Lecture 7

# Lecture 7 - Overview Lecture #7 Overview What are common...

This preview shows pages 1–2. Sign up to view the full content.

Overview ± Lecture #7 ± Risk and Contaminant Concentrations ± NAAQS (ppmv) and MCLs (ppm) (ICP#4,5) ± Flow and Flux Units (ICP#6) ± Reading: V: Ch. 2 (pg 26-28); course pack N: 1.C.1 (pg. 7-10) Overview ± What are common concentrations units for water and air pollutants? ± How does one convert weight per weight (e.g., ppmw) or volume per volume (e.g., ppmv) concentration units to weight per unit volume (e.g., mg/m 3 or mg/L) units? (ICP#4,5) ± What is volumetric flow rate and mass flow rate? ± How does one convert between flow and flux units? (ICP#6) Risk Assessment ± risk evaluation is performed in terms of the probability for an individual to suffer an adverse effect (e.g., cancer or toxic response) from exposure to a chemical ± risk = f (hazard, exposure) ± hazard: toxic properties of a chemical ± exposure: ingestion, inhalation, or dermal ± we need to be able to model exposure from emission source to receptor (i.e., human or other target of concern) ± mass balance equation models ± but first back to NAAQS and MCLs (concentration units!) that we will be modeling see V: Ch 2 (SI units and conversions) NAAQS (ppmv or mg/m 3 ) MCLs (mg/L or ppm) b Maximum Contaminant Level (MCL); c Maximum Contaminant Level Goal; e million fibers per liter Air Quality Concentrations (ppmv) ± PV = nRT (ideal gas law) ± P: pressure (Pa; 1 atm = 1.01325 x 10 5 Pa) ± T: temperature (ºK = ºC + 273.15) ± R: gas constant (8.314 J-mol -1 K -1 =8.205x10 -5 atm-m 3 - mol -1 K -1 ) ± Σ i P i =P; Σ i V i = V; Σ i n i = n ± P = (n/V)RT; P i = (n i /V)(RT) ± Likewise V = (n/P)(RT); V

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

## Lecture 7 - Overview Lecture #7 Overview What are common...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online