Session 4: Air Pollution Measurements CE 5326 AIR POLLUTION CONTROL Fall 2008 Session 4: Air Pollution Measurements Fall 2008 By Wen-Whai Li Air Pollution Effects

De Nevers Problems 4.7; 4.8; 4.15; 4.16;4.17 Reading Assignment: H.W. #4: Due Sep. 24, 2008 De Nevers Problems 4.7; 4.8; 4.15; 4.16;4.17 Reading Assignment: De Never: Chapter 4 U.S. EPA siting regulations (Appendices D and E to Part 58), p61316-61328 Fall 2008 By Wen-Whai Li Air Pollution Effects

Ambient Monitoring Measurements of Air Pollutants. Time-integrated Air Monitoring Particulate Matter Hi-vol: 1 m3/min Mid-vol: 100 l - 1 m3/min Low-vol: 10 l - 100 l /min Personal: < 10 l/min Vapor Grab samples Canister Media Continuous Air Monitoring Fall 2008 By Wen-Whai Li Air Pollution Effects

Ambient Monitoring Meteorological Measurements. Surface Meteorology Wind Direction Wind Speed Atmospheric Temperature Atmospheric Humidity Atmospheric Pressure Vertical Temperature Profile Upper Air Measurement Balloon Measurements Radiosonde: Rawinsonde: Rocket-fired Equipment falling through the atmosphere: Remote Sensing: Fall 2008 By Wen-Whai Li Air Pollution Effects

Air Monitoring Objectives Provide air pollution data to the general public in a timely manner Support compliance with NAAQS and emission strategy development Support for air pollution research studies Fall 2008 By Wen-Whai Li Air Pollution Effects

Types of Air Monitoring Sites Highest concentration Population-oriented community exposure Source impacts Background Regional transport Welfare impacts on visibility, vegetation, wild life, etc Fall 2008 By Wen-Whai Li Air Pollution Effects

Air Monitoring Design Stage of Air Monitoring Pre-construction/remediation (Background) Monitoring Post-construction/remediation Monitoring Monitoring during Construction/remediation Activities Pollutants to be Monitored Criteria Pollutants Non-criteria Pollutants Monitoring Locations Case I: Free from the impacts from other sources Case II: Multisource emissions in flat terrain Case III: Multisource emissions in complex terrain Fall 2008 By Wen-Whai Li Air Pollution Effects

Air Monitoring Design Duration Sampling Methods Sampling Locations Sampling Plan Sampling Media Fall 2008 By Wen-Whai Li Air Pollution Effects

Distance to PM Sampler Fall 2008 By Wen-Whai Li Air Pollution Effects

Distance to Other Samplers Fall 2008 By Wen-Whai Li Air Pollution Effects

Siting Summary Fall 2008 By Wen-Whai Li Air Pollution Effects

Isokinetic Sampling When the sampling inlet axis is aligned parallel to the air stream and the air velocity entering the probe is the same as the free stream velocity approaching the inlet, the sampling procedure is called isokinetic sampling. Fall 2008 By Wen-Whai Li Air Pollution Effects

Anisokinetic Sampling Fall 2008 By Wen-Whai Li Air Pollution Effects

Anisokinetic Sampling: Superisokinetic Fall 2008 By Wen-Whai Li Air Pollution Effects

Anisokinetic Sampling: Subisokinetic Fall 2008 By Wen-Whai Li Air Pollution Effects

Dichotomous Air Monitors Fall 2008 By Wen-Whai Li Air Pollution Effects

Dichotomous Air Monitors Fall 2008 By Wen-Whai Li Air Pollution Effects

Principle of Operation Operation Principle Large particles with greater inertia cannot follow the sharp turn made by the air steam and continue to move in their initial directions and therefore are separated from the air stream. Virtual Impaction The air stream is forced to make a turn not by physical obstruction but by the reduction of flow velocity, a virtual impaction. Aerodynamic Diameter The behavior of a particle in the air stream is based on its aerodynamic properties rather than the physical size and shape. Fall 2008 By Wen-Whai Li Air Pollution Effects

Conceptual diagram of particle deposition mechanisms Fall 2008 By Wen-Whai Li Air Pollution Effects

Schematics of Dichotomous Air Monitor PM10 inlet Fall 2008 By Wen-Whai Li Air Pollution Effects

Example for Dichotomous PM Measurements Cc= 30 μg/m3 CF= 10 μg/m3 FT= 16.7l/min or 1m3/hr t = 24 hrs MF= CF · FF· t = (10 μg/m3)· (0.9 m3/hr) · (24 hrs) = 216 μg MC= (CC · FT· t) + (CF · FC· t) = (30 μg/m3)· (1.0 m3/hr) · (24 hrs) + = (10 μg/m3)· (0.1 m3/hr) · (24 hrs) = 720 μg + 24 μg = 744 μg Mc= 744 μg MF= 216 μg Fall 2008 By Wen-Whai Li Air Pollution Effects

Derivation of the Concentration Equations CF, CC FF FC t = sampling time, hr A= Actual mass to be collected, μg M= mass collected on the filter, μg F= flowrate, m3/hr Subscript: C: coarse particulate F: fine particulate T: total Fall 2008 By Wen-Whai Li Air Pollution Effects

Bioassay Implication PM2.5 Filter The mass collected on the PM2.5 filter represents FF/FT of the actual ambient concentration. Under standard operating conditions, FF/FT is 0.9 (or 90 %). In other words, if the average ambient PM2.5 concentration is 10 μg/m3, the dose retained on the filter for bioassay analysis is equivalent to an ambient PM2.5 concentration of 9 μg/m3. PM10-2.5 Filter The mass collected on the PM10-2.5 filter represents the sum of actual coarse PM (PM10-2.5) plus a fraction of fine PM (PM2.5), an amount of (FT-FF)/FT collected during the sampling period. Under standard operating conditions, (FT-FF)/FT is 0.1 (or 10 %). In other words, if the average ambient PM10-2.5 concentration is 30 μg/m3 and PM2.5 concentration is 10 μg/m3, the dose retained on the filter for bioassay analysis is equivalent to 30 μg/m3 of PM10-2.5 plus 1 μg/m3 of PM2.5. Fall 2008 By Wen-Whai Li Air Pollution Effects

Data Processing for Chemical Concentrations Determine the concentration of each compound on either filter (CF or CC) by multiplying the compound concentration in solution by the amount of solution Determine the air concentration of each compound in either size category by using paired concentrations and the two dichotomous equations. Fall 2008 By Wen-Whai Li Air Pollution Effects

Composite Samples Composite each pair of PM2.5 and PM10-2.5 samples for bioassay effects of PM10 for the same sample duration at the same location. Composite multiple PM2.5 filters for bioassay effects of concentrations at k·(FF/FT)·∑CF, where k is a dilution factor. Composite multiple PM10-2.5 filters for bioassay effects of concentrations at k·{(FT-FF)/FT)·∑CF + ∑CC}, where k is a dilution factor. May be used together to evaluate incremental effects. Fall 2008 By Wen-Whai Li Air Pollution Effects

Uncertainties Instrumentation Field Operations Laboratory Operations Loss of mass Size cut-off Humidity Field Operations Flow Rates Filter Handling Laboratory Operations Gravimetric Weighing Temperature Electrostatics Fall 2008 By Wen-Whai Li Air Pollution Effects