ISO 14644-1:2015规定了洁净室和洁净区内空气颗粒物浓度方面的空气清洁度分类；以及ISO 14644-7中定义的分离装置。 出于分类目的，仅考虑具有基于阈值（下限）粒径范围为0.1μm至5μm的累积分布的粒子群。 使用光散射（离散）空气颗粒计数器（LSAPC）是在指定采样位置确定等于或大于指定尺寸的空气颗粒浓度的基础。 ISO 14644-1:2015未对规定的下限粒径范围（0.1μm至5μm）以外的颗粒群进行分类。超细颗粒（小于0.1μm的颗粒）的浓度将在单独的标准中进行说明，以通过纳米颗粒来规定空气洁净度- 缩放粒子。M描述符（见附录C）可用于量化大颗粒（大于5μM的颗粒）的数量。 ISO 14644-1:2015不能用于描述空气中颗粒物的物理、化学、辐射、活性或其他性质。

ISO 14644-1:2015 specifies the classification of air cleanliness in terms of concentration of airborne particles in cleanrooms and clean zones; and separative devices as defined in ISO 14644？7. Only particle populations having cumulative distributions based on threshold (lower limit) particle sizes ranging from 0,1 μm to 5 μm are considered for classification purposes. The use of light scattering (discrete) airborne particle counters (LSAPC) is the basis for determination of the concentration of airborne particles, equal to and greater than the specified sizes, at designated sampling locations. ISO 14644-1:2015 does not provide for classification of particle populations that are outside the specified lower threshold particle-size range, 0,1 μm to 5 μm. Concentrations of ultrafine particles (particles smaller than 0,1 μm) will be addressed in a separate standard to specify air cleanliness by nano-scale particles. An M descriptor (see Annex C) may be used to quantify populations of macroparticles (particles larger than 5 μm). ISO 14644-1:2015 cannot be used to characterize the physical, chemical, radiological, viable or other nature of airborne particles.