Formaldehyde is used in many home products (paint, fabric, detergent, flooring), and it can cause irritation, trigger asthma attacks, and have more serious health effects. There aren’t any brands that are particularly bad, but try to choose products that say “no added formaldehyde” on the label. And take precautions. Fresh air, low temperatures, and a no-smoking rule will go a long way in lowering formaldehyde emissions in your home.