Previous standards, which remain in force, allow ozone concentrations to reach twelve-hundredths of a part per million, and do not regulate soot less than 10 microns across.
42.
Starting now, the hole's surface decreases in size because it is filled up by middle latitude air with higher ozone concentrations _ until Antartic's next spring season.
43.
European researchers last year discovered that ozone concentrations over the Northern Hemisphere during the winter of 1995-96 reached record lows, sometimes dipping to 64 percent of normal levels.
44.
Trees should not be labeled as polluters because their total benefits on air quality and emissions reduction far outweigh the possible consequences of BVOC emissions on ozone concentrations.
45.
Then, in 1985, British Antarctic Survey scientists Joe Farman, Brian Gardiner and Jonathan Shanklin published results of abnormally low ozone concentrations above Halley Bay near the South Pole.
46.
The ozone layer contains less than 10 parts per million of ozone, while the average ozone concentration in Earth's atmosphere as a whole is about 3 parts per million.
47.
Starting now, the hole's surface decreases in size because it is filled up by middle latitude air with higher ozone concentrations _ until Antartic's next spring season . ( eo)
48.
Environment Minister Angela Merkel boasted that Germany is " the first nation in the world where extensive driving bans will be automatically imposed when ozone concentrations are especially high ."
49.
Heavily ozone-depleted air from the Arctic region settled over England about a month ago, dropping ozone concentrations below 200 Dobson Units for the first time in 17 years of measurement.
50.
The higher the outdoor ventilation rate, the higher the indoor ozone concentration and the more likely the reactions will occur, but even at low levels, the reactions will take place.
