Short-term effects of low-level winter pollution on respiratory health of asthmatic adults

The effect of acute outdoor air pollution on peak expiratory flow in individuals with asthma: A systematic review and meta-analysis

OBJECTIVES

Acute exposures to outdoor air pollution have been shown to reduce lung function in children with asthma, but the effect on adults with asthma has not been established in a meta-analysis. The objective of this study was to conduct a systematic literature review and meta-analysis of studies that assessed the relationship of outdoor air pollution and peak expiratory flow (PEF) in adults with asthma.

METHODS

Studies that contained data on outdoor air pollution levels (PM_10, PM_2.5, or NO₂) and PEF in adults with asthma were eligible for inclusion. Effect estimates were quantified for each air pollution measure using random effects models. Heterogeneity was investigated with the Q-test and I² statistics. Meta-regression and subgroup analyses were conducted to determine differences in effect by air pollution measures and the inclusion of smokers.

RESULTS

A total of 22 effect estimates from 15 studies were included in this review. A 10 μg/m³ increase in acute PM₁₀ exposure was associated with a -0.19 L/min (95% CI: 0.30, -0.09) change in PEF. For both PM₁₀ and PM_2.5, the inclusion of current smokers was a significant source of heterogeneity among studies (meta-regression: p = 0.04 and p = 0.03). Among studies that only included non-smokers, a 10 μg/m³ increase in acute exposure to PM₁₀ and PM_2.5 was associated with changes in PEF of -0.25 L/min (95% CI: 0.38, -0.13) and -1.02 L/min (95% CI: 1.79, -0.24), respectively.

CONCLUSIONS

This study provides evidence that acute increases in PM₁₀ and PM_2.5 levels are associated with decreases in PEF in adults with asthma, particularly among non-smokers.

Public-health impact of outdoor air pollution for 2(nd) air pollution management policy in Seoul metropolitan area, Korea

Objectives

Air pollution contributes to mortality and morbidity. We estimated the impact of outdoor air pollution on public health in Seoul metropolitan area, Korea. Attributable cases of morbidity and mortality were estimated.

Methods

Epidemiology-based exposure-response functions for a 10 μg/m3 increase in particulate matter (PM_2.5 and PM₁₀) were used to quantify the effects of air pollution. Cases attributable to air pollution were estimated for mortality (adults ≥ 30 years), respiratory and cardiovascular hospital admissions (all ages), chronic bronchitis (all ages), and acute bronchitis episodes (≤18 years). Environmental exposure (PM_2.5 and PM₁₀) was modeled for each 3 km × 3 km.

Results

In 2010, air pollution caused 15.9% of total mortality or approximately 15,346 attributable cases per year. Particulate air pollution also accounted for: 12,511 hospitalized cases of respiratory disease; 20,490 new cases of chronic bronchitis (adults); 278,346 episodes of acute bronchitis (children). After performing the 2^nd Seoul metropolitan air pollution management plan, the reducible death number associated with air pollution is 14,915 cases per year in 2024. We can reduce 57.9% of death associated with air pollution.

Conclusion

This assessment estimates the public-health impacts of current patterns of air pollution. Although individual health risks of air pollution are relatively small, the public-health consequences are remarkable. Particulate air pollution remains a key target for public-health action in the Seoul metropolitan area. Our results, which have also been used for economic valuation, should guide decisions on the assessment of environmental health-policy options.

Quantifying the co-benefits of energy-efficiency policies: a case study of the cement industry in Shandong Province, China

In 2010, China's cement industry accounted for more than half of the world's total cement production. The cement industry is one of the most energy-intensive and highest carbon dioxide (CO2)-emitting industries, and thus a key industrial contributor to air pollution in China. For example, it is the largest source of particulate matter (PM) emissions in China, accounting for 40% of industrial PM emissions and 27% of total national PM emissions. In this study, we quantify the co-benefits of PM10 and sulfur dioxide (SO2) emission reductions that result from energy-saving measures in the cement industry in Shandong Province, China. We use a modified form of the cost of conserved energy (CCE) equation to incorporate the value of these co-benefits. The results show that more than 40% of the PM and SO2 emission reduction potential of the electricity-saving measures is cost effective even without taking into account the co-benefits for the electricity-saving measures. The results also show that including health benefits from PM10 and/or SO2 emission reductions reduces the CCE of the fuel-saving measures. Two measures that entail changing products (production of blended cement and limestone Portland cement) result in the largest reduction in CCE when co-benefits were included, since these measures can reduce both PM10 and SO2 emissions, whereas the other fuel-saving measures do not reduce PM10.

