Long-term Time Trends Research Articles

Fine Particulate Air Pollution and Hospital Admissions for Asthma: A Case-Crossover Study in Taipei

This study was undertaken to determine whether there was a correlation between fine particles (PM2.5) levels and hospital admissions for asthma in Taipei, Taiwan. Hospital admissions for asthma and ambient air pollution data for Taipei were obtained for the period of 2006–2010. The relative risk of hospital admissions for asthma was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. For the single-pollutant model (without adjustment for other pollutants), increased asthma admissions were significantly associated with PM2.5 levels both on warm days (>23°C) and cool days (<23°C), with an interquartile range rise associated with a 12% (95% CI = 6–18%) and 3% (95% CI = 0–8%) elevation in admissions for asthma, respectively. In the two-pollutant models, PM2.5 levels remained significant for increased asthma admissions after inclusion of SO2 or O3 both on warm and cool days. This study provides evidence that higher levels of PM2.5 elevate the risk of hospital admissions for asthma in Taiwan.

An integrative risk assessment approach for persistent chemicals: A case study on dioxins, furans and dioxin-like PCBs in France

For persistent chemicals slowly eliminated from the body, the accumulated concentration (body burden), rather than the daily exposure, is considered the proper starting point for the risk assessment. This work introduces an integrative approach for persistent chemical risk assessment by means of a dynamic body burden approach. To reach this goal a Kinetic Dietary Exposure Model (KDEM) was extended with the long term time trend in the exposure (historic exposure) and the comparison of bioaccumulation with body burden references for toxicity. The usefulness of the model was illustrated on the dietary exposure to PolyChlorinatedDibenzo-p-Dioxins (PCDDs), PolyChlorinatedDibenzoFurans (PCDFs) and PolyChlorinated Biphenyls (PCBs) in France. Firstly the dietary exposure to these compounds was determined in 2009 and combined with its long term time trend. In order to take differences between the kinetics of PCDD/F and dl-PCBs into account, three groups of congeners were considered i.e. PCDD/Fs, PCB 126 and remaining dl-PCBs. The body burden was compared with reference body burdens corresponding to reproductive, hepatic and thyroid toxicity. In the case of thyroid toxicity this comparison indicated that in 2009 the probability of the body burden to exceed its reference ranged from 2.8% (95% CI: 1.5–4.9%) up to 3.9% (95% CI: 2.7–7.1%) (18–29 vs. 60–79year olds). Notwithstanding the decreasing long-term time trend of the dietary dioxin exposure in France, this probability still is expected to be 1.5% (95% CI: 0.3–2.5%) in 2030 in 60–79 olds. In the case of reproductive toxicity the probability of the 2009 body burden to exceed its reference ranged from 3.1% (95% CI: 1.4–5.0%) (18–29year olds) to 3.5% (95% CI: 2.2–5.2%) (30–44year olds). In 2030 this probability is negligible in 18–29year olds, however small though significant in 30–44year olds (0.7%, 95% CI: 0–1.6%). In the case of hepatic toxicity the probability in 2009 even in 60–79year olds already was negligible. In conclusion this approach indicates that in France dioxin levels in food form a declining, though still present, future health risk with respect to thyroid and reproductive toxicity.

Associations between ambient air pollution and blood markers of inflammation and coagulation/fibrinolysis in susceptible populations

