Relation of peak expiratory flow rates and symptoms to ambient ozone.

The temporal association between peak expiratory flow rates (PEFRs) and ambient ozone (O3) was studied in a group of 287 children and 523 nonsmoking adults in Tucson. In children, noon PEFRs were decreased on days when there was a higher O3 concentration; children with physician-confirmed asthma experienced the greatest decrease in noon PEFR. Evening PEFR levels were also significantly related to O3 in children, especially asthmatics. Among adults, evening PEFRs were decreased in asthmatics who spent more time outdoors on days when O3 levels were higher. After we adjusted for covariates, significant effects of interactions of 8-h O3 levels with particulate matter (PM10) and temperature on daily PEFR were found. There was some overnight effect of 8-h O3 on morning PEFRs. In general, the respiratory response to low-level ambient O3 is acute, occurs more in asthmatics, and increases as temperature and PM10 increase.     

Collection of a single alveolar exhaled breath for volatile organic compounds analysis

Measurement of specific organic compounds in exhaled breath has been used as an indicator of recent exposure to pollutants or as an indicator of the health of an individual. A typical application involves the collection of multiple breaths onto a sorbent cartridge or into an evacuated canister with the use of a relatively complex sampling apparatus. A new method has been developed wherein a single exhaled breath is directly transferred from the mouth into an evacuated 1 1 or 1.8 1 stainless steel SUMMA® canister. The single breath canister (SBC) method avoids the necessity for a complex sampling system requiring maintenance and cleaning and allows easy collection of samples. Additionally, it is possible to collect a rapid sequence of samples from a subject to establish the elimination curve subsequent to an exposure to specific volatile organic compounds with a theoretical resolution of adjacent breaths. The SBC method was compared to an accepted canister based sampling system to assure comparability and then used to demonstrate its utility by measuring the absorption and elimination of chloroform during and after exposure to chlorinated shower water. © 1995 Wiley-Liss, Inc.     

Distribution of volatile organic compounds in ambient air of Tehran

Transportation sources have created a major hydrocarbon pollution problem in the ambient air of Tehran. The authors used a Carbotrap tube to determine volatile organic compounds in air. Such compounds can be desorbed thermally and analyzed with gas chromatography-mass spectrometry. Samples were obtained from 8 sites in Tehran at which traffic flow varied between 500 and 2,500 vehicles/hr. A total of 54 hydrocarbons were identified in the ambient air of Tehran, and the average measured concentrations of benzene, toluene, m- and p-xylene, ethyl benzene, and o-xylene were 127.6 microg/m3, 201.1 microg/m3, 110.7 microg/m3, 58.1 microg/m3, and 57.6 microg/m3, respectively (standard deviation = 3.8-51.7 microg/m3). Emissions of individual pollutants in south Tehran exceeded those in north Tehran, and these emissions were higher during the afternoon than during the morning. The geographical parameters and the photochemical reaction also played important roles in the pollution conditions.     

Daily air pollution effects on children's respiratory symptoms and peak expiratory flow

To identify acute respiratory health effects associated with air pollution due to coal combustion, a subgroup of elementary school-aged children was selected from a large cross-sectional study and followed daily for eight months. Children were selected to obtain three equal-sized groups: one without respiratory symptoms, one with symptoms of persistent wheeze, and one with cough or phlegm production but without persistent wheeze. Parents completed a daily diary of symptoms from which illness constellations of upper respiratory illness (URI) and lower respiratory illness (LRI) and the symptom of wheeze were derived. Peak expiratory flow rate (PEFR) was measured daily for nine consecutive weeks during the eight-month study period. Maximum hourly concentrations of sulfur dioxide, nitrogen dioxide, ozone, and coefficient of haze for each 24-hour period, as well as minimum hourly temperature, were correlated with daily URI, LRI, wheeze, and PEFR using multiple regression models adjusting for illness occurrence or level of PEFR on the immediately preceding day. Respiratory illness on the preceding day was the most important predictor of current illness. A drop in temperature was associated with increased URI and LRI but not with increased wheeze or with a decrease in level of PEFR. No air pollutant was strongly associated with respiratory illness or with level of PEFR, either in the group of children as a whole, or in either of the symptomatic subgroups; the pollutant concentrations observed, however, were uniformly lower than current ambient air quality standards. Moreover, since exposure estimation based on monitoring of ambient air likely results in misclassification of the true exposure, the negative findings of this study must be interpreted cautiously.     

