Presented at MIT CENSAM Workshop on June 2014 as a part of collaborative project between ETH and MIT in Singapore. Air pollution at street level: http://censam.mit.edu/research/Pages/Characterization%20of%20airborne%20particles%20in%20outdoor%20environments%20of%20Singapore.aspx related publication: http://www.atmos-meas-tech.net/8/3563/2015/ poster:http://censam.mit.edu/research/CENSAM%20Publications/Urban/Characterization%20of%20airborne%20particles%20in%20outdoor%20environments%20of%20Singapore/Vahid%20poster.pdf