Air Quality Index Levels Research Articles

Characteristics of Aerosol Types in Beijing and the Associations with Air Pollution from 2004 to 2015

With the fast development of the economy and expansion, a large number of people have concentrated in Beijing over the past few decades, leading to the result that Beijing has become home to one of the most complex mixtures of aerosol types in the world. The various aerosol types play different roles in the determination of global climate change, visibility, and human health. However, to the best of our knowledge, research has rarely analyzed the correlation between aerosol types and air quality index (AQI) in Beijing (urban and suburban) over a long-term series of observations. Therefore, in this study, we aim to identify and discuss the different aerosol types and AQI in Beijing from 2004 to 2015. The aerosol types are classified into six categories: dust, mixed, highly-absorbing, moderately-absorbing, slightly-absorbing, and scattering by a multiple clustering method with the fine mode fraction (FMF) and single scattering albedo (SSA) data of retrievals from the global Aerosol Robotic Network (AERONET) sun photometer sites. The AQI levels: are good (0–50); moderate (51–100); unhealthy for sensitive groups (101–150); unhealthy (151–200); very unhealthy (201–300); and hazardous (>300). The results show that a significant FMF variability occurred among different seasons in Beijing, with maximum values present in spring and minimum values in winter. The SSA values exhibit variation, with small fluctuations from season to season. In the case of BJ station, the scattering aerosols are more frequent in summer (39%) and less in winter (1%), while the coarse particles (dust) are more frequent in spring (18%) and less in autumn (6%). In contrast, the absorbing aerosols (especially slightly-absorbing) are more frequent in summer (35%) and winter (15%). However, the mixed aerosol types are more frequent in spring (38%) and less in summer (8%). There is a similar seasonal variation in XH. In the past 12 years, the slightly-absorbing aerosol type in Beijing has increased by approximately 14%, which is believed to be due to the rapid development of industrial cities. In addition, comparing the urban and suburban regions, the slightly-absorbing aerosol type is the dominant aerosol type in both areas. Furthermore, to identify the dominant aerosol types which lead to air pollution, a related analysis was carried out by analyzing different aerosol types and the relationship between aerosol types and AQI. The results indicate that the air pollution was strongly correlated to slightly-absorbing aerosols, in which the percentage of slightly-absorbing aerosols was about 49% during the hazardous days in 2013–2015, and the correlation between AQI and aerosol types is also strong (R2 = 0.76 and 0.97, in Beijing and Xianghe).

Run away? Air pollution and emigration interests in China

This paper investigates the impact of air pollution on people’s interest in emigration. Using an online search index on “emigration” which is positively correlated with its search volume, we develop a city-by-day measurement of people’s emigration sentiment. We find that searches on “emigration” will grow by approximately 2.3–4.8% the next day if today’s air quality index (AQI) is increased by 100 points. In addition, such an effect is more pronounced when the AQI level is above 200, a sign of “heavily polluted” and “severely polluted” days. We also find that such effect differs by destination countries and by metropolitan areas.

Abstract P002: Long Term Exposure to Outdoor Air Pollution and Cardiovascular Health

BACKGROUND: Although the link between air pollution and cardiovascular disease has been controversial in recent decades, it remains a top global health concern. Most studies have assessed only the relationship between pollutant concentrations and morbidity or mortality in populous cities. In this study, we investigated the association of long term exposure to major air pollutants with current cardiovascular health. This outcome was a measure of health rather than disease, as measured by the Cardiovascular Health Index (CVHI) developed by the American Heart Association. METHODS: We analyzed 2011 data from 3007 counties across the US using Behavioral Risk Factor Surveillance System and Area Health Resources File. Air Quality Index (AQI) for five major pollutants from 2001-2011; Ozone, Sulfur dioxide and Carbon monoxide and Fine particulate matter (aerodynamic diameter of 10 and ≤2.5 μm) were obtained from the EPA Air Quality System database. Categories were based on the 11-year average pollutant AQI level and using Jenks optimization method; persistently good, variant and persistently bad. Associations between categories and the mean CVHI were evaluated using Poisson regression models adjusting for age, sex, race/ethnicity and socioeconomic status at the individual and population level. RESULTS: PM2.5 was most frequently measured (938 counties) and carbon monoxide least frequently (224 counties). Correlations between pollutants were moderate and significant (p<0.0001), ranging from r=0.30 between CO and Oz to r=0.52 between SD and PM2.5. Four pollutants had 11-year average AQI levels significantly associated with increased mean CVHI score of individuals. Living in a county categorized as ‘persistently good’ or ‘variant’ AQI levels for ozone is significantly associated with an estimated 3% increase in CVHI (95% CI 0.1% - 5.0%) as compared to living in a county of ‘persistently bad’ AQI levels. In addition, living in a county of only ‘persistently good’ AQI levels for PM2.5 is significantly associated with an estimated 5% increase in CVHI (95% CI 3% - 9%) as compared to living in a county of ‘persistently bad’ AQI levels. Inverse relationships existed for both PM10 and carbon monoxide. CONCLUSIONS: It is difficult to tease apart the independent effects of individual air pollutants on health as humans are exposed to a mixture of gases. However we have shown that at the individual level, there is an association between long term exposure to air pollution and its effects on current cardiovascular health. Further research is needed to determine whether these effects exist at varying levels of subject characteristics.

