Studies of ozone effects on conifers and the formation of oxides of Nitrogen during ozone generation : Air Pollution and Forest Decline. 14th International Meeting for Specialists in Air Pollution Effects on Forest Ecosystems

1989

5 Abb., 20 Lit. Ang., En, Zfsg. En, Fr

Unselbständiges Werk

9091

200034669

Experiments are in progress at the Central Electricity Research Laboratories, Leatherhead, UK to investigate the effects environmental factors on conifer. An constructed to expose trees of Picea abies, Picea sitchensis and Pinus sylvestris to controlled concentrations of S02 and 03 oer hemispherical glasshouse chembers habe also been constructed to examine the effects of 03, acid mists and soil nitritional status on P. abies, Abies alba and Fagus sylvatica. Past fimigation experiments on acid leaching of foliar nutrients have revealed increases in the leachable Mg, Ca, Zn, Mn, Na, NH4 and NO3 from needles of P. abies exposed to 03 generated rom an electric discharge ozonator. Susch ozonators also produce N2O5 and HNO3 when operated using air. An experiment in which ozonated air was bubbled through water before fumigation resulted in no NO3 accumulation in the foliage and no significant increases in the amount of leaching of cations fom spruce needles may have been at least partly due to the effects of N205 and HNO3. Other effects, including visivle symptoms, enhanced frost sensitivity, growth stimulation and changes in pest or pathogen response which have been attributed to =3 generated by electric discharge in air must be interpreted with caution. Future experiments should use ozonators operating on pure 02 or use purification methods to remove the N2O5 and HNO3 from the ozonated air.