Indoor air pollutants in homes and schools.

Exposure to the four indoor air pollutants mentioned in this article may cause illnesses and fatalities in children. It is important for pediatricians to be aware of each of them and to remove children from environments contaminated with these pollutants. Guidance about monitoring the indoor air and interpreting the results is difficult to find. A chart of proposed guidelines may help the pediatrician faced with an indoor air problem (Table 1).

Workshop to identify critical windows of exposure for children's health: immune and respiratory systems work group summary.

Fetuses, infants, and juveniles (preadults) should not be considered simply "small adults" when it comes to toxicological risk. We present specific examples of developmental toxicants that are more toxic to children than to adults, focusing on effects on the immune and respiratory systems. We describe differences in both the pharmacokinetics of the developing immune and respiratory systems as well as changes in target organ sensitivities to toxicants. Differential windows of vulnerability during development are identified in the context of available animal models. We provide specific approaches to directly investigate differential windows of vulnerability. These approaches are based on fundamental developmental biology and the existence of discrete developmental processes within the immune and respiratory systems. The processes are likely to influence differential developmental susceptibility to toxicants, resulting in lifelong toxicological changes. We also provide a template for comparative research. Finally, we discuss the application of these data to risk assessment.

Cardiopulmonary baroreceptor control of muscle sympathetic nerve activity in heat-stressed humans.

Whole body heating decreases central venous pressure (CVP) while increasing muscle sympathetic nerve activity (MSNA). In normothermia, similar decreases in CVP elevate MSNA, presumably via cardiopulmonary baroreceptor unloading. The purpose of this project was to identify whether increases in MSNA during whole body heating could be attributed to cardiopulmonary baroreceptor unloading coincident with the thermal challenge. Seven subjects were exposed to whole body heating while sublingual temperature, skin blood flow, heart rate, arterial blood pressure, and MSNA were monitored. During the heat stress, 15 ml/kg warmed saline was infused intravenously over 7-10 min to increase CVP and load the cardiopulmonary baroreceptors. We reported previously that this amount of saline was sufficient to return CVP to pre-heat stress levels. Whole body heating increased MSNA from 25 +/- 3 to 39 +/- 3 bursts/min (P < 0. 05). Central blood volume expansion via rapid saline infusion did not significantly decrease MSNA (44 +/- 4 bursts/min, P > 0.05 relative to heat stress period) and did not alter mean arterial blood pressure (MAP) or pulse pressure. To identify whether arterial baroreceptor loading decreases MSNA during heat stress, in a separate protocol MAP was elevated via steady-state infusion of phenylephrine during whole body heating. Increasing MAP from 82 +/- 3 to 93 +/- 4 mmHg (P < 0.05) caused MSNA to decrease from 36 +/- 3 to 15 +/- 4 bursts/min (P < 0.05). These data suggest that cardiopulmonary baroreceptor unloading during passive heating is not the primary mechanism resulting in elevations in MSNA. Moreover, arterial baroreceptors remain capable of modulating MSNA during heat stress.

Air pollution and bronchitic symptoms in Southern California children with asthma.

People who live in cities with dirty air have blacker lungs than people who live in rural areas with less air pollution. This is because, although particulates larger than 10 microm are filtered out when inhaled air passes through the nose, smaller particulates reach the lower airways. The particulates that reach the alveoli (the terminal air pockets of the lungs) stay there permanently. This accounts for the fact that a person who has lived in a polluted city for many years has blacker lungs than one who has lived in a polluted city for a shorter time.

Overview of investigations into pulmonary hemorrhage among infants in Cleveland, Ohio.

Idiopathic pulmonary hemorrhage was diagnosed in 37 infants in the Cleveland, Ohio, area between 1993 and 1998. This rare disorder has been related to 12 deaths, including 7 originally thought to be sudden infant death syndrome. Thirty of the infants were African American, all of whom lived in a limited geographic area of eastern metropolitan Cleveland, an area of older housing stock. An investigation led by the Centers for Disease Control and Prevention has found an association with household exposure to a toxigenic mold, Stachybotrys chartarum, and other fungi. The rapidly growing lungs of young infants appear to be especially vulnerable to the toxins made by toxigenic molds. Environmental tobacco smoke was frequently present in the infants' homes and may be a trigger precipitating the acute bleeding. Stachybotrys, although not thought to be a common mold, is known to have a wide geographic distribution. An additional 101 cases of acute, idiopathic pulmonary hemorrhage have been reported in infants in the United States over the past 5 years. In this overview, the investigations are summarized, the clinical profile is described, the toxicity of S. chartarum is discussed, and pathophysiologic concepts are presented.

