Air pollution and emergency hospital admissions for cardiovascular diseases in Valencia, Spain

Ambient carbon monoxide and the risk of cardiovascular disease emergency room visits: a time-series study in Lanzhou, China

Until now, the epidemiological evidence on the association between short-term exposure to ambient carbon monoxide (CO) and cardiovascular diseases (CVDs) is relatively lacking and controversial. This study aims to examine the relationship between ambient CO and daily emergency room visits (ERVs) for total and cause-specific CVD in Lanzhou, China. A distributed lag nonlinear model was used to examine the association. For every 1 mg/m3 increase in the CO concentration, the relative risks of daily ERVs were 1.041 (95% CI: 1.017, 1.065) for total CVD, 1.065 (95% CI: 1.018, 1.114) for ischemic heart disease (IHD), 1.083 (95% CI: 1.020, 1.149) for heart rhythm disturbances (HRD), 1.062 (95% CI: 1.011, 1.115) for heart failure (HF), and 1.057 (95% CI: 1.017, 1.098) for cerebrovascular diseases (CD). For the two different gender subgroups, the short-term impact of CO on total CVD, IHD, and CD was relatively stronger for the females than for the males, while the opposite was true for HRD and HF. In the age subgroup analyses, the effect of ambient CO on total CVD and IHD appeared to be greater for the age ≥ 65 years group, while the opposite was true for HRD, HF, and CD. The associations for all disease categories were stronger in cold seasons than in warm seasons. We also observed a nearly linear correlation between CO and CVD ERVs. In conclusion, the study showed that exposure to ambient CO may increase the risks of ERVs for total and cause-specific CVD. Besides, CO-ERVs associations may vary by gender and age.

Evaluation of an air quality warning system for vulnerable and susceptible individuals in Korea: an interrupted time series analysis

OBJECTIVES

This study was conducted to elucidate the effects of an air quality warning system (AQWS) implemented in January 2015 in Korea by analyzing changes in the incidence and exacerbation rates of environmental diseases.

METHODS

Data from patients with environmental diseases were extracted from the National Health Insurance Service-National Sample Cohort database from 2010 to 2019, and data on environmental risk factors were acquired from the AirKorea database. Patient and meteorological data were linked based on residential area. An interrupted time series analysis with Poisson segmented regression was used to compare the rates before and after AQWS introduction. Adjustment variables included seasonality, air pollutants (carbon monoxide, nitrogen dioxide, sulfur dioxide, particulate matter less than 10 μm in diameter, and ozone), temperature, and humidity.

RESULTS

After AQWS implementation, the incidence of asthma gradually decreased by 20.5%. Cardiovascular disease and stroke incidence also significantly decreased (by 34.3 and 43.0%, respectively). However, no immediate or gradual decrease was identified in the exacerbation rate of any environmental disease after AQWS implementation. Sensitivity analyses were performed according to age, disability, and health insurance coverage type. Overall, the AQWS effectively mitigated the occurrence of most environmental diseases in Korea. However, the relationships between alarm system implementation and reduced incidence differed among diseases based on the characteristics of vulnerable and sensitive individuals.

CONCLUSIONS

Our results suggest that by tailoring the AQWS to demographic and sociological characteristics and providing enhanced education about the warning system, interventions can become an efficient policy tool to decrease air pollution- related health risks.

Analysis of Spatial Distribution of CVD and Multiple Environmental Factors in Urban Residents

Cardiovascular disease (CVD) poses a serious threat to urban health with the development of urbanization. There are multifaceted and comprehensive influencing factors for CVD, so clarifying the spatial distribution characteristics of CVD and multiple environmental influencing factors is conducive to improving the active health intervention of urban environment and promoting the sustainable development of cities The spatial distribution characteristics of CVD deaths in a certain district, Bengbu City, Huaihe River Basin, China, in 2019 were explored, and the correlation between multiple environmental factors and CVD mortality was investigated in this study, to reveal the action mechanism of multiple environmental factors affecting the risk of mortality. Relevant studies have shown that (1) CVD deaths are characterized as follows: male deaths are more than females; the mortality is higher in those of higher age; most of them are unemployed; cardiocerebral infarction is the main cause of death; and the deaths are mainly distributed in the central city and near the old urban area. (2) The increased CVD mortality can be attributed to the increased density of restaurants and cigarette and wine shops around the residential area, the increased traffic volume, the dense residential and spatial forms, the low green space coverage, and the distance from rivers. Therefore, appropriate urban planning and policies can improve the active health interventions in cities and reduce CVD mortality.

Mortality attributable to fine particulate matter in Asia, 2000-2015: a cross-sectional cause-of-death analysis

OBJECTIVES

To investigate the effect that particulate matter with a diameter of 2.5 μg (PM2.5) had on mortality in Asian populations in years 2000-2015.

SETTING

Mortality and level of PM2.5 data from the United Nations, Global Burden of Disease and University of Chicago were used.

OUTCOME MEASURES

Age pattern of mortality and the number of life-years lost (LYL) attributable to PM2.5 in years 2000-2015. LYL were further separated into causes of death to quantify the contribution of each cause.

RESULTS

Ischaemic heart disease (IHD) mortality increased to represent over 31% of the LYL attributable to PM2.5 between 2005-2010 and 2010-2015 in Asia (females 31% and males 35%). However, great diversity in LYL attributable to PM2.5 by causes-of-death were found across the region, with IHD proportions of LYL ranging from 25% to 63% for males from Eastern and Central Asia, respectively. Similar diversity was observed for mortality attributable to PM2.5 for other causes of death across Asia: chronic obstructive pulmonary disease (LYL ranging from 6% to 28%), lung cancer (4% to 20%) and stroke (11% to 22%).

CONCLUSION

PM2.5 is a crucial component in the rising health effects in Asia. The diverse trends in cause-specific mortality attributable to PM2.5 creates a further challenge for health systems in the region. These findings highlight that immediate interventions are needed to mitigate the increasing levels of air pollution and with that reduce its detrimental effect on the health and mortality of Asian populations.

Ambient Air Pollution and Hospital Admissions for Peptic Ulcers in Taipei: A Time-Stratified Case-Crossover Study

Very few studies have been performed to determine whether there is a relationship between air pollution and increases in hospitalizations for peptic ulcer, and for those that have occurred, their results may not be completely relevant to Taiwan, where the mixture of ambient air pollutants differ. We performed a time-stratified case-crossover study to investigate the possible association between air pollutant levels and hospital admissions for peptic ulcer in Taipei, Taiwan. To do this, we collected air pollution data from Taiwan's Environmental Protection Agency and hospital admissions for peptic ulcer data for the years 2009-2013 from Taiwan's National Health Insurance's research database. We used conditional logistic regression to analyze the possible association between the two, taking temperature and relative humidity into account. Risk was expressed as odds ratios and significance was expressed with 95% confidence intervals. In our single pollutant model, peptic ulcer admissions were significantly associated with all pollutants (PM₁₀, PM_2.5, SO₂, NO₂, CO, and O₃) on warm days (>23 °C). On cool days (<23 °C), peptic ulcer admissions were significantly associated with PM₁₀, NO₂, and O₃. In our two-pollutant models, peptic ulcer admissions were significantly associated NO₂ and O₃ when combined with each of the other pollutants on warm days, and with PM₁₀, NO₂, and O₃ on cool days. It was concluded that the likelihood of peptic ulcer hospitalizations in Taipei rose significantly with increases in air pollutants during the study period.

