HVAC filters are exposed to a diverse mixture of aerosols during their service life. Aerosol physiochemical properties can have a significant impact on the removal efficiency and loading behavior of a filter. New aerosol generation techniques are needed to age HVAC filters with particle size distributions (PSDs) representative of those found in outdoor (urban) and indoor environments. This study evaluated the physical characteristics of salt aerosol produced by a newly designed commercially available thermal aerosol generator. The thermal aerosol generator produced a high mass output of sub-micron (≤ 1,000 nm) sodium chloride (NaCl) and potassium chloride (KCl) particles by burning a salt stick in an oxygen-propane flame. The shape of the number and mass PSDs is similar to those found in outdoor (urban) and indoor air and can be modulated by varying the rate at which the salt stick is fed into the flame. The morphology of the NaCl and KCl particles varied with size, with compact spherical or cubic structures observed below 100 nm and agglomerates observed above 100 nm. The thermal aerosol generator is a cost-effective technique for rapid ageing of HVAC filters with a PSD that more accurately represents, compared to conventional loading dusts, what filters encounter in real HVAC installations.

HVAC过滤器在使用寿命期间会暴露于多种气溶胶混合物中。气溶胶的物理化学性质可能会对过滤器的去除效率和负载行为产生重大影响。需要新的气雾生成技术来老化具有代表在室外（城市）和室内环境中发现的粒径分布（PSD）的HVAC过滤器。这项研究评估了由新设计的市售热气溶胶发生器产生的盐气溶胶的物理特性。通过在氧气丙烷火焰中燃烧盐棒，热气溶胶发生器可产生大量的亚微米（≤1,000 nm）氯化钠（NaCl）和氯化钾（KCl）颗粒。数量和质量PSD的形状类似于在室外（城市）和室内空气中发现的PSD的形状，并且可以通过改变盐棒被送入火焰的速率进行调节。NaCl和KCl颗粒的形态随尺寸而变化，在100 nm以下观察到致密的球形或立方结构，在100 nm以上观察到附聚物。热气溶胶发生器是一种具有成本效益的技术，可以使带有PSD的HVAC过滤器快速老化，与传统的装载粉尘相比，PSD更准确地表示了实际HVAC装置中遇到的过滤器。