Ozone vegetables

Soriano, N. U., Migo, V. P, Sato, K., and Matsumura, M. 2005. Crystallization Behavior of Neat Biodiesel and Biodiesel Treated With Ozonized Vegetable Oil. Eur. J. Lipid Sci. Technol., 107, 689-696. 

Although it does not physically explain the nature of the removal process, deposition velocity has been used to account for removal due to impaction with vegetation near the surface or for chemical reactions with the surface. McMahon and Denison (12) gave many deposition velocities in their review paper. Examples (in cm s ) are sulfur dioxide, 0.5-1.2 ozone, 0.1-2.0 iodine, 0.7-2.8 and carbon dioxide, negligible. 

For any pollutant, air quality criteria may refer to different types of effects. For example. Tables 22-1 through 22-6 list effects on humans, animals, vegetation, materials, and the atmosphere caused by various exposures to sulfur dioxide, particulate matter, nitrogen dioxide, carbon monoxide, ozone, and lead. These data are from fhe Air Quality Criteria for these pollutants published by the U.S. Environmental Protection Agency. 

Taha, H. (1996). Modeling the Impacts of Increased Urban Vegetation on the Ozone Air Quality in the South Coast Air Basin. Atmospheric Environment 3(1 20) 3423—3430. 

However, ozone may have some undesirable effects. There have been a few reports of changes in aroma and surface colour of some fruits and vegetables (Kim etal., 1999 Perez etal., 1999). Ozone can also be hazardous to humans. A concentration above 0.1 ppm in air has a strong odour that causes irritation of the nose, throat and skin (Sharma, 2005). In addition, long-term exposure to the gas may lead to mutagenic effects and even death. 

Sharma, R. (2005) Ozone decontamination of fresh fruit and vegetables , in Jongen, W., Improving the Safety of Fresh Fruit and Vegetables, Woodhead Publishing, Cambridge, 373-386. 

Nitriles have good resistance to oil, aliphatic and aromatic hydrocarbons and vegetable oils, but are swollen by polar solvents such as ketones. The unsaturated main chain means that protection against oxygen, ozone and UV light is required. 

The planned directive to limit volatile organic compound (VOC) emissions from solvents has experienced a major step forward on its way to being implemented. The Council of European Environment Ministers was united on a common position regarding the draft directive. Provisions for VOC emissions are reviewed up to 2010. Sources of VOC emissions are discussed including fossil fuels and vegetation, as well as VOC contact with soil particles and sunlight, and ozone implications. 

Organic aerosols formed by gas-phase photochemical reactions of hydrocarbons, ozone, and nitrogen oxides have been identified recently in both urban and rural atmospheres. Aliphatic organic nitrates, such dicarboxylic acids as adipic and glutaric acids, carboxylic acids derived from aromatic hydrocarbons (benzoic and phenylacetic acids) and from terpenes emitted by vegetation, such as pinonic acid from a pinene, have been identified. The most important contribution in this held has been that of Schuetzle et al., who used computer-controlled... 

When a monitoring site is selected, it is important to take account of environmental features. For example, ozone measured in or near automotive traffic can drop to 50% of the areawide value, owing to reaction with the nitric oxide firom exhaust emission. Ozone measured 7.5 m from a large tree in green leaf can drop to 70% of the areawide value, but it may also be reduced within 1 m of shrubs and grass. Paint, asphalt, concrete, dry soil, and dead vegetation are not as reactive and so have less effect. Peak ozone values observed in sunlit windscreened. 

This includes data obtained from laboratory studies of chemical reactions, plant and material damage, and animal and human toxicology from field studies of air quality and vegetation and ecosystem effects and from population exposures. In all such studies, irrespective of the method used, the measurement of oxidants is based on a standardized source of ozone. 

A number of reviews of varied quality cover general or special effects of photochemical oxidants on vegetation (Table 11-1). Thomas fairly comprehensively covered the available information on the effects of photochemical oxidants on plants. Middleton gave the first comprehensive coverage of the phytotoxic effects of photochemical oxidants in 1961. A number of excellent reviews have appeared since 1%1. Rich presented an early review of ozone effects. Dugger and associates presented the physiologic and biochemical effects of oxidants on plants. Heck covered factors that influenced the expression of oxidant dam-... 

An important factor in the response of vegetation to oxidants (primarily ozone) is the presence of biotic pathogens. Such responses have been studied from several perspectives since Yarwood and Middleton accidentally found that rust-infected bean leaves were less sensitive to photochemical oxidants (probably PAN). Several investigators have looked at the protection from ozone injury afforded to plants with active infections others have noted that ozone injury increases the sensitivity of plants to... 

TABLE 11-23 Ozone Concentrations for Short-Term Exposures that Produce 5% or 20% Injury to Vegetation Grown under Sensitive Conditions ... 

Heck and Brandt discussed the effectiveness of green belts in relation to vegetation as a pollutant sink and concluded that vegetation probably acts as a major sink for air pollutants, including oxidants and ozone, over time, but has a relatively minor effect on oxidant concentrations during high-pollution episodes is more effective in some seasons than others or with some cultural and management practices than others and should not be considered an important contributor to short-term reductions in oxidant or ozone concentrations. 

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