May 30 2019
A new study performed by scientists from the Columbia University Mailman School of Public Health and Drexel University states that New York City Clean Air Taxi rules are effective in lowering the emissions and air pollution.
(Credit: Columbia University Mailman School of Public Health)
From 2009 to 2015, the rule increased more than twice the fuel efficiency of the fleet of 13,500 yellow taxis, which resulted in the estimated declines in air pollution emissions. The study outcomes have been reported in the Journal of Exposure Science & Environmental Epidemiology.
The researchers reported that overall fuel efficiency of the medallion taxi fleet increased from 15.7 to 33.1 MPG, and the corresponding estimates of nitrous oxide and particulate exhaust emissions decreased by 82% and 49%, respectively. They also discovered that these reductions in emission were related to the decreases in the concentrations of the pollutants present in the city’s atmosphere.
With the introduction in 2006, Clean Air Taxi law ordered that approximately 9% of new medallions for yellow taxis be set apart for compressed or hybrid natural gas vehicles and encouraged people to switch to low-emission taxis by extending the permitted period of models categorized as “clean air” by the United States Environmental Protection Agency. A total of 100,000 for-hire vehicles such as Ubers and Lyfts in the city are not regulated by Clean Air Taxi laws as they are governed by separate laws and regulations.
The past decade has seen steady improvements in the quality of air in New York City, and clean-air taxis appear to be one contributing factor. This is good news for New Yorkers’ health since we know air pollution raises the risks of low birth weight and asthma in children.
Dustin Fry, MPH, Scientist, Dornsife School of Public Health, Drexel University
The scientists developed maps to determine the taxi traffic intensity throughout the city and used inspection and trip data to approximate taxi-related exhaust emissions of two important sources of air pollution, namely, particulate matter and nitric oxide. Later, using New York City Community Air Survey data collected from >100 monitoring sites across the city, they estimated the effect of these changes.
The greatest impact was in Manhattan neighborhoods with a high density of yellow taxis and not in low-income and outer borough areas with increased rates of respiratory disease. The authors explained that this discovery suggested that other policies are required to make meaningful progress in enhancing respiratory health.
This study provides evidence that air pollution legislation can have real impact. Even though overall, yellow taxis account for a small proportion of vehicular miles traveled on New York City’s streets, in midtown they account for almost half. Similar regulations targeting other vehicles could make an even bigger difference.
Frederica Perera, PhD, Study Co-author, Dornsife School of Public Health, Drexel University
Perera is also Professor of Environmental Health Sciences and Director of Translational Research at the Columbia Center for Children’s Environmental Health.
The additional authors of the study include Marianthi-Anna Kioumourtzoglou, Christian A. Treat, David Evans, Kimberly R. Burke, and Daniel Carrion at the Columbia Mailman School and Columbia University Irving Medical Center and Loni P. Tabb and Gina S. Lovasi at Dornsife School of Public Health, Drexel University.
The study was carried out together with the New York City Department of Health and Mental Hygiene and was financially supported by National Institute of Environmental Health Sciences (NIEHS) and the Environmental Protection Agency (P50ES09600), the NIEHS Center for Environmental Health in Northern Manhattan (P30ES009089), the John and Wendy Neu Family Foundation, and the Blanchette Hooker Rockefeller Foundation.