Effect of increasing central venous pressure during passive heating on skin blood flow.

Whole body heating in humans increases skin blood flow (SkBF) and decreases central venous pressure (CVP). This study sought to identify whether elevations in SkBF are augmented during passive heating if CVP is increased during the heat stress. Seven subjects were exposed to passive heating. Once SkBF was substantially elevated, 15 ml/kg warm saline were rapidly infused intravenously. Whole body heating significantly increased cutaneous vascular conductance and decreased CVP from 7.7 +/- 0.6 to 4.9 +/- 0.5 mmHg (P < 0.05). Saline infusion returned CVP to pre-heat-stress pressures (7.9 +/- 0.6 mmHg; P > 0.05) and significantly increased cutaneous vascular conductance relative to the period before saline administration. Moreover, saline infusion did not alter mean arterial pressure, pulse pressure, or esophageal temperature (all P > 0.05). To serve as a volume control, 15 ml/kg saline were rapidly infused intravenously in normothermic subjects. Saline infusion increased CVP (P < 0.05) without affecting mean arterial pressure, pulse pressure, or cutaneous vascular conductance (all P > 0.05). These data suggest that cardiopulmonary baroreceptor unloading during passive heating may attenuate the elevation in SkBF in humans, whereas loading cardiopulmonary baroreceptors in normothermia has no effect on SkBF.

Study of toxin production by isolates of Stachybotrys chartarum and Memnoniella echinata isolated during a study of pulmonary hemosiderosis in infants.

A cluster of cases of pulmonary hemosiderosis among infants was reported in Cleveland, Ohio, during 1993 and 1994. These unusual cases appeared only in infants ranging in age from 1 to 8 months and were characterized by pulmonary hemorrhage, which caused the babies to cough up blood. A case-control study identified major home water damage (from plumbing leaks, roof leaks, or flooding) as a risk factor for development of pulmonary hemorrhage in these infants. Because of an interest in the possibility that trichothecene mycotoxins might be involved in this illness, a number of isolates of Stachybotrys chartarum were grown in the laboratory on rice, and extracts were prepared and analyzed both for cytotoxicity and for specific toxins. Two isolates of Memnoniella echinata, a fungus closely related to S. chartarum, were also included in these studies. S. chartarum isolates collected from the homes were shown to produce a number of highly toxic compounds, and the profiles of toxic compounds from M. echinata were similar; the most notable difference was the fact that the principal metabolites produced by M. echinata were griseofulvins.

Acute pulmonary hemorrhage in infants associated with exposure to Stachybotrys atra and other fungi.

BACKGROUND: A geographic cluster of 10 cases of pulmonary hemorrhage and hemosiderosis in infants occurred in Cleveland, Ohio, between January 1993 and December 1994. STUDY DESIGN: This community-based case-control study tested the hypothesis that the 10 infants with pulmonary hemorrhage and hemosiderosis were more likely to live in homes where Stachybotrys atra was present than were 30 age- and ZIP code-matched control infants. We investigated the infants' home environments using bioaerosol sampling methods, with specific attention to S atra. Air and surface samples were collected from the room where the infant was reported to have spent the most time. RESULTS: Mean colony counts for all fungi averaged 29 227 colony-forming units (CFU)/m3 in homes of patients and 707 CFU/m3 in homes of controls. The mean concentration of S atra in the air was 43 CFU/m3 in homes of patients and 4 CFU/m3 in homes of controls. Viable S atra was detected in filter cassette samples of the air in the homes of 5 of 9 patients and 4 of 27 controls. The matched odds ratio for a change of 10 units in the mean concentration of S atra in the air was 9.83 (95% confidence interval, 1.08-3 X 10(6)). The mean concentration of S atra on surfaces was 20 X 10(6) CFU/g and 0.007 x 10(6) CFU/g in homes of patients and controls, respectively. CONCLUSION: Infants with pulmonary hemorrhage and hemosiderosis were more likely than controls to live in homes with toxigenic S atra and other fungi in the indoor air.

Children's health and the environment: a new agenda for prevention research.

