#ozone

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The scale, which runs from 0 to 500, was designed by the #EPA & measures the density of five different #pollutants in the #air: ground-level #ozone, #particulates, #CarbonMonoxide, #NitrogenDioxide & #SulfurDioxide. Several spots in northeastern Minnesota, closest to the fires recorded had AQI readings well into the “hazardous” range on Wednesday. #wildfires #PublicHealth #AirQuality #pollution #air #ExtremeWeather #ClimateChange #ClimateCrisis
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Over the past few years, the number of #satellite launches has skyrocketed. There are now nearly 15 000 active #satellites in orbit around the Earth, most of them part of mega-constellations in which each satellite has a service life of only a few years. New satellites must be quickly launched as replacements. To avoid leaving old, dead satellites in Earth’s already-crowded low orbits, most satellite operators deliberately de-orbit them into Earth’s upper atmosphere. That approach is now being taken to a vastly larger scale and there are implications for Earth’s #climate and #atmosphere. Rocket launches already contribute to climate change and #ozone depletion. Scaling them up to deploy a million aircraft-sized satellites would push upper-atmosphere heating and ozone loss far beyond previous estimates, with the steady burn-up of dead satellites compounding the impacts. This is just a fraction of what is to come if planned mega-constellations go ahead. Operators worldwide have already asked for a combined total of over one million satellites. The very smallest particles, finer than a human hair, can stay suspended in the atmosphere for years, contributing to ozone depletion and climate change. A million satellites could mean that a teragram of alumina accumulates in the upper atmosphere – enough, alongside launch emissions, to significantly alter atmospheric chemistry and heating in dramatic ways we do not yet understand. There is no public mandate for a single company in one country to make changes on that scale to the planet’s atmosphere. #space #astronomy
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