Polluted air and fading memory: Effects of air pollution on Alzheimer’s disease and vascular dementia

Roles of pollution in the prevalence and exacerbations of allergic diseases in Asia

Pregnancy and early childhood are periods with high plasticity in neurological development. Environmental perturbations during these sensitive windows can have lifelong developmental consequences. This review summarizes key findings relevant to the effects of air pollution on neurological development. Mounting evidence suggests that exposure to air pollution, both during pregnancy and childhood, is associated with childhood developmental outcomes ranging from changes in brain structures to subclinical deficits in developmental test scores, and, ultimately, developmental disorders such as attention-deficit/hyperactivity disorders or autism spectrum disorders. Although the biological mechanisms of effects remain to be elucidated, multiple pathways are probably involved and include oxidative stress, inflammation, and/or endocrine disruption. Given the alarming global increase in developmental disorders in recent years, and increased human exposures to pollution, it is critical to reduce personal and community-level exposures through tight collaboration of interdisciplinary and multi-level bodies including community partners, physicians, industry partners, policy makers, public health practitioners, and researchers. WHAT THIS PAPER ADDS: Exposure to air pollution is associated with a range of childhood developmental complications. Biological mechanisms may include oxidative stress, inflammation, and endocrine disruption.

Air Pollution and Coronary Risk in Kidney Transplant Recipients

Air pollution is one of the major causes of mortality and morbidity in the world today. World Health Organization (WHO) data show that almost all of the global population (99%) breathe air that exceeds WHO guideline limits and contains high levels of pollutants, with low- and middle-income countries suffering most from air pollution exposure. In China, the largest developing country, the poor air quality is primarily attributed to the rapid economic expansion the country experienced since the reform and opening-up in 1978, resulting in a drastic increase in coal-powered industrial production and electricity demand, as well as an exponential rise in private vehicles. Although there has been continuous air quality improvement following a series of stringent control policies, air pollution remains an important public health threat in China. The Global Burden of Disease Study estimated that in 2019, air pollution was responsible for 1.85 million deaths in China[1]. Meanwhile, non-communicable diseases (NCDs), such as cardiovascular disease and cancer, have placed much more disease burden on the population than ever[2]. It has been estimated that cardiovascular disease is now the leading cause of death in the Chinese population of adults 40 years of age and older, accounting for around 40% of total mortality. A growing body of human and animal evidence has led to a concern about the potential deleterious effects of ambient air pollution on the cardiovascular system[3,4]. For example, using the largest nationwide data in 272 Chinese cities, Chen et al. reported that a 10 μg/m3 increment of PM2.5 was associated with an increase of 0.27% in cardiovascular mortality. Similarly, in 652 cities of 24 countries, Liu et al. reported that an increase of 10 μg/m3 increment of PM2.5 was associated with increases of 0.36% in daily cardiovascular mortality[5]. The mixture of air pollutants may adversely affect the cardiovascular system directly and indirectly[6]. Direct effects may occur via agents that readily cross the pulmonary epithelium into the circulation, such as ultra-fine particles (UFPs), soluble constituents of particles (e.g., sulfate and nitrate), and gaseous pollutants (e.g., nitrogen oxides). Indirect effects may occur via induction of pulmonary inflammation and oxidative stress, leading to systemic inflammation and endothelial dysfunction. Although the adverse cardiovascular effects of air pollution have been documented in China, questions remain to be solved in human-based studies, especially for a stronger causal inference[7]. In this issue, we invited esteemed colleagues from some of the most reputable institutions in China and the United States, including Yale University, the Chinese Center for Disease Control and Prevention, Fudan University, and Chinese Academy of Medical Sciences and Peking Union Medical College to report their latest findings on air pollution and cardiovascular disorders. Their intriguing findings underscore the importance of understanding the health impacts of air pollution, particularly in China where the problem is especially severe due to rapid industrialization and urbanization. Ban et al. investigated the linear and non-linear patterns for the association between PM2.5 and acute incidence of myocardial infarction (MI) based on a multi-county registry dataset. They evaluated the reduction of premature MI incidence under different pollution control objectives in China[8]. This study provided valuable insights into the impact of PM2.5 on cardiovascular health on a national scale, and its findings can help inform policies aimed at reducing the burden of cardiovascular disease in China. Du et al. investigated the health effects of short-term exposure to PM2.5 from agricultural sources on acute MI onset using a nationwide database in China[9]. The study found that exposure to agricultural PM2.5 was associated with an increased risk of acute MI, highlighting the need for more research on estimating the adverse health effects of different air pollution sources. The study conducted by Jiang et al. explored the impacts of PM2.5 and PM2.5–10 on the onset of stable and unstable angina at an