The high optical brightness of the BlueWalker 3 satellite.

Large constellations of bright artificial satellites in low Earth orbit pose significant challenges to ground-based astronomy. Current orbiting constellation satellites have brightnesses between apparent magnitudes 4 and 6, whereas in the near-infrared Ks band, they can reach magnitude 2 (ref. ).

Particulate air pollution and health effects for cardiovascular and respiratory causes in Temuco, Chile: a wood-smoke-polluted urban area.

Temuco is one of the most highly wood-smoke-polluted cities in the world. Its population in 2004 was 340,000 inhabitants with 1587 annual deaths, of which 24% were due to cardiovascular and 11% to respiratory causes. For hospital admissions, cardiovascular diseases represented 6% and respiratory diseases 13%.

Nutrients dynamics in the main river basins of the centre-southern region of Chile.

Chilean basins have long been exposed to nutrient discharges from human activities and land use changes. A historical seasonal NO(3)(-)-N and PO(4)(3-)-P database of the last 23 years of the main nine rivers of central-southern region of Chile was analysed. Generalized additive models indicated that annual trends in NO(3)(-)-N and PO(4)(3-)-P are nonlinear.

Health risk estimation due to carbon monoxide pollution at different spatial levels in Santiago, Chile.

The Metropolitan Region of Santiago has been declared as nonattainment area for carbon monoxide (CO). The data was based on seven air monitoring stations that do not necessarily represent the real population exposure. Usually, a series of coefficients that relates the concentration of pollutants with health effects (betas of the concentration-response equations) are used.

[Impact of air pollution by fine particulate matter (PM10) on daily mortality in Temuco, Chile].

Background: Temuco (304,000 inhabitants) has high levels of air pollution, mainly due to fine particulate matter of less than 10 microm (PM10). The effects of this pollution on population health have not been studied.

Aim: To study the short-term effects of PM10 on daily mortality in Temuco, in Southern Chile, due to respiratory and cardiovascular causes.

An environmental decision-making tool for evaluating ground-level ozone-related health effects.

A computer model called the Ozone Risk Assessment Model (ORAM) was developed to evaluate the health effects caused by ground-level ozone (O3) exposure. ORAM was coupled with the U.S.