Variation in PM_(10) chemical composition on low and high pollution days

摘要

In addition to concerns about mass concentrations of particulate matter in the atmosphere, there are also concerns about specific chemical components (such as transition metals). It is thought that these components may be responsible for particular health end-points. There are also plans to introduce stricter mandatory EU particulate matter air quality standards for the year 2010. Consideration will need to be given to the contribution that natural materials may make to these tighter limits. In order to understand better the chemical composition of particulate matter and the way in which this alters over time, this study collected a series of daily PM_(10) filter samples from a coastal roadside site on the south coast of the UK. These samples were subsequently weighed and then analysed using Scanning Electron Microscopy and Electron Detection (SEM/EDS) techniques. Results to date have shown marked changes in chemical composition of particulate matter (PM_(10)) between high and low pollution days. Low pollution days are characterised by uniform deposits of sodium chloride across the filter, while high pollution days (with concentrations approaching or breaching the UK and EU PM_(10) air quality standards) consist of mixed carbonaceous, mineral and metal deposits.