hourly temporal resolution, adjusting for key confounders[10]. They suggest that life-threatening cardiovascular disease risk from transient exposure to air pollution must be considered by healthcare professionals including cardiologists and patient caregivers to avoid negative cardiorespiratory outcomes. Finally, Zhou et al. reviewed available evidence quantifying the relationship between exposure to ambient gaseous and particulate air pollutants and cardiovascular symptoms[11]. The study found that exposure to air pollution was associated with a wide range of cardiovascular symptoms, including heart failure, arrhythmias, and hypertension. Although the findings above confirm that air pollution contributes to the cardiovascular disorders in China, several questions or challenges remain to be solved in human-based studies, especially for a stronger causal inference. Although some recent prospective cohort studies in China have examined the long-term effects of air pollution on cardiovascular mortality or morbidity[12], cohort studies are still lacking in examining a full spectrum of cardiometabolic diseases. Most Chinese studies on air pollution and cardiovascular health are observational in nature, thus limiting the power of causal inference. Accountability studies that evaluate long-term health benefits of clean air policies and intervention studies that reduce individual exposure may help to establish a causal relationship between air pollution and cardiovascular health[13]. The application of the difference-in-differences approach and randomized crossover design in intervention studies have been shown to further improve the causality[14]. Controlled-exposure human trials are particularly useful to establish the biological causation for the adverse cardiovascular effects of air pollution[15]. As research on the relationship between air pollution and cardiovascular health in the Chinese population continues to evolve, it is important to remember the many questions and challenges that remain. One area requiring further investigation is the lifetime course of cardiovascular damage effects, which could be addressed through prospective cohort studies. By following a large cohort of individuals over time, researchers can better understand how air pollution exposure affects the development and progression of cardiovascular diseases over the course of an individual's life. In addition to clarifying the long-term effects of air pollution on cardiovascular health, it is also important to examine the relevance of cumulative exposure. This requires not only tracking the levels of air pollution that individuals are exposed to over time but also considering how exposure to other risk factors, such as smoking, physical activities, green space, or a poor diet, may interact with air pollution exposure to affect cardiovascular health outcomes. By taking a more comprehensive approach to understanding the health impacts of air pollution, researchers can help to identify the most vulnerable populations and periods and develop more effective public health interventions to mitigate the negative health effects of air pollution. Another crucial area for future research is the investigation of genetic–environment interactions in relation to air pollution exposure and cardiovascular health. While genetic factors have been shown to play a role in the development of cardiovascular disease, their interaction with environmental factors such as air pollution is still poorly understood. By identifying genetic variations that may increase an individual's susceptibility to the negative health effects of air pollution, researchers can help to develop more personalized approaches to the prevention and treatment of cardiovascular diseases. Finally, it is important to establish the pathophysiologic link between air pollution and cardiometabolic diseases in the Chinese population. This requires identifying the specific mechanisms by which air pollution exposure leads to cardiovascular disease and understanding how these mechanisms may differ across different population subgroups. By gaining a more detailed understanding of the biological pathways that link air pollution exposure to cardiovascular disease, researchers can help to develop more targeted and effective interventions to mitigate the negative health effects of air pollution. Beyond these research priorities, there is clear evidence showing that climate change poses significant health risks to the population, and population health risks due to environmental factors under changing climate will become more severe in the future[16]. Air quality is closely linked to the earth's climate and ecosystems globally, as many of the air pollutants and greenhouse gases share the same sources (e.g., combustion of fossil fuels). Therefore, policies to reduce air pollution offer a win-win strategy for both climate and health, lowering the burden of disease attributable to air pollution, and contributing to the near- and long-term mitigation of climate change can be accomplished at the same time. Therefore, air pollution, climate change, and population health need to be considered simultaneously. Meanwhile, health risks from environmental factors will persist under climate change, and gaps in research evidence that may support population adaptation should be filled. In addition, innovative technologies and methodologies that may be applied to population health interventions should be developed. In summary, consideration of the health impacts and coping strategies of air pollution and climate change can help the government move forward towards sustainable development with appropriate urgency, reducing the disease burden and promoting a more healthy and sustainable future for all. CONFLICTS OF INTEREST STATEMENT Haidong Kan is an Editorial Board member of Cardiology Plus.

