THE MINIMAL LETHAL CONCENTRATION OF OZONE IN WATER WAS DETERMINED FOR THREE BACTERIAL SPECIES: Escherichia coli, Bacillus cereus, and Bacillus megaterium. A contact period of 5 min was selected. The lethal threshold concentration for the cells of B. cereus was 0.12 mg/liter while that for E. coli and B. megaterium was 0.19 mg/liter. Low concentrations of ozone were ineffective when organic matt...

Most studies on the effects of ambient ozone on asthmatics have been based on ozone concentration measurements taken by air monitors in downtown areas. Using a passive ozone sampler, we investigated the effects of on-site ozone concentrations on the pulmonary function and symptoms of asthmatics. Twenty moderate to severe asthmatics who had been managed for at least 2 months without changes of t...

It is well established that anthropogenic chlorine-containing chemicals contribute to ozone layer depletion. The successful implementation of the Montreal Protocol has led to reductions in the atmospheric concentration of many ozone-depleting gases, such as chlorofluorocarbons. As a consequence, stratospheric chlorine levels are declining and ozone is projected to return to levels observed pre-...

A spatio-temporal statistical model is proposed for 1to 24-hour-ahead prediction of hourly ozone concentrations. This is a joint work with the National Environmental Agency Singapore, and is Singapore’s first predictive model for ozone concentrations. Unlike many existing models which focus on either daily maximum or 8h average daylight ozone concentrations, the present work is concerned with t...

Passive samplers with two different collection substrates were used to obtain an average ozone concentration for 1 month during the summer of 2002 for each South Carolina county. One sampler contained a filter coated with indigo carmine, whose color fades when exposed to ozone. The fading was measured by reflectance spectroscopy. The other sampler contained filters that were coated with nitrite...

In an open-top chamber study in east Texas, ozone-sensitive loblolly pine (Pinus taedu L.) seedlings were treated with either the antioxidant Ozoban (74.5% sodium erythorbate active ingredient (a.i.)) at 0, 1030, or 2060 mg liter-’ or ethylenediurea (EDU 50% a.i.) at 0, 150, or 300 ppm every 2 weeks while being subjected to a range of ozone exposures beginning in April 1994. The ozone exposures...

High ground-level ozone concentrations are typical of Mediterranean climates. Plant exposure to this oxidant is known to reduce carbon assimilation. Ozone damage has been traditionally measured through manipulative experiments that do not consider long-term exposure and propagate large uncertainty by up-scaling leaf-level observations to ecosystem-level interpretations. We analyzed long-term co...

Ozone decomposition in the teflon pipe and its influence on the preciseness of experimental measurements has been studied. The ozone was produced by DC corona discharge fed by carbon dioxide. The ozone concentration has been measured by UV spectrometry method directly in the reactor and indirectly in the cell made of glass connected with the outlet of the reactor. It was found out that the diff...

BACKGROUND Airway responsiveness after acute inhalation of ozone is related to the concentration and duration of ozone exposure. Using barometric whole-body plethysmography and increase in enhanced pause (Penh) as an index of airway obstruction, we measured the response of BALB/c mice to acute ozone inhalation to study the time course change of pulmonary function after ozone exposure. METHODS...