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Extreme Weather Affects Indoor Air Quality

Climate Changes May Increase Health Problems Related to Indoor Air Quality, Report Finds

Not Easy Being Green

The biggest source of indoor air quality problems is central air conditioning, says Jeffrey May, principal scientist at May Indoor Air Investigations in Tyngsborough, Mass., and author of several books, including Jeff May's Healthy Home Tips. “With global warming, we use more air conditioning in most climates, and when you cool air, you reduce the temperature of the air and the humidity increases,” he says.

“If you cool air, you get water,” May says. “You have moisture in the coil of the air conditioner and if you don’t have a good filtration system, the dust builds up, and wet dust turns into mold,” he says.

An air conditioner is akin to a Petri dish in this sense, he says. Minimum efficiency reporting value (MERV) ratings are used to rate how well an air conditioning filter removes dust from the air as it passes through the filter. “Never have an air conditioner with anything less than MERV-8 rating or a MERV-11 if you have allergies,” he says.

Such filters can be purchased at hardware stores and will prevent mold in a new air conditioning system and lessen it in an older system.

“One of the most important things people do to be green is to save energy,” he says. Tightening buildings to make sure no air leaks from the outside makes buildings super-efficient and airtight, so you bring in fresh air through mechanical ventilation systems and blowers and the air gets filthy and moldy,” he says.

“It’s risky business being green,” May says.

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