Long-term trends in mortality risk associated with short-term exposure to air pollution in 10 Japanese cities between 1977 and 2015

Short-term associations of low-level fine particulate matter (PM2.5) with cardiorespiratory hospitalizations in 139 Japanese cities

There have been few studies in non-western countries on the relationship between low levels of daily fine particulate matter (PM_2.5) exposure and morbidity or mortality, and the impact of PM_2.5 concentrations below 15 μg/m³, which is the latest World Health Organization Air Quality Guideline (WHO AQG) value for the 24-h mean, is not yet clear. We assessed the associations between low-level PM_2.5 exposure and cardiorespiratory admissions in Japan. We collected the daily hospital admission count data, air pollutant data, and meteorological condition data recorded from April 2016 to March 2019 in 139 Japanese cities. City-specific estimates were obtained from conditional logistic regression models in a time-stratified case-crossover design and pooled by random-effect models. We estimated that every 10-μg/m³ increase in the concurrent-day PM_2.5 concentration was related to a 0.52% increase in cardiovascular admissions (95% CI: 0.13-0.92%) and a 1.74% increase in respiratory admissions (95% CI: 1.41-2.07%). These values were nearly the same when the datasets were filtered to contain only daily PM_2.5 concentrations <15 μg/m³. The exposure-response curves showed approximately sublinear-to-linear curves with no indication of thresholds. These associations with cardiovascular diseases weakened after adjusting for nitrogen dioxide or sulfur dioxide, but associations with respiratory diseases were almost unchanged when additionally adjusted for other pollutants. This study demonstrated that associations between daily PM_2.5 and daily cardiorespiratory hospitalizations might persist at low concentrations, including those below the latest WHO AQG value. Our findings suggest that the updated guideline value may still be insufficient from the perspective of public health.

Peculiar weather patterns effects on air pollution and COVID-19 spread in Tokyo metropolis

As a pandemic hotspot in Japan, between March 1, 2020-October 1, 2022, Tokyo metropolis experienced seven COVID-19 waves. Motivated by the high rate of COVID-19 incidence and mortality during the seventh wave, and environmental/health challenges we conducted a time-series analysis to investigate the long-term interaction of air quality and climate variability with viral pandemic in Tokyo. Through daily time series geospatial and observational air pollution/climate data, and COVID-19 incidence and death cases, this study compared the environmental conditions during COVID-19 multiwaves. In spite of five State of Emergency (SOEs) restrictions associated with COVID-19 pandemic, during (2020-2022) period air quality recorded low improvements relative to (2015-2019) average annual values, namely: Aerosol Optical Depth increased by 9.13% in 2020 year, and declined by 6.64% in 2021, and 12.03% in 2022; particulate matter PM2.5 and PM10 decreased during 2020, 2021, and 2022 years by 10.22%, 62.26%, 0.39%, and respectively by 4.42%, 3.95%, 5.76%. For (2021-2022) period the average ratio of PM2.5/PM10 was (0.319 ± 0.1640), showing a higher contribution to aerosol loading of traffic-related coarse particles in comparison with fine particles. The highest rates of the daily recorded COVID-19 incidence and death cases in Tokyo during the seventh COVID-19 wave (1 July 2022-1 October 2022) may be attributed to accumulation near the ground of high levels of air pollutants and viral pathogens due to: 1) peculiar persistent atmospheric anticyclonic circulation with strong positive anomalies of geopotential height at 500 hPa; 2) lower levels of Planetary Boundary Layer (PBL) heights; 3) high daily maximum air temperature and land surface temperature due to the prolonged heat waves (HWs) in summer 2022; 4) no imposed restrictions. Such findings can guide public decision-makers to design proper strategies to curb pandemics under persistent stable anticyclonic weather conditions and summer HWs in large metropolitan areas.

Change in Air Quality during 2014-2021 in Jinan City in China and Its Influencing Factors

Air pollution affects climate change, food production, traffic safety, and human health. In this paper, we analyze the changes in air quality index (AQI) and concentrations of six air pollutants in Jinan during 2014-2021. The results indicate that the annual average concentrations of PM₁₀, PM_2.5, NO₂, SO₂, CO, and O₃ and AQI values all declined year after year during 2014-2021. Compared with 2014, AQI in Jinan City fell by 27.3% in 2021. Air quality in the four seasons of 2021 was obviously better than that in 2014. PM_2.5 concentration was the highest in winter and PM_2.5 concentration was the lowest in summer, while it was the opposite for O₃ concentration. AQI in Jinan during the COVID epoch in 2020 was remarkably lower compared with that during the same epoch in 2021. Nevertheless, air quality during the post-COVID epoch in 2020 conspicuously deteriorated compared with that in 2021. Socioeconomic elements were the main reasons for the changes in air quality. AQI in Jinan was majorly influenced by energy consumption per 10,000-yuan GDP (ECPGDP), SO₂ emissions (SDE), NOx emissions (NOE), particulate emissions (PE), PM_2.5, and PM₁₀. Clean policies in Jinan City played a key role in improving air quality. Unfavorable meteorological conditions led to heavy pollution weather in the winter. These results could provide a scientific reference for the control of air pollution in Jinan City.