Winter chemical partitioning of metals bound to atmospheric fine particles in Dongguan, China, and its health risk assessment

To analyze the relationship between nanoparticles and the chemical forms in an urban atmospheric environment, metallic particles with different diameters were collected using a nanoparticle sampling system and analyzed for chemical and morphological characteristics, bioactivity, and the risk of carcinogenic and non-carcinogenic effects. The source of the atmospheric particles was analyzed based on the enrichment factor method, and the carcinogenicity of the atmospheric particles was analyzed using the health risk model. The partition contents of metals extractable by a weak acid, including As, Ca, Cd, Cs, Pb, Sr, and Zn, were in a range of 32.17-71.4%, with an average value of 47.07%. The content of oxides and reducible metals of all of the elements was generally low. Potassium was distributed mainly in the residual and weak-acid-extractable fractions. Barium had a high proportion of the oxidation state. Each fraction of Zn was basically the same, while the content of the weak-acid-extractable fraction was slightly higher. We found bio-access potential to be positively correlated with a high proportion of the weak acid extracts such as Mg, Sr, and Zn. We also found there to be a large weak-acid-extractable fraction (F1) and residual fraction (F4) and relatively enriched elements and strongly enriched elements, which means F1 and F4 may be the cause of enrichment. The hazard index (HI) and the total cancer risk (TCR) were far beyond the safety threshold when the diameter of the particle was in the range of 0.1-0.5 μm, indicating that the residents in Dongguan city were experiencing obvious non-carcinogenic and carcinogenic risks.

Study of the Effects of Air Pollutants on Human Health Based on Baidu Indices of Disease Symptoms and Air Quality Monitoring Data in Beijing, China

There is an increasing body of evidence showing the impact of air pollutants on human health such as on the respiratory, and cardio- and cerebrovascular systems. In China, as people begin to pay more attention to air quality, recent research focused on the quantitative assessment of the effects of air pollutants on human health. To assess the health effects of air pollutants and to construct an indicator placing emphasis on health impact, a generalized additive model was selected to assess the health burden caused by air pollution. We obtained Baidu indices (an evaluation indicator launched by Baidu Corporation to reflect the search popularity of keywords from its search engine) to assess daily query frequencies of 25 keywords considered associated with air pollution-related diseases. Moreover, we also calculated the daily concentrations of major air pollutants (including PM10, PM2.5, SO₂, O₃, NO₂, and CO) and the daily air quality index (AQI) values, and three meteorological factors: daily mean wind level, daily mean air temperature, and daily mean relative humidity. These data cover the area of Beijing from 1 March 2015 to 30 April 2017. Through the analysis, we produced the relative risks (RRs) of the six main air pollutants for respiratory, and cardio- and cerebrovascular diseases. The results showed that O₃ and NO₂ have the highest health impact, followed by PM10 and PM2.5. The effects of any pollutant on cardiovascular diseases was consistently higher than on respiratory diseases. Furthermore, we evaluated the currently used AQI in China and proposed an RR-based index (health AQI, HAQI) that is intended for better indicating the effects of air pollutants on respiratory, and cardio- and cerebrovascular diseases than AQI. A higher Pearson correlation coefficient between HAQI and RRTotal than that between AQI and RRTotal endorsed our efforts.

Effects of ambient carbon monoxide on daily hospitalizations for cardiovascular disease: a time-stratified case-crossover study of 460,938 cases in Beijing, China from 2013 to 2017

BACKGROUND

Evidence focused on exposure to ambient carbon monoxide (CO) and the risk of hospitalizations for cardiovascular diseases (CVD) is lacking in developing countries. This study aimed to examine the effect of CO exposure on hospitalizations for CVD in Beijing, China.

METHODS

A total of 460,938 hospitalizations for cardiovascular diseases were obtained from electronic hospitalization summary reports from 2013 to 2017. A time-stratified case-crossover design was conducted to investigate the association between CO exposure and hospitalizations for total and cause-specific CVD, including coronary heart disease (CHD), atrial fibrillation (AF), and heart failure (HF). Stratified analysis was also conducted by age group (18-64 years and ≥ 65 years) and sex.

RESULTS

Linear exposure-response curves for the association between ambient CO exposure and hospitalizations for CVD was observed. Ambient CO was positively associated with hospitalizations for total CVD and CHD. However, the observed increased risk was not statistically significant for hospitalizations for AF and HF. The strongest effect of CO concentration was observed on the current- and previous-day of exposure (lag _0-1 day). For a 1 mg/m³ increase in a 2-day moving average CO concentration, an increase of 2.8% [95% confidence interval (CI): 2.2 to 3.3%] and 3.0% (95% CI: 2.4 to 3.6%) in daily hospital admissions for CVD and CHD were estimated, respectively. This association was robust after adjusting for other copollutants and did not vary by age group and sex.

CONCLUSIONS

Ambient CO exposure increased the risk of hospitalizations for CVD, especially for CHD in Beijing. Further studies are warranted to explore the association between ambient CO and hospitalizations for AF and HF.

Numerical Simulation of Particulate Matter 2.5 Distribution in a Roadway

Large amounts of dust particles pose serious hazards to the health and safety of China’s coal miners during roadway blasting processes. It is known that among these dust particles, Particulate Matter 2.5 (PM_2.5) does the greatest amount of harm. In order to study the distributions of the PM_2.5 in roadway blasting processes, a mathematical model of the gas-solid two-phase flow was established in this study, which was based on a Direct Simulation Monte Carlo Method (DSMC). Then, a multiphase flow program was developed. This study’s results indicated that following the blasting processes, fine dust particles gradually floated up and were suspended for long durations in the underground roadway space. The medium-sized dust particles slowly sink to the ground and were eventually expelled before settling to the floor of the roadway. The coarse particles were rapidly settled to the roadway floor. It was determined that the PM_2.5 particles in the front end of the dust group could not be quickly diluted, and the concentrations were high until it is expelled from the roadway, whereas the PM_2.5 dust particles in the back end of the underground roadway were found to be gradually diluted. Eventually, the PM_2.5 concentrations exhibited an alternating thin to dense phase distribution. When compared with the Particulate Matter 5 (PM₅), it was found that the PM_2.5 was more difficult to discharge, and easily formed serious PM_2.5 dust air pollution. This study’s results were determined to be conductive to the future control of PM_2.5 in the underground roadway blasting processes.

The role of weather conditions and normal level of air pollution in appearance of stroke in the region of Southeast Europe

We investigated correlation between the normal level of air pollution, weather conditions and stroke occurrence in the region of Southeast Europe with a humid continental climate. This retrospective study included 1963 patients, 1712 (87.2%) with ischemic (IS) and 251 (12.8%) with hemorrhagic stroke (HS) admitted to emergency department. The number of patients, values of weather condition (meteorological parameters) [air temperature (°C), atmospheric pressure (kPa), relative humidity (%)] and concentrations of air pollutants [particulate matter (PM₁₀), nitrogen dioxide (NO₂), ozone (O₃)], were recorded and evaluated for each season (spring, summer, autumn, winter) during 2 years (July 2008-June 2010). The highest rate of IS was observed during spring (28.9%) (p = 0.0002) and HS in winter (33.9%) (p = 0.0006). We have found negative Spearman's correlations (after Bonferroni adjustment for the multiple correlations) of the number of males with values of relative humidity (%) (day 0, rho = - 0.15), the total number of strokes (day 2, rho = - 0.12), females (day 2, rho = - 0.12) and IS (day 2, rho = - 0.13) with concentrations of PM₁₀ (µg/m³), as well as negative correlations of the number of females (day 2, rho = - 0.12) and IS (day 2, rho = - 0.12) with concentrations of NO₂ (µg/m³) (for all p < 0.002). In winter, the number of HS (day 0, rho = 0.25, p = 0.001) positively correlated with concentrations of O₃ (µg/m³). The appearance of stroke has seasonal variations, with the highest rates during spring and winter. Positive correlation between the number of HS and values of O₃ requires an additional reduction of the legally permitted pollutants concentrations.

