Changes in weather and the effects on pediatric asthma exacerbations

Climate change. A global threat to cardiopulmonary health

Recent changes in the global climate system have resulted in excess mortality and morbidity, particularly among susceptible individuals with preexisting cardiopulmonary disease. These weather patterns are projected to continue and intensify as a result of rising CO2 levels, according to the most recent projections by climate scientists. In this Pulmonary Perspective, motivated by the American Thoracic Society Committees on Environmental Health Policy and International Health, we review the global human health consequences of projected changes in climate for which there is a high level of confidence and scientific evidence of health effects, with a focus on cardiopulmonary health. We discuss how many of the climate-related health effects will disproportionally affect people from economically disadvantaged parts of the world, who contribute relatively little to CO2 emissions. Last, we discuss the financial implications of climate change solutions from a public health perspective and argue for a harmonized approach to clean air and climate change policies.

Weather and air pollutants have an impact on patients with respiratory diseases and breathing difficulties in Munich, Germany

This study determined the influence of various meteorological variables and air pollutants on airway disorders in general, and asthma and/or chronic obstructive pulmonary disease in particular, in Munich, Bavaria, during 2006 and 2007. This was achieved through an evaluation of the daily frequency of calls to medical and emergency call centres, ambulatory medical care visits at general practitioners, and prescriptions of antibiotics for respiratory diseases. Meteorological parameters were extracted from data supplied by the European Centre for Medium Range Weather Forecast. Data on air pollutant levels were extracted from the air quality database of the European Environmental Agency for different measurement sites. In addition to descriptive analyses, a backward elimination procedure was performed to identify variables associated with medical outcome variables. Afterwards, generalised additive models (GAM) were used to verify whether the selected variables had a linear or nonlinear impact on the medical outcomes. The analyses demonstrated associations between environmental parameters and daily frequencies of different medical outcomes, such as visits at GPs and air pressure (-27 % per 10 hPa change) or ozone (-24 % per 10 μg/m(3) change). The results of the GAM indicated that the effects of some covariates, such as carbon monoxide on consultations at GPs, or humidity on medical calls in general, were nonlinear, while the type of association varied between medical outcomes. These data suggest that the multiple, complex effect of environmental factors on medical outcomes should not be assumed homogeneous or linear a priori and that different settings might be associated with different types of associations.

Impact of ambient humidity on child health: a systematic review

BACKGROUND AND OBJECTIVES

Changes in relative humidity, along with other meteorological factors, accompany ongoing climate change and play a significant role in weather-related health outcomes, particularly among children. The purpose of this review is to improve our understanding of the relationship between ambient humidity and child health, and to propose directions for future research.

METHODS

A comprehensive search of electronic databases (PubMed, Medline, Web of Science, ScienceDirect, OvidSP and EBSCO host) and review of reference lists, to supplement relevant studies, were conducted in March 2013. All identified records were selected based on explicit inclusion criteria. We extracted data from the included studies using a pre-designed data extraction form, and then performed a quality assessment. Various heterogeneities precluded a formal quantitative meta-analysis, therefore, evidence was compiled using descriptive summaries.

RESULTS

Out of a total of 3797 identified records, 37 papers were selected for inclusion in this review. Among the 37 studies, 35% were focused on allergic diseases and 32% on respiratory system diseases. Quality assessment revealed 78% of the studies had reporting quality scores above 70%, and all findings demonstrated that ambient humidity generally plays an important role in the incidence and prevalence of climate-sensitive diseases among children.

CONCLUSIONS

With climate change, there is a significant impact of ambient humidity on child health, especially for climate-sensitive infectious diseases, diarrhoeal diseases, respiratory system diseases, and pediatric allergic diseases. However, some inconsistencies in the direction and magnitude of the effects are observed.

Predictive factors of hospitalization in children with acute asthma at a university emergency care unit

OBJECTIVE

This study analyzed the factors that predicted the hospitalization of children with asthma following standardized treatment in emergency care unit (ECU).

METHODS

This retrospective study examined data collected from the clinical records of children, 14 years or younger, who were diagnosed with asthma (often with bronchopneumonia, pneumonia, or other illnesses) and treated at the ECU of Santo André from January 2005 to December 2009. The following data were analyzed: month and year of care, child's age and sex, period of observation, and need for hospitalization. A pediatrician confirmed the clinical diagnoses of all participants. The children were first given clinical treatments and were then admitted to ECU for follow-up assessment.