Patterns of illness in American children have changed dramatically in this century. The ancient infectious diseases have largely been controlled. The major diseases confronting children now are chronic and disabling conditions termed the "new pediatric morbidity"--asthma mortality has doubled; leukemia and brain cancer have increased in incidence; neurodevelopmental dysfunction is widespread; hypospadias incidence has doubled. Chemical toxicants in the environment as well as poverty, racism, and inequitable access to medical care are factors known and suspected to contribute to causation of these pediatric diseases. Children are at risk of exposure to over 15,000 high-production-volume synthetic chemicals, nearly all of them developed in the past 50 years. These chemicals are used widely in consumer products and are dispersed in the environment. More than half are untested for toxicity. Children appear uniquely vulnerable to chemical toxicants because of their disproportionately heavy exposures and their inherent biological susceptibility. To prevent disease of environmental origin in America's children, the Children's Environmental Health Network (CEHN) calls for a comprehensive, national, child-centered agenda. This agenda must recognize children's vulnerabilities to environmental toxicants. It must encompass a) a new prevention-oriented research focus; b) a new child-centered paradigm for health risk assessment and policy formulation; and c) a campaign to educate the public, health professionals, and policy makers that environmental disease is caused by preventable exposures and is therefore avoidable. To anchor the agenda, CEHN calls for long-term, stable investment and for creation of a national network of pediatric environmental health research and prevention centers.

Exposure to environmental tobacco smoke and risk factors for heart disease among never smokers in the Third National Health and Nutrition Examination Survey.

The relative risk of coronary artery disease among never smokers exposed to environmental tobacco smoke (ETS) versus never smokers not exposed to ETS is approximately 1.2 based on more than a dozen epidemiologic studies. Most of these studies have controlled for the major heart disease risk factors, but residual or uncontrolled confounding remains a possible explanation for the epidemiologic findings. The authors studied 3,338 never-smoking adults aged 17 years or older, who are representative of all US never smokers, in the 1988-1991 Third National Health and Nutrition Examination Survey (NHANES III) to determine whether selected risk factors for heart disease differ between ETS-exposed and -nonexposed persons. Both self-reported ETS exposure (at home and at work) and serum cotinine levels were available, the latter reflecting recent ETS exposure. After adjustments were made for age, sex, race, and education among adults aged 17 years or older, no significant differences were found between the ETS exposed and the nonexposed for any of 13 cardiovascular risk factors with the exception of dietary carotene, which was lower among the exposed. On the other hand, significant positive linear trends were found between serum cotinine and two risk factors (body mass index and alcohol consumption), and significant inverse trends were found with dietary carotene. There were also few differences between exposed and nonexposed never smokers among adults aged 40 years or older, who are most at risk of heart disease. In this group, however, there was an inverse linear trend between serum cotinine and high density lipoprotein cholesterol (p < 0.001). This finding could result from ETS exposure rather than be an indication of confounding; a similar inverse trend was found for children, confirming other results in the literature. Overall, these data suggest little potential for confounding by the heart disease risk factors studied here when ETS exposure is determined by self-report.

Evidence of functional beta-adrenoceptors in the cutaneous vasculature.

During a hyperthermic challenge, skin blood flow (SkBF) increases primarily through activation of the cutaneous active vasodilator system. However, mechanisms through which activation of this system elevates SkBF remain unknown. In this project, we sought to identify whether functional beta-adrenoceptors exist on cutaneous vessels and, if present, whether these receptors play an important role in elevating SkBF during a hyperthermic challenge. In protocol 1, SkBF was assessed over two intradermal microdialysis probes. Initially, both probes were perfused with lactated Ringer solution. Probe A was then perfused with a 200 microM solution of the beta-adrenoceptor agonist isoproterenol while probe B was perfused with a 1.7 mM solution of the beta-adrenoceptor antagonist propranolol. Isoproterenol perfusion significantly increased SkBF from 17.7 +/- 2.4 to 70.8 +/- 13.2 perfusion units (PU; P < 0.05), whereas propranolol perfusion did not significantly affect SkBF (23.4 +/- 6.5 to 27.0 +/- 6.8 PU; P > 0.05). After this period, the solutions perfusing the probes were switched. Isoproterenol did not significantly change SkBF at the propranolol-treated site (27.0 +/- 6.8 to 26.4 +/- 7.5 PU; P < 0.05). In protocol 2, SkBF was assessed over two microdialysis probes during indirect whole body heating. One probe was perfused with Ringer solution while the other probe was perfused with 1.7 mM propranolol. The degree of elevation in SkBF during heat stress at the propranolol-treated site (10.4 +/- 1.5 to 35.8 +/- 3.1 PU) was similar to the elevation in SkBF at the Ringer solution site (11.6 +/- 1.0 to 35.0 +/- 1.2 PU). These data demonstrate the presence of functional beta-adrenoceptors in the skin; however, these receptors play no significant role in mediating cutaneous vasodilation during indirect whole body heating.