The pathophysiological pathways linking particulate air pollution to cardiovascular disease are still not fully understood. We examined the association between ambient air pollutants and blood markers of inflammation and coagulation/fibrinolysis in three potentially susceptible populations.Three panels of non-smoking individuals were examined between 3/2007 and 12/2008: 1) with type 2 diabetes mellitus (T2D, n=83), 2) with impaired glucose tolerance (IGT, n=104), and 3) with a potential genetic predisposition which could affect detoxifying and inflammatory pathways (n=87) defined by the null polymorphism for glutathione S-transferase M1 (GSTM1) in combination with a certain single nucleotide polymorphism on the C-reactive protein (CRP) or the fibrinogen gene. Study participants had blood drawn up to seven times every four to six weeks. In total, 1765 blood samples were analysed for CRP, interleukin (IL)-6, soluble CD40 ligand (sCD40L), fibrinogen, myeloperoxidase (MPO), and plasminogen activator inhibitor-1 (PAI-1). Hourly mean values of particulate air pollutants, particle number concentrations in different size ranges and gaseous pollutants were collected at fixed monitoring sites and individual 24hour averages calculated. Associations between air pollutants and blood markers were analysed for each panel separately and taking the T2D panel and the IGT panel together, using additive mixed models adjusted for long-term time trend and meteorology.For the panel with potential genetic susceptibility, CRP and MPO increased for most lags, especially with the 5-day average exposure (% change of geometric mean and 95% confidence interval: 22.9% [12.0;34.7] for CRP and 5.0% [0.3;9.9] for MPO per interquartile range of PM2.5). Small positive associations were seen for fibrinogen while sCD40L, PAI-1 and IL-6 mostly decreased in association with air pollution concentrations. Except for positive associations for fibrinogen we did not see significant results with the two other panels.Participants with potential genetic susceptibility showed a clear association between inflammatory blood biomarkers and ambient air pollutants. Our results support the hypothesis that air pollution increases systemic inflammation especially in susceptible populations which may aggravate atherosclerotic diseases and induce multi-organ damage.

The effects of fine particulate air pollution on daily mortality: a case-crossover study in a subtropical city, Taipei, Taiwan.

This study was undertaken to determine whether there was an association between PM2.5 levels and daily mortality in Taipei, Taiwan, the largest metropolitan city with a subtropical climate. Daily mortality, air pollution, and weather data for Taipei were obtained for the period from 2006–2008. The relative risk of daily mortality was estimated using a time-stratified case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. For the single pollutant model, PM2.5 showed association with total mortality both on warm (>23 °C) and cool days (<23 °C). There is no indication of an association between PM2.5 and risk of death due to respiratory diseases both on warm and cool days. PM2.5 had effects on the risk of death from cardiovascular diseases only on cool days. In the two-pollutant models, PM2.5 remained effects on the risk of mortality for all cause and cardiovascular disease after the inclusion of SO2 and O3 both on warm and cool days. This study provides evidence that short-term exposure to PM2.5 increased the risk of death for all cause and cardiovascular disease.

Heat-related morbidity in brisbane, australia: spatial variation and area-level predictors.

Background: Extreme heat is a leading weather-related cause of illness and death in many locations across the globe, including subtropical Australia. The possibility of increasingly frequent and severe heat waves warrants continued efforts to reduce this health burden, which could be accomplished by targeting intervention measures toward the most vulnerable communities.Objectives: We sought to quantify spatial variability in heat-related morbidity in Brisbane, Australia, to highlight regions of the city with the greatest risk. We also aimed to find area-level social and environmental determinants of high risk within Brisbane.Methods: We used a series of hierarchical Bayesian models to examine city-wide and intracity associations between temperature and morbidity using a 2007–2011 time series of geographically referenced hospital admissions data. The models accounted for long-term time trends, seasonality, and day of week and holiday effects.Results: On average, a 10°C increase in daily maximum temperature during the summer was associated with a 7.2% increase in hospital admissions (95% CI: 4.7, 9.8%) on the following day. Positive statistically significant relationships between admissions and temperature were found for 16 of the city’s 158 areas; negative relationships were found for 5 areas. High-risk areas were associated with a lack of high income earners and higher population density.Conclusions: Geographically targeted public health strategies for extreme heat may be effective in Brisbane, because morbidity risk was found to be spatially variable. Emergency responders, health officials, and city planners could focus on short- and long-term intervention measures that reach communities in the city with lower incomes and higher population densities, including reduction of urban heat island effects.Citation: Hondula DM, Barnett AG. 2014. Heat-related morbidity in Brisbane, Australia: spatial variation and area-level predictors. Environ Health Perspect 122:831–836; http://dx.doi.org/10.1289/ehp.1307496