RESULTS

The number of hospital admissions was analyzed, and correlations were found with regard to this variable and child age (χ(2) = 166.9; P = 0.00001), the presence of associated illnesses (χ(2) = 63.8; P < 0.00001), and the observation period length (χ(2) = 11.4; P = 0.009). The number of hospital admissions was not correlated with child sex (χ(2) = 0.013; P = 0.9) or time of year (χ(2) = 15.8; P = 0.1). The 3-day observation period was not significant (P = 0.4) with regard to the remainder of the variables in the multiple logistic regression analysis.

CONCLUSIONS

Age, mainly children younger than 1 year, the presence of associated illnesses, and the observation period length predicted the hospitalization of children with asthma following treatment in ECU. Sex and seasonality did not affect the need for hospitalization.

Lungs in a warming world: climate change and respiratory health

Climate change is a health threat no less consequential than cigarette smoking. Increased concentrations of greenhouse gases, and especially CO₂, in the earth's atmosphere have already warmed the planet substantially, causing more severe and prolonged heat waves, temperature variability, air pollution, forest fires, droughts, and floods, all of which put respiratory health at risk. These changes in climate and air quality substantially increase respiratory morbidity and mortality for patients with common chronic lung diseases such as asthma and COPD and other serious lung diseases. Physicians have a vital role in addressing climate change, just as they did with tobacco, by communicating how climate change is a serious, but remediable, hazard to their patients.

Acute asthma exacerbations in childhood: risk factors, prevention and treatment

Asthma is a heterogeneous disease more appropriately seen as a syndrome rather than a single pathologic entity. Although it can remain quiescent for extended time periods, the inflammatory and remodeling processes affect the bronchial milieu and predispose to acute and occasionally severe clinical manifestations. The complexity underlying these episodes is enhanced during childhood, an era of ongoing alterations and maturation of key biological systems. In this review, the authors focus on such sudden-onset events, emphasizing on their diversity on the basis of the numerous asthma phenotypes.

Association of ambient air pollution and meteorological factors with primary care visits at night due to asthma attack

AIM

The association of outdoor air pollution and meteorological elements with primary care visits at night due to asthma attack was studied.

METHODS

A case-crossover study was conducted in a primary care clinic in Himeji City, Japan. The subjects were 956 children aged 0-14 years who visited the clinic with an asthma attack between the hours of 9 p.m. and 6 a.m. Daily concentrations of particulate matter, ozone, nitrogen dioxide, and a number of meteorological elements were measured, and a conditional logistic regression model was used to estimate odds ratios (ORs) of primary care visits per unit increment of air pollutants or meteorological elements. The analyses took into consideration the effects of seasonality.

RESULTS

Of the 956 children, 73 (7.6 %) were aged <2 years and 417 (43.6 %) were aged 2-5 years. No association between daily ozone levels and primary care visits due to asthma attack at night in the spring or summer was found. An inverse relation between suspended particulate matter and primary care visits due to asthma attack was detected in the winter. ORs in the summer per degree increment in daily mean temperature was 1.31 [95 % confidential interval (CI) 1.09-1.56], and ORs in the autumn per hourly increment in daily hours of sunshine was 0.94 (95 % CI 0.90-0.99).

CONCLUSION

The findings of our study fail to support any association between daily mean concentration of air pollutant and primary care visits at night. However, we did find evidence indicating that certain meteorological elements may be associated with primary care visits.

Diurnal temperature change is associated with testicular torsion: a nationwide, population based study in Taiwan

PURPOSE

We investigated the association between climatic variables and testicular torsion in Taiwanese males.

MATERIALS AND METHODS

Using the Taiwan Longitudinal Health Insurance Database, we reviewed the files of patients who were diagnosed with testicular torsion and underwent orchiectomy or orchiopexy between January 1996 and December 2008. Children younger than 1 year were excluded from the study. Climatic data were provided by the Taiwan Central Weather Bureau and included ambient temperature, relative humidity, diurnal temperature change and barometric pressure. Patients with acute appendicitis who underwent appendectomy were chosen as the control group. Climatic variables in relation to testicular torsion were analyzed using the Mann-Whitney U test and chi-square test, and seasonal climatic variations using the Kruskal-Wallis H test. Relative risk was calculated to compare the incidence of testicular torsion for diurnal temperature changes.

