  ce/article/pii/s2352710223020284 open fireplaces without outdoor air intake emit up to 62.2 mg pm2.5/kg of firewood.  using such fireplaces for 4 h/day can decrease occupant life expectancy by 1.6 years.  woodstoves without outdoor air intake emit up to 23.2 mg pm2.5/kg of firewood.  devices with outdoor air intake have negligible emissions so basically running an old wood stove emits high levels of pm 2.5  who: the who guidelines state that annual average concentrations of pm2.5 should not exceed 5 g/m3, while 24-hour average exposures should not exceed 15 g/m3 more than 3 - 4 days per year.
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