RESUMO
It is very important to study the occurrence of high levels of particulate matter due to the potential harm to people's health and to the environment. In the present work we use a non-homogeneous Poisson model to analyse the rate of exceedances of particulate matter with diameter smaller that 2.5 microns (PM 2.5 ). Models with and without change-points are considered and they are applied to data from Bogota, Colombia, and Mexico City, Mexico. Results show that whereas in Bogota larger particles pose a more serious problem, in Mexico City, even though nowadays levels are more controlled, in the recent past PM 2.5 were the ones causing serious problems.
RESUMO
During spring of 2009, a new influenza virus AH1N1 spread in the world causing acute respiratory illness and death, resulting in the first influenza pandemic since 1968. Blood levels of potentially-toxic and essential elements of 40 pneumonia and confirmed AH1N1 were evaluated against two different groups of controls, both not infected with the pandemic strain. Significant concentrations of potentially-toxic elements (lead, mercury, cadmium, chromium, arsenic) along with deficiency of selenium or increased Zn/Cu ratios characterized AH1N1 cases under study when evaluated versus controlled cases. Deficiency of selenium is progressively observed from controls I (influenza like illness) through controls II (pneumonia) and finally pneumonia-AH1N1 infected patients. Cases with blood Se levels greater than the recommended for an optimal cut-off to activate glutathione peroxidase (12.5 µg/dL) recovered from illness and survived. Evaluation of this essential element in critical pneumonia patients at the National Institutes is under evaluation as a clinical trial.
Assuntos
Influenza Humana/sangue , Metais/sangue , Adulto , Arsênio/sangue , Cádmio/sangue , Estudos de Casos e Controles , Feminino , Glutationa Peroxidase/sangue , Humanos , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Influenza Humana/epidemiologia , Influenza Humana/virologia , Chumbo/sangue , Masculino , Mercúrio/sangue , México , Pessoa de Meia-Idade , Pandemias , Pneumonia/sangue , Pneumonia/diagnóstico , Selênio/sangue , Adulto JovemRESUMO
To evaluate the impact of improved wood burning stoves on indoor air pollution, 53 homes in a rural town in Michoacán, Mexico, were selected from a health intervention study and monitored before and after receiving improved wood-burning stoves. Fine particulate matter--particles with aerodynamic diameter less than 2.5 microm (PM(2.5))--concentrations were measured in the central plaza of the community and in three microenvironments in the home (next to the stove, in the kitchen away from the stove, and outdoor patio). Forty-eight hour mean PM(2.5) concentrations in homes that burned wood in open fires were 693 microg/m(3) (95% CI: 246-1338) near the stove, 658 microg/m(3) (95% CI: 67-1448) in the kitchen away from the stove, and 94 microg/m(3) (95% CI: 36-236) on the patio. Mean ambient 24-h concentrations in the main plaza of the community were 59 microg/m(3) (95% CI: 29-92). Paired measurements before and after the installation of the Patsari improved wood-burning stove indicate a median 71% reduction in PM(2.5) concentrations near the stove and 58% reductions in kitchen concentrations, whereas patio and main plaza concentrations remain unaffected. Only 44% of participants reported to use their Patsari stoves exclusively during the transition period. Even with the predominant mixed use of the Patsari stove with open fires, estimated daily average personal exposures to PM(2.5) were reduced by 50%.