The public health benefits of air pollution control

Synergistic effects of air pollutants on meteorological fields at the junction of the Loess Plateau, Mongolian Plateau and Tibetan Plateau over Northwest China during summer

Inequities in air pollution exposure and gaps in air quality monitoring

South Korea has suffered from high levels of air pollution in recent years. South Korea experiences sand storms originating from deserts in west China and Inner Mongolia every spring for over 2,000 years. Over the last decade, as the coal-based Chinese economy continues to grow explosively, air pollutants from industrial zones and coal-combusting power plants started blowing over on the prevailing westerly wind to the nearby countries, Korea and Japan. Further, the problem gets more severe when more fossil fuels are burned for winter heating in China. The Chinese government also acknowledges that a part of emissions generated in their mainland may travel long distances and affect air quality in neighboring countries, however, the level of contribution is still a subject of considerable debate. The long-range transport of air pollutants from China accounts for roughly 26-50% of annual contributions of PM_10 in Korea (Korean Government 2013, Li et al. 2014, Park and Han 2014). In this study, I attempt to econometrically identify the role of wind in the local air quality as a transport of air pollution. The regression models analyze the marginal effects of long-range transport and determines which specific wind directions have the greatest effects each season on South Korean ambient air quality. This paper uses two sets of panel data: daily average concentrations of PM_10 and weather monitoring data (precipitation, temperature, wind speed, and wind direction). The data are collected from seven metropolitan cities and nine provinces in South Korea for nine years (2006-2014). I find that westerly wind increases PM_10 concentrations in South Korea. The marginal effect of the westerlies on annual PM_10 is 0.883 μg/m^3 higher than the east wind, accounting for 3.38% with the annual mean wind speed. Seasonally, the effect of westerlies peaks in winter (8.13%) when more pollutants are generated in China, followed by summer (7.55%), spring (5.99%), and fall (3.21%). More specifically, the northwest (NW) wind has the greatest effects in summer (13.75%) and winter (11.11%) and is in the direction from Beijing to South Korea. Furthermore, the west-southwest (WSW) shows the largest impacts in spring (8.36%) and fall (7.71%), and southwest wind (SW) is the greatest year-round, accounting for 12.26% of the annual mean PM_10. These winds correspond to the direction from Shanghai to South Korea. This is important because it not only shows the effects of transboundary air pollution from China, but also informs us about the air pollutants’ likely main contributing sources, Beijing and Shanghai in China. Based on the results, the average effects of the transboundary air pollution are estimated to account for 7.71-13.75% of the mean PM_10 concentrations depending on season. This brings about a sharp contrast with that of previous studies that estimate the Chinese contribution on PM_10 in South Korea of approximately 26-50%.

Previous studies have shown an association between mortality and ambient air pollution in South Korea. However, these studies may have been subject to bias, as they lacked adjustment for spatio-temporal structures. This paper addresses this research gap by examining the association between air pollution and cause-specific mortality in South Korea between 2012 and 2015 using a two-stage Bayesian spatio-temporal model. We used 2012–2014 mortality and air pollution data for parameter estimation (i.e., model fitting) and 2015 data for model validation. Our results suggest that the relative risks of total, cardiovascular, and respiratory mortality were 1.028, 1.047, and 1.045, respectively, with every 10-µg/m3 increase in monthly PM2.5 (fine particulate matter) exposure. These findings warrant protection of populations who experience elevated ambient air pollution exposure to mitigate mortality burden in South Korea.