Active and passive smoking: hazards for children.

This manuscript describes the tobacco industry's efforts to recruit active smokers among the adolescent population, the effects of environmental tobacco smoke on nonsmokers, and lists some steps pediatricians can take to influence smoking behavior. Six health effects result from passive smoking. Children exposed to environmental tobacco smoke have increased lower respiratory illness rates, especially in the first year of life, passive smoking is associated with increased rates of chronic middle ear effusion in children. Exposure to cigarette smoke is associated with small changes in pulmonary function. Exposure to environmental tobacco smoke increases an asthmatic child's exacerbations. Exposure to environmental tobacco smoke is a risk factor for sudden infant death syndrome. Passive exposure during childhood to a parents smoking increases a child's risk of leukemia and lymphoma during adulthood. Pediatricians and others who care for children must try to limit as much as possible, the exposure of children to the cigarette smoke produced by others.

Asthma. The states' challenge.

At the national level, asthma is increasingly being recognized as an important public health problem. Because of the significant role of environmental exposure in asthma morbidity, public health agencies have a critical role to play in the surveillance and prevention of the disease. In April 1996, the Council of State and Territorial Epidemiologists, with assistance from the Centers for Disease Control and Prevention, surveyed state and territorial public health departments to determine the status of their asthma surveillance and intervention programs. Of the 51 health departments that responded, only eight reported that they had implemented an asthma control program within the previous 10 years. Reasons cited for not having programs included lack of funds, shortage of personnel, and asthma not being a priority. Most states were unable to assess the burden of asthma because they lack data or face barriers to using existing data. Removing barriers to the use of data is a first step toward defining the scope of the asthma problem.

Reexamination of epidemic asthma in New Orleans, Louisiana, in relation to the presence of soy at the harbor.

Epidemic asthma occurred in New Orleans, Louisiana, in the 1950s and 1960s, but its causes were never fully understood. Subsequently, similar outbreaks of epidemic asthma in Barcelona, Spain, were shown to be caused by the release of soy dust at the harbor. To investigate whether airborne soy dust may have contributed to epidemic asthma in New Orleans, the authors examined historical data on vessel cargo from the New Orleans harbor together with data on emergency department visits for asthma, for the period from 1957 through 1968. Days on which there were 64 or more visits for asthma were twice as likely to have occurred on days when a vessel carrying soy was at the harbor (odds ratio (OR) = 2.3, 95% confidence interval (CI) 1.5-3.3). The association was stronger when the maximum wind speed was less than 12 miles/hour (19.3 km/hour) (OR = 4.0, 95% CI 2.1-7.7) and strongest when wind speeds were low and the prevailing winds were from the south or southwest, the direction of two grain elevators from the hospital (OR = 6.7, 95% CI 1.5-46.7). Various temporal and climatic factors that had been associated with the occurrence of asthma outbreaks did not appear to be important confounding factors. The association was specific to soy cargo; no association was observed between asthma-epidemic days and the presence of either wheat or corn in vessels at the harbor. The results of this analysis provide further evidence that ambient soy dust is very asthmogenic and that asthma morbidity in a community can be influenced by exposures in the ambient atmosphere.

Blood benzene concentrations in workers exposed to oxygenated fuel in Fairbanks, Alaska.

