Air pollution, PM2.5 composition, source factors, and respiratory symptoms in asthmatic and nonasthmatic children in Santiago, Chile.

The objective of this study was to determine the association of respiratory symptoms and medication use and exposure to various air pollutants, PM2.5 components, and source factors in a panel of asthmatic and nonasthmatic children in Santiago, Chile. To this end, 174 children (90 asthmatics and 84 nonasthmatics) were followed throughout the winter months of 2010 and 2011. During the study period, children filled out daily diaries to record respiratory symptoms and medication use. Air pollution data were obtained from government central site measurements and a PM2.5 characterization campaign. PM2.5 source factors were obtained using positive matrix factorization (PMF). Associations of symptoms and exposure to pollutants and source-factor daily scores were modeled separately for asthmatic and nonasthmatic children using mixed logistic regression models with random intercepts, controlling for weather, day of the week, year, and viral outbreaks. Overall, high concentrations of air pollutants and PM2.5 components were observed. Six source factors were identified by PMF (motor vehicles, marine aerosol, copper smelter, secondary sulfates, wood burning, and soil dust). Overall, single pollutant models showed significant and strong associations between 7-day exposures for several criteria pollutants (PM2.5, NO2, O3), PM2.5 components (OC, K, S, Se, V), and source factors (secondary sulfate) and coughing, wheezing and three other respiratory symptoms in both in asthmatic and nonasthmatic children. No associations were found for use of rescue inhalers in asthmatics. Two-pollutant models showed that several associations remained significant after including PM2.5, and other criteria pollutants, in the models, particularly components and source factors associated with industrial sources. In conclusion, exposure to air pollutants, especially PM2.5, NO2, and O3, were found to exacerbate respiratory symptoms in both asthmatic and nonasthmatic children. Some of the results suggest that PM2.5 components associated with a secondary sulfate source may have a greater impact on some symptoms than PM2.5. In general, the results of this study show important associations at concentrations close or below current air quality standards.

Inhalación masiva de amoniaco: reporte de dos casos / Massive ammonia inhalation: report of two cases

Ammonia (NH3) is an irritant and corrosive gas whose inhalation at high concentrations mainly occurs during agricultural and industrial activities, as occupational accidents. The extent and severity of the damage depends on the concentration and time of exposure to the toxic, which can cause skin, eye, respiratory and life-threatening injuries. We present two cases of patients acutely exposed to high concentrations of NH3. Both patients survived to the acute phase of the respiratory injury, but developed chronic lung derangements.

El amoniaco (NH3) es un gas irritante y corrosivo cuya inhalación aguda en altas concentraciones se produce principalmente durante accidentes laborales en el sector agrícola e industrial. La extensión y severidad del daño depende de la concentración y tiempo de exposición al tóxico, el cual puede causar lesiones a nivel cutáneo, ocular, respiratorio y riesgo vital. Presentamos dos casos de pacientes expuestos en forma aguda a NH3 en altas concentraciones. Ambos pacientes sobrevivieron a la fase aguda y evolucionaron con lesiones respiratorias crónicas.

Lung morphology and growth of rats exposed to tobacco smoke and alcohol.

PURPOSE: Investigate the morphological effects of chronic exposure to tobacco smoke inhalation and alcohol consumption on the lungs and on the growth of rats. METHODS: Sixty male Wistar rats were divided into four groups: control, tobacco, alcohol, tobacco + alcohol, for a period of study 260 days. Morphological analysis was conducted by optical and electron microscopy. Rat growth was investigated by measuring the snout-anus length, body mass index and body weight. RESULTS: The three groups exposed to the drugs presented lower growth and lower weight than the control group. The percentages of alveolitis, bronchiolitis and the mean alveolar diameter were greater, particularly in the groups exposed to tobacco smoke, but were not significantly different from the control group. Electron microscopy revealed more intense apoptotic and degenerative lesions in the smoking group, while degenerative lesions in the lamellar bodies were more intense with the association of both drugs. CONCLUSIONS: This experimental model showed morphological alterations observed by electron microscopy, principally due to tobacco smoke exposure. Alcohol and tobacco hindered the growth of rats, such that tobacco showed a greater effect on body length and alcohol on body weight.

