SCIENCE / MEDICINE : Ozone Levels Doubled in 100 Years, Experts Say

The concentration of harmful ozone pollution in the lower atmosphere has more than doubled in the last 100 years, and it will likely rise at an even faster rate in the next 30 years, researchers said last week.

Researchers from Britain’s Harwell Laboratory said recent measurements of ground-level ozone indicate that levels of the gas are, on the average, twice as high as recorded by French researchers in Paris in the late 1800s.

When it is in the upper atmosphere, ozone shields Earth from the sun’s ultraviolet rays, which can cause skin cancer and other health problems. But when found near ground level, the highly corrosive form of oxygen can cause respiratory distress.

Ozone is not emitted directly into the air, but is formed through complex reactions with nitrogen oxide and other chemicals found in automobile and industrial emissions containing nitrogen oxide.

Based on projected increases in nitrogen oxide emissions, researchers said their computer simulations show that between now and 2020, concentrations of ground-level or, “tropospheric,” ozone will rise “at a rate faster than during the past 100 years.” In fact, the study, in the journal Nature, found the increase in tropospheric ozone during the next 30 years could equal that for the entire last century.