Asia's air: population health after rapid industrialisation

우리나라는 고령화 사회로 빠르게 진입함에 따라 치매환자가 급속히 증가하고 있다. 본 연구는 대도시에 위치한 5개 V병원의 자료를 활용하여 12년간 치매 신환자의 특성 추이를 분석하고 향후 치매환자 증가 수요에 대처하고 치매환자 관리에 기초자료를 제공하고자하는 것이 목적이다. 5개 V병원의 전체 치매 신환자수는 2003년 410명이었으나 2014년에는 5,048명으로 11.3배 증가하였으며, 5개 병원중에서는 P병원이 2003년에 비해 2014년은 30.3배로 가장 많이 증가하였고, D병원은 6.0배 증가하여 병원간에 차이가 많았으나 전반적으로 5개 V병원 치매환자 수가 크게 증가한 것으로 나타났다. 연령별에서는 75세~84세군에서 40.4%로 가장 높았고, 85세 이상 20.2%로 65세 이상이 93.5%로 대부분을 차지하여 고령층에서도 치매환자의 비율이 높게 나타났다. 치매환자 유형별에서는 알츠하이머병이 44.4%로 가장 높게 차지하였으며, 상세불명의 치매는 33.3%, 혈관성치매가 20.4% 순이었다. 연구결과는 12년 동안 큰 폭으로 증가하였으며, 치매환자는 연령이 높을수록 발생률이 높기 때문에 앞으로 5개 V병원의 치매환자 수는 더욱 증가할 것이다. 치매환자 증가 수요에 따른 효과적인 치매관리를 위한 체계적이고 지속적인 추진방안이 요구된다. South Korea is becoming an aging society, increasing the population with dementia. This study analyzed the characteristics of the trend of dementia patients by utilizing 12 years' worth of data from five V hospitals within metropolitan cities. The results show that there has been an 11.3 times increase in the total number of new dementia patients in these five hospitals from 410 in 2003 to 5,048 in 2014; and among them, the rate of increase was highest in P hospital with a 30.3 times increase. Conversely, there has been a 6-times increase in D hospital, illustrating a noticeable gap between these hospitals. Overall, these hospitals have shown an enormous increasing ratio. In an analysis according to age, it's been shown that those aged between 75 and 84 showed the highest prevalence, and most patients, approximately 93.5%, were 65 years or older, while 20.2% were 85 years or older, showing a high ratio of elderly among dementia patients. In an analysis by type of dementia, it's been shown that Alzheimer's was the most prevalent with 44.4%, followed by unspecified dementia with 33.3%, and vascular dementia with 20.4%. As evident by the outcome of the study, there's been a drastic increase in the number of dementia patients in the past 12 years; since the prevalence of dementia was shown to be higher with older age, it is expected that the number of dementia patients will rise further in these five hospitals, where there's a high ratio of elderly patients. More elaborate and continuous plans are necessary for the management of dementia patients following the growing number of dementia patients.

The term “smog”—a combination of smoke and fog—was invented by a British doctor a century ago. In 21st century Europe, air pollution has greatly improved by most measures but is...

BackgroundVarious factors can modify the health effects of outdoor air pollution. Prior findings about modifiers are inconsistent, and most of these studies were conducted in developed countries.ObjectivesWe conducted a time-series analysis to examine the modifying effect of season, sex, age, and education on the association between outdoor air pollutants [particulate matter < 10 μm in aerodynamic diameter (PM10), sulfur dioxide, nitrogen dioxide, and ozone] and daily mortality in Shanghai, China, using 4 years of daily data (2001–2004).MethodsUsing a natural spline model to analyze the data, we examined effects of air pollution for the warm season (April–September) and cool season (October–March) separately. For total mortality, we examined the association stratified by sex and age. Stratified analysis by educational attainment was conducted for total, cardiovascular, and respiratory mortality.ResultsOutdoor air pollution was associated with mortality from all causes and from cardiorespiratory diseases in Shanghai. An increase of 10 μg/m3 in a 2-day average concentration of PM10, SO2, NO2, and O3 corresponds to increases in all-cause mortality of 0.25% [95% confidence interval (CI), 0.14–0.37), 0.95% (95% CI, 0.62–1.28), 0.97% (95% CI, 0.66–1.27), and 0.31% (95% CI, 0.04–0.58), respectively. The effects of air pollutants were more evident in the cool season than in the warm season, and females and the elderly were more vulnerable to outdoor air pollution. Effects of air pollution were generally greater in residents with low educational attainment (illiterate or primary school) compared with those with high educational attainment (middle school or above).ConclusionsSeason, sex, age, and education may modify the health effects of outdoor air pollution in Shanghai. These findings provide new information about the effects of modifiers on the relationship between daily mortality and air pollution in developing countries and may have implications for local environmental and social policies.

