Raun and Ensor conclude that federal air quality standards are adequate where ozone levels are concerned (at 75 parts per billion), but that lives would be saved if particulate matter standards were tightened below the current level of 35 micrograms per cubic meter of air.
Current designs can produce two kilowatts per cubic meter of liquid reactor volume and without any drawbacks (some models produce methane as a by-product, this tech does not).