Toward Better and Healthier Air Quality: Global PM2.5 and O3 Pollution Status and Risk Assessment Based on the New WHO Air Quality Guidelines for 2021.

To reduce the high burden of disease caused by air pollution, the World Health Organization (WHO) released new Air Quality Guidelines (AQG) on September 22, 2021. In this study, the daily fine particulate matter (PM2.5) and surface ozone (O3) data of 618 cities around the world is collected from 2019 to 2022. Based on the new AQG, the number of attainment days for daily average concentrations of PM2.5 (≤ 15 µg m-3) and O3 (≤ 100 µg m-3) is approximately 10% and 90%, respectively. China and India exhibit a decreasing trend in the number of highly polluted days (> 75 µg m-3) for PM. Every year over 68% and 27% of cities in the world are exposed to harmful PM2.5 (> 35 µg m-3) and O3 (> 100 µg m-3) pollution, respectively. Combined with the United Nations Sustainable Development Goals (SDGs), it is found that more than 35% of the world's cities face PM2.5-O3 compound pollution. Furthermore, the exposure risks in these cities (China, India, etc.) are mainly categorized as "High Risk", "Risk", and "Stabilization". In contrast, economically developed cities are mainly categorized as "High Safety", "Safety", and "Deep Stabilization." These findings indicate that global implementation of the WHO's new AQG will minimize the inequitable exposure risk from air pollution.

Runoff change controlled by combined effects of multiple environmental factors in a headwater catchment with cold and arid climate in northwest China.

The limited runoff in cold and arid regions is sensitive to environmental changes, and it is thus urgent to explore the change and controlling factors of runoff under the background of global warming and intensified human activities. However, previous studies have rarely considered the combined effects of multiple controlling factors at varying scales over time. With the headwater region of the Manas River in northwest China as the study area, we investigated the change in runoff for the period of 1954-2016 and its relationship with regional environmental factors (e.g. precipitation PCP, temperature TMP, potential evapotranspiration ET0, snow cover extent SCE, land use, and normalized difference vegetation index NDVI) and/or global atmospheric circulation (e.g. North Atlantic Oscillation NAO, Arctic Oscillation AO, Pacific Interdecadal Oscillation PDO, and El Nino Southern Oscillation ENSO). In particular, the combined effects of multiple environmental factors were determined at different scales by the multiple wavelet coherence. The annual runoff significantly increased at a rate of 0.508 × 108 m3/decade, and the climate tended to be warmer and wetter. Among the regional and global environmental factors, NDVI and ENSO were the single factor mostly correlated with runoff, while NDVI-TMP and ENSO-PDO were the combined factors with the stronger relations on runoff, respectively. The regional environmental factors had larger impacts on runoff than the global environmental factors, and the natural factors outperformed human activities in controlling runoff. The accelerated melting of snow/glacier induced by the increasing temperature dominated runoff change, and the increasing water inputs from wetter climate may play a second role in runoff. The runoff characteristics in cold and arid regions seem to be different from those regions with little snow/glacier, which should be paid more attention. The employed multiple wavelet coherence is helpful in determining the processes dominating runoff change.

Manifestation of lower extremity atherosclerosis in diabetic patients with high ankle-brachial index.

BACKGROUND: The ankle brachial index (ABI) is a simple, inexpensive, noninvasive tool that correlates well with angiographic disease severity and functional symptoms. The aim of this study was to identify the manifestation of lower extremity atherosclerotic lesions in patients with high ABI by retrospective clinical study. METHODS: A cohort of 184 diabetic patients, (63 +/- 14) years old, 144 males, who underwent simultaneously ABI testing and low extremity arterial duplex ultrasound within one week, were enrolled randomly into this study. According to the ABI value, they were divided into three groups: the high, normal and low ABI groups. The severity and location of atherosclerotic lesions in the lower extremity were determined based on the results of low extremity artery duplex ultrasound. The chi-square test was used to compare the atherosclerosis severity grade and lesion location across the three groups. RESULTS: The prevalence of low extremity artery occlusion was significantly lower in the high ABI group than in the low ABI group (3.3% vs. 63.5%, P < 0.01), and the main atherosclerotic lesions were diffuse dot-like hyperechogenicity spots or small plaques (86.7%). In addition, the atherosclerotic lesions were mostly found in the distal segment of the lower extremity in patients with high ABI (46.3%). CONCLUSION: A high ABI may be an integrative marker for intimal and medial calcification, which has a high positive predictive value for artery calcification.