The Size of Suspended Particulate Matter in Air

Abstract

By means of the NASN cascade impactor the particle sizes of ambient aerosols can be measured by fractionating the particles according to their aerodynamic dimensions, and the fractions can be quantified gravimetrically. Data obtained with this instrument show that particulate matter suspended in urban air in the United States and Great Britain is remarkably uniform in distribution and that the particles are predominantly less than 1 microm in diameter. In Ankara, Turkey, the high proportion of particles larger than 1 microm in diameter are associated with the incomplete combustion of lignite; particulate concentrations in Ankara, however, are considerably higher than those measured elsewhere. The growth of particles in air during temperature inversions occurs in Cincinnati; the greater proportion of large particles found there during inversion periods can account for the reduction in visibility. Aerosols in the vicinity of highways are composed of particles larger than those found some distance away because of the reentrainment of debris by the traffic-induced turbulence. On the other hand, highway configuration and traffic volume have little effect on the size distribution of aerosols in samples collected away from the turbulence area of the roadway. Aerosols measured inside buildings are predominantly smaller in size and exhibit a narrower range of sizes than aerosols outside buildings.

Variation in the Effect of Particulate Matter on Pulmonary Function in Schoolchildren in Western Japan and Its Relation with Interleukin-8

“…PM 10 is defined as any particle measuring less than l0 μm in diameter with a 50% cut-off, while PM 2.5 as any particle measuring less than 2.5 μm in diameter with the same cut-off as PM 10 [ 19 ]. In Japan, suspended particulate matter (SPM) is defined under the National Air Quality Standard as any particle with a diameter of less than 10 μm with a 100% cut-off [ 20 ]. The theoretical 50% cut-off diameter for SPM is assumed to be approximately 7 μm [ 20 ].…”

“…In Japan, suspended particulate matter (SPM) is defined under the National Air Quality Standard as any particle with a diameter of less than 10 μm with a 100% cut-off [ 20 ]. The theoretical 50% cut-off diameter for SPM is assumed to be approximately 7 μm [ 20 ]. The particle diameter of SPM measurement in Japan is intermediate to the diameters that are used in the evaluation of PM 2.5 and PM 10 .…”

“…The particle diameter of SPM measurement in Japan is intermediate to the diameters that are used in the evaluation of PM 2.5 and PM 10 . Although the daily fluctuations of SPM are similar to those of PM 2.5 [ 19 , 20 ], the constituents of PM may differ across countries. The Japanese Ministry of the Environment monitors the levels of SPM instead of PM 10 .…”

Estimating daily full-coverage and high-accuracy 5-km ambient particulate matters across China: considering their precursors and chemical compositions

“…Particulate matters with aerodynamic equivalent diameters less than 2.5 μm (PM2.5) and 10 μm (PM10) have been considered as major air pollutants for decades (Finlayson-Pitts et al, 1997;Hall et al, 1992;Lee, 1972), which can hazard the environment and human health (Crippa et al, 2019;Liu et al, 2020;Ma et al, 2017;Venkataraman et al, 2018). The ambient concentrations of PM2.5 and PM10 are strongly relevant to living conditions and required to be accurately monitored.…”

Validation of MODIS aerosol products by CSHNET over China

“…Tropospheric aerosol has a substantial climatic influence through direct and indirect radiactive forcing and taking part in cloud processes [3][4][5][6] , and aerosol also plays a most important role in environmental change [7,8] . However, climatic and environment influence of aerosol is still uncertain due to the incomplete knowledge of the microphysical and optical properties of aerosols and their extreme heterogeneous spatial distribution [9,10] .…”