The effect of ozone short-term exposure on flow-mediated dilation: Using data before and after COVID-19 lockdown in Shanghai

Association of ambient ozone with time to pregnancy and the modifying effect of ambient temperature: a population-based cohort study

Research on the impact of ozone (O3) on fecundability has been inconclusive, lacking evidence examining the lagged pattern of ozone exposure and temperature modification. Current studies have predominantly been conducted in North America and Europe, leaving a gap in research from the Asian population. This population-based prospective cohort study involved 594,110 couples in Yunnan Province, China, enrolled in the National Free Preconception Health Examination Project. We calculated time-varying cycle-specific O3 concentration across 1-12 menstrual cycles before conception, according to each female's menstrual cycle length and residential addresses. Time to pregnancy was used as an outcome indicator. A discrete-time Cox regression model integrated with a distributed lag model (DLM) was employed for analysis. We observed that O3 exposure was negatively associated with fecundability, with the effect diminishing over time relative to conception. The first menstrual cycle before conception appeared most sensitive to O3 exposure, showing a 6.2 % decrease (HR: 0.938; 95 % CI: 0.936 to 0.941) in fecundability per one IQR increase of O3. Combined exposure to O3 and ambient temperature may exert a synergistic effect. The modifying effect of temperature was most pronounced in the first cycle before conception, with HRs of 0.891 (95 % CI: 0.886 to 0.895), 0.859 (95 % CI: 0.853 to 0.865), and 0.833 (95 % CI: 0.826 to 0.840) under low-, median-, and high-temperature conditions, respectively. Targeted policy interventions are needed to mitigate the dual impact of air pollution and rising temperatures.

Alternations of antibiotic resistance genes and microbial community dynamics on shared bicycles before and after pandemic lockdown

The prevalence of shared bicycles has raised concerns over their potential to transmit pathogens and microbes harboring antibiotic resistance genes (ARGs), which pose significant human health risks. This study investigated the impact of anthropogenic activities on the composition of ARGs and microbial communities on shared bicycles during the COVID-19 pandemic and subsequent lockdown when shared bicycle usage was altered. A total of 600 swab samples from shared bicycle surfaces were collected in Shanghai before and during COVID-19 lockdown periods. Even during lockdown, 12 out of 14 initially detected ARG subtypes persisted, indicating their tenacity in the face of reduced anthropogenic activities. These ARGs displayed significantly higher absolute and relative abundance levels before the lockdown. In addition, the percentage of potential pathogens in the total microbial abundance remained at 0.029 % during the lockdown, which was lower than the pre-lockdown percentage of 0.035 % and suggested that these risks persist within shared bicycle systems. Interestingly, although microbial abundance decreased without the consecutive use of shared bicycles during lockdown, the microbial diversity increased under the impact of restricted anthropogenic activities (p < 0.001). This emphasizes the need for continuous monitoring and research to comprehend microbial community behaviors in various environments. This study uncovered the underlying impacts of the COVID-19 lockdown on the microbial and ARG communities of shared bicycles, providing comprehensive insights into the health management of shared transportation. Although lockdown can decrease the abundance of ARGs and potential pathogens, additional interventions are needed to prevent their continued spread.