Relax~ Do not think much. Most likely, you will pass 3-hour test. I failed the 1-hour test (my value is 152 higher than 129 the cutting off value), but did well for the 3-hour test.
废话,当然是符合规定的情况下越低越好。 假设使用较严格的规定限量16ppb,如果菜车能做到6ppb,那么豪车要做到3ppb以下才 能对得起“豪车”的称号吧。 至于限量,不同部门也设立了不同标准: The National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of 16 ppb. The Occupational Health and Safety Administration (OSHA) has set a workplace permissible exposure limit (PEL) of 750 ppb.
废话,当然是符合规定的情况下越低越好。 假设使用较严格的规定限量16ppb,如果菜车能做到6ppb,那么豪车要做到3ppb以下才 能对得起“豪车”的称号吧。 至于限量,不同部门也设立了不同标准: The National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of 16 ppb. The Occupational Health and Safety Administration (OSHA) has set a workplace permissible exposure limit (PEL) of 750 ppb.