Ozone exposure affects tree defoliation in a continental climate.

Ground-level ozone (O3) affects trees through visible leaf injury, accelerating leaf senescence, declining foliar chlorophyll content, photosynthetic activity, growth, carbon sequestration, predisposing to pests attack and a variety of other physiological effects. Tree crown defoliation is one of the most important parameters that is representative of forest health and vitality. Effects of air pollution on forests have been investigated through manipulative experiments that are not representative of the real environmental conditions observed in the field. In this work we investigated the role of O3 concentration and other metrics (AOT40 and POD0) in affecting crown defoliation in temperate Romanian forests. The impacts of O3 were estimated in combination with nitrogen pollutants, climatic factors and orographic conditions, by applying a non-linear modelling approach (Random Forest and Generalised Regression Models). Ozone concentration and AOT40 under Romanian conditions were more important than meteorological parameters in affecting crown defoliation. In these particular conditions, POD0 never exceeded the critical level suggested by previous literature for forest protection, and thus was not important in affecting crown defoliation.

Risk of bronchi obstruction among non-smokers--review of environmental factors affecting bronchoconstriction.

In order to find relationship between exposure to traffic and traffic-related air pollutants, pulmonary function tests and a detailed questionnaire were conducted among 3997 selected inhabitants of Warsaw (Poland) and 988 residents of rural areas. Advanced statistical analyses (including GRM models, correspondence analysis and parametrical tests) have been completed. Statistically significant differences between average percentages of predicted values of pulmonary function parameters were found. Among urban area inhabitants the values of FEV1, MEF50 and FEV1/FVC were statistically significant (p<0.05) lower compared with the residents of rural areas (in the non-smoking group this differences were strong (p<0.001)). General linear regression models indicated that residence in the vicinity of urban busy roads fosters a decrease of spirometric parameters. Physical activity however has a positive effect on pulmonary function (exemplified by FEV1) and allows to reduce part of the negative health effects of traffic-related emissions. The results of the presented study demonstrate that long-term residence under the influence of heavy traffic and high concentrations of traffic-related air pollutants reduces respiratory function parameters, which may result in increased bronchial hyperresponsiveness.

Future impacts of nitrogen deposition and climate change scenarios on forest crown defoliation.

Defoliation is an indicator for forest health in response to several stressors including air pollutants, and one of the most important parameters monitored in the International Cooperative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests). The study aims to estimate crown defoliation in 2030, under three climate and one nitrogen deposition scenarios, based on evaluation of the most important factors (meteorological, nitrogen deposition and chemical soil parameters) affecting defoliation of twelve European tree species. The combination of favourable climate and nitrogen fertilization in the more adaptive species induces a generalized decrease of defoliation. On the other hand, severe climate change and drought are main causes of increase in defoliation in Quercus ilex and Fagus sylvatica, especially in Mediterranean area. Our results provide information on regional distribution of future defoliation, an important knowledge for identifying policies to counteract negative impacts of climate change and air pollution.