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Proposed PM2.5 Measures for the Austin -Round Rock -Georgetown MSA Regional Air Quality Plan <br />How are the Design Values Determined? <br />When EPA determines if an area's PM2.5 levels are in compliance with the NAAQS,they will use the most recent <br />three years' worth of data from all of the official PM2.5 monitors that the state operates or has approved for use <br />in comparison to the NAAQS. These numbers are known as "design values," The highest design value for the <br />whole region becomes that region's design value. In the Austin -Round Rock -Georgetown MSA, there are two <br />such PM2.5 monitors that will be used to assess the region's compliance for the 2018-2020 period: <br />* AQSNumber 484G30O21/[AMSNumber 171inEast Austin: <br />w AQ3Number 484531068/CAK8S10G8along |H'35,just north ofthe intersection with US -183: <br />These two sites are located where EPA and the state have determined would be the locations mostlikely to <br />measure the highest region -wide PM2.5 concentrations over a three-year period. <br />For the annual PM2.5 NAAQS, EPA calculates quarterly averages for each year, and then calculates a 3 -year <br />average to determine the design value. If that 3 -year average is 12.0 Vg/M3 or below, the region is considered in <br />compliance with the NAAQS. For the 24-hour PM2.5 NAAQS, EPA calculates the 98 1h percentile 24-hour <br />concentration for each year, and then calculates a 3 -year average. If that 3 -year average is 35 [tg/M3 or below, <br />the region isconsidered incompliance with the NAAUS. <br />What Specific Actions can be Implemented? <br />This section outlines in detail the specific activities that CAC members could implement under each category <br />identified above. This is meant to provide an idea of specific activities, and it is not required that CAC members <br />list in detail which specific action (e.g., water application) is planned to be implemented. <br />1. Reduce emissions from construction and demolition activities <br />There are a number of ways to reduce PM emissions during construction and demolition. The list <br />below iocompiled from the WRAP Fugitive Dust Hondboo1<2and obest practice document from <br />Canada <br />b. Water application <br />c. Dust suppressants <br />d. Reschedule large dust generating activities from high wind days or forecasted high PM days <br />e. Design: <br />L Plan for minimizing dust generation <br />ii Choosing building material toreduce dust generation <br />iii. Minimize distances travelled for delivery of materials <br />iv. Use ofgreen building materials <br />v. Design and construction for maximum energy efficiency <br />Site preparation <br />zWestern Regional Air Partnership's (NRAPs)Fugitive Dust Handbook, <br />Page 6 of 10 <br />