RESULTS

A total of 65 patients with a mean age of 16.2 years presented with testicular torsion and were treated surgically. Four children younger than 1 year were excluded, and thus the study population consisted of 61 patients. The estimated incidence of testicular torsion was 2.58 per 100,000 person-years. There were no special climatic conditions on days of admission. However, 73.7% of the patients had testicular torsion when the diurnal temperature change was 6C or greater. Compared to the torsion rate for diurnal temperature changes less than 6C, the relative risk of testicular torsion at 6C or greater was 1.8 (p = 0.05). Average seasonal diurnal temperature change in the 2 days before hospitalization showed increases in all seasons except spring, which fluctuated.

CONCLUSIONS

Diurnal temperature change was associated with testicular torsion and may be an etiological climatic factor affecting this condition. This is the first known study to demonstrate an association between diurnal temperature change and testicular torsion.

Diurnal temperature range and childhood asthma: a time-series study

BACKGROUND

Hot and cold temperatures have been associated with childhood asthma. However, the relationship between daily temperature variation and childhood asthma is not well understood. This study aimed to examine the relationship between diurnal temperature range (DTR) and childhood asthma.

METHODS

A Poisson generalized linear model combined with a distributed lag non-linear model was used to examine the relationship between DTR and emergency department admissions for childhood asthma in Brisbane, from January 1st 2003 to December 31st 2009.

RESULTS

There was a statistically significant relationship between DTR and childhood asthma. The DTR effect on childhood asthma increased above a DTR of 10°C. The effect of DTR on childhood asthma was the greatest for lag 0-9 days, with a 31% (95% confidence interval: 11% - 58%) increase of emergency department admissions per 5°C increment of DTR. Male children and children aged 5-9 years appeared to be more vulnerable to the DTR effect than others.

CONCLUSIONS

Large DTR may trigger childhood asthma. Future measures to control and prevent childhood asthma should include taking temperature variability into account. More protective measures should be taken after a day of DTR above 10°C.

Relating weather types to asthma-related hospital admissions in New York State

Many previous studies have looked into the relationship between asthma and individual weather variables, but comparatively few have looked at this relationship using holistic weather types (WTs). Utilizing the Spatial Synoptic Classification, this research considers up to 6 days of lag time while investigating the asthma-to-WT relationship in two age groups (under 18 and 18 and over) throughout New York State. Results indicate that a cold and dry WT in autumn corresponds to increased asthma admissions and spike days in admissions in New York City (NYC) for the school-aged population, while hot and dry WTs in summer correspond to spike days in asthma admissions in both age groups. However, results vary considerably for other regions, seasons and WTs, and spike day analysis yields clearer results than the analysis of total anomalous admissions. When stratified by multiple regions and age groups, the sample size of daily asthma admissions is a limiting factor outside of NYC.

Short-term outdoor temperature change and emergency department visits for asthma among children: a case-crossover study

Although weather changes are known to cause asthma symptoms, their impact on asthma-related health-care utilization is poorly understood. The objective of the present study was to determine the association between short-term outdoor temperature change and asthma-related emergency department (ED) visits among children 3-18 years of age in Detroit, Michigan, in 2000-2001. Descriptive analyses of patient and ED visit characteristics were performed. A case-crossover study utilizing time-stratified controls was conducted to determine the impact of maximum temperature change and change rate measured during 4-, 8-, 12-, and 24-hour periods. Multivariable conditional logistic regression demonstrated the relation between ED visits and temperature change after controlling for other weather and pollutant measures. There were 4,804 asthma-related ED visits during the study period, and they occurred most frequently in the fall and during morning hours. The case-crossover study showed a statistically significant inverse relation between ED visits and maximum 24-hour temperature change after adjustment for climatic factors (for temperature change, odds ratio = 0.992, P = 0.04; for temperature change rate, odds ratio 0.972, P = 0.01). The association persisted after air pollutant measures were added to the model, although the association was not significant. Despite the finding that a greater 24-hour temperature change decreased the risk of asthma-related ED visits, the overall results suggested a negligible association with short-term temperature change.

Environmental risk factors for persistent asthma in Lucknow

OBJECTIVE

To identify the risk factors for persistent asthma among common environmental exposures, like ambient air pollutants and second hand smoke, animals, place of residence, decreased ventilation, dust, as well as history of allergic conditions like rhinitis, dermatitis and family history of asthma in children.

METHODS

This hospital-based, cross-sectional study was conducted after institutional ethical clearance. Children aged 1-12 y with asthma were recruited after parental consent. Children were classified into asthma severity categories according to GINA 2002 and level of control categories according to GINA 2009 guidelines. Adjusted logistic regression analysis was used to identify factors associated with persistent asthma.

