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TOAR shows present-day global ozone distribution and trends relevant to health; public database

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Ozone levels across much of North America and Europe dropped significantly between 2000 and 2014. People living in parts of southern Europe, South Korea and southern Japan and China also experienced more than 15 days a year of ozone levels above 70 ppb. Trends in daily maximum ozone levels (known as 4MDA8) at urban and non-urban sites.

Ozone 255
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Study finds pollution emitted near equator has biggest impact on global ozone

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They found that the increase in ozone burden due to the spatial distribution change slightly exceeds the combined influences of the increased emission magnitude and global methane. Based on their findings, they suggested that emission increases in Southeast, East and South Asia may be most important for the ozone change.

Ozone 230
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Study finds rising emissions of ozone-depleting CFC-11, banned by Montreal Protocol

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Emissions of one of the chemicals most responsible for the Antarctic ozone hole are on the rise, despite an international treaty that required an end to its production in 2010, a new study by researchers at NOAA and their colleagues shows. —NOAA scientist Stephen Montzka, lead author of the paper.

Ozone 170
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Study Links Springtime Ozone Increases Above Western North America to Emissions in Asia

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Springtime ozone distributions for 1984, 1995–2008 in the mid-troposphere (3.0–8.0 Springtime ozone levels above western North America are rising primarily due to air flowing eastward from the Pacific Ocean, a trend that is largest when the air originates in Asia. The US EPA recently proposed new tougher ground-level ozone standards.

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Researchers fully characterize reaction that affects ground-level ozone formation; a small but significant impact on predictive models

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The two combine in the atmosphere to make either nitric acid or peroxynitrous acid; the so-called branching ratio of these two chemicals is important in models of ozone production. This means less of the hydroxyl radical and nitrogen dioxide go away, leading to proportionately more ozone, mostly in polluted areas, Okumura said.

Ozone 210
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MECA report finds additional NOx emission reductions from new heavy-duty trucks achievable and cost-effective

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NO x is a precursor for both ground level ozone and secondary PM 2.5 The main conclusions of the report include: Compared to emission controls on MY 2010 US diesel trucks, today’s compact aftertreatment systems are 40% lighter, 60% smaller, and substantially less expensive.

Emissions 291
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UN report projects that increasing use of HFCs likely to have a significant climate impact by 2050; equivalent to current total annual emissions from transport

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The decrease in CO 2 equivalent emissions of ODSs (ozone-depleting substances: CFCs, halons, HCFCs, and others) may be offset by the projected increase in their non-ozone depleting substitutes (HFCs) (lines designated as HFC scenarios). Climate and the Ozone Layer. Source: UNEP. Click to enlarge.

Climate 287