Cloaked in the clouds of emissions and exhaust that hang over the city are clues about the polluting culprits.
A University of Houston (UH) research team, headed by Shankar Chellam, is hot on their trail. The case hinges on fine particulate matter, a mixture of organic, inorganic or metal material.
It is given off by natural sources such as sea spray and grassfires, and manmade sources like vehicles and factories, and then suspended in the air.
When the began six years ago, Chellam said the team was surprised that most research at the time focused on ozone, which is formed when emissions mix with sunlight. Much less attention was paid to airborne particulate matter.
“Most previous studies have been concerned with gases, particularly ozone,” Chellam explained.
“It is the particulate matter — both fine matter that is smaller than 2.5 micrometers, and coarse matter that is larger than 2.5 micrometers, but smaller than 10 micrometers — that we are interested in.”
Chellam said identifying pollution sources — even if only by industry or machine type, rather than individual factory or operator — is a public safety issue, because fine particulate matter is easily absorbed by the lungs and enters the bloodstream.
“Studies show that people living close to highways and refineries are more likely to become seriously ill,” he said.