Is daily exposure to ozone associated with respiratory morbidity and lung function in a representative sample of schoolchildren? Results from a panel study in Greece

Long-term ozone exposure and lung function in middle childhood

BACKGROUND

Ozone (O3) exposure interrupts normal lung development in animal models. Epidemiologic evidence further suggests impairment with higher long-term O3 exposure across early and middle childhood, although study findings to date are mixed and few have investigated vulnerable subgroups.

METHODS

Participants from the CANDLE study, a pregnancy cohort in Shelby County, TN, in the ECHO-PATHWAYS Consortium, were included if children were born at gestational age >32 weeks, completed a spirometry exam at age 8-9, and had a valid residential history from birth to age 8. We estimated lifetime average ambient O3 exposure based on each child's residential history from birth to age 8, using a validated fine-resolution spatiotemporal model. Spirometry was performed at the age 8-9 year study visit to assess Forced Expiratory Volume in the first second (FEV1) and Forced Vital Capacity (FVC) as primary outcomes; z-scores were calculated using sex-and-age-specific reference equations. Linear regression with robust variance estimators was used to examine associations between O3 exposure and continuous lung function z-scores, adjusted for child, sociodemographic, and home environmental factors. Potential susceptible subgroups were explored using a product term in the regression model to assess effect modification by child sex, history of bronchiolitis in infancy, and allergic sensitization.

RESULTS

In our sample (n = 648), O3 exposure averaged from birth to age 8 was modest (mean 26.6 [SD 1.1] ppb). No adverse associations between long-term postnatal O3 exposure were observed with either FEV1 (β = 0.12, 95% CI: -0.04, 0.29) or FVC (β = 0.03, 95% CI: -0.13, 0.19). No effect modification by child sex, history of bronchiolitis in infancy, or allergic sensitization was detected for associations with 8-year average O3.

CONCLUSIONS

In this sample with low O3 concentrations, we did not observe adverse associations between O3 exposures averaged from birth to age 8 and lung function in middle childhood.

Effects of air pollution on restricted activity days: systematic review and meta-analysis

BACKGROUND

The adverse effects of air pollution on human health include many diseases and health conditions associated with mortality, morbidity and disability. One example of these outcomes that can be translated into economic costs is the number of days of restricted activity. The aim of this study was to assess the effect of outdoor exposure to particulate matter with an aerodynamic diameter less than or equal to 10 and 2.5 μm (PM₁₀, PM_2.5), nitrogen dioxide (NO₂), and ozone (O₃), on restricted activity days.

METHODS

Observational epidemiological studies with different study designs were included, and pooled relative risks (RR) with 95% confidence intervals (95%CI) were calculated for an increase of 10 μg/m³ of the pollutant of interest. Random-effects models were chosen because of the environmental differences between the studies. Heterogeneity was estimated using prediction intervals (PI) and I-Squared (I2) values, while risk of bias was assessed using a tool developed by the World Health Organization specifically designed for air pollution studies, and based on different domains. Subgroup and sensitivity analyses were performed where possible. The protocol for this review was registered with PROSPERO (CRD42022339607).

RESULTS

We included 18 articles in the quantitative analysis. Associations between pollutants and restricted activity days in time-series studies of short-term exposures, measured as work-loss days, school-loss days, or both were significant for PM₁₀ (RR: 1.0191; 95%CI: 1.0058-1.0326; 80%PI: 0.9979-1.0408; I2: 71%) and PM_2.5 (RR: 1.0166; 95%CI: 1.0050-1.0283; 80%PI: 0.9944-1.0397; I2: 99%), but not for NO₂ or O₃. Some degree of heterogeneity between studies was observed, but sensitivity analysis showed no differences in the direction of the pooled relative risks when studies with a high risk of bias were excluded. Cross-sectional studies also showed significant associations for PM_2.5 and restricted activity days. We could not perform the analysis for long-term exposures because only two studies analysed this type of association.

CONCLUSION

Restricted activity days and related outcomes were associated with some of the pollutants under evaluation, as shown in studies with different designs. In some cases, we were able to calculate pooled relative risks that can be used for quantitative modelling.

