New research, funded by NASA, has highlighted the impact of large warehouse facilities in America on local air quality.
Building on previous research, which has highlighted emissions associated with individual warehouses, a team from George Washington University used satellite information from the European Space Agency to study nitrogen dioxide (NO2) around 150,000 large warehouses across the United States.
They also studied traffic information and demographic data supplied by the Federal Highway Administration and the US Census Bureau respectively.
When the world locked-down in 2020, the e-commerce industry was a major beneficiary as were the warehouses that service that industry.
Pointing out the immense scale of the transportation infrastructure needed to ship mail-order goods, the researchers cite the fact that in 2021, Amazon operated 175,000 delivery vans and more than 37,000 articulated lorries.
The team, lead by Gaige Kerr, an assistant research professor of environmental and occupational health at the George Washington University Milken Institute School of Public Health, were aware that warehouses tend not to be situated in prosperous areas and wanted to discover how much their presence added to the burden of already disadvantaged communities.
During this study they found, for example, that the proportion of Hispanic and Asian people living close to the largest clusters of warehouses is about 250% higher than the average nationwide.
This localised problem was exacerbated during the recent warehouse-building boom as the new, usually larger, warehouses that were built during this period were usually located in areas that already contained a large number of such buildings.
To illustrate this phenomena, 20% of all warehouses in the US are located in just 10 counties: Los Angeles, California; Harris, Texas; Cook, Illinois; Miami-Dade, Florida; Maricopa, Arizona; San Bernardino, California; Orange, California; Dallas, Texas; Alameda, California; and Cuyahoga, Ohio.
The research found a significant increase in NO2 levels around warehouses – on average 20% higher than would be expected. In reality, levels could be even higher as the satellite providing the data passes over the US in the early afternoon, whereas the highest levels of heavy-duty vehicle activity takes place in the mid-morning.
Gaige Kerr said: ‘Increased truck traffic to and from these recently built large warehouses means people living downwind are inhaling an increased amount of harmful nitrogen dioxide pollution. Communities of color are disproportionately affected because they often live in close proximity to warehouses, especially dense clusters of warehouses.’
The team say the new study highlights the need for regulations such as indirect source rules, incentives for replacing old trucks, and greater corporate commitments towards electrification.
Kerr adds: ‘Such measures would mean people living near warehouses could breathe cleaner air. In addition to a reduced risk of pollutant-related diseases, such measures would also reduce greenhouse gas emissions associated with climate change.’
The full research can be read here.