increased, thus increasing particle emission. The carcinogenic risk of Cr on the platform was unacceptable. Moreover, the health risks induced by Ba should be investigated. The findings indicate that PM control at metro stationss, particularly on platforms in winter, should be emphasized.

Mortality Burden of Cardiovascular Disease Attributable to Ozone in China: 2019 vs 2050.

Due to a combination of lifestyle risk factors, the burden of cardiovascular disease (CVD) has been increasing in China, affecting an estimated 330 million people. Environmental risk factors can exacerbate these risks or independently contribute to CVD. Ozone is an overlooked and invisible risk factor, and it plays a significant role in the development of CVD. Our study provides a novel quantification of the ozone-attributable CVD mortality burden based on daily maximum 8-h average ozone concentration during May to October (6mDMA8) in Chinese adults in 2050, projected under Shared Socioeconomic Pathways 585 and 126, and using the updated WHO air quality guideline level. The study also considers the contributions made by changes in ozone exposure, population aging, population size, and baseline death rates of CVD between 2019 and 2050. While adopting a sustainable and green pathway (SSP 126) can reduce the projected magnitude of premature CVD deaths to 359,200 in 2050, it may not be sufficient to reduce the CVD mortality burden significantly. Therefore, it is crucial to implement strategies for stricter ozone control and reducing the baseline death rate of CVD to mitigate the impacts of ozone on Chinese adults.

Tissue-Specific Transcriptome and Metabolome Analysis Reveals the Response Mechanism of Brassica napus to Waterlogging Stress.

During the growth period of rapeseed, if there is continuous rainfall, it will easily lead to waterlogging stress, which will seriously affect the growth of rapeseed. Currently, the mechanisms of rapeseed resistance to waterlogging stress are largely unknown. In this study, the rapeseed (Brassica napus) inbred lines G230 and G218 were identified as waterlogging-tolerant rapeseed and waterlogging-sensitive rapeseed, respectively, through a potted waterlogging stress simulation and field waterlogging stress experiments. After six days of waterlogging stress at the seedling stage, the degree of leaf aging and root damage of the waterlogging-tolerant rapeseed G230 were lower than those of the waterlogging-sensitive rapeseed G218. A physiological analysis showed that waterlogging stress significantly increased the contents of malondialdehyde, soluble sugar, and hydrogen peroxide in rape leaves and roots. The transcriptomic and metabolomic analysis showed that the differential genes and the differential metabolites of waterlogging-tolerant rapeseed G230 were mainly enriched in the metabolic pathways, biosynthesis of secondary metabolites, flavonoid biosynthesis, and vitamin B6 metabolism. Compared to G218, the expression levels of some genes associated with flavonoid biosynthesis and vitamin B metabolism were higher in G230, such as CHI, DRF, LDOX, PDX1.1, and PDX2. Furthermore, some metabolites involved in flavonoid biosynthesis and vitamin B6 metabolism, such as naringenin and epiafzelechin, were significantly up-regulated in leaves of G230, while pyridoxine phosphate was only significantly down-regulated in roots and leaves of G218. Furthermore, foliar spraying of vitamin B6 can effectively improve the tolerance to waterlogging of G218 in the short term. These results indicate that flavonoid biosynthesis and vitamin B6 metabolism pathways play a key role in the waterlogging tolerance and hypoxia stress resistance of Brassica napus and provide new insights for improving the waterlogging tolerance and cultivating waterlogging-tolerant rapeseed varieties.

Comprehensive evaluation of high-oleic rapeseed (Brassica napus) based on quality, resistance, and yield traits: A new method for rapid identification of high-oleic acid rapeseed germplasm.

To scientifically evaluate and utilize high-oleic acid rape germplasm resources and cultivate new varieties suitable for planting in the Hunan Province, 30 local high-oleic acid rape germplasms from Hunan were used as materials. The 12 personality indices of quality, yield, and resistance were comprehensively evaluated by variability, correlation, principal component, and cluster analyses. The results of variability showed that except for oleic acid, the lowest coefficient of variation was oil content, which was 0.06. Correlation analysis showed that oil content was positively correlated with main traits such as yield per plant and oleic acid, which could be used in the early screening of high-oleic rape germplasm. The results of principal component analysis showed that the 12 personality indicators were integrated into four principal components, and the cumulative contribution rate was 62.487%. The value of comprehensive coefficient 'F' was positively correlated with the first, second, and fourth principal components and negatively correlated with the third principal component. Cluster analysis showed that 30 high-oleic rape germplasms could be divided into four categories consisting of 9 (30%), 6 (20%), 7 (23%), and 8 (27%) high-oleic rape germplasms, each with the characteristics of "high disease resistance", "high yield", "high protein", and "more stability". This study not only provides a reference basis for high-oleic rape breeding but also provides a theoretical basis for their early screening.