Is life expectancy higher in countries and territories with publicly funded health care? Global analysis of health care access and the social determinants of health

Background

To better understand factors influencing life expectancy, this paper examines how the availability of publicly funded health care in a country and multiple social determinants of health impact longevity of life.

Methods

In this descriptive statistical analysis, data regarding publicly funded health care, life expectancy, and social determinants of health were obtained for 196 countries and 4 territories. Social determinants included 10 indicators detailing country-level information to represent 5 key categories: economic stability, education, health & health care, neighbourhood & built environment, and social & community context. Analyses consisted of: 1) comparison of mean life expectancy among countries and territories with- and without- publicly funded health care; 2) correlations in life expectancy across social determinants by health care access and level of burden; and 3) correlations in life expectancy within social determinants for health care access by level of burden.

Results

Overall, life expectancy in countries and territories with- publicly funded health care (Mean (m) = 76.7 years) was significantly longer compared to countries and territories without- publicly funded health care (m = 66.8 years, P < 0.0001). For each social determinant, we observed longer life expectancy continued to be associated with publicly funded health care access across stratum (P < 0.0001), but difference in years of life expectancy existed both by burden of social determinant, as well as access to health care within quartiles of burden (Publicly funded care (yes): 68.12-80.88 years, (no): 62.39-77.33 years, all P < 0.05). Both social determinants as well as the availability of publicly funded health care were individually and simultaneously associated with mean longevity of life between countries and territories worldwide.

Conclusions

These findings demonstrate how, if made widely available, publicly funded health care could extend longevity of life. If combined with programs to reduce the burden of social determinants, a substantial impact can be made to promote more equitable distribution of life expectancies across the world. Ultimately, both access to publicly funded care and reducing inequalities in social determinants are needed in order to promote longer and healthier aging in populations worldwide.

Risk of illness-related school absenteeism for elementary students with exposure to PM2.5 and O3

Air pollution addresses short-term health effects on morbidity, especially for children. Assessing the impacts of air pollution on elementary students is critical for developing preparedness response strategies for this sensitive group. In the 2016-17 academic year, up to 687,748 groups of illness-related absence records and the information on whether the absentee had gone to a hospital or not were collected from 2564 elementary schools across Jiangsu Province China. We explored the associations between air pollution and illness-related records using a time-stratified case-crossover analysis with distributed lag non-linear design. An increase of 10 μg/m³ in the current-day concentration of PM_2.5 and O₃ was positively associated with illness-related absenteeism overall. The excess risk of absenteeism was 4.52 % (95%CI 4.37-4.67 %) for PM_2.5 and 0.25 % (95%CI 0.01-0.36 %) for O₃. The risk associated with O₃ was boosted for the frequent absentees who tended to have basic diseases or were more vulnerable to infectious diseases. Students in 43.1 % illness-related absenteeism, mainly due to highly infectious diseases, only received home nursing without going to a hospital. The increase in the number of illness cases associated with PM_2.5 and O₃ estimated based on the illness-related absence data was 41.5 % and 18.6 % higher than that evaluated based on hospital visit records. Such underestimations persisted in sensitivity analyses and persisted in subgroups classified by gender or grade. Together, the performance of illness-related absence records far outweighed that of hospital visit data regarding the thorough evaluation of air pollution-related illness cases for elementary students. Improvement in air quality and home health care education are warranted as well for the health benefits of children.

Acute effects of exposure to fine particulate matter and ozone on lung function, inflammation and oxidative stress in healthy adults

Both fine particulate matter (PM_2.5) and ozone (O₃) may have adverse effects on human health. However, previous studies on the effects of air pollutants mainly have focused on susceptible population, and evidence on healthy young adults is limited. We aimed to examine the associations of the two main air pollutants (PM_2.5 and O₃) with lung function, inflammation and oxidative stress in healthy young adults. We recruited 30 healthy young adults for a longitudinal panel study in Beijing and implemented health examination seven times, including lung function (FEV₁ and PEF) and biomarkers of inflammation and oxidative stress (i.e. C-reactive protein, CRP; interleukin-6, IL-6; malondialdehyde, MDA) from December 2019 to May 2021. Hourly ambient air pollutants data were obtained from the closest air quality monitoring station. Linear mixed-effect model was applied to explore the associations between air pollutants and lung function, inflammation and oxidative stress. We observed higher PM_2.5 exposure was associated with decrement in lung function and increment in CRP and MDA. Each 10 μg/m³ increase in PM_2.5 (lag 2 day) is associated with a 17.06 ml (95% CI: -31.53, -2.58) decrease in FEV₁, 46.34 ml/s (95% CI: -76.41, -16.27) decrease in PEF and increments of 2.86% (95% CI: 1.47%, 4.27%) in CRP, 1.63% (95% CI: 0.14%, 3.14%) in MDA respectively. However, there is no significant association between ozone exposure and health indicators. The study suggested that short-term exposure to PM_2.5 may decrease lung function and induce inflammation and oxidative stress in healthy adults, but there is no association between O₃ and each outcome.

