The short-term effects of air pollution on adolescent lung function in Taiwan

A mass screening of lung function associated with air pollutants for children is limited. This study assessed the association between air pollutants exposure and the lung function of junior high school students in a mass screening program in Taipei city, Taiwan. Among 10,396 students with completed asthma screening questionnaires and anthropometric measures, 2919 students aged 12-16 received the spirometry test. Forced vital capacity (FVC) and forced expiratory flow in 1 s (FEV₁) in association with daily ambient concentrations of particulate matter with diameter of 10 μm or less (PM₁₀), sulfur dioxide (SO₂), carbon monoxide (CO), nitrogen dioxide (NO₂), and ozone (O₃) were assessed by regression models controlling for the age, gender, height, weight, student living districts, rainfall and temperature. FVC, had a significant negative association with short-term exposure to O₃ and PM₁₀ measured on the day of spirometry testing. FVC values also were reversely associated with means of SO₂, O₃, NO₂, PM₁₀ and CO exposed 1 d earlier. An increase of 1-ppm CO was associated with the reduction in FVC for 69.8 mL (95% CI: −115, −24.4 mL) or in FEV₁ for 73.7 mL (95% CI: −118, −29.7 mL). An increase in SO₂ for 1 ppb was associated with the reductions in FVC and FEV₁ for 12.9 mL (95% CI: −20.7, −5.09 mL) and 11.7 mL (95% CI: −19.3, −4.16 mL), respectively. In conclusion, the short-term exposure to O₃ and PM₁₀ was associated with reducing FVC and FEV₁. CO and SO₂ exposure had a strong 1-d lag effect on FVC and FEV₁.     

Effects of individual ozone exposure on lung function in the elderly: a cross-sectional study in China

The aim of this study was to assess the acute health effects of individual ozone (O₃) exposure on the respiratory system in the elderly. A total of 40 non-smoking elderly volunteers completed personal 24 h of measurement for O₃ and fine particulate matter (PM_2.5). To assess health effects, we measured the pulmonary function and five inflammatory biomarkers in exhaled breath condensate (EBC), including interleukin-2 (IL-2), interferon-γ (IFN-γ), prostaglandin E₂ (PGE₂), and tumor necrosis factor α/β (TNFα/β). We used the generalized additive model to analyze the association between O₃ and these health effects, after adjusting PM_2.5, BMI, and sex as confounders. As a result, we found a negative correlation between O₃ and forced vital capacity (FVC) or forced expiratory volume-one second (FEV1). With the increasing of O₃ by 10 μg/m³, FVC and FEV1 decreased by 0.13 L (95% CI 0.01, 0.26) and 0.11 L (95% CI 0.02, 0.20), respectively. We found no statistical significance between O₃ and biomarkers in EBC. The results suggested that individual 24-h O₃ exposure was associated with decreased pulmonary function in the elderly.

     

A Statistical Model for FEV1 Response to Arbitrary Dynamic Ozone Exposure Conditions

ABSTRACT

Lung function response to inhaled ozone at ambient air pollution levels is known to be a function of ozone concentration, exposure duration, and minute ventilation. Most data-driven exposure-response models address exposures under static condition (i.e., with a constant ozone concentration and exercise pattern). Such models are simplifications, as both ambient ozone concentrations and normal human activity patterns change with time. The purpose of this study was to develop a dynamic model of response with the advantages of a statistical model (a relatively simple structure with few parameters). A previously proposed mechanistic model for changes in specific airways resistance was adapted to describe the percent change in forced expiratory volume in one second (FEV₁). This model was then reduced using the fit to three existing exposure-response data sets as criterion. The resulting model consists of a single linear differential equation together with an algebraic logistic equation. Under restricted static conditions the model reduces to a logistic model presented earlier by the authors.     

Predicting Respiratory Morbidity from Pulmonary Function Tests: A Reanalysis of Ozone Chamber Studies

Some consequences of acute exposure to ozone are best measured In studies of human respiratory responses in controlled exposure chambers. These studies typically examine relationships between exposures to alternative pollutant concentrations and Indicators of lung function as measured by spirometry, such as forced expiratory volume In one second, FEV₁ However, the association of respiratory morbidity with these changes In lung function is not well established. To gain a better understanding of the relationship between ozonerelated changes in pulmonary function and respiratory symptoms, data from several clinical studies have been reanalyzed. Logistic regression models were used to determine the quantitative relationship between changes in FEV₁ and the probability of a mild or moderate lower respiratory symptom. Models were developed that corrected for repeated sampling of individuals and both population-averaged and subject-specific effects were determined. The results indicate the existence of a strong and consistent quantitative relationship between changes in lung function and the probability of a respiratory symptom. Specifically, a 10 percent reduction in FEV₁ is associated with a 15 percentage point increase In the probability of a mild, moderate or severe lower respiratory symptom and a 6 percentage point increase in the probability of a moderate or severe lower respiratory symptom.     

