The adverse health effects of ozone (O3) and nitrogen dioxide (NO2) have been known for decades. The Clean Air Act was established in 1963, but ambient a quality was not regulated until 1970, and by 1971 EPA had established one hour National Ambient Air Quality Standard (NAAQS) of 0.08 ppm for both O3 and nitrogen dioxide. Nitrogen dioxide and ozone are two of the major outdoor ambient chemical pollutants affecting asthmatics. In addition, nitrogen dioxide plays a role in formation of acid rain, contributes to global warming, and hampers the growth of plants. Ground-level ozone interferes with a plant's ability to manufacture (photosynthesize) and store food, and lowers plant resistance to disease.
Just when we think that we are getting a handle on the entire criminal record of these two compounds, scientists from the University of California, Irvine have linked them to another environmental and health outlaw, lead (Pb). In an abstract published in Environ. Sci. Technology, October 14, 2009 (article ASAP) R. D. Edwards, N. L. Lam, L. Zhang, M. A. Johnson and M. T. Kleinman from the School of Medicine, University of California, Irvine reported that nitrogen dioxide (NO2) and ozone (O3) from vehicles emissions react with surfaces painted with lead based paint and increase the release of lead. According to Edwards, paint is made of two basic components: pigment granules and an unsaturated polymeric binder that holds them together. O3 and NO2 typically react with unsaturated compounds. Edwards and colleagues suspected that this characteristic might make lead pigment granules become deposited in house dust or be more available to children's hands in urban environments where O3 and NO2 are frequently in high concentration.
The researchers coated stainless steel with a thin layer of lead based paint and exposed them to NO2 and O3. They then evaluated the coated surfaces using reflectometry and scanning electron microscopy. They also wiped the surfaces and calculated the amount of lead on the wipes. Edwards and his colleagues reported that NO2 and O3 changed the surfaces' morphology and significantly increased the amount of lead that can were wiped off them.
The results of this research suggests that a lot more emphasis must be placed on eliminating lead based paint from the urban environment and lowering the emission of O3 and NO2 in American cities that are still remediating old buildings and in developing nations where lead based paint is still being sold.
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Roberta Barbalace. Nitrogen Dioxide, Ozone & Lead Partner to Increase Pollution Dangers to Urban Children. EnvironmentalChemistry.com. Dec. 3, 2009. Accessed on-line: 10/20/2020