The causes of ADHD can come from the most unlikely sources. A groundbreaking new study published in the American Journal of Epidemiology shows that preschool children who had more gas appliances at home had lower cognitive abilities and are more likely to have ADHD symptoms than their peers. The relationship seems strange, until you realize that gas appliances can be a source of indoor pollution. They release an odorless gas called nitrogen dioxide, a toxic pollutant that can interfere with the body’s ability to carry oxygen to the lung. If the ventilation at the kitchen is poor, this toxin can stay trapped inside the house and slowly waft up to the bedrooms. Young children do not have the immune system defenses to properly guard themselves against toxic substances. As a result, the smallest exposure to toxic chemicals may interfere with their nervous system growth and development.

For the study, researchers visited the homes of 482 babies during the first twelve weeks to count how many gas appliances were in the house. They also installed a device that measures the nitrogen dioxide levels in the kitchen every two weeks. When the children turned four, the researchers did detailed tests on their behavior and intelligence. They discovered that there was a positive relationship between the number of gas appliances, the nitrogen dioxide levels in the house, and the symptoms of ADHD, especially inattention. Children who had more gas appliances at home also had slightly lower scores in executive function tests and verbal intelligence tests. The relationship remained the same even after checking for factors like income, educational level of parents, drinking or smoking during pregnancy, or breastfeeding.

Researchers also noted that some kids are more sensitive to the effects of nitrogen dioxide than others. They took a DNA sample from every baby and looked for the glutathione gene GSTP1, which is the gene that produces a specific antioxidant. This enables the body to eliminate environmental toxins more efficiently. Half of the children were found to have faulty GSTP1 genes, and had a stronger association between the nitrogen dioxide levels at home and ADHD symptoms.

Although it’s too soon to make any definite conclusions, this is the first major study done on indoor pollution and the risk of ADHD. It’s also important to note that the study does not claim that gas appliances cause ADHD; merely that there seems to be a relationship between the two. Nonetheless, there is an increasing amount of evidence that links air pollution with impaired brain development, and some studies show that indoor air pollution can actually be worse than outdoor air pollution.
So what can you do with this information? First of all, I don’t suggest that you make a mad rush to the appliance store and switch to an electric stove. Just make sure that your kitchen (and other rooms with gas appliances) has a fan and excellent ventilation. Keep the fan on and the windows open when you use the gas stove. You should also consider placing a spider plant in the kitchen. Believe it or not, NASA researchers have tested the ability of spider plants to remove environmental pollutants linked to gas appliances. They discovered that one spider plant in a one gallon container can remove over 99% of the nitrogen dioxide buildup within just 6 hours!

Environmental pollution might seem like it’s beyond our control, but there’s a lot we can do to control the air quality in our homes for our children. And it doesn’t even have to be expensive to do so!