Personal and ambient air pollution is associated with increased exhaled nitric oxide in children with asthma

BACKGROUND: Research has shown associations between pediatric asthma outcomes and airborne particulate matter (PM). The importance of particle components remains to be determined. METHODS: We followed a panel of 45 schoolchildren with persistent asthma living in Southern California. Subjects were monitored over 10 days with offline fractional exhaled nitric oxide (FeNO), a biomarker of airway inflammation. Personal active sampler exposures included continuous particulate matter < 2.5 microm in aerodynamic diameter (PM2.5), 24-hr PM2.5 elemental and organic carbon (EC, OC), and 24-hr nitrogen dioxide. Ambient exposures included PM2.5, PM2.5 EC and OC, and NO2. Data were analyzed with mixed models controlling for personal temperature, humidity and 10-day period. RESULTS: The strongest positive associations were between FeNO and 2-day average pollutant concentrations. Per interquartile range pollutant increase, these were: for 24 microg/m3 personal PM2.5, 1.1 ppb FeNO [95% confidence interval (CI), 0.1-1.9]; for 0.6 microg/m3 personal EC, 0.7 ppb FeNO (95% CI, 0.3-1.1); for 17 ppb personal NO2, 1.6 ppb FeNO (95% CI, 0.4-2.8). Larger associations were found for ambient EC and smaller associations for ambient NO2. Ambient PM2.5 and personal and ambient OC were significant only in subjects taking inhaled corticosteroids (ICS) alone. Subjects taking both ICS and antileukotrienes showed no significant associations. Distributed lag models showed personal PM2.5 in the preceding 5 hr was associated with FeNO. In two-pollutant models, the most robust associations were for personal and ambient EC and NO2, and for personal but not ambient PM2.5. CONCLUSION: PM associations with airway inflammation in asthmatics may be missed using ambient particle mass, which may not sufficiently represent causal pollutant components from fossil fuel combustion.     

Personal exposure to volatile organic compounds. I. Direct measurements in breathing-zone air, drinking water, food, and exhaled breath

A pilot study to test methods of estimating personal exposures to toxic substances and corresponding body burdens was carried out between July and December 1980. Individual exposures to about a dozen volatile organic compounds in air and drinking water were measured for nine volunteers in Bayonne and Elizabeth, New Jersey, and for three volunteers in Research Triangle Park, North Carolina during three 3-day visits over the 6-month period. Breath samples were also collected from all subjects on each visit. Composite food samples were collected in each locality. Sampling and analytical methods for air, water, food, and breath were evaluated and found generally capable of detecting concentrations as low as 1 microgram/m3 in air and breath, and 1 ng/g in water and food. About 230 personal air samples, 170 drinking water samples, 66 breath samples, and 4 food samples (16 composites) were analyzed for the target chemicals. Ten compounds were present in air and eight were transmitted mainly through that medium. The two target trihalomethanes (chloroform and bromodichloromethane) were predominantly transmitted through water and beverages. Food appeared to be a minor route of exposure, except possibly for trichloroethylene in margarine. Seven compounds were present in more than half of the breath samples. Diurnal and seasonal variations were noted in air and water concentrations of some compounds, with summer levels generally higher. For some chemicals, weekday air exposures were significantly higher than weekend exposures. Some, but not all, of the potentially occupationally exposed individuals had significantly higher workplace exposures to several chemicals. Distributions of air exposures were closer to log normal than normal for most chemicals. Several chemicals were highly correlated with each other in personal air samples, indicating possible common sources of exposure.     

Traffic-related air pollution affects peak expiratory flow, exhaled nitric oxide, and inflammatory nasal markers