Interaction of ambient air pollution with asthma medication on exhaled nitric oxide among asthmatics

The interaction between ambient air pollution and asthma medication remains unclear. The authors compared airway inflammation response to air pollution among asthmatics. Increases of 10 ppb of nitrogen dioxide (NO2) and of 10 microg/m3 of particulate matter < 10 micron in diameter (PM10) daily concentrations were associated with an increase in exhaled nitric oxide (eNO) of 0.13 ppb (95% confidence interval = 0.06, 0.19) and of 0.07 ppb (95% confidence interval = 0.02, 0.12), respectively, in models adjusted for important covariates. The results show that the medication could not counteract airway inflammation effects of air pollution. Specifically, the patients on triamcinolone decreased the sensitivity to PM10 but increased the sensitivity to NO2. The patients on salmeterol were more vulnerable to both NO2 and PM10. This study indicates that the current pollution levels may still enhance airway inflammation among patients with persistent asthma even when they are on asthma medications.

Associations between air pollution and peak expiratory flow among patients with persistent asthma

Responses of patients with persistent asthma to ambient air pollution may be different from those of general populations. For example, asthma medications may modify the effects of ambient air pollutants on peak expiratory flow (PEF). Few studies examined the association between air pollution and PEF in patients with persistent asthma on well-defined medication regimens using asthma clinical trial data. Airway obstruction effects of ambient air pollutants, using 14,919 person-days of daily self-measured peak expiratory flow (PEF), were assessed from 154 patients with persistent asthma during the 16 wk of active treatment in the Salmeterol Off Corticosteroids Study trial. The three therapies were an inhaled corticosteroid, an inhaled long-acting beta-agonist, and placebo. The participants were nonsmokers aged 12 through 63 yr, recruited from 6 university-based ambulatory care centers from February 1997 to January 1999. Air pollution data were derived from the U.S. Environmental Protection Agency Aerometric Information Retrieval System. An increase of 10 ppb of ambient daily mean concentrations of NO2 was associated with a decrease in PEF of 1.53 L/min (95% confidence interval [CI] -2.93 to -0.14) in models adjusted for age, gender, race/ethnicity, asthma clinical center, season, week, daily average temperature, and daily average relative humidity. The strongest association between NO2 and PEF was observed among the patients treated with salmeterol. Negative associations were also found between PEF and SO2 and between PEF and PM(10), respectively. The results show that the two medication regimens protected against the effects of PM(10). However, salmeterol increased the sensitivity to NO2 and triamcinalone enhanced the sensitivity to SO2.

Low-carbon energy policy and ambient air pollution in Shanghai, China: a health-based economic assessment

Energy and related health issues are of growing concern worldwide today. To investigate the potential public health and economic impact of ambient air pollution under various low-carbon energy scenarios in Shanghai, we estimated the exposure level of Shanghai residents to air pollution under various planned scenarios, and assessed the public health impact using concentration-response functions derived from available epidemiologic studies. We then estimated the corresponding economic values of the health effects based on unit values for each health outcome. Our results show that ambient air pollution in relation to low-carbon energy scenarios could have a significant impact on the future health status of Shanghai residents, both in physical and monetary terms. Compared with the base case scenario, implementation of various low-carbon energy scenarios could prevent 2804-8249 and 9870-23,100 PM10-related avoidable deaths (mid-value) in 2010 and 2020, respectively. It could also decrease incidence of several relevant diseases. The corresponding economic benefits could reach 507.31-1492.33 and 2642.45-6192.11 million U.S. dollars (mid-value) in 2010 and 2020, respectively. These findings illustrate that a low-carbon energy policy will not only decrease the emission of greenhouse gases, but also play an active role in the reduction of air pollutant emissions, improvement of air quality, and promotion of public health. Our estimates can provide useful information to local decision-makers for further cost-benefit analysis.

Effects of ambient air pollutants on asthma medication use and wheezing among fourth-grade school children from 12 Southern California communities enrolled in The Children's Health Study

To investigate the effects of 12 monthly average air pollution levels on monthly prevalence of respiratory morbidity, the authors examined retrospective questionnaire data on 2034 4th-grade children from 12 Southern California communities that were enrolled in The Children's Health Study. Wheezing during the spring and summer months was associated with community levels of airborne particulate matter with a diameter < or = 10 microm (PM10) (odds ratio (OR) = 2.91; 95% confidence interval (CI) = 1.46-5.80), but was not associated with community levels of ozone, nitrogen dioxide, PM2.5 (diameter < or = 2.5), nitric acid, or formic acid. Logistic regression was performed on data stratified into two seasonal groups, spring/summer and fall/winter. Among asthmatics, the monthly prevalence of asthma medication use was associated with monthly levels of ozone, nitric acid, and acetic acid (OR = 1.80 [95%CI = 1.19-2.70]; OR = 1.80 [95%CI = 1.23-2.65]; OR = 1.57 [95% CI = 1.11-2.21]; respectively). Asthma medication use was more prevalent among children who spent more time outdoors--with consequential exposure to ozone--than among children who spent more time indoors (OR = 3.07 [95%CI = 1.61-5.86]; OR = 1.31 [95%CI = 0.47-2.71]; respectively). The authors concluded that monthly variations in some ambient air pollutants were associated with monthly respiratory morbidity among school children.