Daily Associations of Air Pollution and Pediatric Asthma Risk Using the Biomedical REAI-Time Health Evaluation (BREATHE) Kit

Background: Exposure to air pollution is associated with acute pediatric asthma exacerbations, including reduced lung function, rescue medication usage, and increased symptoms; however, most studies are limited in investigating longitudinal changes in these acute effects. This study aims to investigate the effects of daily air pollution exposure on acute pediatric asthma exacerbation risk using a repeated-measures design. Methods: We conducted a panel study of 40 children aged 8−16 years with moderate-to-severe asthma. We deployed the Biomedical REAI-Time Health Evaluation (BREATHE) Kit developed in the Los Angeles PRISMS Center to continuously monitor personal exposure to particulate matter of aerodynamic diameter < 2.5 µm (PM2.5), relative humidity and temperature, geolocation (GPS), and asthma outcomes including lung function, medication use, and symptoms for 14 days. Hourly ambient (PM2.5, nitrogen dioxide (NO2), ozone (O3)) and traffic-related (nitrogen oxides (NOx) and PM2.5) air pollution exposures were modeled based on location. We used mixed-effects models to examine the association of same day and lagged (up to 2 days) exposures with daily changes in % predicted forced expiratory volume in 1 s (FEV1) and % predicted peak expiratory flow (PEF), count of rescue inhaler puffs, and symptoms. Results: Participants were on average 12.0 years old (range: 8.4−16.8) with mean (SD) morning %predicted FEV1 of 67.9% (17.3%) and PEF of 69.1% (18.4%) and 1.4 (3.5) puffs per day of rescue inhaler use. Participants reported chest tightness, wheeze, trouble breathing, and cough symptoms on 36.4%, 17.5%, 32.3%, and 42.9%, respectively (n = 217 person-days). One SD increase in previous day O3 exposure was associated with reduced morning (beta [95% CI]: −4.11 [−6.86, −1.36]), evening (−2.65 [−5.19, −0.10]) and daily average %predicted FEV1 (−3.45 [−6.42, −0.47]). Daily (lag 0) exposure to traffic-related PM2.5 exposure was associated with reduced morning %predicted PEF (−3.97 [−7.69, −0.26]) and greater odds of “feeling scared of trouble breathing” symptom (odds ratio [95% CI]: 1.83 [1.03, 3.24]). Exposure to ambient O3, NOx, and NO was significantly associated with increased rescue inhaler use (rate ratio [95% CI]: O3 1.52 [1.02, 2.27], NOx 1.61 [1.23, 2.11], NO 1.80 [1.37, 2.35]). Conclusions: We found significant associations of air pollution exposure with lung function, rescue inhaler use, and “feeling scared of trouble breathing.” Our study demonstrates the potential of informatics and wearable sensor technologies at collecting highly resolved, contextual, and personal exposure data for understanding acute pediatric asthma triggers.

Quantifying the short-term effects of air pollution on health in the presence of exposure measurement error: a simulation study of multi-pollutant model results

BACKGROUND

Most epidemiological studies estimate associations without considering exposure measurement error. While some studies have estimated the impact of error in single-exposure models we aimed to quantify the effect of measurement error in multi-exposure models, specifically in time-series analysis of PM_2.5, NO₂, and mortality using simulations, under various plausible scenarios for exposure errors. Measurement error in multi-exposure models can lead to effect transfer where the effect estimate is overestimated for the pollutant estimated with more error to the one estimated with less error. This complicates interpretation of the independent effects of different pollutants and thus the relative importance of reducing their concentrations in air pollution policy.