The authors used a longitudinal observational design, with repeated measures, to study the association between traffic-related air pollutants (i.e., nitric oxide, nitrogen dioxide, carbon monoxide, and Black Smoke) and respiratory symptoms. Subjects (N = 82) attended an elementary school in either Utrecht (i.e., urban children) or Bilthoven (i.e., suburban children). These two geographic areas differed with respect to levels of Black Smoke (means = 53 microg/m3 and 18 microg/m3, respectively). Levels of nitric oxide, nitrogen dioxide, carbon monoxide, and Black Smoke were consistently higher in Utrecht than in Bilthoven (mean daily ratios were 8, 1.5, 1.8, and 2.7, respectively). The authors compared mean levels of short-term effects of the aforementioned air pollutants on suburban and urban children. Urban children had higher mean levels (p = .05) of interleukin-8 (32%), urea (39%), uric acid (26%), albumin (15%), and nitric oxide metabolites (21%) in nasal lavage than did suburban children. Peak expiratory flow, exhaled nitric oxide levels, and nasal markers were associated with levels of particulate matter with diameters less than or equal to 10 microm, Black Smoke, nitrogen dioxide, and nitric oxide. With respect to per-unit increases in air pollution, urban children had more increased peak expiratory flow, higher levels of exhaled nitric oxide, and more increased release of uric acid, urea, and nitric oxide metabolites than suburban children. In summary, urban children had increased levels of inflammatory nasal markers, and their responses were more pronounced than were the suburban children's responses to the same increments of air pollution.     

Home-monitoring of peak expiratory flow rate using mini-Wright peak flow meter in diagnosis of asthma

Home-monitoring of peak expiratory flow rate using the mini-Wright peak flow meter is a useful technique for determining whether or not unexplained respiratory symptoms are caused by asthma. It is of particular value when airflow obstruction cannot be demonstrated at the time of consultation.     

便携式气相色谱-质谱法快速测定环境空气中的痕量挥发性有机物

目的采用便携式气相色谱-质谱(GC-MS)仪直接测定环境空气中35种痕量挥发性有机物。方法抽取1.0、2.0、5.0、10.0、25.0和50.0 m L的混合标准气分别注入1.0 L纯净氮气中,采用便携式气相色谱-质谱仪手持探头直接采样检测,以保留时间和特征离子定性,内标法定量。结果在所建立的试验条件下,35种化合物分离良好且准确定性,方法相对标准偏差3.2%~15.1%,平均回收率为75.1%~121.4%(n=6)。结论便携式GC-MS法可用于环境空气中挥发性有机物的定性定量检测。     

Short-term effects of formaldehyde on peak expiratory flow and irritant symptoms

The authors studied the respiratory effects of formaldehyde exposure among students who dissected cadavers in a gross anatomy laboratory. Peak expiratory flow and respiratory symptoms were measured before and after each weekly laboratory session. Each of 38 students was exposed to formaldehyde for 2.5 hr/wk for 14 wk. Individual, daily formaldehyde measurements averaged 1.1 ppm (standard deviation = 0.56 ppm). Multivariate models demonstrated two different time scales of effect of formaldehyde on peak expiratory flow: (1) exposure during the previous 2.5 hr reduced peak expiratory flow by -1.0% per ppm, and (2) average exposure during all preceding weeks reduced peak expiratory flow by an additional -0.5% per ppm of formaldehyde. However, the short-term exposure effect was diminished during the first 4 wk, suggesting at least partial acclimatization. Symptom reporting was also associated with exposure during the previous 2.5 hr, and similar evidence of acclimatization was observed. These results suggest that there are two different time scales of response to formaldehyde, and they emphasize the need for longitudinal studies, characterized by quantitative exposure characterization, and frequent measurements of outcome.     

Value of maximum expiratory volume per second and peak expiratory flow monitoring in asthma. 77 patients

A retrospective study was conducted on a sample of 77 subjects to assess the interest of computerized flowmeter "one-flow" in the diagnosis and follow up of asthma. 77 patients and a control group matched for age and sex, measured four times by day, the forced expiratory volume in one second as well as the peak expiratory flow during 15 to 30 days. The monitoring of these two variables allowed to participate to the exclusion from the study of fifteen patients whose asthma diagnosis was informed. It also allowed the confirmation of four occupational asthma. Concerning the adherence of the treatment by patients, the conclusion of the study showed that 47% of patients modified their treatment at home without consulting their doctors, 38% resorted to their doctor and only 3% resorted to the emergencies.     

Impact of ambient air pollution on the prevalence of main symptoms of asthma in children

The impact of ambient air pollution on the prevalence of main symptoms of asthma was analyzed in children. A total of 3,506 children were interviewed using the ISAAC questionnaire. The prevalence of the abnormality was studied via continuous questioning in children aged 7-8 and 13-14 years, who lived in areas with varying aerogenic loads. The higher rates of main asthma-like symptoms and clinically diagnosed asthma were ascertained in the children living in higher ambient air pollution areas.     