OBJECTIVE: In November 1992 residents of Fairbanks, Alaska became concerned about the potential health effects of an oxygenated fuel program during which 15% (by volume) methyl tertiary butyl ether (MTBE) was added to gasoline. To address those concerns, we earlier completed a survey of occupational exposure to MTBE. We conducted a follow-up survey of workers' exposure to benzene from gasoline in Fairbanks. DESIGN: Cross-sectional exposure survey. METHODS: We examined blood concentrations of benzene from a convenience sample of workers taken in December 1992 during the oxygenated fuel program and from another convenience sample of workers taken in February 1993 after the program was suspended. RESULTS: In December, the median blood benzene concentration of samples taken from four mechanics after their workshift (postshift) was 1.32 micrograms/l (range, 0.84-2.61 micrograms/l), and seven nonmechanics (drivers and other garage workers) had a median postshift blood benzene concentration of 0.27 microgram/l (range, 0.09-0.45 microgram/l). In February, nine mechanics had a median postshift blood benzene concentration of 1.99 micrograms/l (range, 0.92-3.23 micrograms/l), and nine nonmechanics had a median postshift blood benzene concentration of 0.26 microgram/l (range, 0.2-0.46 microgram/l). CONCLUSION: Mechanics had higher blood benzene concentrations than did nonmechanics, but further study is needed to determine the impact of the oxygenated fuel program on exposure to benzene.

Environmental risk factors associated with pediatric idiopathic pulmonary hemorrhage and hemosiderosis in a Cleveland community.

BACKGROUND: Unexplained pulmonary hemorrhage and hemosiderosis are rarely seen in infancy. A geographic cluster of 10 infants with this illness was identified in a large pediatric referral hospital in Cleveland, Ohio, during the period of January 1993 through December 1994. One infant died of severe respiratory failure. METHODS: A case-control study was conducted. Three control infants were matched by age with each case infant. All study infants' guardians were interviewed. Questions were asked about child care practices and home conditions for the period before case infants' illnesses. All infants' records were reviewed, their homes were visited, and a structural and environmental survey was conducted. RESULTS: All 10 case infants were black, and 9 were male, whereas 50.0% of control infants were male, and 83.3% were black. The case infants' mean age was 10.2 weeks (range, 6 weeks to 6 months). Matched analysis demonstrated that case infants' homes were more likely to have had water damage preceding the pulmonary hemorrhage event (odds ratio, 16.25; 95% confidence interval, 2.55 to infinity). Case infants were also more likely to have had close relatives with pulmonary hemorrhage (odds ratio, 33.14; 95% confidence interval, 5.10 to infinity). In addition, 50.0% of case infants experienced recurrent pulmonary hemorrhaging after returning to their homes. CONCLUSION: The results of this investigation of a cluster of infants with massive, acute pulmonary hemorrhage and hemosiderosis suggest that the affected infants may have been exposed to contaminants in their homes. Epidemiologic clues, such as water damage in the case infants' homes, suggest that environmental risk factors may contribute to pulmonary hemorrhage.

Mercury exposure in high school chemistry teachers.

To assess whether high school chemistry teachers had higher urinary mercury concentrations than other high school teachers, 24 high school teachers from nine schools in northeastern Ohio were studied. First morning voided urine samples and air samples from the teachers' classrooms were analyzed for total mercury content by cold vapor atomic absorption. The median adjusted urinary mercury concentration in the 12 chemistry teachers was 4.6 microg/g creatinine (range 2.2-8.2 microg/g creatinine) and it was 6.3 microg/g creatinine in the 12 non-chemistry teachers. All classroom air samples contained mercury levels below detection limits. No evidence was provided that high school chemistry teachers are at increased risk of chronic mercury exposure from their teaching activities compared to other high school teachers.

Effects of air pollution on the respiratory health of asthmatic children living in Mexico City.

The relation between air pollution and the exacerbation of childhood asthma was studied in a panel of 71 children (aged 5 to 7 yr) with mild asthma who resided in the northern part of mexico City. During the follow-up, ambient measures of particulate matter less than 10 microns (PM10, 24-h average) and ozone (1-h maximum) frequently exceeded the Mexican standards for these contaminants. The peak expiratory flow rate (PEFR) was strongly associated with PM10 levels and marginally with ozone levels. Respiratory symptoms (coughing, phlegm production, wheezing, and difficulty breathing) were associated with both PM10 and ozone levels. An increase of 20 micrograms/m3 of PM10 was related to an 8% increase in lower respiratory illness (LRI) among children on the same day (95% confidence interval [CI] = 1.04-1.15), and an increase of 10 micrograms/m3 in the weekly mean of particulate matter less than 2.5 microns (PM2.5) was related to a 21% increase in LRI (95% CI = 1.08-1.35). A 50 parts per billion (ppb) increase in ozone was associated with a 9% increase in LRI (95% CI = 1.03-1.15) on the same day. We concluded that children with mild asthma are affected by the high ambient levels of particulate matter and ozone observed in the northern part of Mexico City.