Acute myocardial infarction and COPD attributed to ambient SO2 in Iran

Acute myocardial infarction (MI) and chronic obstructive pulmonary disease (COPD) are important diseases worldwide. Inhalation is the major route of short-term exposure to air sulfur dioxide (SO₂) that negatively affect human health. The objective of this study was to estimate the health effects of short-term exposure to SO₂ in Khorramabad, Iran using the AirQ software developed by the World Health Organization (WHO). Daily mean SO₂ concentrations were used as the estimates of human short-term exposure and allow calculation of the attributable excess relative risk of an acute MI and hospital admissions due to COPD (HACOPD). The annual mean SO₂ concentration in Khorramabad was 51.33µg/m³. Based on the relative risk (RR) and baseline incidence (BI) approach of WHO, an increased risk of 2.7% (95% CI: 1.1-4.2%) of acute MI and 2.0% (95% CI: 0-4.6%) of HACOPD, respectively, were attributed to a 10µg/m³ SO₂ increase. Since the geographic, demographic, and climatic characteristics are different from the areas in which the risk relationships were developed and not evaluated here, further investigations will be needed to fully quantify other health impacts of SO₂. A decreased risk for MIs and COPD attributable to SO₂ could be achieved if mitigation strategies and measures are implemented to reduce the exposure.

Association of air pollution sources and aldehydes with biomarkers of blood coagulation, pulmonary inflammation, and systemic oxidative stress

Using data collected before, during, and after the 2008 Summer Olympic Games in Beijing, this study examines associations between biomarkers of blood coagulation (vWF, sCD62P and sCD40L), pulmonary inflammation (EBC pH, EBC nitrite, and eNO), and systemic oxidative stress (urinary 8-OHdG) with sources of air pollution identified utilizing principal component analysis and with concentrations of three aldehydes of health concern. Associations between the biomarkers and the air pollution source types and aldehydes were examined using a linear mixed effects model, regressing through seven lag days and controlling for ambient temperature, relative humidity, gender, and day of week for the biomarker measurements. The biomarkers for pulmonary inflammation, particularly EBC pH and eNO, were most consistently associated with vehicle and industrial combustion, oil combustion, and vegetative burning. The biomarkers for blood coagulation, particularly vWF and sCD62p, were most consistently associated with oil combustion. Systemic oxidative stress biomarker (8-OHdG) was most consistently associated with vehicle and industrial combustion. The associations of the biomarkers were generally not significant or consistent with secondary formation of pollutants and with the aldehydes. The findings support policies to control anthropogenic pollution sources rather than natural soil or road dust from a cardio-respiratory health standpoint.

Association between emergency admission for peptic ulcer bleeding and air pollution: a case-crossover analysis in Hong Kong's elderly population

BACKGROUND

Air pollution increases intestinal permeability, alters the gut microbiome, and promotes inflammation, which might contribute towards gastrointestinal bleeding. In the present study, we aim to examine whether short-term elevations in air pollution are associated with increased numbers of emergency hospital admissions for peptic ulcer bleeding in Hong Kong.

METHODS

Daily air pollution (particulate matter with aerodynamic diameter less than 2·5 μm [PM_2·5], nitric oxide [NO₂], sulpher dioxide [SO₂], and ozone [O₃]) data during 2005-10 were collected from the Environmental Protection Department and emergency admission data for peptic ulcer bleeding in elderly people (aged 65 years or older) from the Hospital Authority of Hong Kong. A time stratified case-crossover analysis with conditional logistic regression was used to estimate the excess risk of peptic ulcer bleeding associated with each air pollutant, in single-pollutant and multi-pollutant models. Cardiorespiratory diseases were used as positive controls.

FINDINGS

8566 emergency admissions for peptic ulcer bleeding were recorded among Hong Kong's elderly population during 2005-10; the daily number of admissions ranged from 0 to 13. An IQR increment of 5-day moving average (lag₀₄) of NO₂ concentration (25·8 μg/m³) was associated with a 7·6% (95% CI 2·2-13·2) increase in emergency admissions for peptic ulcer bleeding. Multi-pollutant models confirmed the robustness of the risk estimates for NO₂. Other pollutants (PM_2·5, SO₂, and O₃) were not associated with peptic ulcer bleeding admissions.

INTERPRETATION

Short-term elevation in ambient NO₂ might trigger peptic ulcer bleeding events and increase the risk of emergency admissions for peptic ulcer bleeding in Hong Kong's elderly population. These findings strengthen the hypothesis that air pollution affects not just cardiopulmonary diseases, but also certain diseases of the digestive system.

FUNDING

None.

Air quality perception of pedestrians in an urban outdoor Mediterranean environment: A field survey approach

Perception plays a significant role on people's response to preventive measures. In the view of public awareness, the aim of this study was to explore factors that affect air quality perception and to reveal its potential patterns. Air quality perception of individuals, in terms of dust and overall air quality, was examined in relation to air pollutants concentrations, meteorological variables, personal characteristics as well as their thermal sensation and health condition. The data used were obtained from environmental measurements, in situ and from stations, and questionnaire surveys conducted in an outdoor urban Mediterranean area, Athens, Greece. The participants were asked to report their air quality perception and thermal sensation based on predefined scales. A thermal index, Physiological Equivalent Temperature (PET), was estimated to obtain an objective measure of thermal sensation. Particulate matter (PM₁₀) and nitrogen oxide (NO) were associated with dust perception. Nitrogen oxides (NO_x) and carbon monoxide (CO) were associated to air quality perception. Age, area of residence, health symptoms and thermal sensation also affected the perception of air quality. Dusty or poor air quality conditions were more likely to be reported when pollutants' concentrations were increased. Younger people, participants residing in the city center, experiencing health symptoms or warm thermal sensation showed a trend towards reporting more unfavorable air quality conditions.

Association between atmospheric pollutants and hospital admissions in Lisbon

Ambient air pollution is recognised as one of the potential environmental risk factors causing health hazards to the exposed population, demonstrated in numerous previous studies. Several longitudinal, ecological and epidemiological studies have shown associations between outdoor levels of outdoor atmospheric pollutants and adverse health effects, especially associated with respiratory and cardiovascular hospital admissions. The aim of this work is to assess the influence of atmospheric pollutants over the hospital admissions in Lisbon, by Ordinary Least Squares Linear Regression. The pollutants (CO, NO, NO2, SO2, O3, PM10 and PM2.5) were obtained from 13 monitoring stations of the Portuguese Environmental Agency, which provide hourly observations. Hospital admission data were collected from the Central Administration of the Health System and were compiled by age: <15, 15-64, >64 years old. The study period was 2006-2008. Results showed significant positive associations between the following: (1) the pollutants CO, NO, NO2, SO2, PM10 and PM2.5 and circulatory diseases for ages between 15 and 64 years (0.5% hospital admissions (HA) increase with 10 μg m(-3) NO increase) and above 64 years (1.0% stroke admission increase with 10 μg m(-3) NO2 increase); (2) the pollutants CO, NO, NO2, SO2, PM10 and PM2.5 and respiratory diseases for ages below 15 years (up to 1.9% HA increase with 10 μg m(-3) pollutant increase); and (3) the pollutants NO, NO2 and SO2 and respiratory diseases for ages above 64 years (1.3% HA increase with 10 μg m(-3) CO increase).