METHODS

Measurement error was defined as the difference between ambient concentrations and personal exposure from outdoor sources. Simulation inputs for error magnitude and variability were informed by the literature. Error-free exposures with their consequent health outcome and error-prone exposures of various error types (classical/Berkson) were generated. Bias was quantified as the relative difference in effect estimates of the error-free and error-prone exposures.

RESULTS

Mortality effect estimates were generally underestimated with greater bias observed when low ratios of the true exposure variance over the error variance were assumed (27.4% underestimation for NO₂). Higher ratios resulted in smaller, but still substantial bias (up to 19% for both pollutants). Effect transfer was observed indicating that less precise measurements for one pollutant (NO₂) yield more bias, while the co-pollutant (PM_2.5) associations were found closer to the true. Interestingly, the sum of single-pollutant model effect estimates was found closer to the summed true associations than those from multi-pollutant models, due to cancelling out of confounding and measurement error bias.

CONCLUSIONS

Our simulation study indicated an underestimation of true independent health effects of multiple exposures due to measurement error. Using error parameter information in future epidemiological studies should provide more accurate concentration-response functions.

Systematic Review of Ozone Effects on Human Lung Function, 2013 through 2020

Background

Ozone effects on lung function are particularly important to understand in the context of the air pollution-health outcomes epidemiologic literature, given the complex relationships between ozone and other air pollutants with known lung function effects.

Research Question

What has been learned about the association between ozone exposures and lung function from epidemiology studies published from 2013 through 2020?

Study Design and Methods

On March 18, 2018, and September 8, 2020, PubMed was searched using the terms health AND ozone, filtering to articles in English and about humans, from 2013 or later. An additional focused review searching for ozone AND (lung function OR FEV₁OR FVC) was performed June 26, 2021. Articles were selected for this review if they reported a specific relationship between a lung function outcome and ozone exposure.

Results

Of 3,271 articles screened, 53 ultimately met criteria for inclusion. A systematic review with assessment of potential for bias was conducted, but a meta-analysis was not carried out because of differences in exposure duration and outcome quantification. Consistent evidence exists of small decreases in children’s lung function, even associated with very low levels of short-term ozone exposure. The effects on adult lung function from exposure to low-level, short-term ozone are less clear, although ozone-associated decrements may occur in the elderly. Finally, long-term ozone exposure decreases both lung function and lung function growth in children, although few new studies have examined long-term ozone and lung function in adults.

Interpretation

Much of this literature involves concentrations below the current US Environmental Protection Agency’s National Ambient Air Quality Standard of 70 parts per billion over an 8-h averaging time, suggesting that this current standard may not protect children adequately from ozone-related decrements in lung function.

Outdoor air pollutants exposure associated with pulmonary function and EBC pH value in atopic asthmatic and non-asthmatic children

OBJECTIVE

Air pollution is associated with the prevalence of respiratory diseases. This study aimed to evaluate the impacts of outdoor air pollutants and indoor Dermatophagoides pteronyssinus 1 (Der p 1) exposure on levels of fractional exhaled nitric oxide (FeNO), exhaled breath condensate (EBC) pH, and pulmonary function in atopic children.

METHODS

This study recruited 59 atopic mild-to-moderate asthmatic children and 23 atopic non-asthmatic children. Data on personal characteristics, FeNO, EBC pH, and pulmonary function were collected. Group 1 allergens of Der p 1 were measured on the tops of mattresses and on bedroom floors in the children's homes, and outdoor air pollutant concentrations were estimated from air quality monitoring stations, using the ordinary kriging method.

RESULTS

Exposure levels of outdoor air pollutants, except for particulate matter (PM)_2.5, for the recruited children met outdoor air quality standards set by the Taiwan Environmental Protection Agency. The lag effect of outdoor PM₁₀ exposure was negatively associated with the forced expiratory volume in one second (FEV₁) [(Lag 1: β=-0.771, p = 0.028), and O₃ (Lag 1-7: β=-2.02, p = 0.04, Lag 1-28: β=-3.213, p = 0.029)]. Median pulmonary function parameters differed significantly in forced vital capacity (FVC) (p = 0.004) and FEV₁ (p = 0.024) values between atopic asthmatic and non-asthmatic children. No association was found between the FeNO/EBC pH level and exposure to Der p 1 allergen and air pollutants in the recruited children.