Inhalation Route Effects on Exposure to 2.0 Parts Per Million Sulfur Dioxide in Normal Subjects

A number of Investigations have attributed the control of the nasal to oral/nasal ventilation transition to nasal resistance. To investigate possible changes In nasal resistance due to sulfur dioxide (SO₂) exposure, 14 subjects (7 men and 7 women), healthy nonsmokers, between the ages of 20 and 46 years, were exposed for 30 minutes to filtered air while free breathing and to 2.0 ppm SO₂ with either free breathing, forced oral or forced nasal breathing with continuous exercise at a workload 300 kg>m/min below the workload which Initiated cross-over from nasal to oral/nasal breathing in a preliminary incremental workload test. An Incremental work test under the ambient conditions was performed immediately following the 30-minute exercise to ascertain any change in the cross-over ventilation. Pre- and post-measures of pulmonary functions were obtained to ascertain any changes In these parameters due to the exposure. There was a significant difference in the workload at which cross-over occurred following forced oral breathing in 2.0 ppm sulfur dioxide. The nasal ventilation prior to cross-over and the nasal component of ventilation were significantly smaller for this exposure condition, indicating a possible change in nasal dynamics following the 30 minutes of forced oral breathing in 2.0 ppm SO₂. Lack of concomitant changes in pulmonary function tests including airway resistance suggests that breathing 2.0 ppm SO₂ does not affect normal subjects whether administration is by free, forced oral or forced nasal breathing.     

Considering the effects of ambient particulate matter on the lung function of motorcycle taxi drivers in Bangkok,Thailand

The motorcycle taxi drivers of Bangkok have been heavily exposed to high concentrations of PM₁₀ (particulate matter with an aerodynamic diameter ≤10 μm), and the impact of this on their lungs has been neither documented nor studied. This study examines the association between exposure to PM₁₀ and lung function decline among motorcycle taxi drivers. A cross-sectional study was conducted in Bangkok between two groups: a subject group of motorcycle taxi drivers and control group of enclosed vehicle taxi drivers. The findings of the Thailand Pollution Control Department were used to estimate the annual ambient PM₁₀ concentration levels in the metropolis. Pulmonary functions of motorcycle taxi drivers and enclosed vehicle taxi drivers were measured and compared using the Mann-Whitney test. Multiple linear regression analysis was applied to estimate the effects of PM₁₀ exposure on the lung function of motorcycle taxi drivers. A total of 1283 motorcycle taxi drivers and 600 taxi drivers were investigated. The mean forced expiratory volume in 1 sec/forced vital capacity (FEV₁/FVC) of the motorcycle taxi drivers was significantly lower than that of the taxi drivers (P < 0.001). The mean FEV₁/FVC of motorcycle taxi drivers exposed to ≥50 µg/m³ PM₁₀ was statistically lower (?2.82%; 95% confidence interval [CI]: ?4.54% to ?1.09%) and the mean % vital capacity (%VC) of those exposed to 40–49.9 µg/m³ PM₁₀ was statistically lower than that of motorcycle taxi drivers exposed to <30 µg/m³ PM₁₀ (?3.33%; 95% CI: ?5.79% to ?0.87%). Motorcycle taxi drivers were directly exposed to air pollution in their working environment. As a result, their lung function might decrease more than that of enclosed vehicle taxi drivers. With the possible exposure to ≥50 µg/m³ PM₁₀, the vehicular emission standards should be vigorously enforced. Further investigation is warranted to clarify the effect of lung dysfunction on the work and lifestyle of motorcycle taxi drivers.

Implications: Motorcycle taxi drivers are directly exposed to air pollution in their work environment; therefore, their lung function might decrease more than that of enclosed vehicle taxi drivers, especially when exposed to ≥50 µg/m³ PM₁₀. World Health Organization (WHO) vehicular emission standards should be recognized and eventually enforced.     