Short term exposure to air pollution and stroke: systematic review and meta-analysis

OBJECTIVE

To review the evidence for the short term association between air pollution and stroke.

DESIGN

Systematic review and meta-analysis of observational studies

DATA SOURCES

Medline, Embase, Global Health, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Web of Science searched to January 2014 with no language restrictions.

ELIGIBILITY CRITERIA

Studies investigating the short term associations (up to lag of seven days) between daily increases in gaseous pollutants (carbon monoxide, sulphur dioxide, nitrogen dioxide, ozone) and particulate matter (<2.5 µm or <10 µm diameter (PM2.5 and PM10)), and admission to hospital for stroke or mortality.

MAIN OUTCOME MEASURES

Admission to hospital and mortality from stroke.

RESULTS

From 2748 articles, 238 were reviewed in depth with 103 satisfying our inclusion criteria and 94 contributing to our meta-estimates. This provided a total of 6.2 million events across 28 countries. Admission to hospital for stroke or mortality from stroke was associated with an increase in concentrations of carbon monoxide (relative risk 1.015 per 1 ppm, 95% confidence interval 1.004 to 1.026), sulphur dioxide (1.019 per 10 ppb, 1.011 to 1.027), and nitrogen dioxide (1.014 per 10 ppb, 1.009 to 1.019). Increases in PM2.5 and PM10 concentration were also associated with admission and mortality (1.011 per 10 μg/m(3) (1.011 to 1.012) and 1.003 per 10 µg/m(3) (1.002 to 1.004), respectively). The weakest association was seen with ozone (1.001 per 10 ppb, 1.000 to 1.002). Strongest associations were observed on the day of exposure with more persistent effects observed for PM(2·5).

CONCLUSION

Gaseous and particulate air pollutants have a marked and close temporal association with admissions to hospital for stroke or mortality from stroke. Public and environmental health policies to reduce air pollution could reduce the burden of stroke.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO-CRD42014009225.

Air pollution, avoidance behaviour and children's respiratory health: evidence from England

Despite progress in air pollution control, concerns remain over the health impact of poor air quality. Governments increasingly issue air quality information to enable vulnerable groups to avoid exposure. Avoidance behaviour potentially biases estimates of the health effects of air pollutants. But avoidance behaviour imposes a cost on individuals and therefore may not be taken in all circumstances. This paper exploits panel data at the English local authority level to estimate the relationship between children's daily hospital emergency admissions for respiratory diseases and common air pollutants, while allowing for avoidance behaviour in response to air pollution warnings. A 1% increase in nitrogen dioxide or ozone concentrations increases hospital admissions by 0.1%. For the subset of asthma admissions - where avoidance is less costly - there is evidence of avoidance behaviour. Ignoring avoidance behaviour, however, does not result in statistically significant underestimation of the health effect of air pollution.

Exposure to air pollutants and mortality in hypertensive patients according to demography: a 10 year case-crossover study

This study evaluated whether short term exposures to NO2, O3, particulate matter <10 mm in diameter (PM10) were associated with higher risk of mortality. A total of 223,287 hypertensive patients attended public health-care services and newly prescribed at least 1 antihypertensive agent were followed-up for up to 5 years. A time-stratified, bi-directional case-crossover design was adopted. For all-cause mortality, significant positive associations were observed for NO2 and PM10 at lag 0-3 days per 10 μg/m(3) increase in concentration (excess risks 1.187%-2.501%). Significant positive associations were found for O3 at lag 1 and 2 days and the excess risks were 1.654% and 1.207%, respectively. We found similarly positive associations between these pollutants and respiratory disease mortality. These results were significant among those aged ≥65 years and in cold seasons only. Older hypertensive patients are susceptible to all-cause and respiratory disease-specific deaths from these air pollutants in cold weather.

An evidence-based appraisal of global association between air pollution and risk of stroke

BACKGROUND

The aim of this study was to evaluate the transient effects of air pollutants on stroke morbidity and mortality using the meta-analytic approach.

METHODS

Three databases were searched for case-crossover and time series studies assessing associations between daily increases in particles with diameter<2.5 μm (PM2.5) and diameter<10 μm (PM10), sulfur dioxide (SO2), carbon monoxide (CO), nitrogen dioxide (NO2), ozone, and risks of stroke hospitalizations and mortality. Risk estimates were combined using random-effects model.

RESULTS

A total of 34 studies were included in the meta-analysis. Stroke hospitalizations or mortality increased 1.20% (95%CI: 0.22-2.18) per 10 μg/m3 increase in PM2.5, 0.58% (95%CI: 0.31-0.86) per 10 μg/m3 increase in PM10, 1.53% (95%CI: 0.66-2.41) per 10 parts per billion (ppb) increase in SO2, 2.96% (95%CI: 0.70-5.27) per 1 ppm increase in CO, and 2.24% (95%CI: 1.16-3.33) per 10ppb increase in NO2. These positive associations were the strongest on the same day of exposure, and appeared to be more apparent for ischemic stroke (for all 4 gaseous pollutants) and among Asian countries (for all 6 pollutants). In addition, an elevated risk (2.45% per 10 ppb; 95%CI: 0.35-4.60) of ischemic stroke associated with ozone was found, but not for hemorrhagic stroke.

CONCLUSION

Our study indicates that air pollution may transiently increase the risk of stroke hospitalizations and stroke mortality. Although with a weak association, these findings if validated may be of both clinical and public health importance given the great global burden of stroke and air pollution.

Epidemiological evidence on association between ambient air pollution and stroke mortality

BACKGROUND

Inconsistent results have been found on the association between air pollution and stroke mortality. Additionally, evidence on people who are potentially sensitive to air pollution-associated stroke mortality is limited.

METHODS

Daily stroke mortality of adults aged over 65 between 2003 and 2008 in Shanghai, China were collected. The time-stratified case-crossover approach was used to assess the association between daily concentrations of air pollutants including particles with size <10 µm, sulfur dioxide (SO2) and nitrogen dioxide (NO2) and stroke mortality.

RESULTS

Both total-stroke and ischaemic-stroke mortalities were found to be significantly associated with all three air pollutants. Haemorrhagic stroke was significantly associated with SO2 and NO2 only. Substantial differences were observed for effect estimates of ischaemic-stroke mortality in relation to NO2 among people with cardiac diseases compared with those without; for an increase of 10 μg/m(3) in NO2, the increase in ischaemic-stroke mortality was 7.05% (95% CI 1.92% to 12.17%) for people with comorbid cardiac diseases versus 0.60% (95% CI -0.49% to 1.68%) for those without. We did not find evidence of effect modification by hypertension and diabetes.

CONCLUSIONS

This study provides new evidence for the association between exposure to ambient air pollution and stroke mortality. Our results also suggest that underlying cardiac disorder may increase the risk for ischaemic-stroke mortality in relation to air pollution exposure, especially NO2. .

Estimation of short-term effects of air pollution on stroke hospital admissions in Wuhan, China

Background and Objective

High concentrations of air pollutants have been linked to increased incidence of stroke in North America and Europe but not yet assessed in mainland China. The aim of this study is to evaluate the association between stroke hospitalization and short-term elevation of air pollutants in Wuhan, China.

Methods

Daily mean NO₂, SO₂ and PM₁₀ levels, temperature and humidity were obtained from 2006 through 2008. Data on stroke hospitalizations (ICD 10: I60–I69) at four hospitals in Wuhan were obtained for the same period. A time-stratified case-crossover design was performed by season (April-September and October-March) to assess effects of pollutants on stroke hospital admissions.

