When I was a kid, I knew the house was clean because it smelled like fake lemons and pine. But it may not have been as clean as my family thought: The EPA estimates that the air inside our homes can be as more polluted than the air outside, in part because of chemical cleaning products. Indoor air pollution can lead to serious health problems like allergies and asthma; childhood asthma rates are now at epidemic levels, with more than seven million children affected, according to the Centers for Disease Control and Prevention. That’s one in 10 kids. So I’ve spent the last few years replacing those  familiar from childhood with green cleaning…