COPD deaths attributable to ozone in 2019 and future projections using the WHO AQG 2021 in urban China.

Chronic obstructive pulmonary disease (COPD) is an epidemic in China. Ozone is a possible risk factor of COPD, with ozone concentrations increasing in China, despite air pollution mitigation measures that reduced particulate matter. The WHO Air Quality Guidelines (AQG) recommendations in 2021 are a turning point that formally recognizes the crucial role of indoor air pollution. We aimed to investigate the premature COPD deaths attributable to ozone in 2019, taking the WHO AQG 2021 level into account to determine the gap to bridge ozone control in China. First, we assessed ozone exposures initiated from indoor and outdoor sources by gender and age groups in 344 cities under four scenarios: 2019 as a baseline, and outdoor ozone at WHO AQG 2021 level in 2019, 2030, and 2050, respectively. Subsequently, we estimated COPD deaths attributable to ozone. The results show that the COPD deaths attributable to ozone are 77,737 in 2019, and 527, 872, 1355 if the outdoor ozone concentration is reduced to the WHO AQG 2021 level in 2019 (counterfactual scenario), 2030, and 2050, respectively in urban China. The indoor ozone sources only contribute to less than 5% of COPD deaths. A gap of 68.5 µg/m3 for the highest seasonal ozone concentration should be bridged to meet the WHO AQG 2021 and avoid over 76 thousand (98%) COPD deaths in 2019 in urban China.

Phytochrome-interacting factor (PIF) in rapeseed (Brassica napus L.): Genome-wide identification, evolution and expression analyses during abiotic stress, light quality and vernalization.

Phytochrome-interacting factors (PIFs) are members of basic helix-loop-helix (bHLH) transcription factors and the primary partners of phytochromes (PHY) in light signaling. PIFs interact with the Pfr forms of phytochrome to play an important role in the pathways of response to light and temperature in plants. In this study, 30, 12, and 16 potential PIF genes were identified in Brassica napus, Brassica rapa, Brassica oleracea, respectively, which could be divided into three subgroups. The Br/Bo/BnaPIF genes are intron-rich and similar to the PIF genes in Arabidopsis. However, unlike the AtPIFs that exist in multiple alternative-splicing forms, the majority of Br/Bo/BnaPIF genes have no alternative-splicing forms. A total of 52 Br/Bo/BnaPIF proteins have both the conserved active PHYB binding (APB) and bHLH domains. The Ka/Ks ratio revealed that most BnaPIFs underwent purifying selection. A promoter analysis found that light-related, abscisic acid-related and MYB-binding sites were the most abundant in the promoters of BnaPIFs. BnaPIF genes displayed different spatiotemporal patterns of expression and were regulated by light quality, circadian rhythms, cold, heat, and vernalization. Our results are useful for understanding the biological functions of PIF proteins in rapeseed.

Outdoor-to-indoor transport of ultrafine particles: Measurement and model development of infiltration factor.

Ambient ultrafine particles (UFPs: particles of diameter less than 100 nm) cause significant adverse health effects. As people spend most time indoors, the outdoor-to-indoor transport of UFPs plays a critical role in the accuracy of personal exposure assessments. Herein, a strategy was proposed to measure and analyze the infiltration factor (Finf) of UFPs, an important parameter quantifying the fraction of ambient air pollutants that travel inside and remain suspended indoors. Ninety-three measurements were conducted in 11 residential rooms in all seasons in Beijing, China, to investigate Finf of UFPs and its associated influencing factors. A multilevel regression model incorporating eight possible factors that influence infiltration was developed to predict Finf and FinfSOA (defined as the ratio of indoor to outdoor UFP concentrations without indoor sources, but with indoor secondary organic aerosol (SOA) formation). It was found that the air change rate was the most important factor and coagulation was considerable, while the influence of SOA formation was much smaller than that of other factors. Our regression model accurately predicted daily-average Finf. The annually-averaged Finf of UFPs was 0.66 ± 0.10, which is higher than that of PM2.5 and PM10, demonstrating the importance of controlling indoor UFPs of outdoor origin.