Results

Pollution levels were higher in October-March with averages of 136.1 µg/m³ for PM₁₀, 63.6 µg/m³ for NO₂ and 71.0 µg/m³ for SO₂ than in April-September when averages were 102.0 µg/m³, 41.7 µg/m³ and 41.7 µg/m³, respectively (p<.001). During the cold season, every 10 µg/m³ increase in NO₂ was associated with a 2.9% (95%C.I. 1.2%–4.6%) increase in stroke admissions on the same day. Every 10 ug/m³ increase in PM₁₀ daily concentration was significantly associated with an approximate 1% (95% C.I. 0.1%–1.4%) increase in stroke hospitalization. A two-pollutant model indicated that NO₂ was associated with stroke admissions when controlling for PM₁₀. During the warm season, no significant associations were noted for any of the pollutants.

Conclusions

Exposure to NO₂ is significantly associated with stroke hospitalizations during the cold season in Wuhan, China when pollution levels are 50% greater than in the warm season. Larger and multi-center studies in Chinese cities are warranted to validate our findings.

Short-term effects of gaseous pollutants and particulate matter on daily hospital admissions for cardio-cerebrovascular disease in Lanzhou: evidence from a heavily polluted city in China

Panel studies show a consistent association between increase in the cardiovascular hospitalizations with air pollutants in economically developed regions, but little evidence in less developed inland areas. In this study, a time-series analysis was used to examine the specific effects of major air pollutants [particulate matter less than 10 microns in diameter (PM₁₀), sulfur dioxide (SO₂), and nitrogen dioxides (NO₂)] on daily hospital admissions for cardio-cerebrovascular diseases in Lanzhou, a heavily polluted city in China. We examined the effects of air pollutants for stratified groups by age and gender, and conducted the modifying effect of seasons on air pollutants to test the possible interaction. The significant associations were found between PM₁₀, SO₂ and NO₂ and cardiac disease admissions, SO₂ and NO₂ were found to be associated with the cerebrovascular disease admissions. The elderly was associated more strongly with gaseous pollutants than younger. The modifying effect of seasons on air pollutants also existed. The significant effect of gaseous pollutants (SO₂ and NO₂) was found on daily hospital admissions even after adjustment for other pollutants except for SO₂ on cardiac diseases. In a word, this study provides the evidence for the detrimental short-term health effects of urban gaseous pollutants on cardio-cerebrovascular diseases in Lanzhou.

[The spatial distribution of population exposure to outdoor air pollution in Valencia (Spain) and its association with a privation index]

OBJECTIVE

To evaluate spatial variation in exposure to nitrogen dioxide (NO2) air pollution in the city of Valencia, Spain, and its association with socioeconomic deprivation and age.

METHODS

Census tract population data were obtained from the National Statistics Institute of Spain. Outdoor NO2 was monitored in 100 sites in the study area, through the use of passive samplers, in three campaigns between 2002 and April 2004. Land use regression (LUR) was used to obtain a map of NO2 levels. The LUR predictions were compared with the NO2 level obtained by: a) the nearest sampler of the monitoring network, b) the nearest passive sampler, c) the mean distance-weighted levels of the samplers in the neighborhood, and d) the NO2 level obtained by using Kriging. For each census tract, the NO2 levels were obtained. The association of NO2 air pollution exposure with population age (≥65 years) and the 5-category deprivation index was analyzed.

RESULTS

The LUR models showed less error than the other prediction methods. The safety levels proposed by the World Health Organization were exceeded in more than 99% of the population. An inverse relationship was found between NO2 levels and the deprivation index (β = -2.01μg/m(3) in the most deprived quintile compared with lower deprivation, 95%CI: -3.07; -0.95) and a direct relationship was found with age (β = 0.12μg/m(3) per unit increase in percentage of the population ≥ 65 years, 95%CI: 0.08; 0.16).

CONCLUSIONS

The method allowed pollution maps to be obtained and the association between NO2 levels and sociodemographic characteristics to be described.

Health effects for the population living near a cement plant: an epidemiological assessment

Epidemiological studies have shown the association between the exposure to air pollution and several adverse health effects. To evaluate the possible acute health effects of air pollution due to the emissions of a cement plant in two small municipalities in Italy (Mazzano and Rezzato), a case-control study design was used. The risks of hospital admission for cardiovascular or respiratory diseases for increasing levels of exposure to cement plant emissions were estimated, separately for adults (age>34 years) and children (0-14 years). Odds ratios (OR) were estimated using unconditional regression models. Attributable risks were also calculated. Statistically significant risks were found mainly for respiratory diseases among children: OR 1.67 (95% CI 1.08-2.58) for the moderately exposed category (E1), OR 1.88 (95% CI 1.19-2.97) for the highly exposed category (E2), with an attributable risk of 38% of hospital admissions due to the exposure to cement plant exhausts. Adults had a weaker risk: OR 1.38 (95% CI 1.18-1.61) for group E1, OR 1.31 (95% CI 1.10-1.56) for group E2; the attributable risk was 23%. Risks were higher for females and for the age group 35-64. These results showed an association between the exposure to plant emissions and the risk of hospital admission for cardiovascular or respiratory causes; this association was particularly strong for children.

Measurement of air exchange rates in different indoor environments using continuous CO2 sensors

A new air exchange rate (AER) monitoring method using continuous CO2 sensors was developed and validated through both laboratory experiments and field studies. Controlled laboratory simulation tests were conducted in a 1-m3 environmental chamber at different AERs (0.1-10.0 hr(-1)). AERs were determined using the decay method based on box model assumptions. Field tests were conducted in classrooms, dormitories, meeting rooms and apartments during 2-5 weekdays using CO2 sensors coupled with data loggers. Indoor temperature, relative humidity (RH), and CO2 concentrations were continuously monitored while outdoor parameters combined with on-site climate conditions were recorded. Statistical results indicated that good laboratory performance was achieved: duplicate precision was within 10%, and the measured AERs were 90%-120% of the real AERs. Average AERs were 1.22, 1.37, 1.10, 1.91 and 0.73 hr(-1) in dormitories, air-conditioned classrooms, classrooms with an air circulation cooling system, reading rooms, and meeting rooms, respectively. In an elderly particulate matter exposure study, all the homes had AER values ranging from 0.29 to 3.46 hr(-1) in fall, and 0.12 to 1.39 hr(-1) in winter with a median AER of 1.15.

Effects of several environmental factors on longevity and health of the human population of Zhongxiang, Hubei, China

Increasing human health and longevity is of global interest. Environmental, genetic, and stochastic factors all affect longevity. Among these factors, the environment is extremely important. To investigate the relationship between the environment and longevity, we studied the environment in Zhongxiang (China), where the inhabitants commonly have long life spans. Air was analyzed for negative oxygen ions, SO2, and inhalable particles, while drinking water and rice were analyzed for macro- and micro-elements. The air quality in this area was determined to be grade I with high negative oxygen ion content and low SO2 and inhalable particle contents. Apart from Fe, Mn, and F, all tested elements and the pH were within national standards and World Health Organization guidelines. The percentage of long-lived people in the area was closely related to the macro- and micro-element contents of their staple food, rice. The elements in rice could be classified into three categories according to their effect on longevity: Sr, Ca, Al, Mo, and Se, which were positively correlated with longevity; Fe, Mn, Zn, Cr, P, Mg, and K, which had a weak effect on local longevity, and Cu and Ba, which had a negative effect on longevity.

