High concentrations of energy use from fossil fuels can lead to poor air quality, resulting in adverse health effects as well as economic consequences. A prime example is found where large numbers of idling vehicles congregate (e.g., schools and hospital drop-off/pick-up zones), leading to microclimates of unhealthy air. Workers, such as valet parking attendants, can spend their entire workday in these microenvironments, and children passing through these zones can experience up to 60% higher levels of pollution than adults, because of their height.