Enough information exists now to say we are concerned about levels in the ambient air and the potential adverse long-term health effects posed by formaldehyde, benzene, carbon tetrachloride and chloroform. The first action recommended is sharing information about the chemicals in this group with our partners and the public. 2.current information highlights need for more study. Current data suggest that ethylene dibromide, 1,3-butadiene, acrolein, arsenic, nickel and chromium are pollutants of concern, but additional information is necessary to confirm their significance. Of the six pollutants in this group, it appears likely that, with additional data, nickel will fall from the list.
Concentrations appear to be stable over the past four years.
The widespread exceedances of health benchmarks for formaldehyde, which is a respiratory irritant and probable carcinogen, suggest that a public health issue exists. Both monitoring and modeling data show benzene concentrations above the lower range of the health benchmark in the Twin Cities metropolitan area and in the state's smaller cities, including Duluth, Rochester, Mankato and St. Cloud. About two-thirds of benzene emissions can be attributed to mobile sources. In the metropolitan area, there has been a slight decrease in benzene concentrations since 1991, for which the reason is unclear. Given the magnitude of the measured concentrations, it would appear that benzene, a known human carcinogen, presents a potential health problem in both the Twin Cities metropolitan area and in smaller population centers.