Is your green home making you sick?
Although millions of American homes will get a lot greener in the next decade, there may be problems caused by energy efficient homes having less ventilation.
While that may bode well from an energy-efficiency standpoint, the trend certainly doesn’t have everyone breathing easier. “For every solution, there’s a problem,” said Nathan Rabinovitch, MD, an asthma specialist at National Jewish Health in Denver. “Energy efficiency is important, but at the same time, with the homes that we are building today, allergens getting into the house, are staying in the house.”
That includes things like smoke, mold, bacteria and pet dander. And for the nearly 26 million Americans who suffer from asthma, that’s causing a wide range of problems. “It used to be when homes were built, a lot of air would come out through the roof and through the windows,” said Dr. Rabinovitch, “but now we’ve become so efficient at sealing off those areas that everything is getting trapped inside the house, and that’s making a lot of people sick.”
Rabinovitch said the movement to build more energy-efficient homes began in the 1970s, after the nation’s first energy crisis. Since then, concerns about the environment and a downturn in the economy have all converged to make energy efficiency much more of a priority in the housing industry.
But something else happened during that same timeframe: asthma rates started going up. In fact, since 1970, the number of Americans who have asthma has nearly tripled.
That’s not a coincidence, says Dr. Rabinovitch. “The problem is, a lot of the air pollution in our home is actually in the carpet or on the soft furniture. If someone walks on the carpet or sits on the couch, they end up getting this kind of personal exposure,” he said, “and with little ventilation in homes today, that pollution has nowhere to go, so it settles into our lungs.”
Fabrics such as carpet and those found on furniture can contribute to the problem, even if they don't have any harmful chemicals in them when new. "Carpet absorbs everything around it and then slowly releases it, even when the chemicals are not originally in the carpet," said Charlene W. Bayer, Ph.D., principal research scientist at Georgia Tech and chief science officer Hygieia Science.
To see just how much air pollution we may be exposed to in our homes, Rabinovitch conducted a study in which he asked school children to carry air monitors with them for several weeks. Twenty-four hours a day, seven days a week, those monitors collected air samples in the children’s homes and as they walked to and from school. Samples were also collected as the children played outside, and as they studied in the classroom.
After analyzing the data, Dr. Rabinovitch found that air quality was worst where you might expect it least.
“For many of these kids, the amount of air pollution that they were being exposed to was often higher inside the home than outside the home,” he said.
But it’s not just natural allergens like mold and pollen that can trigger asthma attacks. Some of the biggest problems are caused by choices we make.
“Pet dander and cigarette smoke are probably two of the most dangerous triggers there are,” said Dr. Rabinovitch. “I always tell my patients that if there are smokers in the house or pets that are causing problems, those have to be addressed before anything else.”
Rabinovitch also offers some simple advice. “The best way to control indoor air pollution is to look outdoors,” he said. “Simply opening your windows more often will ventilate your house and will help dry out and clear out many of the things that could be making you sick.”
It’s a concept that raises a lot of eyebrows in this era of super energy-efficient homes. “Homes were built 50 years ago in a way where there was ventilation, so I don’t think it’s difficult to go back to that,” said Dr. Rabinovitch. “But the question is: How do we do that and at the same time keep our energy efficiency? We don’t want to solve one problem and then end up with another.”
To improve indoor air quality, the first step is to ensure there's a quality filter on the heating and cooling system. Also consider having the ducts cleaned and halting any contamination sources.
"If you have a dirty system it doesn’t matter what kind of a filter you have, said Jeffrey C. May, an indoor air quality investigator based in Tyngsborough, Mass. "You have to clean your system first before you install a high quality filter."
For more information, see our Indoor Air Quality Research Center.
Photo via Flickr/nikcname