RESULTS

From August 2008 through October 2010, 205 asthmatic children were recruited of which 73 (35.60 %) had intermittent and 132 (64.40 %) had persistent asthma. Asthma was controlled in 19 (9.26 %), partly controlled in 90 (43.90 %) and uncontrolled in 96 (46.82 %). Patients with persistent asthma were more likely to have uncontrolled asthma (OR = 8.28; 95 % CI: 2.43-31.01; p < 0.001). Adjusting for age, sex, socioeconomic status and place of residence, persistent asthma was associated with residence within 1.5 km from heavy traffic (OR = 4.58; 95%CI: 2.18-9.59; p < 0.001) and father smoking indoors >5 cigarettes or "bidi"/day (OR = 17.76; 95 % CI: 1.85-170.76; p = 0.01).

CONCLUSIONS

Since patients with persistent asthma are more likely to have uncontrolled asthma and since persistent asthma is associated with residence closer to heavy traffic and exposure to second hand smoke, minimizing exposures to these may help in better asthma control.

Modifiable factors associated with severe asthma exacerbations in urban patients

BACKGROUND

Rates of asthma morbidity, mortality, and resource use are highest among African American individuals residing in inner-city locations, yet factors associated with adverse outcomes are not well established.

OBJECTIVE

To identify modifiable factors associated with asthma exacerbations.

METHODS

A total of 104 adult patients who presented to an inner-city hospital or emergency department (ED) with an asthma exacerbation from October 1, 2009, through June 31, 2010, completed surveys of clinical status, acute events, sociodemographic characteristics, current asthma knowledge, self-efficacy, attitudes toward asthma self-management, and perceived barriers to asthma care questionnaires. Associations with asthma hospitalizations and ED visits were assessed.

RESULTS

The mean age of the patients was 42 years, 91% were African American, 33% were insured, 57% were taking a controller medication, and 63% had an income level below the federal poverty line. On bivariate analysis, males, years of asthma, history of smoking, self-classification of asthma severity, history of admission to intensive care unit or intubation, use of peak flow meter or asthma action plan, controller medication use, and history of oral corticosteroid bursts were positively associated, whereas self-efficacy was negatively associated with number of ED visits or hospitalizations. No association was found for asthma knowledge, perceived barriers to care, or attitudes toward asthma management. On multivariate analysis, low self-efficacy remained associated with both asthma hospitalizations and ED visits.

CONCLUSION

Short-term use of health services for asthma is negatively associated with asthma self-efficacy. Self-management programs that enhance self-efficacy, rather than those that focus on knowledge or attitudes, may be effective in reducing adverse asthma outcomes for inner-city, predominantly African American populations.

Effects of ambient pollen concentrations on frequency and severity of asthma symptoms among asthmatic children

BACKGROUND

Previous studies on the associations between ambient pollen exposures and daily respiratory symptoms have produced inconsistent results. We investigated these relationships in a cohort of asthmatic children using pollen exposure models to estimate individual ambient exposures.

METHODS

Daily symptoms of wheeze, night symptoms, shortness of breath, chest tightness, persistent cough, and rescue medication use were recorded in a cohort of 430 children with asthma (age 4-12 years) in Connecticut, Massachusetts, and New York. Daily ambient exposures to tree, grass, weed, and total pollen were estimated using mixed-effects models. We stratified analyses by use of asthma maintenance medication and sensitization to grass or weed pollens. Separate logistic regression analyses using generalized estimating equations were performed for each symptom outcome and pollen type. We adjusted analyses for maximum daily temperature, maximum 8-hour average ozone, fine particles (PM2.5), season, and antibiotic use.

RESULTS

Associations were observed among children sensitized to specific pollens; these associations varied by use of asthma maintenance medication. Exposures to even relatively low levels of weed pollen (6-9 grains/m(3)) were associated with increased shortness of breath, chest tightness, rescue medication use, wheeze, and persistent cough, compared with lower exposure among sensitized children on maintenance medication. Grass pollen exposures ≥ 2 grains/m(3) were associated with wheeze, night symptoms, shortness of breath, and persistent cough compared with lower exposure among sensitized children who did not take maintenance medication.

CONCLUSION

Even low-level pollen exposure was associated with daily asthmatic symptoms.