Short-Term Effect of Fine Particulate Air Pollution on Daily Mortality: A Case-Crossover Study in a Tropical City, Kaohsiung, Taiwan

Many studies have examined the short-term effects of air pollution on frequency of daily mortality over the past two decades. However, information on the relationship between levels of fine particles (PM2.5) and daily mortality is relatively sparse due to limited availability of monitoring data. Further the results are inconsistent. This study was undertaken to determine whether there was an association between PM2.5 levels and daily mortality rate in Kaohsiung, Taiwan, a large industrial city with a tropical climate. Daily mortality rate, air pollution parameters, and weather data for Kaohsiung were obtained for the period from 2006 through 2008. The relative risk of daily mortality occurrence was estimated using a time-stratified case-crossover approach, controlling for (1) weather variables, (2) day of the week, (3) seasonality, and (4) long-term time trends. For the single-pollutant model (without adjustment for other pollutants), no significant effects were found between PM2.5 and frequency of daily mortality on warm days (≥25°C). On cool days, PM2.5 showed significant correlation with increased risk of mortality rate for all causes and circulatory diseases in single-pollutant model. There was no indication of an association between PM2.5 and deaths due to respiratory diseases. The relationship appeared to be stronger on cool days. This study provided evidence of associations between short-term exposure to PM2.5 and elevated risk of death for all cause and circulatory diseases.

Fine Particulate Air Pollution and Hospital Admissions for Pneumonia in a Subtropical City: Taipei, Taiwan

This study was undertaken to determine whether there was a correlation between fine particles (PM2.5) levels and hospital admissions for pneumonia in Taipei, Taiwan. Hospital admissions for pneumonia and ambient air pollution data for Taipei were obtained for the period from 2006 to 2010. The relative risk of hospital admissions for pneumonia was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. For the single-pollutant model (without adjustment for other pollutants), increased numbers of admissions for pneumonia were significantly associated with higher PM2.5 levels both on warm days (>23°C) and on cool days (<23°C). This was accompanied by an interquartile range elevation correlated with a 12% (95% CI = 16%–13%) and 4% (95% CI = 3%–6%) rise in number of admissions for pneumonia, respectively. In the two-pollutant models, PM2.5 remained significant after inclusion of sulfur dioxide (SO2) or ozone (O3) both on warm and on cool days. This study provides evidence that higher levels of PM2.5 increase the risk of hospital admissions for pneumonia.

Extreme Precipitation and Beach Closures in the Great Lakes Region: Evaluating Risk among the Elderly

As a result of climate change, extreme precipitation events are expected to increase in frequency and intensity. Runoff from these extreme events poses threats to water quality and human health. We investigated the impact of extreme precipitation and beach closings on the risk of gastrointestinal illness (GI)-related hospital admissions among individuals 65 and older in 12 Great Lakes cities from 2000 to 2006. Poisson regression models were fit in each city, controlling for temperature and long-term time trends. City-specific estimates were combined to form an overall regional risk estimate. Approximately 40,000 GI-related hospital admissions and over 100 beach closure days were recorded from May through September during the study period. Extreme precipitation (≥90th percentile) occurring the previous day (lag 1) is significantly associated with beach closures in 8 of the 12 cities (p < 0.05). However, no association was observed between beach closures and GI-related hospital admissions. These results support previous work linking extreme precipitation to compromised recreational water quality.

Birth-cohort patterns in Crohn’s disease and ulcerative colitis

To test the long-term time trends of mortality from inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), for the presence of birth-cohort phenomena. We analyzed mortality data from the national statistical offices of Canada, England and Wales, Italy, the Netherlands, Switzerland, and the USA for the past 60-80 years. Age-specific rates of death were plotted against the period of death, as period-age contours, and against the period of birth, as cohort-age contours. In all six countries alike, the general time trends of IBD have been shaped by an underlying birth-cohort pattern. This pattern was also observed in the data of CD and UC analyzed separately. UC mortality increased in all generations born during the 19th century. It peaked among generations born shortly before the turn of the century and then decreased in all subsequent generations born throughout the 20th century. Compared with UC, the birth-cohort pattern of CD was delayed by 30-50 years. In addition to one risk factor responsible for the general occurrence of IBD and possibly UC alone, there exists at least one additional risk factor responsible for CD. Exposure to both separate risk factors must occur during early life.

