New research suggests airborne pollutants are just as prevalent and toxic as those contained in sediment depositis in homes flooded by Hurricane Katrina in 2005.
Using existing data, researchers from Louisiana State University in Baton Rouge conducted a modelling study to determine the level of air contamination in flooded homes following the devastation of Katrina.
In the study published in the April issue of the peer-reviewed journal Environmental Engineering Science the researchers, led by Nicholas Ashley, suggest that indoor gases, mold, and aerosols may have exposed residents, emergency workers, and demolition crews to dangerous contaminant levels without the need for direct skin contact.
The journal article describes the possible types and levels of volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) that might have been, and likely still are, present inside the flooded homes. These are exactly the types of chemicals which are thought to cause multiple chemical sensitivity (MCS) and sick building syndrome, and to trigger symptoms in these conditions.
Multiple chemical sensitivity is a debilitating condition in which sufferers experience a wide range of symptoms from neurological dysfunction, respiratory symptoms, fatigue, and aches and pains when exposed to a minute amounts of airborne chemicals (VOCs/SVOCs). The condition typically presents after an acute exposure to such chemicals or chronic exposure to lower concentrations. In many cases neurological damage/dysfunction can be demonstrated on SPECT scans.
Sick building syndrome is a condition in which an individual experiences symptoms when inside a specific building but is generally fine when away from it. Symptoms in sick buildings can be caused by VOCs/SVOCs, mold, other pathogens, temperature and humidity levels etc.
Ashley and colleagues at Louisiana State University believe polluted sediment remained in homes after the flood waters had been pumped out and that the pollution can become airborne.
They say: "Because the houses sat unoccupied for weeks and months after the storm, volatile and semivolatile sediment pollutants partition into the vapor space inside the home, where they present a gas-phase exposure to persons entering the home."
In other words, anyone entering or living in the homes is exposed to harmful VOCs and SVOCs.
The researchers specifically mention in their paper pollutants including polycyclic aromatic hydrocarbons (PAH), pesticides and phthalates, which are plasticizers and have received much publicity lately over safety concerns. They also mention aldehydes and organic acids as contributors to the airborne contaminants inside the flooded houses.
Also identified in the study was the major role that mold growth can play in total indoor pollution levels. The warm, damp conditions inside the flooded homes led to the growth of mold on walls, furniture, and other interior surfaces, which the researchers believe may have absorbed contaminant gases. This mold growth then emits contaminated spores and re-emits the VOCs/SVOCs back into the air.
The role of mold in contributing to indoor air pollution levels in Katrina affected homes is being seen as a breakthrough finding of the study as data in this area is currently lacking. The researchers say that assessments that only consider direct airborne pollutants in homes may be underestimating the total pollution residents are exposed to through other routes such as mold.
As well as multiple chemical sensitivity the US Federal Emergency Management Agency warns that exposure to mold can cause respiratory tract infections, especially for infants, children, immune-compromised patients, pregnant women, the elderly and individuals with existing respiratory conditions, allergies, and asthma.
Learn more about multiple chemical sensitivity (MCS)