Air Pollution, Passive Smoking, and Respiratory Symptoms in Adults

We studied the independent role of air pollution and passive smoking on respiratory symptoms and group of symptoms by following 46 adult nonsmokers for 14 wk. Outcomes included the incidence of 15 symptoms. After adjustment for passive smoking, clear rhinorrhea and cough were positively related to nitrogen dioxide (NO2), particles (PM10), and black smoke (BS); whereas headache was positively related to BS. Sneezing, sore throat, and cough were independently positively related to passive smoking. After adjustment for passive smoking, the occurrence of groups of symptoms and of the "sore throat group" were related to three pollutants. The occurrence of the "possible infection group" was positively related to BS. The occurrence of every group of symptoms was independently related to passive smoking. In conclusion, the prevailing levels of air pollution and passive smoking had independent effects on symptoms and groups of symptoms.

Particulate air pollution in urban areas of Shanghai, China: health-based economic assessment

Urban air quality is becoming a serious public health concern in China. To obtain the quantitative result of the impact of particulate air pollution on human health and the subsequent economic costs in Shanghai, we used epidemiology-based exposure-response functions to calculate the attributable number of cases due to particulate air pollution in urban areas of Shanghai in 2001, and then we estimated the corresponding economic costs of the health damage based on unit values of the health outcomes. It was estimated that the total economic cost of health impacts due to particulate air pollution in urban areas of Shanghai in 2001 was approximately 625.40 million US dollars, accounting for 1.03% of gross domestic product of the city. The results suggest that the impact of particulate air pollution on human health could be substantial in urban Shanghai, whether in physical and economic terms.

PM10 and asthma medication in schoolchildren

The authors found that the use of asthma medication among elementary schoolchildren was associated with particulate pollution (particulate matter < 10 microm in aerodynamic diameter [PM10]) in a locale where PM10 consisted primarily of coarse fraction material derived from road sanding and reentrained volcanic ash. School nurses' records in 12 neighborhood schools located close to an ambient air monitoring station were abstracted, and the numbers of oral and inhaled doses of asthma medication given daily over a period of 2.5 yr were calculated. Time-series regression models, adjusted for autocorrelation, were developed, with temperature, time trend, day of the week, and month as additional variables. Regression models were estimated, and a lagged moving average of PM10 for 7, 14, 21, and 28 days was used. All models showed positive and significant coefficients for PM10 during periods when asthma medication was administered to the schoolchildren. However, the 21-day moving average was the best fit to the model.

Short-term effects of low-level air pollution on respiratory health of adults suffering from moderate to severe asthma

Only a few studies have been carried out on the health effects of air pollution on patients suffering from severe asthma. We wanted to test the sensitivity of these patients to Paris air pollution. During 13 months, 60 severe asthmatics (62- female; mean age 55 years) were monitored by their physician, who filled in a follow-up form at each consultation and reported any asthma attacks. Daily levels of SO(2), PM10, NO(2), and O(3) were provided by the air quality network. Statistical analysis (generalized estimating equation models that accounted for autocorrelation of responses, temporal, meteorological, and aerobiological variables, and some individual characteristics) revealed significant associations between PM10, O(3), and incident asthma attacks. Odds Ratio (OR) for an increase of 10 microg/m(3) of PM10 was 1.41; 95% confidence interval (CI) [1.16; 1.71]. An increase of 10 microg/m(3) of O(3) was significantly associated with asthma attacks; OR=1.20; 95% CI [1.03; 1.41]. These relations were observed after a delay between exposure and asthma attacks of 3 to 5 days for PM10 and 2 days for O(3), and they tended to differ according to atopic status. The results of our study suggest that ambient Paris levels of PM10 and O(3) affected health of severe asthmatics, despite their treatment.

A comparison of the prevalence of respiratory illness and non-specific health symptoms in two Victorian cities

OBJECTIVE

To compare the prevalence of respiratory illness and non-specific health symptoms among adults and children aged 4-15 years living in Portland and Warrnambool, Victoria.

METHODS

A postal survey of 3,903 adults in Portland and Warrnambool systematically selected from the electoral roll was undertaken. Both an adults and children's questionnaire were enclosed in the mailing to each adult. If there were children aged 4-15 years in the household, an adult was asked to complete a questionnaire for the child who would next celebrate a birthday. Questionnaires were returned by 2,111 adults (54%) and for 585 children.

