STARKVILLE, Miss. -- All the good smells of the holidays brought into the house by candles, cooking, live greenery and holiday plants can contribute to poor indoor air quality.

David Buys, health specialist with the Mississippi State University Extension Service, said indoor air quality affects human health in several ways.

“The things we bring into our homes can emit chemicals and gases into the air we breathe. We refer to those gases as volatile organic compounds, or VOCs,” Buys said. “The same air can carry toxic substances into our lungs, putting us at risk for becoming ill.”

Artificial fragrances are found in many decorations used at the holidays, but Buys said candles and air fresheners can release chemicals that can irritate respiratory tracts and trigger asthmatic reactions.

“Candles can release particulates and soot that can adhere to surfaces in our homes and cause poor air quality,” Buys said. “Improperly vented fireplaces may emit carbon monoxide and other combustion gases back into the house, so it is critical to have smoke detectors and carbon monoxide sensors installed and working correctly.”

Susan Cosgrove, an Extension agent in Newton County, said inside air can be more polluted than outside air. Cold weather that keeps doors closed and people indoors contributes to the problem.

“Holidays often bring on a wave of extra cooking, and proper ventilation is necessary in the kitchen to remove food particulates, steam and smoke from the air,” Cosgrove said. “Bathrooms also need proper ventilation year-round to control moisture levels. Without proper ventilation, we risk the building of moisture, which leads to mold growth, and that contaminates the air we breathe.”

Cosgrove said consumers may purchase an indoor hygrometer to measure humidity, which should be within the range of 30-50 percent. Excessive moisture leads to the growth of mold. Many hygrometers are affordable and also serve as thermometers.

Buys said other common causes of poor indoor air quality are contaminants such as asbestos, formaldehyde, pesticides, dust mites, cigarette smoke, lead paint dust, hazardous household products, and pet dander and pests.

“Sometimes there are also things going on outside that can ‘leak’ inside and make us sick,” Buys said. “Depending on where we live, these might include vehicle exhaust, pollen or industrial pollutants. Radon, a gas that can be emitted into homes from the ground through basements or floors, can be a concern for people living in northeast Mississippi.”

Homeowners can do several things to keep their indoor air quality good. These include keeping the house dry by preventing leaks, keeping the house clean by creating smooth and cleanable surfaces and reducing clutter, and keeping it pest-free by sealing cracks and openings and limiting access to food and water inside.

Proper maintenance keeps the house in good repair, preventing small problems from becoming large repair jobs.

Renters or those living in multiunit housing have fewer options, but they can still take proactive steps to improve indoor air quality.

“Renters should take control of things within their purview, such as keeping food stored well away from pests, keeping the house clean and reporting problems to landlords,” Buys said. “Mississippi law spells out when landlords must make repairs to rental units, and it defines the obligations of the tenants in reporting a problem.”