Is air quality index associated with cardiometabolic risk factors in adolescents? The CASPIAN-III Study

ObjectiveThis study aims to evaluate the association of air quality index (AQI) with cardiometabolic risk factors in a nationally representative sample of healthy adolescents. MethodsThis nationwide survey was conducted among a stratified multi-stage probability sample of students, aged 10–18 years, from 27 provinces of Iran. Those students with history of any acute or chronic diseases, any medication use, as well as active or passive smoking were not included to the current study. Dietary and physical activity habits were documented by valid questionnaires. Physical examination and blood sampling were conducted under standard protocols. AQI data were obtained from air pollution monitoring sites from the entire country by considering air pollutants concentration, which includes all provincial counties containing different clusters. ResultsThe study participants consisted of 1413 students (48.8% boys) with a mean (SD) age of 14.81±2.48 years. The mean AQI level was 285.37±30.11 at national levels. After adjustment for confounding factors including age, sex, and anthropometric measures, as well as for dietary and physical activity habits, multiple linear regressions based on correlation of coefficients of the AQI with cardiometabolic risk factors showed significant positive correlations of AQI with systolic blood pressure, fasting blood glucose, total cholesterol, LDL-cholesterol, and triglycerides, as well as significant negative correlations with HDL-cholesterol. After adjustment for abovementioned confounding factors, binary logistic regressions analyses showed that AQI increased the risk of abnormal levels of some risk factors as elevated levels of systolic blood pressure, total cholesterol, and triglycerides. ConclusionThe associations of low air quality with some cardiometabolic factors in the current survey, although not strong, might be considered as an evidence of the adverse cardiometabolic consequences of exposure to air pollutants in the pediatric age group, and predisposing them to earlier development of non-communicable diseases.

Ischemic Heart Disease and Ambient Air Pollution of Particulate Matter 2.5 in 51 Counties in the U.S.

Ischemic heart disease (IHD) is one of the most common health threats to the adult population of the U.S. and other countries. The objective of this study was to examine the association between exposure to elevated annual average levels of Particulate matter 2.5 (PM2.5) air quality index (AQI) and IHD in the general population. We combined data from the Behavioral Risk Factor Surveillance System and the U.S Environmental Protection Agency air quality database. We analyzed the data using SUDAAN software to adjust the effects of sampling bias, weights, and design effects. The prevalence of IHD was 9.6% among respondents who were exposed to an annual average level of PM2.5 AQI > 60 compared with 5.9% among respondents exposed to an annual average PM2.5 AQI < or = 60. The respondents with higher levels of PM2.5 AQI exposure were more likely to have IHD (adjusted odds ratio = 1.72, 95% confidence interval 1.11, 2.66) than respondents with lower levels of exposure after adjusting for age, gender, race/ethnicity, education, smoking, body mass index, diabetes, hypertension, and hypercholesterolemia. Our study suggested that exposure to relatively higher levels of average annual PM2.5 AQI may increase the likelihood of IHD. In addition to encouraging health-related behavioral changes to reduce IHD, efforts should also focus on implementing appropriate measures to reduce exposure to unhealthy AQI levels.