Meteorological Parameters and the Onset of Chest Pain in Subjects with Acute ST-Elevation Myocardial Infarction: an Eight-Year, Single-Center Study in China

Objective: The purpose of this study was to investigate the influence of weather on the occurrence of acute ST-elevation myocardial infarction in Chinese subjects. Methods: Weather and climate data, as well as the occurrence of STEMI, were monitored at 2 am, 8 am, 2 pm, and 8 pm between 2003 and 2010. Generalized additive Poisson models were utilized to plot the numbers of patients with STEMI within 6 hour intervals against climatological variations, after accounting for the effects of the hour and season. Results: The inclusion of meteorological conditions, including observed atmospheric pressure (hPa, hectopascal) variations during the previous three hours and temperature (°C, degrees Celsius), significantly affected the occurrence of STEMI, as measured every six hours. Compared with the 50th percentile of atmospheric pressure variations, the RRs (95% CI) for the first percentile, 10th percentile, 25th percentile, 75th percentile, 90th percentile, and 99th percentile of atmospheric pressure variation over lag 0 were 1.66 (1.36∼2.03), 1.47 (1.30∼1.67), 1.22 (1.12∼1.33), 1.16 (1.07∼1.25), 1.27 (1.13∼1.43), and 1.16 (0.92∼1.46), respectively. Compared to the 50th percentile of temperature, the RRs (95% CI) for the first percentile, 10th percentile, 25th percentile, 75th percentile, 90th percentile, and 99th percentile of temperature over lag 0 were 0.58 (0.40∼0.83), 0.60 (0.46∼0.78), 0.69 (0.57∼0.83), 1.33 (1.14∼1.56), 1.39 (1.13∼1.71), and 1.17 (0.84∼1.63), respectively. Conclusions: Based on the eight-year, single-center study, significant relationships were observed among the occurrence of STEMI and atmospheric pressure variations during the previous three hours and temperature after account for long-term time trends.

The impact of climate change on heat-related mortality in six major cities, South Korea, under representative concentration pathways (RCPs).

Background:We aimed to quantify the excess mortality associated with increased temperature due to climate change in six major Korean cities under Representative Concentration Pathways (RCPs) which are new emission scenarios designed for the fifth assessment report of the Intergovernmental Panel on Climate Change (IPCC).Methods:We first examined the association between daily mean temperature and mortality in each during the summertime (June to September) from 2001 to 2008. This was done using a generalized linear Poisson model with adjustment for a long-term time trend, relative humidity, air pollutants, and day of the week. We then computed heat-related mortality attributable to future climate change using estimated mortality risks, projected future populations, and temperature increments for both future years 2041–2070 and 2071–2100 under RCP 4.5 and 8.5. We considered effects from added days with high temperatures over thresholds and shifted effects from high to higher temperature.Results:Estimated excess all-cause mortalities for six cities in Korea ranged from 500 (95% CI: 313–703) for 2041–2070 to 2,320 (95% CI: 1430–3281) deaths per year for 2071–2100 under two RCPs. Excess cardiovascular mortality was estimated to range from 192 (95% CI: 41–351) to 896 (95% CI: 185–1694) deaths per year, covering about 38.5% of all-cause excess mortality. Increased rates of heat-related mortality were higher in cities located at relatively lower latitude than cities with higher latitude. Estimated excess mortality under RCP 8.5, a fossil fuel-intensive emission scenario, was more than twice as high compared with RCP 4.5, low to medium emission scenario.Conclusions:Excess mortality due to climate change is expected to be profound in the future showing spatial variation. Efforts to mitigate climate change can cause substantial health benefits via reducing heat-related mortality.

