The U. In many cases they are the products of the combustion of fossil fuels or industrial processes. The National Emissions Standards for Hazardous Air Pollutants cover many other chemicals, and require the maximum achievable reduction that the EPA determines is feasible. The six criteria air pollutants were the first set of pollutants recognized by the United States Environmental Protection Agency as needing standards on a national level. The primary standards are designed to protect the health of 'sensitive' populations such as asthmatics, children, and the elderly. The secondary standards are concerned with protecting the environment.
depletion of ozone layer Essay Examples
Ozone and caries: a review of the literature
The thinning is most pronounced in the polar regions, especially over Antarctica. The Montreal Protocol , ratified in , was the first of several comprehensive international agreements enacted to halt the production and use of ozone-depleting chemicals. As a result of continued international cooperation on this issue, the ozone layer is expected to recover over time. In Dutch chemist Paul Crutzen published a paper that described the major nitrogen oxide catalytic cycle affecting ozone levels. Crutzen demonstrated that nitrogen oxides can react with free oxygen atoms , thus slowing the creation of ozone O 3 , and can also decompose ozone into nitrogen dioxide NO 2 and oxygen gas O 2.
Health and Environmental Effects of Ozone Layer Depletion
Research article 15 Apr Correspondence : Apostolos Voulgarakis a. Interactions between aerosols and gases in the atmosphere have been the focus of an increasing number of studies in recent years. Here, we focus on aerosol effects on tropospheric ozone that involve meteorological feedbacks induced by aerosol—radiation interactions. Specifically, we study the effects that involve aerosol influences on the transport of gaseous pollutants and on atmospheric moisture, both of which can impact ozone chemistry.
When some people think of science, they think of formulas and facts to memorize. While this knowledge is an important part of science, it is not all of science. In addition to a body of knowledge that includes formulas and facts, science is a practice by which we pursue answers to questions that can be approached scientifically.