CONCLUSIONS

Outdoor PM₁₀ and O₃ exposure was associated with reduction in FEV₁ in atopic asthmatic and non-asthmatic children.

The association between ambient NO2 and PM2.5 with the respiratory health of school children residing in informal settlements: A prospective cohort study

BACKGROUND

No previous epidemiological study has investigated the combined association of long-term ambient nitrogen dioxide (NO₂) and particulate matter of diameter size-2.5 (PM_2.5) exposure with asthma outcomes among schoolchildren in Africa.

OBJECTIVES

This study investigated the independent and co-pollutant association of long-term exposures to ambient air pollutants on asthma-associated outcomes in a cohort of schoolchildren in the Western Cape Province of South Africa.

METHODS

A total of 590 grade-4 schoolchildren residing in four informal settlements were studied. Spirometry and fractional exhaled nitric-oxide (FeNO) measurements were conducted, including a standardized questionnaire administered to caregivers at baseline and 12-months follow-up. Annual NO₂ and PM_2.5 levels were estimated for each child's home using land-use regression modelling. Single- and two-pollutant models were constructed to assess the independent and co-pollutant association of both air pollutants (NO₂ and PM_2.5) on new cases of asthma-associated outcomes adjusting-for host characteristics, indoor exposures and study area.

RESULTS

The annual average concentration of PM_2.5 and NO₂ were 10.01μg/m³ and 16.62μg/m³ respectively, across the four study areas, and were below the local Standards of 20μg/m³ and 40μg/m³, for both pollutants, respectively. In the two-pollutant-adjusted models, an interquartile range (IQR) increase of 14.2μg/m³ in NO₂ was associated with an increased risk of new onset of ocular-nasal symptoms (adjusted odds ratio-aOR: 1.63, 95% CI: 1.01-2.60), wheezing (aOR: 3.57, 95% CI: 1.18-10.92), more than two or more asthma symptom score (aOR: 1.71, 95% CI: 1.02-2.86), and airway inflammation defined as FeNO > 35 ppb (aOR: 3.10, 95% CI: 1.10-8.71), independent of PM_2.5 exposures.

CONCLUSION

This study provided evidence that ambient NO₂ levels below local standards and international guidelines, independent of PM_2.5 exposure, increases new cases of asthma-associated outcomes after 12-months.

Long-term exposure to ozone and children's respiratory health: Results from the RESPOZE study

BACKGROUND

Although there is evidence on the effects of short-term ozone (O₃) exposures on children's respiratory health, few studies have reported results on the effects of long-term exposures. We report the effects of long-term exposure to O₃ on respiratory health outcomes in 10-11-year old children.

METHODS

We conducted a panel study in a sample of the general population of school children in two cities with high average O₃ concentrations, Athens and Thessaloniki, Greece. All 186 participating students were followed up intensively for 5 weeks spreading across a school year. Data was collected through questionnaires, weekly personal O₃ measurements, spirometry, FeNO and time-activity diaries. Long-term O₃ exposure was assessed using fixed site measurements and modeling, calibrated for personal exposures. The associations between measured lung function parameters and lung function growth over the study period, as well as FeNO and the occurrence of symptoms with long-term O₃ exposure were assessed through the application of multiple mixed effects 2-level regression models, adjusting for confounders and for short-term exposures.

RESULTS

A 10 μg/m³ increase in calibrated long-term O₃exposure, using measurements from fixed site monitors was associated with lower FVC and FEV₁ by 17 mL (95% Confidence Interval: 5-28) and 13 mL (3-21) respectively and small decreases in lung growth: 0.008% (0.002-0.014%) for FVC and 0.006% (0.000-0.012%) in FEV₁ over the study period. No association was observed with PEF, FeNO or the occurrence of symptoms. A similar pattern was observed when the exposure estimates from the dispersion models were employed.

CONCLUSIONS

Our study provides evidence that long-term O₃ exposure is associated with reduced lung volumes and growth.

