Particulate composition data, chemical mass

The major purpose of ambient particulate sampling is to obtain mass concentration and chemical composition data, preferably as a function of particle diameter. This information is valuable for a variety of problems effects on human health, identification of particulate matter sources, understanding of atmospheric haze, and particle removal processes. 

So far, considerable information of the gaseous exhaust pipe emission factors and some of particulate matter is available from the 1990s. More recent studies reported emission factors for PM mass, organic carbon (OC), elemental carbon (EC) and some metals, which improved present knowledge about composition and size distribution of particulate motor vehicle emissions, and more important which allowed the creation of emission profiles—a prerequisite for source apportionment studies with statistic methods such as chemical mass balance models. However, since fuel composition, engines and vehicle technologies evolve (Kleeman et al. 2000) data on the combined mass emission rate and chemical composition of primary particle emissions from motor vehicles need to be updated periodically. 

Aerosol mass spectrometry (AMS) is used to monitor the chemical composition of particulate matter in the atmosphere. Commercial AMS instruments can provide size and chemical mass loading data on aerosol particles in real time [176]. Such instruments integrate sampling and MS analysis sub-systems. They can be installed permanently or used as components of mobile laboratories [176]. Both quadrupole and TOF AMS devices can provide quantitative data on the chemical composition of volatile/semi-volatile submicrometer aerosols [177]. Importantly, AMS can provide non-refractory aerosol mass... 

This result may be deceptive, however, as we had to eliminate the many studies from Cols. 2 and 3 that contained no size Information, so the two sets of averages are not for the same populations of plants. A further problem with these data may also be the Inclusion of particles up to 2.5-pm dlam, whereas, recent studies (44, 46) indicate that the large changes of composition occur below about 0.5-pm dlam. Thus, our "fine" particles In Table IV Include particulate mass between 0.5 and 2.5 ym that Is chemically similar to larger particles, which reduces the Rvalues. We made the cut at 2.5 ym to develop components for separate CEBs of fine and coarse particles In ambient air, which are commonly divided at about that point. 

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