Outdoor air quality has improved since the 1990s, but many challenges remain in protecting Americans from air quality problems. Ground-level ozone, the main part of smog, and particle pollution are just two of the many threats to air quality and public health in the United States.
- Traffic-related air pollution is highest near major roads. In 2010, 5.0% of Hispanics, 5.4% of Asians/Pacific Islanders, and 5.1% of foreign-born persons lived within 150 meters of a major highway (vs. 3.7% of the overall US population).
- Exposure to traffic-related air pollution leads to asthma attacks and may lead to onset of childhood asthma, other respiratory symptoms, and cardiovascular disease and death.
- Improved access to alternative transportation, financial incentives to reduce traffic, diesel retrofitting, and other measures could help reduce exposure to traffic emissions.