Formaldehyde Dose-Response in Healthy Nonsmokers

Industrial, commercial, and domestic levels of formaldehyde exposure range from <0.1 to >5.0 ppm. Irritation of the eyes and upper respiratory tract predominate, and bronchoconstriction is described in case reports. However, pulmonary function and irritant symptoms together have not been assessed over a range of HCHO concentrations in a controlled environment. We investigated dose response in both symptoms and pulmonary function associated with 3-h exposures to 0.0-3.0 ppm HCHO in a controlled environmental chamber. Ten subjects were randomly exposed to 0.0, 0.5, 1.0, and 2.0 ppm HCHO at rest plus 2.0 ppm HCHO with exercise and nine additional subjects were randomly exposed to 0.0,1.0,2.0, and 3.0 ppm HCHO at rest plus 2.0 ppm HCHO with exercise. Significant dose-response relationships in odor and eye irritation were observed (p < 0.05). Nasal flow resistance was increased at 3.0 ppm (p < 0.01), but not at 2.0 ppm HCHO. There were no significant decrements in pulmonary function (FVC, FEV₁, FEF_25-75%, SGaw) or increases in bronchial reactivity to methacholine (log PD_35SGaw) with exposure to 0.5-3.0 ppm HCHO at rest or to 2.0 ppm HCHO with exercise.     

An Air Quality Data Analysis System for Interrelating Effects,Standards, and Needed Source Reductions: Part 11. A Lognormal Model Relating Human Lung Function Decrease to O3 Exposure

Forced expiratory volume in 1 second (FEV1) was measured in 21 men exercising while exposed to four O₃ concentrations (0.0,0.08,0.10, and 0.12 ppm). A lognormal multiple linear regression model was fitted to their mean FEV1 measurements to predict FEV1 percent decrease as a function of O₃ concentration and exposure duration. The exercise level used was probably comparable to heavy manual labor. The longest O₃, exposure studied was 6 h. Extrapolating cautiously to an 8-h workday of heavy manual labor, the model predicts that O3 concentrations of 0.08, 0.10, and 0.12 ppm would decrease FEV1 by 9,15, and 20 percent, respectively.     

Pulmonary Function Changes Associated with an Air Pollution Episode in January 1987

In January 1987, an air pollution episode occurred In central and western Europe. Levels of SO₂, NO₂, black smoke, sulphates and other components were elevated, with 24 hour average concentrations of SO₂ reaching a maximum of close to 300 μg/m3 In an area In the southeast of the Netherlands. Pulmonary function was measured In a group of children of 6- 12 years old at the end of the episode, and also two and three and a half weeks after the episode. A baseline lung function value was obtained about three months before the episode. Pulmonary function growth between baseline and retest dates was estimated from a simple growth model which was validated using measured pulmonary function growth data from a longitudinal study. A decline of pulmonary function (FVC, FEV₁ and PEF) from predicted baseline levels was observed, starting on the last day of the episode. Two weeks after the episode, FVC, FEV₁ PEF and MMEF were all decreased, and three and a half weeks after the episode, there was still a deficit compared to predicted baseline levels for FVC and FEV₁     

Reproducibility of the Pulmonary Function Response of Older Men and Women to a 2-Hour Ozone Exposure.

To test the reproducibility of the pulmonary function response to ozone exposure in older individuals, eight men and eight women, average age 62.8 years, participated in three 2-hour exposures to 0.45 ppm ozone at 23.3 C and 62.5 percent relative humidity. The first and second exposures were separated by an average time of 17.2 days, and 27.3 days separated the second and third exposures. Subjects alternated riding a bicycle ergometer for 20 minutes at an average minute ventilation of 26 liters BTPS (body temperature pressure, saturated), with 20-minute rest periods. Forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV-1), and forced expiratory flow between 25 and 75% of FVC (FEF 25- 75%) were measured pre and post exposure. The reproducibility of individual pre-post changes were assessed by calculation of the best linear fit and correlation coefficients between exposures. For FVC and FEV-1, the slopes were significantly different from 1, and correlation coefficients not significantly different from zero, implying that older individuals may not respond consistently to similar ozone exposures.     

Health Significance of Pulmonary Function Responses to Airborne Irritants

Exposures to airborne irritants such as O₃, NO₂, SO₂ and H₂SO₄ can produce measurable changes in a variety of pulmonary functions such as respiratory mechanics, pulmonary gas exchange, mucociliary particle clearance, and airway permeability. The most commonly measured indices of pulmonary function are those obtained by analyzing flows and volumes during a maximal forced expiratory maneuver, because they can be obtained readily in both laboratory and field studies in humans. Other functional measures are essentially limited to laboratory studies on relatively small populations of humans, or on experimental animals. Interpretation of respiratory function changes in relation to exposures to airborne irritants is complicated by the large interindividual variability in baseline function and responsiveness, the superposition of both the transient effects of recent acute exposure and the cumulative effects of chronic exposure at any given measurement, and the inherent day-to-day variability of effort dependent indices. Furthermore, community exposures occur as mixtures. Each of several components may affect the same functions, but with different time scales, and may affect different segments of the population to different degrees. The greatest uncertainties lie in the significance of transient and apparently reversible effects, and their contribution, if any, to permanent functional changes. Use of animal models to study the role of transient changes in function on the development of permanent changes is illustrated in terms of the effects of H₂SO₄ on particle clearance function.     

