harmful effects of smoking harmful elements harmful emissions harmful environmental harmful foods harmful for people harmful for the environment harmful free radicals harmful gas harmful gases harmful germs harmful habits harmful health harmful if swallowed harmful impact harmful impacts harmful influence harmful influences harmful information harmful ingredients harmful insects harmful interference harmful levels harmful material harmful materials harmful microbes harmful microorganisms harmful organism harmful organisms harmful particles harmful pathogens harmful pesticides harmful pollutants harmful practice harmful practices harmful products harmful radiation harmful rays harmful side harmful side effects harmful subsidies harmful substance harmful substances harmful tax competition harmful tax practices harmful things harmful to aquatic harmful to children harmful to fish harmful to health harmful to human harmful to human health harmful to humans harmful to our health harmful to people harmful to plants harmful to society harmful to the environment harmful to the eyes harmful to the health harmful to the human harmful to the skin harmful to us harmful to women harmful to you harmful to your health harmful toxins harmful traditional harmful traditional practices harmful ultraviolet harmful use harmfulness harming harming anyone harming me harming others harming people harming the environment harming them harming us harming you harming yourself harmless harmless bacteria harmless enough harmless fun harmless little harmless old harmless substances harmless to humans harmlessly harmon harmon rabb harmondsworth harmonia harmonia gardens harmonia mundi harmonic harmonic analysis