Can NO(2) be used to indicate ambient and personal levels of benzene and 1,3-butadiene in air?

The aim of this study was to investigate the relation between two toxic volatile organic compounds, 1,3-butadiene and benzene, and a commonly used indicator of vehicle exhaust fumes, NO(2). This was to see if NO(2) can be used to indicate personal exposure to carcinogenic substances or at least estimate ambient levels measured at a stationary point. During the winter of 2001, 40 randomly selected persons living in the City of Umea (in the north of Sweden) were recruited to the study. Personal measurements of 1,3-butadiene, benzene and NO(2) were performed for one week, and were repeated for 20 of the 40 participants. Additional information was gathered using a diary kept by each participant. During the same time period weekly stationary measurements were performed at one urban background station and one street station in the city centre. The results from the personal measurements showed a negligible association of NO(2) with 1,3-butadiene (r= 0.06) as well as with benzene (r= 0.10), while the correlation coefficient between 1,3-butadiene and benzene was high and significant (r= 0.67). In contrast to the personal measurements, the stationary measurements showed strong relations between 1,3-butadiene, benzene and NO(2) both within and in-between the street and urban background station. This study supports NO(2) as a potential indicator for 1,3-butadiene and benzene levels in streets or urban background air, while the weak relations found for the personal measurements do not support the use of NO(2) as an indicator for personal 1,3-butadiene and benzene exposure.