Those who live in a particularly smoggy city in the US are able to see the pollution that surrounds them on a daily basis. But a recent study from the Massachusetts Institute of Technology (MIT) reveals that people who live in all types of environments are at risk of pollution-related death.
The study, published in the journal Atmospheric Environment, saw a team from MIT's Laboratory for Aviation and the Environment track emissions from sources including industrial smokestacks, automobile tailpipes, marine and rail activities, and heating systems around the US.
In order to ascertain how many early deaths are a result of air pollution, the researchers used emissions data from the Environmental Protection Agency's National Emissions Inventory, which is a catalog of emissions sources.
They used data from 2005, which was the most recent information available at the start of the study, and then divided it into six emissions sectors:
- Electric power generation
- Commercial and residential sources
- Road transportation
- Marine transportation
- Rail transportation.
Results show that in total, air pollution causes about 200,000 early deaths each year, with the greatest number coming from the roads - exhaust from automobile tailpipes was linked to 53,000 deaths per year.
Steven Barrett, assistant professor of Aeronautics and Astronautics at MIT, says:
"It was surprising to me just how significant road transportation was, especially when you imagine [that] coal-fired power stations are burning relatively dirty fuel."
One reason the researchers give for this finding is that vehicles are dense in likewise densely populated areas - which could increase the pollution exposure for large populations - whereas power plants are usually situated far from dense populations, and their emissions get deposited at a higher altitude.
Barrett says that a person whose death is pollution-related dies on average 10 years earlier than he or she otherwise would have.
Pollution by state and city
Residents of Baltimore, MD, face the highest early emissions-related death rates.
When the MIT team analyzed the data on a state-by-state basis, they found that California's residents have the worst exposure to air pollution, yielding about 21,000 premature deaths each year.
These deaths are mostly related to road transportation and emissions from both residential and commercial heating and cooking.
After mapping emissions in 5,695 cities across the US, the team found that Baltimore has the highest pollution-related mortality rate. In a given year, 130 out of every 100,000 residents will most likely die as a result of air pollution exposure.
Following closely behind automobile pollution, electricity generation emissions accounted for 52,000 early deaths each year.
The researchers note that the largest impact for deaths related to this type of pollution occurred in the east-central US and in the Midwest. They suggest a reason for this may be that Eastern power plants use coal with higher sulfur content than Western plants.
But the West Coast definitely did not escape health impacts. In Southern California alone, for example, marine-derived pollution from shipping and port activities accounted for 3,500 early deaths.
"In the past 5 to 10 years, the evidence linking air-pollution exposure to risk of early death has really solidified and gained scientific and political traction.
There's a realization that air pollution is a major problem in any city, and there's a desire to do something about it."
He notes that although the study is based on numbers from 2005, the results most likely represent today's pollution health risks.
Medical News Today recently reported that even low levels of air pollution can cause lung cancer.