Downtown Rated as Exceptional for Plazas, Okay for Noise, and Among the Worst for Air Pollution and Flood Risk
Spatial Equity NYC, an online database that analyzes how environmental benefits and burdens are shared across various communities in the five boroughs, gives Lower Manhattan failing grades in four categories, passing marks in seven, and cites the community as an exceptional location by several other criteria.
Lower Manhattan (defined here as south of a line traced by Canal, Baxter, and Pearl Streets and the Brooklyn Bridge) faces four serious challenges, according to Spatial Equity NYC, which parses data from the U.S. Census, along with other sources.
Spatial Equity ranks Downtown last among all 59 Community Boards for permeable surface area, a reference to materials such as porous asphalt, along with soil and gravel, that allow storm water to seep into the ground, which can lessen flooding risk, reduce runoff, filter pollutants, and ease the burden on drainage infrastructure. This measurement does not include the use of such surfaces by the Battery Park City Authority (which is managed by the State, rather than City Hall), in its resilience projects. Permeable surfaces have been utilized, for example, at Wagner Park and the ballfields.
Community leaders would like to see permeable surfaces across all of Lower Manhattan. “The absence of permeable surfaces is striking and unacceptable in a flood-prone district,” remarked Alice Blank, the chair of the Environmental Protection Committee of Community Board 1, as well as the Board’s vice chair. “Retrofitting our streets with green infrastructure including permeable paving, bioswales, and expanded tree pits, needs to move from pilot projects to standard practice, especially as climate risks accelerate.”
In a related measure, Lower Manhattan ranks fourth worst among all Community Boards for flood risk, with one out of five residents living in a flood plain. Downtown also ranks 50th out of 59 Community Boards for tree canopy cover, with just 14.9 percent of the local streetscape shaded.
“The relatively low tree canopy is not just an aesthetic issue, it’s a public health and climate issue,” Ms. Blank said. “Expanding shade coverage should be treated as critical infrastructure, particularly in areas with high heat exposure and dense pedestrian use.”
In another worrisome indicator, Community Board 1 has the sixth-worst air pollution anywhere in New York City, as measured by the local benchmark for tracking fine particulate matter, defined as inhalable particles that are 2.5 micrometers or smaller (about one-thirtieth the diameter of a strand of human hair). These particles (labeled PM2.5, and quantified as micrograms per cubic meter) are known to travel into the deeper parts of the lung, where they are associated with tissue damage, inflammation, and cancer. Downtown ranks sixth in PM2.5 exposure, with 8.06 micrograms per cubic meter.
“Air quality is another urgent concern,” Ms. Blank said, “With some of the highest PM2.5 levels in the City, we need more aggressive measures to reduce vehicle emissions in Lower Manhattan, including congestion reduction, electrification of freight and last-mile delivery, and stronger enforcement against idling.”
The local community scores closer to the middle of the bell curve in seven categories: traffic injuries (11th best citywide, with 22.7 serious injuries per 10,000 residents); traffic volume (12th best, with 116.3 million vehicles miles travelled annually within each square mile of the community); bike lanes (13th, with 6.43 percent of street miles featuring protected bike easement); sidewalks (13th, with 33.2 percent of street space given to walking space); noise pollution (17th, with ambient levels of noise at 54.6 average decibels, roughly equivalent to a running dishwasher); public seating (22nd, with 4.24 city benches per 10,000 residents); and bus speeds (37th, with an average pace of 6.99 miles per hour).
Lower Manhattan ranks in the top ten communities by these yardsticks: traffic fatalities (the best, city-wide, with just 0.85 deaths per 10,000 residents); exposure to extreme heat (third, with an average summer surface temperature of 94 degrees Fahrenheit); pedestrian plazas (fifth, with 64.6 percent of residents living within half a mile of an outdoor plaza); the prevalence of childhood asthma (fifth, with 36.7 asthma-related child emergency room visits per 10,000 residents); the availability of bike parking (sixth, with 388.1 local spaces per 10,000 residents); and bus lanes (ninth, with 4.57 percent of local street miles containing a segregated lane for mass transit).
Spatial Equity NYC is a research project of the cycling and pedestrian safety advocacy group Transportation Alternatives.