Association between ozone and emergency department visits: an ecological study

The objective of this study was to examine the association between the levels of ozone concentration and emergency department (ED) visits for respiratory and cardiovascular conditions in Maryland in the United States by considering temporal and spatial characteristics, including socioeconomic status (SES), as a covariate. This study used multiple large datasets derived from government agencies for data of ozone, weather, census, and ED visits to represent Maryland in the summer of 2002. Block kriging was used to estimate the daily ozone and weather factors by ZIP code-day level. Results from a negative binomial regression showed that a 10-ppb increment of the 8-hr ozone level as a three-day average was associated with increased respiratory ED visits by 2.4%, after adjusting for weather factors, SES, and day of the week. For cardiovascular ED visits, an increment of 10 ppb of the 8-hr ozone level as a five-day average increased by 3.5%.

Ambient particulate matter on DNA damage in HepG2 cells

Ambient particulate matter (PM) has been reported to be associated with increased respiratory, cardiovascular, and malignant lung diseases. The aim of the present study was to investigate the variability of the DNA-damage induced by thoracic particles (PM( 10)) sampled in different locations and seasons (2006) in Dalian, China, in human hepatoma G2 (HepG2) cells. Significant differences in percentage of tail DNA induced by the extractable organic matter of PM(10) were revealed between summer and winter seasons and among monitoring sites in single cell gel electrophoresis (SCGE) assay. The percentage of tail DNA in HepG2 cells significantly increased in a dose-dependent manner after exposure to 7.5 and 30 μg/mL extractable organic matter of PM(10) for 1 hour. In order to clarify the underlying mechanisms, we evaluated the level of reactive oxygen species (ROS) production with the 2, 7-dichloro-fluorescein diacetate (DCFH-DA) assay. Significantly increased level of ROS was observed in HepG2 cells at higher concentrations (15 and 30 μg/mL). Significantly increased levels of 8-hydroxydeoxyguanosine (8-OHdG) were also shown in HepG2 cells. In this study, the accumulation of nuclear factor kappa B (NF-κB) p65 protein induced by the extractable organic matter of PM(10) was detected by western blotting in HepG2 cells, and the protein expression of NF-κB p65 significantly increased after the treatment with 30 μg/mL extractable organic matter of PM(10) for 24 hours. These results indicate that the extractable organic matter of PM(10) causes DNA strand breaks in HepG2 cells, and significant differences in percentage of tail DNA in dependence on locality and season are revealed. The extractable organic matter of PM(10) exerts DNA damage effects in HepG2 cells, probably through oxidative DNA damage induced by intracellular ROS, increase of 8-OHdG formation, and protein expression of NF-κB p65.

Short-term effects of ozone air pollution on ischaemic stroke occurrence: a case-crossover analysis from a 10-year population-based study in Dijon, France

OBJECTIVE

To evaluate the association between air pollutants and the occurrence of acute stroke from 10-year population-based study.

METHODS

The daily stroke count was obtained from Dijon Stroke Register between March 1994 and December 2004. The register recorded all first-ever strokes among residents of Dijon (150,000 inhabitants) in France, using standard diagnostic criteria. Pollutant concentrations (SO2, CO, NO2, O3 and PM10) were measured hourly. A bi-directional case-crossover design was used to examine the association between air pollutant and stroke onset. The conditional logistic regression model included the meteorological parameters (temperature, relative humidity), influenza epidemics and holidays.

RESULTS

The authors collected 493 large artery infarcts, 397 small artery infarcts, 530 cardio-embolic infarcts, 67 undeterminate infarcts, 371 transient ischaemic attacks and 220 haemorrhagic strokes. For single-pollutant model and for a 10 mg/m(3) increase of O3 exposure, a positive association was observed only in men, over 40 years of age, between ischaemic stroke occurrence and O3 levels with 1-day lag, (OR 1.133, 95% CI 1.052 to 1.220) and 0-day lag (OR 1.058, 95% CI 0.987 to 1.134). No significant associations were found for haemorrhagic stroke. In two-pollutant models, the effects of O3 remained significant after each of the other pollutants were included in the model, in particular with PM10. A significant association was observed for ischaemic strokes of large arteries (p = 0.02) and for transient ischaemic attacks (p = 0.01). Moreover, the authors found an exposure-response relations between O3 exposure and ischaemic stroke (test for trend, p = 0.01). An increase in association in men with several cardiovascular risk factors (smoker, dyslipidemia and hypertension) was also observed.

CONCLUSION

These observational data argue for an association between ischaemic stroke occurrence and O3 pollution levels; these results still need to be confirmed by other studies.

Sources of uncertainty in calculating mortality and morbidity attributable to air pollution

Quantifying the burden of illness and mortality from air pollution exposure relies on statistical estimates and other assumptions that have inherent uncertainties. Through an intensive study in Hamilton, Canada, this study illustrates for policymakers the sensitivity of health effect estimates to a wide range of possible uncertainties. Dose-response relationships were derived based on pooled and averaged estimates published in the scientific literature from 1997 to 2001. These estimates were applied to local air pollution, mortality, and hospital admissions data for the years 1995-1999. The data were adjusted to reflect uncertainties in the current state of knowledge, including (1) baseline pollution, (2) single versus multipollutant effects, (3) local or pooled estimates, and (4) chronic effects. The estimates of mortality ranged from 96 to 374 annual deaths, while admissions ranged from 139 to 607 respiratory and from 479 to 2000 cardiovascular admissions. Chronic fine particle exposure resulted in 232 annual deaths. As conclusions, first, there should be an effort to reach a consensus on reporting scientific findings from air pollution studies using standardized study designs and reporting formats. Second, given the sensitivity of the estimates to underlying assumptions, an immediate need exists for widely accepted burden of illness and mortality estimation conventions. Third, many areas of air pollution research require considerable refinement before complete estimates can be ascribed.

A protocol for investigation of the effects of outdoor air pollution on stroke incidence, phenotypes and survival using the South London Stroke Register

Stroke is a major cause of death and disability. About 5.3 million people die every year from stroke worldwide with over 9 million people surviving at any one time after suffering a stroke. About 1 in 4 men and 1 in 5 women aged 45 years will suffer a stroke if they live to their 85th year. It is estimated that by 2023 there will be an absolute increase in the number of people experiencing a first ever stroke of about 30% compared with 1983.

In the UK, stroke is the third commonest cause of death and the most common cause of adult physical disability and consumes 5% of the health and social services budget. Stroke is assuming strategic public health importance because of increased awareness in society, an ageing population and emerging new treatments. It is an NHS health service and research priority, being identified as a target in Our Healthier Nation and the NSF for Older People for prevention and risk factor control and in the NHS Plan as a disease requiring intermediate care planning and reduction in inequalities of care.

Whilst a number of risk factors for stroke are well known (e.g. increasing age, ethnicity, socioeconomic deprivation, hypertension), the potential importance of outdoor air pollution as a modifiable risk factor is much less well recognised. This is because studies to date are inconclusive or have methodological limitations. In Sheffield, we estimated that 11% of stroke deaths may be linked to current levels of outdoor air pollution and this high figure is explained by the fact that so many people are exposed to air pollution.

We plan to study the effects of outdoor air pollution on stroke using a series of epidemiological (i.e. population based) studies. The purpose of this project is:

• to examine if short term increases in pollution can trigger a stroke in susceptible individuals;

• to investigate if the occurrence of stroke is higher amongst people living in more polluted areas (which would be explained by a combination of exposure to short term increases and longer term exposure to higher pollution levels); and

• to see if people living in more polluted areas have reduced survival following their stroke.

