Historical clue formulations

• Wildfire season stat, for short — 2023-08-20
• E.P.A. pollution stat — 2023-01-24
• Pollution stat — 2021-11-14
• Stat affected by smog levels: Abbr. — 2020-08-21
• Atmospheric pollution meas. — 2018-07-12
• E.P.A. atmospheric stat — 2015-05-21
• E.P.A. computation — 2013-01-05
• Environmental datum of concern to asthmatics, for short — 2011-11-18
• E.P.A. pollution meas. — 2008-12-04
• Smog stat. — 2008-09-26
• E.P.A. pollution meas. — 2006-05-07
• Pollution meas. — 1998-11-14