|Air Monitoring >> Annual Network Plan >> Network Changes for 2015-2016|
|2015-2016 Annual Monitoring Network Plan for North Carolina Air Quality|
The North Carolina Division of Air Quality (DAQ) operates a network of air quality monitors across the state. The network, consisting of over 90 monitors at more than 40 sites, measures the concentration of regulated pollutants in the ambient (outdoor) air. These pollutants include ozone, lead, fine particles, nitrogen oxides, sulfur dioxide and carbon monoxide. The measured concentrations are compared to the National Ambient Air Quality Standards (NAAQS) as set by the U.S. Environmental Protection Agency or EPA. If violations of these federal standards are detected, the DAQ takes regulatory action to return the ambient air quality to acceptable levels.
Every year the monitoring network is re-evaluated and adjusted to ensure it is providing adequate coverage. In most years these adjustments include starting new monitors, shutting down others, or simply relocating established monitors. The proposed annual network plan is subject to a 30-day public review period prior to being submitted to EPA for approval.
This year's plan continues some of the changes begun in last year's plan. This is a reflection of a shift in monitoring emphasis, with some pollutants becoming less of a concern and others becoming higher priority.
A number of major air pollution control programs have been implemented over the past 10 years, including the Clean Smokestacks Act passed by the North Carolina General Assembly in 2002. Under the act, coal-burning power plants were required to reduce their nitrogen oxide emissions by 77 percent by 2009 and sulfur dioxide emissions by 73 percent in 2013. Those significant emissions reductions have been achieved, and we are seeing the benefits in cleaner air - concentrations of ozone and fine particles are at the lowest levels ever measured in North Carolina.
At the same time, other pollutants are emerging as needing more attention. Specifically, the federal standards for sulfur dioxide (SO2) have been tightened, which results in the pending need for additional SO2 monitoring. The potential for shale gas development in North Carolina has made that a new priority, as well.
The network plan two years ago saw the first signs of this shift in emphasis, as we shut down three fine particle monitoring sites and one ozone monitor. We also established two significant new monitoring sites in 2013. The near-road site (Triple Oak) in Raleigh is the first ever specifically intended to capture concentrations extremely close to a major roadway (I-40). We also established a new site (Blackstone) and additional monitors at other sites (Candor and Millbrook) to specifically monitor baseline conditions prior to shale gas development.
Last year's network plan continued that shift in monitoring emphasis. It proposed shutting down six additional fine particle sites and three more ozone sites. But we also established two new SO2 sites. The EPA approved shutting down five of the fine particle sites and one of the ozone sites.
This year's network plan continues that shift in monitoring emphasis. It proposes shutting down nine fine particle monitoring sites, including the one EPA did not approve last year, and three ozone sites, including one of the sites EPA did not approve last year. During this period of realignment of the monitoring network we continue to plan for an expansion of near road and SO2 monitoring during the next two years. We believe the attached network plan offers the best balance of monitoring the highest priority air pollutants within our available resources. Although not noted in the network plan, we are also directing resources towards upgrading the infrastructure at existing sites and modernizing our remaining fleet of fine particle, sulfur dioxide and ozone monitors.
|2015-2016 Annual Monitoring Network Plan - Volume 1 - By Pollutant|
|By Division of Air Quality Regional Office:|