We will use geographical information systems, robust statistical methods and powerful grid computing facilities to link and analyse the data. The datasets we will use are the South London Stroke Register database, daily monitored pollution data from national monitoring networks and modelled pollution data for London from the Greater London Authority. The South London Stroke Register records information on all patients who suffer a stroke ("incident" cases) living within a defined area. This stroke incidence dataset offers major advantages over previous studies examining the effects of pollution on hospital admissions and mortality, as not all patients with stroke are admitted or die and there may be a delay between the onset of stroke and admission or death. In addition, it contains other useful information, particularly the type of stroke people have suffered.

Air pollution is a potentially modifiable risk factor for stroke. This study will provide robust population level evidence regarding the effects of outdoor air pollution on stroke. If it confirms the link, it will suggest to policy-makers at national and international levels that targeting policy interventions at high pollution areas may be a feasible option for stroke prevention.

Urban air pollution and emergency admissions for cerebrovascular diseases in Taipei, Taiwan

AIMS

This study was designed to evaluate the association between urban air pollutants and emergency admissions for cerebrovascular diseases.

METHODS AND RESULTS

Daily emergency admissions for cerebrovascular diseases (ICD-9-CM, 430-437) to the National Taiwan University Hospital were regressed against daily concentrations of carbon monoxide (CO), nitrogen dioxide (NO(2)), sulphur dioxide (SO(2)), ozone (O(3)), and particulate matters with aerodynamic diameter <2.5 (PM(2.5)) and 10 microm (PM(10)) from 12 April 1997 to 31 December 2002 in Taipei metropolitan areas by the Poisson regression models adjusting for meteorological conditions and temporal trends. Single-pollutant models showed O(3) lagged 0 day, CO lagged 2 days, and PM(2.5) and PM(10) lagged 3 days were significantly associated with increasing emergency admissions for cerebrovascular diseases and CO lagged 2 days was significantly associated with increasing emergency admissions for strokes (ICD-9-CM, 430-434). Such association remained significant for O(3), CO, and cerebrovascular admissions after adjusting for PM(2.5) and PM(10) in two-pollutant models. The odds ratios were 1.021-1.022 per 31.3 ppb O(3) and 1.023-1.031 per 0.8 ppm CO, respectively. However, only CO was significantly associated with emergency admissions for stroke in the three-pollutant models with CO, O(3), and PM(2.5) or PM(10).

CONCLUSION

Emergency admissions for cerebrovascular diseases among adults were positively associated with increasing urban air pollution levels of O(3) lagged 0 day and CO lagged 2 days in Taipei.

Associations between personal exposures and fixed-site ambient measurements of fine particulate matter, nitrogen dioxide, and carbon monoxide in Toronto, Canada

A longitudinal study investigating personal exposures to PM(2.5), nitrogen dioxide (NO(2)), and carbon monoxide (CO) for cardiac compromised individuals was conducted in Toronto, Canada. The aim of the study was (1) to examine the distribution of exposures to PM(2.5), NO(2), and CO; and (2) to investigate the relationship between personal exposures and fixed-site ambient measurements of PM(2.5), NO(2), and CO. In total, 28 subjects with coronary artery disease wore the Rupprecht & Patashnick ChemPass Personal Sampling System one day a week for a maximum of 10 weeks. The mean (SD) personal exposures were 22 microg m(-3) (42), 14 p.p.b. (6), and 1.4 p.p.m (0.5) for PM(2.5), NO(2), and CO, respectively. PM(2.5) and CO personal exposures were greater than central fixed-site ambient measurements, while the reverse pattern was observed for NO(2). Ambient PM(2.5) and NO(2) were correlated with personal exposures to PM(2.5) and NO(2) with median Spearman's correlation coefficients of 0.69 and 0.57, respectively. The correlations between personal exposures and ambient measurements made closest to the subjects' homes or the average of all stations within the study were not stronger than the correlation between personal exposures and central fixed-site measurements. Personal exposures to PM(2.5) were correlated with personal exposures to NO(2) (median Spearman's correlation coefficient of 0.43). This study suggests that central fixed-site measurements of PM(2.5) and NO(2) may be treated as surrogates for personal exposures to PM(2.5) and NO(2) in epidemiological studies, and that NO(2) is a potential confounder of PM(2.5).

Increased resting heart rate with pollutants in a population based study

BACKGROUND

Air pollution is associated with cardiovascular mortality. Changes in the autonomic nervous system may contribute to cardiac arrhythmias and cardiovascular mortality. This study investigated the relations between air pollutant concentrations of sulphur dioxide (SO(2)), ozone (O(3)), nitric dioxide (NO(2)), and resting heart rate (RHR) in a population based study.

METHODS

A sample of 863 middle aged men and women, living in Toulouse (MONICA centre) area, was randomly recruited. A cross sectional survey on cardiovascular risk factors was carried. RHR was measured twice in a sitting position after a five minute rest. Multivariate analyses with quintiles of RHR were performed using polytomous logistic regression. Models were adjusted for temperature, season, relative humidity, sex, physical activity, blood pressure, C reactive protein, and cardiovascular drugs.

RESULTS

For NO(2), the OR (odds ratio) (95% CI) associated with an increase of 5 microg/m(3) in the current day of medical examination was 1.14 (1.03 to 1.25) in quintile Q5 of RHR compared with Q1, p for trend = 0.003. For SO(2), OR was 1.16 (0.94 to 1.44) in Q5 compared with Q1, p for trend = 0.05, and for O(3), OR was 0.96 (0.91 to 1.01) in Q5 compared with Q1, p for trend = 0.11. No significant association was seen when the daily mean concentration of NO(2), SO(2), and O(3) was considered during the previous day as well as when day lag 2 or 3 was considered. The cumulative concentration (three consecutive days) of O(3) is negatively associated with RHR (p for trend = 0.02).

CONCLUSION

Changes in pulse rate could reflect cardiac rhythm changes and may be part of the pathophysiological link between pollution and cardiovascular mortality.

Air pollution and hospitalization due to angina pectoris in Tehran, Iran: a time-series study

BACKGROUND

Health effects of air pollution have been studied in many different parts of the world. Although a fairly large number of studies have explored the cardiovascular impacts of air pollution, because of its unique location we studied the association between air pollutants and hospital admissions due to angina pectoris in Tehran for the first time.

METHODS

This is a retrospective time-series study. The variables of the study include the levels of five air pollutants-nitrogen dioxide (NO(2)), carbon monoxide (CO), ozone (O(3)), sulfur dioxide (SO(2)), and particulate matter <10 microm in aerodynamic diameter (PM(10))-as independent variables; daily hospitalizations due to angina pectoris in 25 academic hospitals in Tehran as the dependent variable; and mean daily temperature and humidity, seasonality, time trend, and day of the week as potential confounders. All variables were measured during a 5-year period from 21 March 1996 to 20 March 2001. The data of mean daily levels of NO(2), CO, O(3), SO(2), and PM(10) were collected from one of the stations of Tehran's Air Quality Control Corp. Data were analyzed using Poisson regression models. Relative risks of angina pectoris admissions were calculated for an increase in 1mg/m(3) for CO and 10 microg/m(3) for the other pollutants.

RESULTS

Daily admissions due to angina pectoris were significantly related to the CO level, after controlling for confounder effects. Each unit increase in the CO level caused a 1.00934 increase in the number of admissions (95% CI, 1.00359--1.01512). This association was verified with a lag of 1 day. There was no significant association between the other air pollutants and the number of daily admission due to angina pectoris.

