Identification of volatile organic compound emissions from anthropogenic and biogenic sources based on satellite observation of formaldehyde and glyoxal.

Anthropogenic volatile organic compounds (VOCs) are serious pollutants in the atmosphere because of their toxicity and as precursors of secondary organic aerosols and ozone pollution. Although in-situ measurements provide accurate information on VOCs, their spatial coverage is limited and insufficient. In this study, we provide a global perspective for identifying anthropogenic VOC emission sources through the ratio of glyoxal to formaldehyde (RGF) based on satellite observations. We assessed typical cities and polluted areas in the mid latitudes and found that some Asian cities had higher anthropogenic VOC emissions than cities in Europe and America. For heavily polluted areas, such as the Yangtze River Delta (YRD), the areas dominated by anthropogenic VOCs accounted for 23 % of the total study areas. During the COVID-19 pandemic, a significant decline in RGF values was observed in the YRD and western United States, corresponding to a reduction in anthropogenic VOC emissions. Furthermore, developing countries appeared to have higher anthropogenic VOC emissions than developed countries. These observations could contribute to optimising industrial structures and setting stricter pollution standards to reduce anthropogenic VOCs in developing countries.

Gender difference in the relationship between personality traits and changes in depressive symptoms before and after the COVID-19 outbreak: A follow-up study among Chinese adults.

OBJECTIVES: Increasing depressive symptoms have become an urgent public health concern worldwide. This study aims to explore the correlation between personality traits and changes in depressive symptoms before and after the COVID-19 outbreak and to examine the gender difference in this association further. METHODS: Data were obtained from the China Family Panel Studies (CFPS, wave in 2018 and 2020). A total of 16,369 residents aged 18 and above were included in this study. Multinomial logistic regression analysis was used to examine whether personality traits were associated with changes in depressive symptoms. We also analyzed whether there was an interaction effect of gender and personality traits on depressive symptoms. RESULTS: Conscientiousness, extroversion, and agreeableness are negatively associated with depressive symptoms, while neuroticism and openness are positively related. Gender moderates the relationship between personality traits and depressive symptoms. Compared to men, women have demonstrated a stronger association between neuroticism (OR = 0.79; 95 % CI = 0.66, 0.94), conscientiousness (OR = 1.40; 95 % CI = 1.15, 1.69), and persistent depressive symptoms. LIMITATIONS: Given its longitudinal study design, it is insufficient to draw a causal inference between personality traits and depressive symptoms. CONCLUSION: Personality traits and their various dimensions are correlated with changes in depressive symptoms. Persistent depressive symptoms are positively related to neuroticism and negatively associated with conscientiousness. Women demonstrate a stronger association between personality traits and persistent depressive symptoms. Thus, in Chinese adults' mental health intervention and prevention programs, personality and gender-specific strategies should be considered, especially in the context of the COVID-19 pandemic.

A novel cartridge for nucleic acid extraction, amplification and detection of infectious disease pathogens with the help of magnetic nanoparticles

Nucleic acid detection (NAD) based on real-time polymerase chain reaction (real-time PCR) is gold standard for infectious disease detection. Magnetic nanoparticles (MNPs) are widely used for nucleic acid extraction (NAE) because of their excellent properties. Microfluidic technology makes automated NAD possible. However, most of the NAD microfluidic chips are too complex to be applied to point-of-care (POC) testing. In this paper, a simple-structure cartridge was developed for POC detection of infectious diseases. This self-contained cartridge can be divided into a magnetic-controlled NAE part, a valve-piston combined fluidic control part and a PCR chip, which is able to extract nucleic acid from up to 500 μL of liquid samples by MNPs and finish the detection process from "sample in” to "answer out” automatically. Performance tests of the cartridges show that it met the demands of automated NAD. Results of on-cartridge detection of hepatitis B virus (HBV) demonstrated that this system has good uniformity and no cross-contamination between different cartridges, and the limit of detection (LOD) of this system for HBV in serum is 50 IU/mL. Multiplex detections of severe acute respiratory syndrome coronaviruses 2 (SARS-CoV-2) with a concentration of 500 copies/mL were carried out on the system and 100% positive detection rate was achieved.

