3.4. SR 08-25-1997 - Laserfiche WebLink

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· contributions of toxic air pollutants to receptor sites. The following list presents some of these questions and issues that have bc~n discussed owr the last scveraI years: A. Inhalation and Direct Exposure to Chemicals What are "background" concentrations of toxic air pollutants in the Twin Cities Metro Area and other urban areas in Minnesota and do these concentrations pose a potential risk to .the general public? The MPCA has some ambient air concentration data for specific VOCs in a' few locations in the Twin Cities Metro are~ However, there is a general lack of ambient air data for most toxic air pollutants in the lliajoi'ity of rttral and urban settings in Minnesota. A state'wide monitoimg effort would collect data to determine "background concentrations" in other COmmtmlties itl other parts of the state. 2. Are people living in urban areas exposed to more toxic air pollution than people living ia mml and small town areas? In genei-al, one would expect that people living in mml and small town areas would have less exposure to toxic air pollution. However, some available data suggests this assumption may not be applicable in all cases. A review of the Toxic Release Inventory data for I994 shows that relatively large sources of air toxics ern{ssions are located in some smaller cornrntmities. A statewid~ toxics monitoring study should be able to deterrn{ne if people in rural areas are beiug exposed to the same level of toxic a/r pollutants as people living in urban and small town areas. In addition, a relative ranking of pollutant levels at locations from throughout the sram will be possible (i.e., the concentrations of toxic air pollutants found in various divergent cor~r~,,-{ties can be compared). The question of which town or region of the state has the lowest ambient air concentrations of toxic air pollutants may be answered (with{n the Hrn{ts of the study). 3. Of the chemicals that am found in ambient air, which have the greatest impact? The MPCA published a report in 1991 entitled: "Priority ranking for pollution prevention demonstration projects: A ranking of Minnesota industrial emitters of toxic air pollutants" (MPCA 1991). A risk 5CI~en[n~ atlalysis was conducted in th[~ rgport arid it identified chromium and arsenic as two important pollutants that may be impacting human health. However, very l~rn~ted monitoring data are available to evaluam whether the current concentrations of these metals in ambient air present a real or potential problem to human health. In addition to the priority ranking report, the MPCA published a report in 1992 entitled: "Estimation and evaluation of cancer risks from air pollution ia the 1Vt~nneapol~St. Paul metropolitan area" (MPCA 1992). This 'ha'ban soup study" identified the following pollutants as potentially contributing the most to excess cancer incidence in the Twin Cities area: diesel and gasoline particulate, wood stove particulate, 1,3-butadiene,