Change in Pulmonary Function in Children Associated with Air Pollution Episodes

Pulmonary function of approximately 200 school children in Steubenville, OH was measured before and immediately following air pollution alerts in the fall of 1978 and 1979. TSP concentrations exceeded the National Primary Ambient Air Quality 24 h standards in 1978. SO₂ exceeded the standard in 1979. The children were then reexamined in three weekly visits following each alert. Estimated mean Forced Vital Capacity (FVC) was approximately 2% lower following each alert, although the lowest means were observed one to two weeks after the episodes. Forced Expired Volume in 0.75 sec (FEV_0.75) did not change during the 1978 study, but was 4% lower immediately following the 1979 alert. The children were measured again in five weekly examinations in the spring and fall of 1980. Air pollution levels did not exceed the standards on either occasion. In the spring of 1980, estimated mean FVC and FEV_0.75 showed a decline similar to that observed following the alerts in 1978 and 1979. In the fall of 1980, there were no significant differences in the estimated mean FVC or FEV_0.75 between the examinations. A total of 335 children were tested in the four studies, including 194 who participated in more than one study. The evidence for each child from all the studies was combined in a regression analysis of pulmonary function on TSP and SO₂ average concentrations in the previous 24 h. The distribution of the individual regression coefficients was centered significantly below zero, implying a decrease in pulmonary function with increasing TSP and SO₂ concentrations. The magnitude of the median change was less than 1% of the mean FVC and FEV_0.75 over the range of TSP and SO₂ concentrations observed.     

Assessment of growth and yield losses in two Zea mays L. cultivars (quality protein maize and nonquality protein maize) under projected levels of ozone

Rapid industrialization and economic developments have increased the tropospheric ozone (O₃) budget since preindustrial times, and presently, it is supposed to be a major threat to crop productivity. Maize (Zea mays L.), a C4 plant is the third most important staple crop at global level with a great deal of economic importance. The present study was conducted to evaluate the performance of two maize cultivars [HQPM1: quality protein maize (QPM)] and [DHM117: nonquality protein maize (NQPM)] to variable O₃ doses. Experimental setup included filtered chambers, nonfiltered chambers (NFC), and two elevated doses of O₃ viz. NFC+15 ppb O₃ (NFC+15) and NFC+30 ppb O₃ (NFC+30). During initial growth period, both QPM and NQPM plants showed hormetic effect that is beneficial due to exposure of low doses of a toxicant (NFC and NFC+15 ppb O₃), but at later stages, growth attributes were negatively affected by O₃. Growth indices showed the variable pattern of photosynthate translocation under O₃ stress. Foliar injury in the form of interveinal chlorosis and reddening of leaves due to increased production of anthocyanin pigments was observed at higher concentrations of O₃. One-dimensional gel electrophoresis of leaves taken from NFC+30 showed reductions of major photosynthetic proteins, and differential response was observed between the two test cultivars. Decline in the number of male flowers at elevated O₃ doses suggested damaging effect of O₃ on reproductive structures which might be a cause of productivity losses. Variable carbon allocation pattern particularly to husk leaves, foliar injury, and damage of photosynthetic proteins led to significant reductions in economic yield at higher O₃ doses. PCA showed that both the cultivars responded more or less similarly to O₃ stress in their respective groupings of growth and yield parameters, but magnitude of their response was variable. It is further supported by difference in the significance of correlations between variables of yield and AOT40. Cultivar response reflects that QPM performed better than NQPM against elevated O₃.     

Ozone exposure and stomatal sluggishness in different plant physiognomic classes

Gas exchange responses to static and variable light were tested in three species: snap bean (Phaseolus vulgaris, two cultivars), California black oak (Quercus kelloggii), and blue oak (Q. douglasii). The effects of 1-month (snap beans) and 2-month (oaks) O₃ (ozone) exposure (70 ppb over 8 h per day in open-top chambers) were investigated. A delay in stomatal responses (i.e., ‘sluggish’ responses) to variable light was found to be both an effect of O₃ exposure and a reason for increased O₃ sensitivity in snap bean cultivars, as it implied higher O₃ uptake during times of disequilibrium. Sluggishness increased the time to open (thus limiting CO₂ uptake) and close stomata (thus increasing transpirational water loss) after abrupt changes in light level. Similar responses were shown by snap beans and oaks, suggesting that O₃-induced stomatal sluggishness is a common trait among different plant physiognomic classes.     

