Graphical abstract

Background Evidence from cohort studies in North America and Europe indicates that long-term exposure to fine particulate matter (PM₂ • ₅) is associated with an increased mortality risk. However, this association has rarely been quantified at higher ambient concentrations. We estimated the hazard ratio (HR) for all-cause mortality from longterm exposure to PM₂ • ₅ in a well established Chinese cohort of older adults. Methods The Chinese Longitudinal Healthy Longevity Survey (CLHLS) is a prospective cohort study of men and women aged 65 years and older enrolled in 2008 and followed up through 2014 for mortality events. We studied individuals for whom residential locations were available in 2008 for linkage to 1 km grids of PM₂ • ₅ concentrations, derived from satellite remote sensing. Cox proportional hazards models were used to estimate the effect of long-term exposure to PM₂ • ₅ on all-cause mortality, controlling for age, sex, smoking status, drinking status, physical activity, body-mass index, household income, marital status, and education. We then used our results to estimate premature mortality related to PM₂ • ₅ exposure in the population aged 65 years and older in China in 2010. Findings 13 344 individuals in the CLHLS cohort had data for all timepoints, yielding follow-up data for 49 440 person-years. In a 3-year window, these individuals were exposed to a median PM₂ • ₅ concentration of 50•7 μg/m³ (range 6•7-113•3). The overall HR for a 10 μg/m³ increase in this value was 1•08 (95% CI 1•06-1•09). In stratified analyses, HRs were higher in rural than in urban locations, in southern versus northern regions, and with exposure to lower versus higher PM₂ • ₅ concentrations. Based on the overall HR, we estimated that 1 765 820 people aged 65 years and older in China in 2010 had premature mortality related to PM₂ • ₅ exposure. Interpretation Long-term exposure to PM₂ • ₅ is associated with an increased risk of all-cause mortality among adults aged 65 years and older in China, but the magnitude of the risk declines as the concentration of PM₂ • ₅ increases.

Due to continuous spread of coronavirus disease 2019 (COVID-19) worldwide, long-term effective prevention and control measures should be adopted for public transport facilities, as they are increasing in popularity and serve as the principal modes for travel of many people. The human infection risk could be extremely high due to length of exposure time window, transmission routes and structural characteristics during travel or work. This can result in the rapid spread of the infection. Based on the transmission characteristics of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and the nature of public transport sites, we identified comprehensive countermeasures toward the prevention and control of COVID-19, including the strengthening of personnel management, personal protection, environmental cleaning and disinfection, and health education. Multi-pronged strategies can enhance safety of public transportation. The prevention and control of the disease during the use of public transportation will be particularly important when all countries in the world resume production. The aim of this study is to introduce experience of the prevention and control measures for public transportation in China to promote the global response to COVID-19.

Background Both air pollution and green space have been shown to affect health. We aimed to assess whether greenness protects against air pollution-related mortality. Methods We used data from the 2008 wave of the Chinese Longitudinal Healthy Longevity Survey. We calculated contemporaneous normalised difference vegetation index (NDVI) in the 500 m radius around each participant's residence. Fine particulate matter (PM 2•5) concentration was calculated using 3-year average concentrations in 1 km × 1 km grid resolution. We used Cox proportional hazards models to estimate the effects of NDVI, PM 2•5 , and their interaction on all-cause mortality, adjusted for a range of covariates. Findings The cohort contained 12 873 participants, totalling 47 884 person-years. There were 7426 deaths between 2008 and 2014. The mean contemporaneous NDVI was 0•42 (SD 0•21), and the mean 3-year average PM 2•5 was 49•63 μg/m³ (13•72). In the fully adjusted model, the mortality hazard ratio for each 0•1-unit decrease in contemporaneous NDVI was 1•08 (95% CI 1•03-1•13), each 10 μg/m³ increase in PM 2•5 was 1•13 (1•09-1•18), and the interaction term was 1•01 (1•00-1•02) with a p value of 0•027. We observed non-linear associations in our stratified analyses: people living in urban areas were more likely to benefit from greenness, and people living in rural areas were more likely to be harmed by air pollution. Interpretation Our study showed some indication of a synergistic effect of greenness and air pollution, suggesting that green space planning and air pollution control can jointly improve public health.

Background The aim of this study was to examine the trends in impairment regarding activities of daily living (ADL), physical performance, and cognitive function among the oldest-old (those aged 80 and older) in China between 1998 and 2014. Methods We used data on 34,297 oldest-old individuals from the seven waves of the Chinese Longitudinal Healthy Longevity Study. We estimated age, period, and cohort effects on the prevalence of self-reported ADL impairment, tested physical performance and cognitive function impairment using the age–period–cohort model. Results Regarding age, the prevalence of ADL, physical performance, and cognitive function impairment were highest in the centenarians, but they did not increase with age in this population. Among the literate subgroup, the prevalence of cognitive impairment increased more rapidly with age than that in the illiterate subgroup. Regarding period, the prevalence of self-reported and tested physical impairment slowly increased between 1998 and 2014, but cognitive impairment remained stable. Regarding cohort, ADL impairment continuously decreased. However, physical and cognitive impairment remained stable after a brief decline in the early birth cohorts. Conclusions The results suggest that the age effect is still the most obvious effect regarding several types of functional impairment. The likelihood of a younger person experiencing functional impairment may not change significantly, but ADL is likely to be amenable to improvement resulting from improved medical and social care. Therefore, increased care for the oldest-old may considerably improve their quality of life, particularly regarding their basic ADL.