成都地区446例正常儿童呼气峰流速正常值探讨

目的 探讨成都地区4.0～14.0岁儿童呼气峰流速的正常值及特点.方法 2011年11月至2012年5月以成都地区446例健康儿童为研究对象,采用呼气峰流速仪及肺功能仪进行肺通气功能测量,参考美国胸科协会（ATS）标准测定呼气峰流速,并对各实测指标作LMS回归,得出预计方程式,探讨其特点.结果 呼气峰流速仪与肺功能仪对呼气峰流速的检测有很好的相关性（r=0.920,P＜ 0.01）,男性儿童高于女性儿童,呼气峰流速与身高关系最密切,其次为体质量、年龄.呼气峰流速随年龄、身高的增长而增长.部分正常儿童呼气峰流速值低于80％正常值下限.将身高、年龄代入预计方程式得出相应的呼气峰流速值.结论 呼气峰流速与身高的关系最为密切.建立了成都地区儿童简易呼气峰流速仪及肺功能仪测定呼气峰流速的预计方程式.     

Acute effects of low levels of ambient ozone on peak expiratory flow rate in a cohort of Australian children

BACKGROUND: We enrolled a cohort of primary schoolchildren with a history of wheeze (n = 148) in an 11-month longitudinal study to examine the relationship between ambient ozone concentrations and peak expiratory flow rate. METHODS: Enrolled children recorded peak expiratory flow rates (PEFR) twice daily. We obtained air pollution, meteorological and pollen data. In all, 125 children remained in the final analysis. RESULTS: We found a significant negative association between daily mean deviation in PEFR and same-day mean daytime ozone concentration (beta-coefficient = 0.88; P = 0.04) after adjusting for co-pollutants, time trend, meteorological variables, pollen count and ALTERNARIA: count. The association was stronger in a subgroup of children with bronchial hyperreactivity and a doctor diagnosis of asthma (beta-coefficient = -2.61; P = 0.001). There was no significant association between PEFR and same-day daily daytime maximum ozone concentration. We also demonstrated a dose-response relationship with mean daytime ozone concentration. CONCLUSIONS: Moderate levels of ambient ozone have an adverse health effect on children with a history of wheezing, and this effect is larger in children with bronchial hyperreactivity and a doctor diagnosis of asthma.     

Acute effects of air pollution on peak expiratory flow rates and symptoms among asthmatic patients in Chiang Mai, Thailand

The open burnings and forest fires have been recognized as the major sources of severe air pollution in the upper north of Thailand; however, there have been no clear evidences to show the associations between the air pollution and health effects in the area. We assessed the effects of air pollutants on the peak expiratory flow rates (PEFR) and symptoms in asthmatics. A cohort of 121 asthmatics was followed daily, for 306 days, for their PEFR and asthma symptoms. The daily air pollutants, including particulate matter with aerodynamic diameter <2.5 μm, particulate matter with aerodynamic diameter <10 μm (PM(10)), carbon monoxide, ozone, nitrogen dioxide (NO(2)), and sulfur dioxide (SO(2)), and the meteorological parameters, including pressure, temperature, relative humidity, rain quantity, and sunshine duration, were monitored. The PEFRs were fitted with general linear mixed models. The asthma symptoms were analyzed with the generalized estimating equations. There were positive associations of NO(2) with morning PEFR, with a coefficient of 0.06 [95% confidence interval (CI), 0.00-0.12]; of SO(2) with evening PEFR [with a range of coefficients of 0.88-1.00 (95% CI, 0.31-1.54)] and daily average PEFR [with a coefficient of 0.47 (95% CI, 0.00-0.94)]; of PM(10) with evening PEFR, with a coefficient of 0.02 (95% CI, 0.00-0.04). There was also negative association of PM(10) with ΔPEFR, with a coefficient of -0.01 (95% CI, -0.01 to -0.00). No pollutants were related to asthma symptoms. More studies are needed, particularly at low dose in adult asthmatics, to validate our findings.     

Elimination of volatile organic compounds in breath after exposure to occupational and environmental microenvironments.

