[BTX monitoring nearby main road traffic in Guangzhou].

In order to study the levels of BTX (benzene, toluene, xylene, etc) nearby the main roads of Guangzhou from November 2010 to December 2010 during the Asian Games, BTX and conventional pollutants such as NO2, O3 in the air were monitored by the DOAS system nearby Huangsha Road, which is in the Liwan District of Guangzhou City. The results showed that, during the entire period, BTX showed a high concentration in the evening and the average concentrations of benzene, toluene, p-xylene, m-xylene and phenol were 15.9 microg x m(-3), 61.3 microg x m(-3), 6.5 microg x m(-3), 16.9 microg x m(-3), 0.88 microg x m(-3), respectively. The average concentrations of benzene and toluene were close to those in other cities, and the ratio of toluene to benzene was in range of 1.2-6.16. Throughout the monitoring period, the correlation coefficient of benzene and toluene was 0.86 and it rose to 0.985 during the high concentration period, indicating that they had the same source in this region. The correlation coefficient between toluene and CO was 0.78, indicating that traffic emissions was the major source of benzene and toluene. Based on the combination of wind speed, wind direction and other meteorological data, it was found that the weather condition was an important factor which affected the BTX concentration, and some possible point sources were suggested nearby the site.