Sen. David Vitter and Congressman Bill Cassidy should be at ease regarding a reduction in the ozone pollution standard. While, technically, any reduction will approach the background level, even the lowest proposal (60 ppb) is well above the policy’s relevant background level (15-35 depending on season and time of day). Those interested in the difficulties involved in determining a background level in the presence of large anthropogenic contributions can start with the EPA website:

(HINT: It involves the global circulation models of which conservatives are so disparaging.)

David Norwood

university professor

Baton Rouge