Breath measurements offer the potential for a direct and noninvasive evaluation of human exposure to volatile organic compounds (VOCs) in the environments in which people live and work. This research study was conducted to further evaluate and develop the potential of this exposure assessment methodology. Several people were exposed to the atmosphere in six microenvironments for several hours. Air concentrations of VOCs were measured during these exposures and breath samples were collected and analyzed at multiple time points after the exposure to evaluate elimination kinetics for 21 VOCs. A new alveolar breath collection technique was applied. Elimination half-lives were estimated using a mono- and bi-exponential model. The alveolar breath collection and analysis methodology proved to be very useful for collecting many samples in short time intervals and this capability was very important for more accurately describing the initial phase of the decay curves. Breath decay curves were generated from samples collected over a four hour period after exposure for 21 of 24 target VOCs. A biexponential function generally provided a better fit for the decay data than did the monoexponential function, supporting a multi-compartment uptake and elimination model for the human body.     

气质联用法同时测定车间空气中多组分挥发性有机物

目的:利用气质联用法,建立一种高效、实用、快速、准确的车间空气中多种挥发性有机物的定性、定量测定方法。方法:用活性炭管采集车间空气中挥发性有机物,经二硫化碳解析后,气质联用法进行检测。结果:方法分离效果好,相关系数在0.99998-1.00000之间,相对标准偏差小于5%,回收率在92.32%~99.80%间。结论:该方法操作简便、灵敏度高、结果准确、适合车间空气样品中多种挥发性有机物的同时检测分析,在实际检测工作应用中取得了满意效果。     

Effects of ambient air pollution on symptoms of asthma in Seattle-area children enrolled in the CAMP study

We observed a panel of 133 children (5-13 years of age) with asthma residing in the greater Seattle, Washington, area for an average of 58 days (range 28-112 days) during screening for enrollment in the Childhood Asthma Management Program (CAMP) study. Daily self-reports of asthma symptoms were obtained from study diaries and compared with ambient air pollution levels in marginal repeated measures logistic regression models. We defined days with asthma symptoms as any day a child reported at least one mild asthma episode. All analyses were controlled for subject-specific variables [age, race, sex, baseline height, and FEV(1) PC(20) concentration (methacholine provocative concentration required to produce a 20% decrease in forced expiratory volume in 1 sec)] and potential time-dependent confounders (day of week, season, and temperature). Because of variable observation periods for participants, we estimated both between- and within-subject air pollutant effects. Our primary interest was in the within-subject effects: the effect of air pollutant excursions from typical levels in each child's observation period on the odds of asthma symptoms. In single-pollutant models, the population average estimates indicated a 30% [95% confidence interval (CI), 11-52%] increase for a 1-ppm increment in carbon monoxide lagged 1 day, an 18% (95% CI, 5-33%) increase for a 10-microg/m(3) increment in same-day particulate matter < 1.0 microm (PM(1.0)), and an 11% (95% CI, 3-20%) increase for a 10-microg/m(3) increment in particulate matter < 10 microm (PM(10)) lagged 1 day. Conditional on the previous day's asthma symptoms, we estimated 25% (95% CI, 10-42%), 14% (95% CI, 4-26%), and 10% (95% CI, 3-16%) increases in the odds of asthma symptoms associated with increases in CO, PM(1.0), and PM(10), respectively. We did not find any association between sulfur dioxide (SO(2)) and the odds of asthma symptoms. In multipollutant models, the separate pollutant effects were smaller. The overall effect of an increase in both CO and PM(1. 0) was a 31% (95% CI, 11-55%) increase in the odds of symptoms of asthma. We conclude that there is an association between change in short-term air pollution levels, as indexed by PM and CO, and the occurrence of asthma symptoms among children in Seattle. Although PM effects on asthma have been found in other studies, it is likely that CO is a marker for vehicle exhaust and other combustion by-products that aggravate asthma.     

呼出气中挥发性有机污染物的采样和分析方法

提出了一种呼出气中挥发性有机污染物（ＶＯＣｓ）的采样和分析方法。用复合膜采气袋收集受试者重复呼出气样品，采用吸附浓缩／热解析／二次冷阱浓缩／再热解析进样，程序升温毛细管色谱柱和ＦＩＤ检测器分析。最低检出限苯为０．５ｎｇ／Ｌ三氯乙烯为５ｎｇ／Ｌ，整个采样与分析的相对标准偏差≤１５％，加标回收率平均为９３％。