Interactive effects of changing stratospheric ozone and climate on tropospheric composition and air quality, and the consequences for human and ecosystem health

The composition of the air we breathe is determined by emissions, weather, and photochemical transformations induced by solar UV radiation. Photochemical reactions of many emitted chemical compounds can generate important (secondary) pollutants including ground-level ozone (O₃) and some particulate matter, known to be detrimental to human health and ecosystems. Poor air quality is the major environmental cause of premature deaths globally, and even a small decrease in air quality can translate into a large increase in the number of deaths. In many regions of the globe, changes in emissions of pollutants have caused significant changes in air quality. Short-term variability in the weather as well as long-term climatic trends can affect ground-level pollution through several mechanisms. These include large-scale changes in the transport of O₃ from the stratosphere to the troposphere, winds, clouds, and patterns of precipitation. Long-term trends in UV radiation, particularly related to the depletion and recovery of stratospheric ozone, are also expected to result in changes in air quality as well as the self-cleaning capacity of the global atmosphere. The increased use of substitutes for ozone-depleting substances, in response to the Montreal Protocol, does not currently pose a significant risk to the environment. This includes both the direct emissions of substitutes during use and their atmospheric degradation products (e.g. trifluoroacetic acid, TFA).

Assessing the associations of daily respiratory symptoms and lung function in schoolchildren using an Air Quality Index for ozone: Results from the RESPOZE panel study in Athens, Greece

BACKGROUND

Air Quality indicators or indices (AQIs) are mainly used for communicating the air pollution levels and risk to the general population. However, very few epidemiological studies have used AQIs for characterizing exposure.

OBJECTIVE

In the framework of the RESPOZE panel study we evaluated the association of daily ozone AQI levels with the daily occurrence of respiratory symptoms and Peak Expiratory Flow (PEF) and compared the effects with those estimated using measurements from fixed outdoor monitoring sites, in the city of Athens, Greece.

MATERIALS AND METHODS

A panel of 97 children, aged 10-11years, was followed intensively for 35days (5weeks) during the academic year 2013-14. PEF and symptoms were recorded daily by each child. Two ozone AQIs classifying the air quality into 7 categories of increasing severity, were calculated; one characterizing the whole Athens area and one the local area around the child's residence and school. Measurements from fixed sites were also used. Mixed effects models for repeated measurements were applied, adjusting for several confounders.

RESULTS

Increasing ozone levels were associated with increased incidence of symptoms, but the strongest and most statistically significant associations were found with the local air quality characterization with the AQI. Specifically, an increase in AQI-local by one category was associated with 34% (95% CI: 9%, 64%) increased odds of stuffy nose. When the AQI categories were "Bad" and "Severe", an increase in the incidence of cough was observed (OR 3.05 (95% CI: 1.29, 7.22) and 6.42 (95% CI: 1.47, 28.03) respectively). We did not observe a statistically significant association between AQI and PEF.

CONCLUSION

Our results show that the use of an AQI based on local conditions may be advantageous over the use of only measurements when investigating the effects of air pollution on health outcomes for improving communication of risk to the public.

Ozone exposure and pulmonary effects in panel and human clinical studies: Considerations for design and interpretation

A wealth of literature exists regarding the pulmonary effects of ozone, a photochemical pollutant produced by the reaction of nitrogen oxide and volatile organic precursors in the presence of sunlight. This paper focuses on epidemiological panel studies and human clinical studies of ozone exposure, and discusses issues specific to this pollutant that may influence study design and interpretation as well as other, broader considerations relevant to ozone-health research. The issues are discussed using examples drawn from the wider literature. The recent panel and clinical literature is also reviewed. Health outcomes considered include lung function, symptoms, and pulmonary inflammation. Issues discussed include adversity, reversibility, adaptation, variability in ozone exposure metric used and health outcomes evaluated, co-pollutants in panel studies, influence of temperature in panel studies, and multiple comparisons. Improvements in and standardization of panel study approaches are recommended to facilitate comparisons between studies as well as meta-analyses. Additional clinical studies at or near the current National Ambient Air Quality Standard (NAAQS) of 70 ppb are recommended, as are clinical studies in sensitive subpopulations such as asthmatics.

