What do Houston, Los Angeles, New York and Chicago have in common? The answer is dense population, high traffic volume and air quality that fails to meet ozone standards set by the U.S. Environmental Protection Agency. Those circumstances made each city a prime candidate for a University of Houston study assessing the impact of vehicle electrification on air quality and public health. What do Houston, Los Angeles, New York and Chicago have in common? The answer is dense population, high traffic volume and air quality that fails to meet ozone standards set by the U.S. Environmental Protection Agency. Those circumstances made each city a prime candidate for a University of Houston study assessing the impact of vehicle electrification on air quality and public health. Environment Phys.org – latest science and technology news stories