Limited agreement between current and long-term asthma control in children: the PACMAN cohort study

BACKGROUND

Several studies have shown that predictors of asthma treatment outcomes differ depending on the definition of the outcome chosen. This provides evidence that different outcomes studied may reflect distinct aspects of asthma control. To assess predictors of asthma control, we need firm outcome phenotypes. The aim of this study was to investigate the association between measurements of current and long-term asthma control.

METHODS

We included 527 children using inhaled corticosteroids participating in the Pharmacogenetics of Asthma medication in Children: Medication with ANti-inflammatory effects cohort. Current asthma control (previous week) was defined using the Asthma Control Questionnaire. Long-term asthma control was based on Global Initiative for Asthma guidelines. Not well-controlled asthma in a season was defined as ≥ 3 of the following items present in a season: (i) day-time or (ii) night-time symptoms, (iii) limitations in activities, and (iv) rescue medication use. Asthma control during (i) the previous season and (ii) the year preceding the pharmacy visit was used as long-term asthma control definitions. Current and long-term asthma control were compared to investigate agreement.

RESULTS

Long-term uncontrolled asthma rates were highest in autumn and winter (50%) and lowest in summer (32%) (p < 0.05). Overall agreement between current and long-term asthma control was limited (66% for previous season and 68% for previous year).

CONCLUSION

Congruence between current and long-term asthma control was limited. Furthermore, we showed significant seasonal differences. It is therefore important to calculate asthma control over a longer period of time, instead of using current asthma control as indicator.

[Asthmatic exacerbations: specific features in children]

L’asthme aurait déjà concerné plus de 10 % des enfants âgés de dix ans. Ce constat mérite une discussion pneumopédiatrique à part entière. Malgré des similitudes entre l’asthme de l’adulte et celui de l’enfant, la population pédiatrique présente certaines spécificités notamment concernant les exacerbations. L’asthme du nourrisson est une entité particulière dont la définition a bénéficié récemment d’une mise à jour officielle. Les étiologies d’exacerbations asthmatiques restent les infections, avec en tête les virus dont le typage joue un rôle pronostique. L’environnement intérieur et extérieur peut aggraver l’asthme, notamment par de fortes concentrations de polluants atmosphériques. Les nutriments semblent jouer un rôle pronostique par le biais de la vitamine D ou de la présence d’allergie alimentaire. La recherche de facteurs prédictifs ou de marqueurs inflammatoires de l’asthme est la clé de voûte pour la maîtrise de ces exacerbations, mais les techniques actuelles ne sont pas encore totalement performantes comme la mesure de l’oxyde nitrique exhalé (eNO), l’étude des crachats/exhalas ou encore de simples questionnaires. La prise en charge précoce et continue avec l’éducation thérapeutique des enfants et de leur famille demeure un outil efficace en termes de prévention de rechute des exacerbations.

Comparison in asthma and allergy prevalence in the two major cities in Greece: the ISAAC phase II survey

BACKGROUND

Variability in the prevalence of allergic diseases has been detected not only between different countries, but also between cities with similar national and different socio-economic or climatic characteristics. The aim of this study was to determine the prevalence of childhood asthma and allergies and which factors are associated with them, in the two largest Greek cities, Athens and Thessaloniki.

METHODS

Two thousand and twenty-three Greek 9-10-year-old schoolchildren from Athens (Central Greece) and Thessaloniki (North Greece, more humid), were included in ISAAC-II study. All participants followed the ISAAC-II protocol by questionnaire, skin prick testing and flexural dermatitis examination.

RESULTS

Compared with Athens, the prevalence of current wheezing (8.4% vs. 5.7%, p=0.002), lifetime asthma (11.5% vs. 7.7%, p=0.004), atopic current asthma (3.2% vs. 1.6%, p=0.02), allergic rhinitis (8.2% vs. 5.2%, p=0.007), and hay fever (21.7% vs. 12.5%, p<0.001) were higher in Thessaloniki. The overall sensitisation rate was also higher in Thessaloniki than in Athens (25.2% vs. 16%, p<0.001) with more prevalent sensitising due to the perennial allergens (D. pteronyssinus, D. farinae, Alternaria tenuis) and cat dander. Perennial allergens sensitisation was a risk factor for current asthma in both cities.

CONCLUSION

A higher prevalence of asthma symptoms, allergic rhinitis, and sensitisation rate was detected in Greek schoolchildren living in Thessaloniki compared to those in Athens. Allergy to mites and mould was more prevalent in Thessaloniki. The more humid weather of Thessaloniki may be implicated.

