Comprehensive studies by the New York City Department of Environmental Conservation have shown that major air pollutants, including fine particles (PM2.5), elemental/black carbon (EC), oxides of nitrogen (NOx), sulfur dioxide (SO2), and ozone (O3) vary more than 200% across New York City. These roadside studies show that higher concentrations occur in areas where fuel combustion sources, especially emissions from buildings and on-road vehicles, are more abundant. Research has linked these pollutants to adverse health effects, especially in individuals with respiratory or cardiovascular conditions. The reported data refers to the average emissions over 2-week periods of time. It is expected that measurements with higher temporal resolution will reveal that traffic congestion generates significantly higher pollution levels.

We propose a study to quantify the effect of traffic congestion on air pollution, focusing on the midtown area of Manhattan. Drawing from resources available from the NYCDOT Midtown In Motion (MIM) program and making use of advanced technologies for real-time monitoring of air pollution, we will assess the impact of traffic congestion on air quality and quantify the actual exposure levels to pedestrians. The study is designed in such a way that variations in air pollutants caused by motor vehicles will be quantified at high temporal resolution. This study will account for the speed variability in stop-and-go operations under congested conditions and will therefore result in a more accurate measure of air pollutant emissions from congested traffic flow.

In Phase I of the study, a complete stationary air quality monitoring system will be installed on Madison Avenue. A portable unit will also be placed in the space. In parallel, we will draw from real-time traffic congestion metrics, namely speed, density, and volume. Results of the Phase I study, including a comparative assessment of the stationary and portable systems exposed to actual street level conditions, will be used as guide for Phase II.

Phase II of the study will employ approximately 20 portable air quality monitors, which will be equipped to measure nitrogen dioxide, nitric oxide, ozone, carbon dioxide, and PM2.5, in addition to solar irradiance, temperature, relative humidity, wind direction, and wind speed. The units will be mounted on lamp poles and powered by batteries, solar cells, or municipal electric power. Measured data will be captured at approximately 5-minute intervals and either communicated via wireless signal or logged onboard for periodic download. Additionally, the data from the above measurements will be compared against data from New York State’s long-term monitoring stations in order to compare air quality parameters measured at the meso level to those measured at street level.