3.1. In-situ measurements
Air pollution was monitored as follows: Nitrogen oxide (NOx) was monitored by 42C NOeNO2eNOx Monitor Labs 9841A, Ozone (O3) was monitored by TEi-49C and particulate matters (PM10) were monitored by TEOM1400AB and Carbon monoxide (CO) was monitored by Drager-PacIII sensors. Data was collected consecutively and stored in data loggers.