Lung morphology and growth of rats exposed to tobacco smoke and alcohol / Estudo morfológico dos pulmões e crescimento de ratos expostos à fumaça do cigarro e ao álcool

PURPOSE: Investigate the morphological effects of chronic exposure to tobacco smoke inhalation and alcohol consumption on the lungs and on the growth of rats. METHODS: Sixty male Wistar rats were divided into four groups: control, tobacco, alcohol, tobacco + alcohol, for a period of study 260 days. Morphological analysis was conducted by optical and electron microscopy. Rat growth was investigated by measuring the snout-anus length, body mass index and body weight. RESULTS: The three groups exposed to the drugs presented lower growth and lower weight than the control group. The percentages of alveolitis, bronchiolitis and the mean alveolar diameter were greater, particularly in the groups exposed to tobacco smoke, but were not significantly different from the control group. Electron microscopy revealed more intense apoptotic and degenerative lesions in the smoking group, while degenerative lesions in the lamellar bodies were more intense with the association of both drugs. CONCLUSIONS: This experimental model showed morphological alterations observed by electron microscopy, principally due to tobacco smoke exposure. Alcohol and tobacco hindered the growth of rats, such that tobacco showed a greater effect on body length and alcohol on body weight.

OBJETIVO: Investigar os efeitos morfológicos da exposição crônica à inalação de fumaça do tabaco e o do consumo de álcool nos pulmões e no crescimento de ratos. MÉTODOS: Sessenta ratos Wistar machos foram distribuídos em quatro grupos: controle, tabaco, álcool e tabaco + álcool, e acompanhados por um período de 260 dias. No final do periodo foi realizada análise morfológica dos pulmões por microscopia óptica e eletrônica. O crescimento dos ratos foi investigado através da medição do comprimento focinho-ânus, peso corporal e índice de massa corporal. RESULTADOS: Os três grupos expostos às drogas apresentaram peso e comprimento significativamente menores que os do grupo controle. As percentagens de bronquiolite e alveolite, e o diâmetro alveolar médio foram maiores nos grupos expostos à fumaça do tabaco, mas sem significancia estatística quando comparadas ao grupo controle. A microscopia eletrônica revelou apoptose mais intensa e lesões degenerativas no grupo de fumantes, enquanto lesões degenerativas nos corpos lamelares foram mais intensas com a associação de ambas as drogas. CONCLUSÕES: Este modelo experimental mostrou alterações morfológicas observadas por microscopia eletrônica, principalmente devido à exposição ao tabaco. Tanto o alcool como o tabaco prejudicaram o crescimento dos animais, o tabaco mostrando um efeito maior sobre o comprimento e o álcool sobre o peso corporal.

Effects of urban air pollutants on emergency visits for childhood asthma in Mexico City.

The metropolitan area of Mexico City, Mexico, has serious air pollution problems. Although air contaminants may contribute to clinical asthma, there are at present no data on the relation between air pollution exposure and childhood asthma in Mexico City. The authors reviewed data on emergency visits from January to June 1990 at one major pediatric hospital in Mexico City. They used a Poisson regression model to study the relation between the number of daily emergency visits for asthma and air pollutant levels. The levels of ozone and sulfur dioxide-exposure were significantly associated with the number of emergency visits for asthma. After adjustment for potential confounding factors, the multivariate regression model predicted that an increase of 50 ppb in the 1-hour maximum ozone level would lead to a 43% increase in the number of emergency visits for asthma on the following day. Exposure to high ozone levels (> 110 ppb) for 2 consecutive days increased the number of asthma-related emergency visits by 68 percent. The results of this study suggest that ozone exposure is positively associated with the number of children's emergency visits for asthma in Mexico City.

PIP: A retrospective analysis of records of emergency visits during January-June 1990 at the Hospital Infantil de Mexico Federico Gomez in the northern section of Mexico City was conducted to examine the association between the 395 children's (16 years) emergency visits for asthma (2.5% of all emergency visits) and daily levels of different air pollutants. Most emergency visits for asthma (67%) included children aged less than 5. The mean ozone daily one-hour maximum level was 90 ppb (range: 10-250 ppb). The ozone level exceeded the Mexican ozone standard (110 ppb) on 49 days (28%). Concentrations of ozone and sulfur dioxide exposure were linked to the number of emergency visits for asthma (p = 0.001 for 1-hour maximum with 1-day lag and p = 0.07 for 1-hour maximum on same day). When the researchers controlled for confounding factors, they found that a rise in the ozone level of 50 ppb was related to a 43% increase in the number of emergency visits for asthma with a one-day lag period. 133% of these visits were made after two consecutive days of ozone levels of at least 110 ppb. Exposure to such high ozone levels increased the number of emergency visits for asthma by 68%. These findings demonstrate a positive relationship between ozone exposure and the number of children living in Mexico City who were treated for asthma. In fact, they suggest that cumulative exposure to ozone strengthens this association.