Multiple Air Toxics Exposure Study In The South Coast Air Basin PDF Download

An evaluation study was done to assess the non-carcinogenic hazardous risk levels of the Southern California Air Basin, based on a claim from the South Coast Air Quality Management District's (AQMD's) Multiple Air Toxics Exposure Study IV (MATES IV) that there is no need to perform a non-carcinogenic assessment due to sufficiently low levels. Utilizing the list of known air toxic constituents and their measured concentrations from each air monitoring location compiled for the MATES IV study, a hazardous health risk assessment for non-carcinogenic health risk was performed in line with the procedures laid out by the U.S. Environmental Protection Agency (EPA) to fully understand the actual risk involved. For each monitoring station, the Average Daily Dose (ADD) of each air toxic was determined for 4 different age demographics including adults, teenagers, children, and babies. With reference concentrations from the EPA IRIS Database, the Hazard Quotient for each compound by age demographic and monitoring station was calculated, as well as the Hazard Index per age demographic. From these results, it was determined that every Hazard Index is well within the safe level of 1, with the highest observed Hazard Index equal to only 0.18. These results fall exactly in line with the expectations of the MATES IV report, but there were some key trends observed when reviewing the data of this study. The non-carcinogenic hazard risk across the entire Air Basin hinges mainly on five main compounds, manganese, acetaldehyde, 1,3 - butadiene, benzene, and naphthalene, with manganese being the main contributor across each monitoring station. It was also observed that much of the necessary reference information for this type of study does not exist, and for many of the compounds measured in the air, there is not enough information available to quantify their impact on the air quality. These findings, while not representative of the entire risk profile of the Southern California Air Basin, reasonably detail that there should be no concerns from breathing the air, but also that there is a lot of room for study and further development in this area of risk assessment.