Ambient Air Particulate Source Activity Measured with Hourly Resolution
A method for collecting ambient air particulate matter (APM) and identifying their sources with hourly time resolution is described. Most air samplers need to sample for at least 24 hours to obtain a measurable sample on either a 47 mm diameter filters or A4 size filters with manual sample changing. A sampler caller the “Streaker” can automatically collect APM in a 7 mm track around an 82 mm diameter disc filter. The deposited APM can be continuous or 35 time-discrete records of one or two size fractions. The sampler has the advantages of being light, compact and portable (battery powered), which allows it to be used in a variety of locations. This sampler is ideal for investigating the activity of air particulate sources which have large fluctuations over short time frames such as traffic or domestic heating. In addition, the improved time resolution of this sampler also allows improved correlation between APM and pollutant gas species. The correlation between pollutant gas species and APM has not been very good when investigated using 24 hour averages because pollutant gas species have more rapid fluctuations in the atmosphere compared to APM. The composition of the APM is determined by ion beam analysis which is a key tool for identifying the proportions of the APM that originate from a variety of natural and manmade sources. The first measurements with this sampler identifying particulate emissions from domestic heating and traffic flow with hourly time resolution are presented.