Presentation on theme: "Urban Air Toxics. The UAT Monitoring Network Urban Sites Asheville Charlotte Winston-Salem Raleigh Research Triangle Park Wilmington Rural Site Candor."— Presentation transcript:
Monitoring Site Information The Following Sites are Operated by: The Asheville Site: The Western NC Regional Air Quality Agency The Charlotte Site: The Mecklenburg County, Land Use and Environmental Services Agency The Winston-Salem Site: The Forsyth County Environmental Affairs Department
Hydrocarbons Hydrocarbons are derived mostly from petroleum sources and are the major components of fossil fuels, and petroleum products as well as plastics, waxes and oils. In urban environments, hydrocarbons (along with nitrogen oxides (NOx) and sunlight) contribute to ozone production. Benzene 1,3-Butadiene Toluene Ethylbenzene Styrene Xylenes
Halogenated VOCs Volatile organic compounds that contain halogens such as chlorine, bromine, fluorine. Industrial solvent. Persistent in the atmosphere. Resist photochemical breakdown. Chronic health effects. Contribute to ozone formation. Carbon Tetrachloride Tetrachloroethylene Vinyl Chloride Freons
Polar Compounds Polar compounds are oxygenated compounds such as ethers, ketones, and alcohols. Many of these compounds are used as gasoline additives so that emissions may be characteristic of those from mobile sources. MTBE MIBK MEK Ethanol
Carbonyl Compounds Organic compounds composed of carbon, hydrogen, and oxygen and at least one carbon- oxygen double bond. Factors that effect may airborne concentrations: 1.Combustion sources, motor vehicles, industrial processes and some natural sources that emit compounds directly into the air. 2.Photochemical reactions that form carbonyl compounds in the air, typically from airborne hydrocarbons. 3.Photochemical reactions that consume carbonyls from the air, generally by photolysis or by reaction with hydroxyl radicals. FormaldehydeAcetaldehyde
Semivolatiles (SVOC) Semivolatile: A substance that evaporates slowly at standard temperature and pressure (20°C & 1 atm). Polynuclear Aromatic Hydrocarbons (PAHs) Polychlorinated Biphenyls (PCBs) Polychlorinated Pesticides
HAPs, TAPs, and Core Compounds HAP: Hazardous Air Pollutant (EPA) TAP: Toxic Air Pollutant (NCDAQ) Core Compound: A HAP or TAP that presents a high health risk due to long term exposure (i.e. 70 years) in an urban environment. Typically a carcinogen or chronic toxicant.
Risk Assessment URE: The Unit Risk Estimate is the upper-bound excess lifetime cancer risk estimated to result from continuous exposure to an agent at a concentration of 1 µg/m3 in air. RfC: Reference Concentration (non-cancer) is an estimate of a concentration in air to which a human population might be exposed that is likely to be without appreciable risks of deleterious effects during a lifetime (assumed to be 70 years). Source: EPA
Your consent to our cookies if you continue to use this website.