Personal exposure to ambient PM2.5, PM10, O3, NO2, and SO2 for different populations in 31 Chinese provinces.

Most epidemiological studies usually employ ambient air pollutant concentrations as a proxy of personal exposure to air pollutants originating outdoors, which could lead to a biased estimation of health effects. Herein, we modeled infiltration and exposure factors as the modifications of personal exposure to ambient PM2.5, PM10, O3, NO2, and SO2 for all seasons, genders, and ages in 31 Chinese provinces. The annual average exposure factors of PM10, PM2.5, O3, NO2, and SO2 were 0.42 ± 0.13 (arithmetic mean ± standard deviation), 0.68 ± 0.14, 0.34 ± 0.12, 0.50 ± 0.14, and 0.40 ± 0.13, respectively. We observed significant age, gender, seasonal, and geographical differences in infiltration and exposure factors for all studied ambient air pollutants. These factors were higher in southern China than in the north, and they were the highest in summer and the lowest in winter. The exposure factor of minors (age < 18 years) was significantly lower than that of adults (age ≥ 18 years, P < 0.01). Adult males had higher exposure factors than females (P < 0.01). Epidemiological studies utilizing outdoor concentrations of air pollutants could overestimate personal exposure to these pollutants. The present study could help in reducing the bias in the estimation of the health effects of air pollutants.

Measurement of ozone deposition velocity onto human surfaces of Chinese residents and estimation of corresponding production of oxidation products.

China has been experiencing a sharp increase in outdoor ozone concentration. The deposition velocity of ozone onto human surfaces strongly affects the indoor ozone concentration, and the production of oxidation products. In this study, we measured the deposition velocity of ozone onto human surfaces in six Chinese residential rooms, each housing 1-3 occupants. In addition, we estimated the corresponding emission rate of oxidation products. The measured mean value of the deposition velocity is 14.8 (±10.1) m/h, which is close to those reported in earlier studies in western countries. We also find that the ozone deposition velocity onto human surfaces is positively correlated to the weighted duration from the last laundry and bath/facial-cleansing, and it is negatively correlated to the relative humidity of the indoor air. The estimated emission rates of 6-MHO, 4-OPA, acetone, geranyl acetone, 1,4-butanedial decanal, and all gas-phase products are 7.7 × 1016, 6.7 × 1016, 9.4 × 1016, 9.7 × 1015, 1.3 × 1016, 3.4 × 1016, and 4.8 × 1017 molecule per person h-1, respectively, with an indoor ozone concentration of 5 ppb at steady state. The measured deposition velocity of ozone onto human surfaces of Chinese residents, and the emission rates of the corresponding oxidation products may be applied for the estimation of human exposure to ozone and its oxidation products in China.

Breathing-rate adjusted population exposure to ozone and its oxidation products in 333 cities in China.

While PM2.5 (particles with aerodynamic diameter less than 2.5 µm) concentrations in China are beginning to decline because of pollution abatement measures, ozone (O3) concentrations continue to rise. In this study, we have used a Monte Carlo approach to estimate breathing-rate adjusted (BRA) population exposure to ozone and its oxidation products based on hourly O3 measurements collected in 2017 from monitoring stations in 333 Chinese cities. The median measured outdoor O3 concentration in these cities was 31 ppb, while the median calculated indoor concentrations of ozone and ozone-derived oxidation products were 7.5 ppb and 21 ppb, respectively. The median BRA O3 exposure concentration was 12 ppb, ranging from 2.2 ppb to 18 ppb among the cities. Eastern and central cities had higher exposure concentrations, while northeastern and western cities had lower. On average, the residents of these cities spent 88% of their time indoors. Consequently, even with breathing rate adjustments, indoor O3 exposure averaged 50% of the total O3 exposure nationwide. The median BRA exposure concentration for ozone-derived products was 18 ppb, ranging from 4.5 ppb to 32 ppb among the cities. On average, BRA exposure concentrations were 1.6 times larger for oxidation products than for ozone, while seasonal variations of exposure concentrations were smaller for oxidation products than for ozone. As many of the products of indoor ozone chemistry are toxic, the health consequences of exposure to such products should be further investigated.