Outdoor particulate matter and childhood asthma admissions in Athens, Greece: a time-series study

<p>Abstract</p> <p>Background</p> <p>Particulate matter with diameter less than 10 micrometers (PM₁₀) that originates from anthropogenic activities and natural sources may settle in the bronchi and cause adverse effects possibly via oxidative stress in susceptible individuals, such as asthmatic children. This study aimed to investigate the effect of outdoor PM₁₀concentrations on childhood asthma admissions (CAA) in Athens, Greece.</p> <p>Methods</p> <p>Daily counts of CAA from the three Children's Hospitals within the greater Athens' area were obtained from the hospital records during a four-year period (2001-2004, n = 3602 children). Mean daily PM₁₀concentrations recorded by the air pollution-monitoring network of the greater Athens area were also collected. The relationship between CAA and PM₁₀concentrations was investigated using the Generalized Linear Models with Poisson distribution and logistic analysis.</p> <p>Results</p> <p>There was a statistically significant (95% CL) relationship between CAA and mean daily PM₁₀concentrations on the day of exposure (+3.8% for 10 μg/m³increase in PM₁₀concentrations), while a 1-day lag (+3.4% for 10 μg/m³increase in PM₁₀concentrations) and a 4-day lag (+4.3% for 10 μg/m³increase in PM₁₀concentrations) were observed for older asthmatic children (5-14 year-old). High mean daily PM₁₀concentration (the highest 10%; >65.69 μg/m³) doubled the risk of asthma exacerbations even in younger asthmatic children (0-4 year-old).</p> <p>Conclusions</p> <p>Our results provide evidence of the adverse effect of PM₁₀on the rates of paediatric asthma exacerbations and hospital admissions. A four-day lag effect between PM₁₀peak exposure and asthma admissions was also observed in the older age group.</p

Possible east side predominance of the optical emissions of the solar corona

A long term analysis of the green and the red line intensities of the emitting solar corona as well as the polarization of the white corona, which have been compiled by the Pic-du-Midi, Kislovodsk, Irkutsk and Lomnisky Styt observatories, has led to some very interesting results. A prominent East-West asymmetry is obvious in most of the data while a very characteristic seasonal variation of this asymmetry with maxima close to December and minima in July-August is also present. All the errors involved in coronal optical measurements have been examined in a previous paper but none of them have been underlined as the possible cause of the east-west asymmetry. In such a case, the presence of this asymmetry should not be ignored while the reason for its existence should be studied, extensively. Two approximations to a possible explanation of the solar E-W asymmetries have been reported in the discussion section of this article. (C) 1997 Elsevier Science B.V