Seven-days-ahead forecasting of childhood asthma admissions using artificial neural networks in Athens, Greece

Artificial Neural Network (ANN) models were developed and applied in order to predict the total weekly number of Childhood Asthma Admission (CAA) at the greater Athens area (GAA) in Greece. Hourly meteorological data from the National Observatory of Athens and ambient air pollution data from seven different areas within the GAA for the period 2001-2004 were used. Asthma admissions for the same period were obtained from hospital registries of the three main Children's Hospitals of Athens. Three different ANN models were developed and trained in order to forecast the CAA for the subgroups of 0-4, 5-14-year olds, and for the whole study population. The results of this work have shown that ANNs could give an adequate forecast of the total weekly number of CAA in relation to the bioclimatic and air pollution conditions. The forecasted numbers are in very good agreement with the observed real total weekly numbers of CAA.

Asthma symptoms in pediatric patients: differences throughout the seasons

INTRODUCTION

Seasonal variation in asthma has been widely recognized. The aim of this study was to describe seasonal patterns of asthma symptoms and asthma medication use in a cohort of pediatric asthma medication users and to study determinants of seasonal childhood asthma.

METHODS

For this study, 602 children participating in the Pharmacogenetics of Asthma medication in Children: Medication with Anti-inflammatory effects) cohort were included. Parents were asked about their child's respiratory symptoms and quick-reliever medication use over the past year. Logistic regression analysis was used to study determinants of seasonality in asthma control (the level of disease control based on symptoms, limitations in activities, and rescue medication use).

RESULTS

There was a decline in asthma symptoms and asthma medication use during the summer period and a peak occurred from autumn to spring. The prevalence of wheeze ranged from 32% in summer to 56% in autumn. The prevalence of respiratory symptoms and medication use was significantly lower during summer (p < .0001). Oral steroids and antibiotics use and strong parental necessity beliefs were associated with uncontrolled asthma, regardless of seasonality. Allergic rhinitis was associated with an increased risk of uncontrolled asthma during spring [odds ratio (OR): 1.9; 95% confidence interval (CI): 1.3-2.8] and summer (OR: 1.9; 95% CI: 1.2-3.0). Eczema was associated with a higher risk of uncontrolled asthma during autumn (OR: 1.5; 95% CI: 1.0-2.2) and winter (OR: 1.3; 95% CI: 1.0-1.9).

CONCLUSION

We showed seasonal patterns in asthma symptoms and medication use. Associations were shown between allergic rhinitis and asthma control during spring/summer and eczema was associated with uncontrolled asthma during autumn/winter. Seasonality in asthma morbidity and health-care use is most likely associated with atopic constitution and viral infections, which are common during fall, winter, and spring.

Associations between ozone and morbidity using the Spatial Synoptic Classification system

BACKGROUND

Synoptic circulation patterns (large-scale tropospheric motion systems) affect air pollution and, potentially, air-pollution-morbidity associations. We evaluated the effect of synoptic circulation patterns (air masses) on the association between ozone and hospital admissions for asthma and myocardial infarction (MI) among adults in North Carolina.

METHODS

Daily surface meteorology data (including precipitation, wind speed, and dew point) for five selected cities in North Carolina were obtained from the U.S. EPA Air Quality System (AQS), which were in turn based on data from the National Climatic Data Center of the National Oceanic and Atmospheric Administration. We used the Spatial Synoptic Classification system to classify each day of the 9-year period from 1996 through 2004 into one of seven different air mass types: dry polar, dry moderate, dry tropical, moist polar, moist moderate, moist tropical, or transitional. Daily 24-hour maximum 1-hour ambient concentrations of ozone were obtained from the AQS. Asthma and MI hospital admissions data for the 9-year period were obtained from the North Carolina Department of Health and Human Services. Generalized linear models were used to assess the association of the hospitalizations with ozone concentrations and specific air mass types, using pollutant lags of 0 to 5 days. We examined the effect across cities on days with the same air mass type. In all models we adjusted for dew point and day-of-the-week effects related to hospital admissions.

RESULTS

Ozone was associated with asthma under dry tropical (1- to 5-day lags), transitional (3- and 4-day lags), and extreme moist tropical (0-day lag) air masses. Ozone was associated with MI only under the extreme moist tropical (5-day lag) air masses.

CONCLUSIONS

Elevated ozone levels are associated with dry tropical, dry moderate, and moist tropical air masses, with the highest ozone levels being associated with the dry tropical air mass. Certain synoptic circulation patterns/air masses in conjunction with ambient ozone levels were associated with increased asthma and MI hospitalizations.