It takes a hot, calm and sunny summer day and enough of two other common air pollutants to cook up a high-ozone day. Along with industrial and area sources, gasoline-powered vehicles are one of the largest sources of VOC pollutants in most urban areas, including St. Louis. Almost anything that burns produces quantities of NOx. Because so many heavy-duty diesel vehicles are involved in interstate transport, their emissions can be more effectively monitored and regulated by federal controls on diesel engine emissions and the quality of diesel fuel. High concentrations of ground-level ozone can cause shortness of breath, coughing, wheezing, headaches, nausea and eye and throat irritation.
Studies show that even healthy adults can experience decreased lung function when exposed to ozone.
Fuchs also explains that people who suffer from lung diseases like emphysema, bronchitis, pneumonia, asthma and even the common cold have even more trouble breathing when the air is polluted. These effects can be worse in children, the elderly, exercising adults and those who spend extended periods of time outdoors like police or construction workers. Getting control of the St. Louis ozone problem involves cutting down the emissions of many major and minor sources of harmful NOx and VOCs. The Gateway Clean Air Program's testing technology is the best available to test most gasoline-powered vehicles. Diesels are not tested because they are exempt.