Associations between extreme precipitation and gastrointestinal-related hospital admissions in Chennai, India.

Background: Understanding the potential links between extreme weather events and human health in India is important in the context of vulnerability and adaptation to climate change. Research exploring such linkages in India is sparse.Objectives: We evaluated the association between extreme precipitation and gastrointestinal (GI) illness-related hospital admissions in Chennai, India, from 2004 to 2007.Methods: Daily hospital admissions were extracted from two government hospitals in Chennai, India, and meteorological data were retrieved from the Chennai International Airport. We evaluated the association between extreme precipitation (≥ 90th percentile) and hospital admissions using generalized additive models. Both single-day and distributed lag models were explored over a 15-day period, controlling for apparent temperature, day of week, and long-term time trends. We used a stratified analysis to explore the association across age and season.Results: Extreme precipitation was consistently associated with GI-related hospital admissions. The cumulative summary of risk ratios estimated for a 15-day period corresponding to an extreme event (relative to no precipitation) was 1.60 (95% CI: 1.29, 1.98) among all ages, 2.72 (95% CI: 1.25, 5.92) among the young (≤ 5 years of age), and 1.62 (95% CI: 0.97, 2.70) among the old (≥ 65 years of age). The association was stronger during the pre-monsoon season (March–May), with a cumulative risk ratio of 6.50 (95% CI: 2.22, 19.04) for all ages combined compared with other seasons.Conclusions: Hospital admissions related to GI illness were positively associated with extreme precipitation in Chennai, India, with positive cumulative risk ratios for a 15-day period following an extreme event in all age groups. Projected changes in precipitation and extreme weather events suggest that climate change will have important implications for human health in India, where health disparities already exist.Citation: Bush KF, O’Neill MS, Li S, Mukherjee B, Hu H, Ghosh S, Balakrishnan K. 2014. Associations between extreme precipitation and gastrointestinal-related hospital admissions in Chennai, India. Environ Health Perspect 122:249–254; http://dx.doi.org/10.1289/ehp.1306807

Short-Term Effects of Fine Particulate Air Pollution on Ischemic Stroke Occurrence: A Case-Crossover Study

This study was undertaken to determine whether there was a correlation between fine particles (PM2.5) levels and hospital admissions for ischemic stroke (IS) in Taipei, Taiwan. Hospital admissions for IS and ambient air pollution data for Taipei were obtained for the period from 2006–2010. The relative risk of hospital admissions was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. For the single-pollutant model (without adjustment for other pollutants), increased admissions for IS were significantly associated with higher levels of PM2.5 on both warm days (>23°C) and cool days (<23°C), with an interquartile range rise associated with a 11% (95% CI = 8–14%) and 4% (95% CI = 2–7%) elevation in admissions for IS, respectively. In the two-pollutant models, PM2.5 remained significantly increased after inclusion of sulfur dioxide (SO2) or ozone (O3) on both warm and cool days. This study provides evidence that higher levels of PM2.5 enhance the risk of hospital admissions for IS.

Fine particulate air pollution and hospital admissions for chronic obstructive pulmonary disease: a case-crossover study in Taipei.

We undertook this study to investigate whether there is an association between atmospheric fine particles (PM2.5) levels and inpatient admissions for chronic obstructive pulmonary disease (COPD) in Taipei, Taiwan. Data on inpatient admissions for COPD and ambient on air pollution levels in Taipei were obtained for years 2006 to 2010. We estimated the relative risk of inpatient admissions for COPD using a case-crossover design with the following control variables: weather measures, day of the week, seasonality, and long-term time trends. For the single-pollutant model (not controlling for other atmospheric pollutants), COPD admissions were significantly and positively associated with higher PM2.5 levels during both warm days (>23 °C) and cool days (<23 °C), with an interquartile range increase of 12% (95% CI = 8–16%) and 3% (95% CI = 0–7%) in COPD admissions, respectively. In the two-pollutant models, PM2.5 remained significant even controlling for SO2 or O3 on both warm and cool days. Taken as a whole, our study demonstrates that higher levels of PM2.5 may increase the risk of inpatient admissions for COPD.