IMPLICATIONS

The pulmonary health impacts of ozone exposure have been well documented using both epidemiological and chamber study designs. However, there are a number of specific methodological and related issues that should be considered when interpreting the results of these studies and planning additional research, including the standardization of exposure and health metrics to facilitate comparisons among studies.

Short-term effects of various ozone metrics on cardiopulmonary function in chronic obstructive pulmonary disease patients: Results from a panel study in Beijing, China

BACKGROUND

Short-term exposure to ambient air pollution has been associated with lower pulmonary function and higher blood pressure (BP). However, controversy remains regarding the relationship between ambient multiple daily ozone (O₃) metrics and cardiopulmonary health outcomes, especially in the developing countries.

OBJECTIVES

To investigate and compare the short-term effects of various O₃ metrics on pulmonary function, fractional exhaled nitric oxide (FeNO) and BP in a panel study of COPD patients.

METHODS

We measured pulmonary function, FeNO and BP repeatedly in a total of 43 patients with COPD for 215 home visits. Daily hourly ambient O₃ concentrations were obtained from central-monitoring stations close to subject residences. We calculated various O₃ metrics [daily 1-h maximum (O₃-1 h max), maximum 8-h average (O₃-8 h max) and 24-h average (O₃-24 h avg)] based on the hourly data. Daily indoor O₃ concentrations were estimated based on estimated indoor/outdoor O₃ ratios. Linear mixed-effects models were used to estimate associations of various O₃ metrics with cardiopulmonary function variables.

RESULTS

An interquartile range (IQR) increase in ambient O₃-8 h max (80.5 μg/m³, 5-d) was associated with a 5.9% (95%CI: -11.0%, -0.7%) reduction in forced expiratory volume in 1 s (FEV₁) and a 6.2% (95%CI: -10.9%, -1.5%) reduction in peak expiratory flow (PEF). However, there were no significant negative associations between ambient O₃-1 h max, O₃-24 h avg and FEV₁, PEF. An IQR increase in ambient O₃-1 h max (85.3 μg/m³, 6-d) was associated with a 6.7 mmHg (95%CI: 0.7, 12.7) increase in systolic BP. The estimated indoor O₃ were still significantly associated with reduction of FEV₁ and PEF. No significant associations were found between various O₃ metrics and FeNO.

CONCLUSIONS

Our results provide clues for the adverse cardiopulmonary effects associated with various O₃ metrics in COPD patients and highlight that O₃-8 h max was more closely associated with respiratory health variables.

Weekly Personal Ozone Exposure and Respiratory Health in a Panel of Greek Schoolchildren

BACKGROUND

The association of ozone exposure with respiratory outcomes has been investigated in epidemiologic studies mainly including asthmatic children. The findings reported had methodological gaps and inconsistencies.

OBJECTIVES

We aimed to investigate effects of personal ozone exposure on various respiratory outcomes in school-age children generally representative of the population during their normal activities.

METHODS

We conducted a panel study in a representative sample of school-age children in the two major cities of Greece, Athens and Thessaloniki. We followed 188, 10- to 11-y-old, elementary school students for 5 wk spread throughout the 2013–2014 academic year, during which ozone was measured using personal samplers. At the end of each study week, spirometry was performed by trained physicians, and the fractional concentration of nitric oxide in exhaled air (F_eNO) was measured. Students kept a daily time–activity–symptom diary and measured PEF (peak expiratory flow) using peak flow meters. Mixed models accounting for repeated measurements were applied.

RESULTS

An increase of 10 μg/m³ in weekly ozone concentration was associated with a decrease in FVC (forced vital capacity) and FEV₁ (forced expiratory volume in 1 s) of 0.03 L [95% confidence interval (CI): −0.05, −0.01] and 0.01 L (95% CI: −0.03, 0.003) respectively. The same increase in exposure was associated with a 11.10% (95% CI: 4.23, 18.43) increase in F_eNO and 19% (95% CI: −0.53, 42.75) increase in days with any symptom. The effect estimates were robust to PM₁₀ adjustment. No inverse association was found between ozone exposure and PEF.

CONCLUSIONS

The study provides evidence that airway inflammation and the frequency of respiratory symptoms increase, whereas lung function decreases with increased ozone exposure in schoolchildren. https://doi.org/10.1289/EHP635.