"if the battery in a mechanical mod over-discharges and the device doesn't contain enough air holes to allow the battery to vent, there is a risk of explosion." http://lm360.us/Brazee-grandma-of-Leforge-from-Fossato-Di-Vico?Mentzerne=234
in particular, the country has extreme levels of nitrogen dioxide due to heavily congested roads in urban areas, .