Technical basis for the EPA's development of the significant impact thresholds for PM2.5 and ozone / 
 Technical basis for the Environmental Protection Agency's development of the significant impact thresholds for Particulate Matter 2.5 and ozone 
Air Quality Assessment Division. 
 - 1 online resource (2 volumes) :  color illustrations, maps 
<br/><br/> "April 2018."  "EPA-454/R-18-001."  Suffix in report number based on information from agency.  CRDP Program record. 
<br/><br/>Includes bibliographical references. 
<br/><br/>[V.1. Without special title] -- [V.2 Appendices]. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Air quality--Standards--United States.<br/>Air--Pollution--Standards--United States.<br/>Air--Pollution--Measurement.--United States<br/>Atmospheric ozone--Measurement.--United States<br/>Atmospheric ozone--Environmental aspects--United States.<br/>Air--Pollution--Measurement.<br/>Air--Pollution--Standards.<br/>Air quality--Standards.<br/>Atmospheric ozone--Environmental aspects.<br/>Atmospheric ozone--Measurement.
<br/><br/><label>Subjects--Geographic Terms: </label><br/>United States.
<br/><br/><label>GPO Item No.: </label>0483-E-22 (online) 
<br/><br/><label>Gov. Doc. Class. No.: </label>EP 4.52:P 25/6/V.1-2 
<br/><br/><label>Report. No.: </label>EPA-454/R-18-001a EPA-454/R-18-001b