Meteorological factors and air pollutants are associated with the spread of pulmonary tuberculosis (PTB), but few studies have examined the effects of their interactions on PTB. Therefore, this study investigated the impact of meteorological factors and air pollutants and their interactions on the risk of PTB in Urumqi, a city with a high prevalence of PTB and a high level of air pollution. The number of new PTB cases in eight districts of Urumqi from 2014 to 2019 was collected, along with data on meteorological factors and air pollutants for the same period. A generalized additive model was applied to explore the effects of meteorological factors and air pollutants and their interactions on the risk of PTB incidence. Segmented linear regression was used to estimate the nonlinear characteristics of the impact of meteorological factors on PTB. During 2014-2019, a total of 14,402 new cases of PTB were reported in eight districts, with March to May being the months of high PTB incidence. The exposure-response curves for temperature (Temp), relative humidity (RH), wind speed (WS), air pressure (AP), and diurnal temperature difference (DTR) were generally inverted "U" shaped, with the corresponding threshold values of - 5.411 °C, 52.118%, 3.513m/s, 1021.625hPa, and 8.161 °C, respectively. The effects of air pollutants on PTB were linear and lagged. All air pollutants were positively associated with PTB, except for O3, which was not associated with PTB, and the ER values for the effects on PTB were as follows: 0.931 (0.255, 1.612) for PM2.5, 1.028 (0.301, 1.760) for PM10, 5.061 (0.387, 9.952) for SO2, 2.830 (0.512, 5.200) for NO2, and 5.789 (1.508, 10.251) for CO. Meteorological factors and air pollutants have an interactive effect on PTB. The risk of PTB incidence was higher when in high Temp-high air pollutant, high RH-high air pollutant, high WS-high air pollutant, lowAP-high air pollutant, and high DTR-high air pollutant. In conclusion, both meteorological and pollutant factors had an influence on PTB, and the influence on PTB may have an interaction.

The health effects of short-term exposure to air pollutants on respiratory deaths and its modifiers such as meteorological indexes have been widely investigated. However, most of the previous studies are limited to single pollutants or total respiratory deaths, and their findings are inconsistent.To comprehensively examine the short-term effects of air pollutants on daily respiratory mortality.Our analysis included 16,931 nonaccidental respiratory deaths (except lung cancer and tuberculosis) among older adults (>65 years) from 2011 to 2017 in Jinan, China. We used a generalized additive Poisson models adjusted for meteorology and population dynamics to examine the associations between air pollutants (particulate matter with an aerodynamic diameter of b2.5μm [PM2.5], particulate matter with an aerodynamic diameter of b10μm [PM10], SO2, NO2, O3) and daily mortality for the total patients, males, females, chronic airway diseases, pneumonia patients, and rest patients in Jinan.Outdoor air pollution was significantly related to mortality from all respiratory diseases especially from chronic airway disease in Jinan, China. The effects of air pollutants had lag effects and harvesting effects, and the effects estimates usually reached a peak at lag 1 or 2 day. An increase of 10 μg/m3 or 10 ppb of PM2.5, PM10, SO2, NO2, and O3 corresponds to increments in mortality caused by chronic airway disease of 0.243% (95% confidence interval [CI]: −0.172–0.659) at lag 1 day, 0.127% (95% CI: −0.161–0.415) at lag 1 day, 0.603% (95% CI: 0.069–1.139) at lag 3 day, 0.649% (95% CI: −0.808–2.128) at lag 0 day and 0.944% (95% CI: 0.156–0.1598) at lag 1 day, respectively. The effects of air pollutants were usually greater in females and varied by respiratory subgroups. Spearman correlation analysis suggested that there was a significant association between meteorological indexes and air pollutants.Sex, age, temperature, humidity, pressure, and wind speed may modify the short-term effects of outdoor air pollution on mortality in Jinan. Compared with the other pollutants, O3 had a stronger effect on respiratory deaths among the elderly. Moreover, chronic airway diseases were more susceptible to air pollution. Our findings provided new evidence for new local environmental and health policies making.