A miniaturized and integrated dual-channel fluorescence module for multiplex real-time PCR in the portable nucleic acid detection system.

A portable nucleic acid detection (PNAD) system based on real-time polymerase chain reaction (real-time PCR) has been developed for point-of-care testing (POCT) of infectious disease pathogens. In order to achieve "sample-in, result-out" while keeping the system compact, the hardware system integrates optical, thermal and motion control modules in a limited space for nucleic acid extraction, purification, amplification and detection. Among these hardware modules, the fluorescence module is one of the most important modules, because its performance directly affects the accuracy and sensitivity of the testing results. In this paper, a miniaturized, high-sensitivity and integrated dual-channel fluorescence module have been proposed for the homemade PNAD system. Based on the principle of confocal optical path, two group of excitation-emission optical paths of different wavelengths are integrated in a small space. In terms of circuitry, a current-light dual negative feedback light emitting diode (LED) drive circuit is applied to improve the stability of the excited light source. All optical and electronic components are integrated in a metal box of 55 mm × 45 mm × 15 mm, that helps miniaturize the detection system. Two different modules have been assembled to fit various fluorescent dyes or probes with the set of excitation and emission as follow: module 1#: 470 nm/525 nm, 570 nm/630 nm; module 2#: 520 nm/570 nm, 630 nm/690 nm. Finally, hepatitis B virus (HBV) concentration gradient detection and multiplex detection of different gene targets of SARS-CoV-2 are carried out on the PNAD system equipped with these two fluorescence modules for evaluating their performances. Compared with the commercial real-time PCR instrument, our fluorescence module has good stability and detection sensitivity.

Improved Anthropogenic SO2 Retrieval from High-Spatial-Resolution Satellite and its Application during the COVID-19 Pandemic.

Sulfur dioxide (SO2) measured by satellites is widely used to estimate anthropogenic emissions. The Sentinel-5 Precursor (S-5P) operational SO2 product is overestimated compared to the ground-based multiaxis differential optical absorption spectroscopy (MAX-DOAS) measurements in China and shows an opposite variation to the surface measurements, which limits the application of TROPOspheric monitoring instrument (TROPOMI) products in emissions research. Radiometric calibration, a priori profiles, and fitting windows might cause the overestimation of S-5P operational SO2 product. Here, we improve the optimal-estimation-based algorithm through several calibration methods. The improved retrieval agrees reasonably well with the ground-based measurements (R > 0.70, bias <13.7%) and has smaller biases (-28.9%) with surface measurements over China and India. It revealed that the SO2 column in March 2020 decreased by 51.6% compared to March 2019 due to the lockdown for curbing the spread of the COVID-19 pandemic, and there was a decrease of 50% during the lockdown than those after the lockdown, similar to the surface measurement trend, while S-5P operational SO2 product showed an unrealistic increase of 19%. In India, the improved retrieval identified obvious "hot spots" and observed a 30% decrease of SO2 columns during the lockdown.

Distinct Regimes of O3 Response to COVID-19 Lockdown in China

Restrictions on human activities remarkably reduced emissions of air pollutants in China during the COVID-19 lockdown periods. However, distinct responses of O3 concentrations were observed across China. In the Beijing–Tianjin–Hebei (BTH) and Yangtze River Delta (YRD) regions, O3 concentrations were enhanced by 90.21 and 71.79% from pre-lockdown to lockdown periods in 2020, significantly greater than the equivalent concentrations for the same periods over 2015–2019 (69.99 and 43.62%, p <0.001). In contrast, a decline was detected (−1.1%) in the Pearl River Delta (PRD) region. To better understand the underlying causes for these inconsistent responses across China, we adopted the least absolute shrinkage and selection operator (Lasso) and ordinary linear squares (OLS) methods in this study. Statistical analysis indicated that a sharp decline in nitrogen dioxide (NO2) was the major driver of enhanced O3 in the BTH region as it is a NOx-saturated region. In the YRD region, season-shift induced changes in the temperature/shortwave radiative flux, while lockdown induced declines in NO2, attributable to the rise in O3. In the PRD region, the slight drop in O3 is attributed to the decreased intensity of radiation. The distinct regimes of the O3 response to the COVID-19 lockdown in China offer important insights into different O3 control strategies across China.