Clean Air

" These particles "worsen respiratory disease, such as emphysema and bronchitis, and aggravate existing heart disease." Moreover, while ozone, in and of itself is not carcinogenic, it can aggravate existing health conditions and lower natural defenses. A recent Sonoma study stated that reducing the NOx emissions in the Houston Galveston region would prevent 45 statistical deaths per year. .
             Critics of national standards argue that the statistical associations used to determine NOx and ozone health effects are weak. However, the Supreme Court clarified in its decision in American Trucking Associations v. EPA that the Clean Air Act is not required to "prove the biological mechanism." The court ruled that showing a statistical correlation is sufficient. In other words, the Clean Air Act requires the EPA to act with an adequate margin of safety. Causation is not a requirement and caution is the approach. In a ruling against the National Petrochemical and Refiners Association, the DC Court of Appeals stated that the EPA "must err on the side of caution" in deciding pollution levels. The EPA has the right to set "whatever level it deems necessary and sufficient to protect the public health with an adequate margin of safety, taking into account both the available evidence and the inevitable scientific uncertainties." .
             Secondary NOx concerns include its contributions to acid rain, deterioration of water quality, and atmospheric visibility. NOx, when reacting with sulfur dioxide forms acid rain, which deteriorates cars, buildings, trees and historical monuments. Acid rain also makes lakes acidic, killing fish and harming water sources. This is turn deteriorates water quality and affects the ecological balance. Along with these effects, the more conspicuous problem is visibility. Particles in NOx block light transmissions that reduce visibility. The ozone haze tends to depreciate land values and decrease the quality of life.