The Impact of Long-Term Exposure to Air Pollution on Conduit Artery and Microvascular Function

Background: Long-term exposure to ambient air pollution, including fine particulate matter (PM2.5), has been associated with cardiovascular morbidity and mortality. Impaired vascular responses may in part explain these findings, but few studies have examined chronic effects of long-term exposures incorporating measures of both conduit artery and microvascular function in a large population-based study. Aims: We evaluated the impact of residential proximity to primary or secondary highway (&lt;100m, 100-200m, 200-400m, &gt;400m) and long term exposure to PM2.5 (1-year average) on brachial artery flow mediated dilation (FMD) and reactive hyperemia in the Framingham Offspring and Third Generation Cohorts. Methods: FMD (%) and hyperemic flow velocity (cm/s) were assessed in the Offspring 7th (1998-2001) and Third Generation 1st (2001-2005) exams (n=5,133). We evaluated associations between residential proximity to major roads and spatially resolved estimated PM2.5 from land use and satellite images with FMD and hyperemic flow using linear regression. Results: Compared to living further than 400m from a major road, living within 100m was associated with -0.31% (95% CI: -0.53, -0.09) lower FMD and -1.49 cm/s (95% CI: -2.9,- 0.09) lower hyperemic flow velocity in models adjusted for age, sex, body mass index, smoking status, long-term time trends, season, cohort, and indicators of socioeconomic position. A 1 µg/m3 higher average PM2.5 was associated with -0.09% (95% CI: -0.24, 0.06) lower FMD, and -1.07 cm/s (95% CI: -2.0, -0.12) lower hyperemic flow. Results were not materially altered after further adjustment for potential mediators. The magnitude of estimates for hyperemic flow became stronger when we excluded smokers and participants using antihypertensive or lipid-lowering medications. Conclusions: In a large, community-based cohort, measures of long-term exposure to air pollution were associated with impaired conduit and microvascular function.

Fine particulate air pollution and hospital admissions for congestive heart failure: a case-crossover study in Taipei

This study was undertaken to determine whether there was an association between fine particles (PM2.5) levels and hospital admissions for congestive heart failure (CHF) in Taipei, Taiwan. Hospital admissions for CHF and ambient air pollution data for Taipei were obtained for the period 2006–2010. The relative risk of hospital admissions was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality and long-term time trends. For the single pollutant model (without adjustment for other pollutants), increased CHF admissions were significantly associated with PM2.5 both on warm days (>23 °C) and cool days (<23 °C), with an interquartile range increase associated with a 13% (95% CI = 9–17%) and 3% (95% CI = 0–7%) increase in CHF admissions, respectively. In the two-pollutant models, PM2.5 remained significant after the inclusion of SO2 or O3 both on warm and cool days. This study provides evidence that higher levels of PM2.5 increase the risk of hospital admissions for CHF.

Review article: historic changes ofHelicobacter pylori-associated diseases

The long-term time trends of multiple gastrointestinal diseases are characterised by a striking rise and fall. These temporal changes provide important clues about disease aetiology. To highlight the importance of Helicobacter pylori infection in shaping the temporal trends of many common gastrointestinal diseases. Literature review of the time trends associated with common digestive diseases. The general trends of gastric ulcer, duodenal ulcer, gastric cancer, colon cancer, rectum cancer have all been shaped by a similar underlying birth-cohort phenomenon. Mortality associated with these diagnoses increased in all generations born during the nineteenth century. It peaked among generations born shortly before the turn of the century and then decreased in all subsequent generations born throughout the twentieth century. These patterns can be observed in the incidence, hospitalisation and mortality data from many different countries. They reflect similar rising and falling trends of H. pylori infection in the general population. Diseases that are inversely associated with H. pylori, such as reflux disease, erosive oesophagitis, Barrett's oesophagus, and oesophageal adenocarcinoma, have seen a striking rise during the recent decline of H. pylori infection. The temporal variations of H. pylori infection have affected the occurrence of gastroenterology's most common disorders.