CONCLUSIONS

We found that with increasing levels of the pollutant CO, the number of admissions due to cardiac angina rose. Ischemic heart disease is the leading cause of death in Iran. Air pollution control will reduce the number of this preventable disease and resulting deaths.

Volcano Related Atmospheric Toxicants in Hilo and Hawaii Volcanoes National Park: Implications for Human Health

Volcanic fog (vog) from Kilauea volcano on the island of Hawaii includes a variety of chemical species including sulfur compounds and traces of metals such as mercury. The metal species seen tended to be in the nanograms per cubic meter range, whereas oxides of sulfur: SO2 and SO3 and sulfate aerosols, were in the range of micrograms per cubic meter and rarely even as high as a few milligrams per cubic meter of air (nominally ppb to ppm). These sulfur species are being investigated for associations with both acute and chronic changes in human health status. The sulfate aerosols tend to be less than 1 microm in diameter and tend to dominate the mass of this submicron size mode. The sulfur chemistry is dynamic, changing composition from predominantly sulfur dioxide and trioxide gasses near the volcano, to predominantly sulfate aerosols on the west side of the island. Time, concentration and composition characteristics of submicron aerosols and sulfur dioxide are described with respect to the related on-going health studies and public health management concerns. Exposures to sulfur dioxide and particulate matter equal to or less than 1 microm in size were almost always below the national ambient air quality standards (NAAQS). These standards do not however consider the acidic nature and submicron size of the aerosol, nor the possibility of the aerosol and the sulfur dioxide interacting in their toxicity. Time series plots, histograms and descriptive statistics of hourly averages give the reader a sense of some of the exposures observed.

Ozone Air Pollution Is Associated With Acute Myocardial Infarction

BACKGROUND

Despite the diversity of the studied health outcomes, types and levels of pollution, and various environmental settings, there is substantial evidence for a positive link between urban air pollution and cardiovascular diseases. The objective of this study was to test the associations between air pollutants and the occurrence of acute myocardial infarction (AMI).

METHODS AND RESULTS

Pollutant concentrations (SO2, NO2, and O3) were measured hourly as part of the automated air quality network. Since 1985, an AMI registry (the Toulouse MONICA Project) has been collecting data in the southwest of France. All cases of AMI and sudden and probable cardiac deaths are recorded for subjects 35 to 64 years of age. We studied the short-term exposure effect of pollution on the risk of AMI (from January 1, 1997, to June 30, 1999) using a case-crossover design method. We performed a conditional logistic regression analysis to calculate relative risks (RRs) and their 95% CIs. After adjustment for temperature, relative humidity, and influenza epidemics, the RRs (for an increase of 5 microg/m3 of O3 concentration) for AMI occurrence were significant for the current-day and 1-day-lag measurements (RR, 1.05; 95% CI, 1.01 to 1.08; P=0.009; and RR, 1.05; 95% CI, 1.01 to 1.09; P=0.007, respectively). Subjects 55 to 64 years of age with no personal history of ischemic heart disease were the most susceptible to develop an AMI (RR, 1.14; 95% CI, 1.06 to 1.23). NO2 and SO2 exposures were not significantly associated with the occurrence of AMI.

CONCLUSIONS

Observational data confirm that short-term O3 exposure within a period of 1 to 2 days is related to acute coronary events in middle-aged adults without heart disease, whereas NO2 and SO2 are not.

Relation Between Short-Term Fine-Particulate Matter Exposure and Onset of Myocardial Infarction

BACKGROUND

Epidemiologic studies have reported increases in the incidence of cardiovascular morbidity and myocardial infarction (MI) associated with increases in short-term and daily levels of fine-particulate matter air pollution, suggesting a role for particulate matter in triggering an MI.

METHODS

We studied the association between onset time of MI and preceding hourly measures of fine-particulate matter using a case-crossover study of 5793 confirmed cases of acute MI. We linked data from a community-wide database on acute MI from 1988-1994 in King County, Washington, with central site air pollution monitoring data on fine-particulate matter determined by nephelometry. We compared air pollution exposure levels averaged 1 hour, 2 hours, 4 hours, and 24 hours before MI onset to a set of time-stratified referent exposures from the same day of the week in the month of the case event.

RESULTS

: The estimated relative risk for a 10-microg/m increase in fine-particulate matter the hour before MI onset was 1.01 (95% CI=0.98-1.05). Analyses of pollutant levels at the other time points demonstrated a similar lack of association. No increased risk was found in all cases with preexisting cardiac disease (odds ratio = 1.05; 0.95-1.16). Stratification by known cardiovascular risk factors (hypertension, diabetes, and smoking status) also did not modify the relation between fine-particulate matter and MI onset.

CONCLUSION

Although a very small effect cannot be excluded, there was no consistent association between ambient levels of fine-particulate matter and risk of MI onset.

Emergency department visits and "vog"-related air quality in Hilo, Hawai'i

Emergency department (ED) visits in Hilo, Hawai'i, from January 1997 to May 2001, were examined for associations with volcanic fog, or "vog", measured as sulfur dioxide (SO(2)) and submicrometer particulate matter (PM(1)). Exponential regression models were used with robust standard errors. Four diagnostic groups were examined: asthma/COPD; cardiac; flu, cold, and pneumonia; and gastroenteritis. Before adjustments, highly significant associations with vog-related air quality were seen for all diagnostic groups except gastroenteritis. After adjusting for month, year, and day of the week, only asthma/COPD had consistently positive associations with air quality. The strongest associations were for SO(2) with a 3-day lag (6.8% per 10 ppb; P=0.001) and PM(1), with a 1-day lag (13.8% per 10 microg/m(3); P=0.011). The association of ED visits for asthma/COPD with month of the year was stronger than associations seen with air quality. Although vog appears influential, non-vog factors dominated associations with the frequency of asthma/COPD ED visits.

Variation saisonnière des accidents vasculaires cérébraux et influence des conditions météorologiques

The aim of this paper was to study the seasonal and Monthly distribution of different subtypes of strokes, and also the influence of the most usual meteorological factors on their incidence. The study, based on the population-based data of the Dijon register of stroke (France), involved 3287 patients with a cerebrovascular event during the Years 1985-1998. The seasonal distribution pointed out a summer decrease for all stroke subtypes. The cerebrovascular risk was the highest in autumn for small artery atheroma infarcts and for cerebral infarcts and, among these later, for cardioembolic infarcts and large artery atheroma infarcts, as well as for subarachnoid hemorrhages and for the total number of strokes. It was followed by spring (total number of strokes, small artery atheroma infarcts, cerebral infarcts) and/or winter (subarachnoid hemorrhages, cerebral infarcts, cardioembolic infarcts and large artery atheroma infarcts). For intracerebral hemorrhages, the risk peaked in spring and secondly in autumn. But the difference from one season to another was significant only for total number of strokes, cerebral infarcts and, among the later, for cardioembolic infarcts and large artery atheroma infarcts. As regards the Monthly distribution, the difference between Months was significant only for the total number of strokes and cerebral infarcts, with a minimum from July to September and a maximum in October for the later. Correlations with meteorological data were found for the total number of strokes, cerebral infarcts, cardioembolic infarcts, large artery atheroma infarcts and small artery atheroma infarcts. They showed an influence of temperature and relative humidity of the day of stroke or of the one to five days before. Correlations with wind speed, duration of sunshine or snow, even if less frequent, could also be found. Such results sometimes differ from those of some earlier studies, for which the climate and the risk factors were not the same, showing that regional epidemiological studies are necessary in order to determine the relations between seasons, meteorological factors and strokes.