[JURIST] US Environmental Protection Agency (EPA) Administrator Stephen L. Johnson [official profile] defended last month's EPA proposal [JURIST report] to toughen standards for US air quality during testimony at a Wednesday Senate Committee on Environment and Public Works subcommittee hearing [meeting materials; recorded video]. Johnson testified that the current standard does not adequately protect public health. While many Democrats, including chair of Wednesday's hearing Sen. Tom Carper (D-Del.) [official website], say the proposed limits should be more rigid [press release], many Republicans have charged that the plan is too strict.

The proposals recommend reducing the amount of ground-level ozone [press release; advisory committee report, PDF] from 0.08 parts per million (ppm) to between 0.07 and 0.075 ppm. The EPA is also seeking comments about the possibility of leaving the level at 0.08 ppm, or reducing it to as low as 0.06 ppm. Ground level ozone, which is harmful to the lungs and aggravates asthma, is the primary component of smog. The planned reductions in ground-level ozone are the first new limits proposed since 1997. AP has more.