Rhode Island air quality today

The Office of Air Resources at the Rhode Island Department of Environmental Management is direct about where the state’s summer problem originates: much of it is attributed to transport of ozone and its precursors from more polluted regions upwind. Rhode Island also sits inside the Ozone Transport Region, the multi-state block written into the Clean Air Act, and membership carries control obligations regardless of whether the state is meeting the standard on its own emissions. The requirements follow from where the state sits in the flow, not from what it puts into the air.

Water shapes the rest. Narragansett Bay reaches most of the way up the state, and RIDEM runs monitors on the open coast as well as around Providence. It publishes a daily air quality forecast and issues alerts when it expects ozone to reach the unhealthy-for-sensitive-groups level. Some of those alerts have been written for southern Rhode Island only, which is a useful thing to know: a gradient exists here across a distance that most states on this site would treat as a single point.

Ozone is what nearly all of those alerts concern, and it needs heat, sunlight and hours of reaction time, so the days that turn are midsummer afternoons rather than winter mornings. Rhode Island is small enough that one metro row can stand in for nearly all of it, which makes our resolution coarser than RIDEM’s: the agency splits the state when it forecasts, and we do not.