Effect of the Fine Fraction of Particulate Matter versus the Coarse Mass and Other Pollutants on Daily Mortality in Santiago,Chile

ABSTRACT

Daily counts of non-accidental deaths in Santiago, Chile, from 1988 to 1996 were regressed on six air pollutants— fine particles (PM_2.5), coarse particles (PM_10–2.5), CO, SO₂, NO₂, and O₃. Controlling for seasonal and meteorological conditions was done using three different models— a generalized linear model, a generalized additive model, and a generalized additive model on previously filtered data. Single- and two-pollutant models were tested for lags of 1-5 days and the average of the previous 2-5 days.

The increase in mortality associated with the mean levels of air pollution varied from 4 to 11%, depending on the pollutants and the way season of the year was considered. The results were not sensitive to the modeling approaches, but different effects for warmer and colder months were found. Fine particles were more important than coarse particles in the whole year and in winter, but not in summer. NO₂ and CO were also significantly associated with daily mortality, as was O₃ in the warmer months. No consistent effect was observed for SO₂. Given particle composition in Santiago, these results suggest that combustion-generated pollutants, especially from motor vehicles, may be associated with increased mortality. Temperature was closely associated with mortality. High temperatures led to deaths on the same day, while low temperatures lead to deaths from 1 to 4 days later.     

Phenogenetic response of silver birch populations and half-sib families to elevated ozone and ultraviolet-B radiation at juvenile age

Phenogenetic response of silver birch populations and half-sib families to separate and combined elevated ozone (O₃) concentrations and ultraviolet-B (UV-B) radiation dozes was studied at juvenile age in the climatic chambers. Significant population and family effects were found for seedling height, lamina width, and leaf damage. The exposure to UV-B radiation decreased genetic variation at the stage of seed germination. Complex exposure to UV-B and O₃ caused an increase of genetic variation at the stage of intensive seedling growth: seedling height genetic variation in separate treatments increased from 23.7–38.6 to 33.7–65.7%, the increase for lamina width was from 10.2–13.9 to 13.6–31.8%. Different populations and families demonstrated differing response to elevated complex UV-B and O₃ exposure. Changes of genetic intra-population variation were population-specific. Such changes in genetic variation under the impact of stressors can alter adaptation, stability, and competitive ability of regenerating populations in a hardly predictive way.     

Comparison of a diurnal vs steady-state ozone exposure profile on growth and yield of oilseed rape (Brassica napus L.) in open-top chambers in the Yangtze Delta, China

Most available exposure-response relationships for assessing crop loss due to elevated ozone (O₃) have been established using data from chamber and open-top chamber experiments, using a simulated constant O₃ concentration exposure (square wave), which is not consistent with the diurnal variation of O₃ concentration that occurs in nature. We investigated the response of oilseed rape (Brassica napus L.) to O₃ as affected by two exposure regimes: one with a diurnal variation (CF100D) and another with a constant concentration (CF100). Although the two exposure regimes have the same mean O₃ concentration and accumulated O₃ concentration above 40 ppb (AOT40), our results show that O₃ at CF100D reduced biomass and number of pods/plant more than O₃ at CF100. Both O₃ exposures resulted in larger seed weights/100 pods compared to CF. Numbers of seeds/100 pods were reduced by CF100, while numbers of seeds/100 pods in the CF100D chambers were comparable to those in CF. Our results suggest that chamber experiments that use a constant O₃ exposure may underestimate O₃ effects on biomass and yields.     

Will photosynthetic capacity of aspen trees acclimate after long-term exposure to elevated CO2 and O3?

Photosynthetic acclimation under elevated carbon dioxide (CO₂) and/or ozone (O₃) has been the topic of discussion in many papers recently. We examined whether or not aspen plants grown under elevated CO₂ and/or O₃ will acclimate after 11 years of exposure at the Aspen Face site in Rhinelander, WI, USA. We studied diurnal patterns of instantaneous photosynthetic measurements as well as A/C_i measurements monthly during the 2004-2008 growing seasons. Our results suggest that the responses of two aspen clones differing in O₃ sensitivity showed no evidence of photosynthetic and stomatal acclimation under either elevated CO₂, O₃ or CO₂ + O₃. Both clones 42E and 271 did not show photosynthetic nor stomatal acclimation under elevated CO₂ and O₃ after a decade of exposure. We found that the degree of increase or decrease in the photosynthesis and stomatal conductance varied significantly from day to day and from one season to another.