RESULTS

No significant differences in the prevalence of self-reported asthma or wheeze were observed among adults or children residing in Portland and Warrnambool. The likelihood of itchy eyes, skin rash and stuffy nose was significantly higher in Portland adults and children compared with those in Warrnambool. Dry cough at night was increased among Portland children, but not significantly so.

CONCLUSIONS

Higher rates of non-specific symptoms were observed in Portland but from a cross-sectional survey such as this, it is not possible to identify the cause of these higher rates. They may be related to environmental factors such as pollens or emissions from aluminium production, fertiliser production or bulk handling activities on the wharf, or they may be attributable to other factors such as response or recall bias.

The effect of ozone on inner-city children with asthma: identification of susceptible subgroups

Within a cohort of 846 inner-city asthmatic children aged 4 to 9 yr, we looked for subgroups that were more susceptible to the effects of summer ozone. Daily diaries were compared with ambient ozone levels to evaluate effect modification by demographic and environmental characteristics. Children born > 3 wk prematurely or weighing < 5.5 lb. had greater declines in morning % peak expiratory flow rate (PEFR) (1.8% versus 0.3% per 15 ppb ozone, p < 0.05) and a higher incidence of morning symptoms (odds ratio = 1.42 versus 1.09 per 15 ppb ozone, p < 0.05) than did children who had been full-term infants of normal birthweight. Among children who had been of low birthweight (LBW) or had been premature infants, greater declines were seen among those whose reported baseline medication category was "no medication" (3.2% decline) or "steroids" (2.7%) as opposed to beta agonists or xanthines (0.8%) or cromolyn without steroids (0. 1%). Among the children who had been normal birthweight and full-term infants, the cromolyn without steroids group had the greatest declines in %PEFR (1.3%, versus < 0.5% in each of the other three groups). Nonatopic children also had greater responses to ozone. We conclude that among an asthmatic cohort, children who had had an LBW or a premature birth showed the greatest responses to ozone.

Public-health impact of outdoor and traffic-related air pollution: a European assessment

BACKGROUND

Air pollution contributes to mortality and morbidity. We estimated the impact of outdoor (total) and traffic-related air pollution on public health in Austria, France, and Switzerland. Attributable cases of morbidity and mortality were estimated.

METHODS

Epidemiology-based exposure-response functions for a 10 microg/m3 increase in particulate matter (PM10) were used to quantify the effects of air pollution. Cases attributable to air pollution were estimated for mortality (adults > or = 30 years), respiratory and cardiovascular hospital admissions (all ages), incidence of chronic bronchitis (adults > or = 25 years), bronchitis episodes in children (< 15 years), restricted activity days (adults > or = 20 years), and asthma attacks in adults and children. Population exposure (PM10) was modelled for each km2. The traffic-related fraction was estimated based on PM10 emission inventories.

FINDINGS

Air pollution caused 6% of total mortality or more than 40,000 attributable cases per year. About half of all mortality caused by air pollution was attributed to motorised traffic, accounting also for: more than 25,000 new cases of chronic bronchitis (adults); more than 290,000 episodes of bronchitis (children); more than 0.5 million asthma attacks; and more than 16 million person-days of restricted activities.

INTERPRETATION

This assessment estimates the public-health impacts of current patterns of air pollution. Although individual health risks of air pollution are relatively small, the public-health consequences are considerable. Traffic-related air pollution remains a key target for public-health action in Europe. Our results, which have also been used for economic valuation, should guide decisions on the assessment of environmental health-policy options.

Animal models of asthma: potential usefulness for studying health effects of inhaled particles

Asthma is now recognized to be a chronic inflammatory disease that affects the whole lung. Incidence appears to be increasing despite improved treatment regimens. There is substantial epidemiological evidence suggesting a relationship between the incidence and severity of asthma (e.g., hospitalizations) and exposure to increased levels of air pollution, especially fine and ultrafine particulate material, in susceptible individuals. There have been a few studies in animal models that support this concept, but additional animal studies to test this hypothesis are needed. However, such studies must be performed with awareness of the strengths and weaknesses of the currently available animal models. For studies in mice, the most commonly used animal, a broad spectrum of molecular and immunological tools is available, particularly to study the balance between Th1 and Th2 responses, and inbred strains may be useful for genetic dissection of susceptibility to the disease. However, the mouse is a poor model for bronchoconstriction or localized immune responses that characterize the human disease. In contrast, allergic lung diseases in dogs and cats may more accurately model the human condition, but fewer tools are available for characterization of the mechanisms. Finally, economic issues as well as reagent availability limit the utility of horses, sheep, and primates.