Green

from High-Profile: September 2022

Corporate

Mitigating the Urban Heat Island Effect in Chelsea

By Tim Corrigan

According to data from the CDC, each year in the U.S. there are on average over 700 deaths, 900 hospitalizations, and 67,000 emergency room visits due to heat. The problem is exacerbated in dense urban areas that are predominantly impervious surfaces with very few trees for shade and cooling. In fact, there can be as much as an 18-degree temperature difference between shaded areas and areas in full sunlight.

An urban heat island (UHI) effect occurs when dense, urban areas with high concentrations of impervious surfaces amplify ambient air temperatures in comparison to surrounding, less developed areas. The major causes of the UHI effect include release of heat from equipment, lack of vegetation, and increased heat absorption by materials like asphalt.

The City of Chelsea, advocacy group GreenRoots, and Weston & Sampson used funding from the Massachusetts Municipal Vulnerability Preparedness (MVP) program to study the UHI effect in Chelsea, Mass., the second most densely populated city in the state and an environmental justice community. This status indicates that residents are disproportionately more vulnerable to environmental conditions such as extreme heat due to several socioeconomic factors.

Urban heat island mitigation techniques can include roadway reconstruction using light-colored aggregates, reflective surface treatments, reducing impervious cover, green infrastructure, and extensive tree plantings.

An urban heat island effect occurs when dense, urban areas with high concentrations of impervious surfaces amplify ambient air temperatures in comparison to surrounding, less developed areas.

Nine “hot spot” areas were identified and categorized into “existing hot spots” and “emerging hot spots.” Based on the type of land cover and social vulnerability index, three out of the nine were selected as potential candidate areas to prioritize. The project team then determined one site, centered around the local Boys & Girls Club, as a “cool block” project area to implement pilot UHI mitigation strategies.

In this area, the heat model determined that a reduction of impervious surface by 25% will reduce the ambient air temperature by up to 3.0° F on a 95-degree day. An increase of tree canopy area to 30% will result in up to a 3.5° F reduction in ambient air temperature as well.

The goal is to pilot various UHI mitigation strategies to inform future infrastructure project capital planning while also improving neighborhood roadway surface condition, local drainage, and pedestrian safety. The pilot design included reflective roof coatings, reconstruction of roads with light colored aggregate pavements, blast treatment of roadway pavement to reveal lighter-colored aggregates, replacement of asphalt sidewalks with concrete, rainwater infiltration swales, and installation of numerous shade trees for canopy.

Installation of these improvements began this past spring and summer and the city is pursuing partnerships with private owners for pilot retrofits of mid-lifecycle synthetic rubber roofs. The project also involved placing a series of sensors in strategic areas to measure actual changes in air temperature, relative humidity, and dew point during pre- and post-project periods. The project is expected to serve as a proof-of-concept in Chelsea and in other areas and for modeling urban heat, identifying heat mitigation strategies, and testing and implementing new strategies.

Tim Corrigan, PE is a team leader at Weston & Sampson.

The Chelsea UHI project will serve as a proof-of-concept in Chelsea and other areas for modeling urban heat and identifying, testing, and implementing new mitigation strategies.

Dacon Completes Kula Bio HQ

Kula Bio HQ Natick, MA – Dacon Corporation has completed construction on the headquarters for Kula Bio, relocating to Natick from Cambridge. A 4-year-old startup positioned within the agricultural solutions market, Kula Bio’s goal is to increase crop yield and reduce environmental impact through sustainable nitrogen fertilizers.

Kula Bio’s product, Kula-N, is a biofertilizer densely populated with nongenetically modified bacteria fortified to carry large stores of energy and nutrients into the soil. The product’s raison d’etre is focused on increasing yield and soil quality, thereby optimizing food production for agricultural enterprises. The headquarters is comprised of four research spaces surrounded by executive offices and common areas. To support these labs, a dedicated mechanical room was built to house compressed air, DI water system, autoclaves and a UV sterilizer.

CEO Bill Brady said, “Over 90% of fertilizer in use is still synthetic and a significant contributor to global greenhouse gas emissions and damage to local water supplies and land.” Kula-N addresses two factors often blocking sustainable solutions: accessibility and affordability. In January, the firm received a $50 million investment led by Lowercarbon Capital that will be used to build manufacturing facilities near key agricultural producers. In recognition of Kula Bio and its groundbreaking work, Dacon’s Designed with Dignity philanthropy is funding a garden therapy program by Massachusetts Horticultural Society (MHS) for senior residents at nonprofit assisted living community, Carmel Terrace. Residents will learn about pollinators, flower arranging, house plants and healthy plant care. Karen Daubmann, director of garden and programs for MHS, said, “Our mission (Commune Bonum – For the Common Good) has helped people and communities change lives for the better through growing plants for 192 years. This program is a great match between our goal of working with senior populations and a community need. We look forward to a productive and fun program.”