Short-Term Effects of Fine Particulate Air Pollution on Emergency Room Visits for Cardiac Arrhythmias: A Case-Crossover Study in Taipei

This study was undertaken to determine whether there was an association between fine particles (PM2.5) levels and number of emergency room (ER) visits for cardiac arrhythmias in Taipei, Taiwan. ER visits for cardiac arrhythmias and ambient air pollution data for Taipei were obtained for the period 2006–2010. The relative risk (RR) of ER visits was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. For the single-pollutant model (without adjustment for other pollutants), increased numbers of ER cardiac arrhythmia visits were significantly associated with PM2.5 on both warm days (>23°C) and cool days (< 23°C), with an interquartile range rise associated with a 10% (95% CI = –15%) and 4% (95% CI = 0–8%) elevation in number of ER visits for cardiac arrhythmias, respectively. In the two-pollutant models, PM2.5 levels remained significant after inclusion of sulfur dioxide (SO2) or ozone (O3) on both warm and cool days. This study provides evidence that higher levels of PM2.5 increase the risk of number of ER visits for cardiac arrhythmias.

Fine Particulate Air Pollution and Hospital Admissions for Myocardial Infarction in a Subtropical City: Taipei, Taiwan

This study was undertaken to determine whether there was a correlation between fine particles (PM2.5) levels and hospital admissions for myocardial infarction (MI) in Taipei, Taiwan. Hospital admissions for MI and ambient air pollution data for Taipei were obtained for the period 2006–2010. The relative risk of hospital admissions for MI was estimated using a casecrossover approach, controlling for weather variables, day of the week, seasonality, and longterm time trends. For the single-pollutant model (without adjustment for other pollutants), increased numbers of MI admissions were significantly associated with higher PM2.5 levels both on warm days (>23°C) and on cool days (<23°C). This was accompanied by an interquartile range elevation correlated with a 10% (95% CI = 6–15%) and 5% (95% CI = 1–9%) rise in number of MI admissions, respectively. In the two-pollutant models, PM2.5 remained significant after inclusion of SO2 or O3 on both warm and cool days. This study provides evidence that higher levels of PM2.5 increase the risk of hospital admissions for MI.

Source Apportionment of Polychlorinated Biphenyls in Chicago Air from 1996 to 2007

While the overall atmospheric polychlorinated biphenyl (PCB) levels in many urban areas are declining, it is not clear whether this decline is due to control strategies or merely due to natural attenuation. To investigate this issue, Positive Matrix Factorization (PMF) was used to identify the dominant sources of gas-phase PCBs in the atmosphere of Chicago, IL using a data set collected from 1996 to 2007 by the Integrated Atmospheric Deposition Network (IADN). Both the older PMF2 software and the newer EPA-sponsored PMF 3.0 software were employed. Both models resolved 5 factors, but they yielded somewhat different results in terms of the congener patterns of the factors and their temporal variation. The PMF2 software resolved factors that better resembled the original Aroclor formulations. While it is possible to apply an exponential decay model to this data set and derive statistically significant rate constants that indicate that ΣPCBs and some of the resolved factors are declining in Chicago air, examining plots of the 365-day moving average concentrations shows that they do not decrease in a fashion consistent with exponential decay. Instead, they display periods of decline as well as periods of increase. Thus an exponential decay model is not appropriate, and long-term time trends identified from this 12-year data set cannot be used to predict the future trends in PCB concentrations in the air of Chicago. Two of the five resolved factors resemble low MW Aroclors, and declined from 1996 to 2007. The other three factors, which represent the majority of the mass in the data set, are either not declining or actually increasing over time. Thus past efforts to eliminate PCBs from the Great Lakes ecosystem have been only marginally effective, if at all. Additional effort is needed to identify and eliminate atmospheric PCB sources in Chicago.