Ambient Air Quality Monitoring Program

Ambient Air Quality Monitoring Program

The State of Nebraska operates an ambient air-monitoring network to comply with the requirements of the Federal Clean Air Act and to determine compliance with the National Ambient Air Quality Standards (NAAQS) and State Ambient Air Quality Standards (SAAQS). In addition, the Nebraska network includes two sites for monitoring regional haze impacts that are part of a national program to help protect National Parks and Monuments.

Three agencies are involved in the day-to-day operation of the network: the Nebraska Department of Environmental Quality, the Douglas County Health Department, and the Lincoln/Lancaster County Health Department. The Omaha Air Quality Program (which is within the Omaha Public Works Department) also provides periodic support for network related activities.

NAAQS have been established for seven pollutants:

Particulate Matter with a diameter of 10 micrometers or less (PM10)
Particulate Matter with a diameter of 2.5 micrometers or less (PM2.5)
Sulfur Dioxide
Nitrogen Dioxide
Carbon Monoxide
Ozone
Lead

The National Ambient Air Quality Standards were established to protect both public health (which is termed a Primary Standard) and Public Welfare (which is termed a Secondary Standard and protects against excessive soiling, materials corrosion and crop damage). For all of the pollutants except sulfur dioxide, the National Ambient Air Quality Standards are listed as combined primary and secondary standards (i.e., protective of both human health and welfare). For Sulfur Dioxide, separate primary and secondary standards are listed.

The State Ambient Air Quality Standards are identical to the National Ambient Air Quality Standards with respect to the seven pollutants above, and also contain a standard for Total Reduced Sulfur (TRS). The TRS standard is a public health based standard.

Monitoring results indicate that all areas of the State are in compliance with the standards, with the exception of some short-term exceedances of the TRS standard in Dakota City (47 minutes in April 2003 and 10 minutes in April 2004). There have been significant reductions in TRS levels since 2001 and the Department continues monitoring in this area. For a more complete explanation of monitoring findings, please refer to the Nebraska Air Quality Report, which is published annually.

The monitoring network within the state is comprised of 36 monitors at 30 sites. See the table below titled Nebraska’s Air Monitoring Network - Summary Description for an overview description of monitor and site locations. For a more detailed description of the network, please refer to the Nebraska Air Monitoring Network Review, which like the Nebraska Air Quality Report is published annually.

The network is re-evaluated annually (see the Nebraska Air Monitoring Network Review) and is subject to ongoing modification to address changing conditions or standards, new information, and modernization. The highlight bullets that follow the Nebraska’s Air Monitoring Network – Summary Description table provide a good summary of recent changes

Nebraska’s Air Monitoring Network - Summary Description
June 2004

Omaha Metro Area (Douglas and Sarpy Counties) Monitors operated by the Douglas County Health Department
PM10	5 monitors at 4 sites
PM2.5	9 monitors at 4 sites, including collocated continuous and speciation monitors
Ozone	3 monitors at 3 sites *
Carbon Monoxide	2 monitors at 2 sites *
Sulfur Dioxide	2 monitors at 2 sites
Lead	None, discontinued in 2002
Toxics	A study of potential toxic air pollutants was conducted in the Dundee Neighborhood in cooperation with the Omaha Air Quality Program,USEPA, Agency for Toxic Substances and Disease Registry (ATSDR - An agency of the US Department of Health and Human Services), and NDEQ.
* The site at 30th & Fort Streets has both ozone and a carbon monoxide monitor.
Lincoln Metro Area Monitors operated by the Lincoln/Lancaster Health Department
PM2.5	2 monitors at 1 site
Ozone	1 monitor at 1 site
Carbon Monoxide	1 monitor at 1 site

Weeping Water	3 PM10 monitors at 2 sites 1 PM2.5 monitor at 1 site	Operated by NDEQ
Blair	1 PM2.5 monitor at 1 site	Operated by DCHD
Cozad	1 PM10 monitor at 1 site	Operated by NDEQ
Gothenburg	1 PM10 monitor at 1 site	Operated by NDEQ
Grand Island	1 PM2.5 monitor at 1 site	Operated by NDEQ
North Platte	1 PM2.5 monitor at 1 site	Operated by NDEQ
Scottsbluff	1 PM2.5 monitor at 1 site	Operated by NDEQ
Dakota City	1 TRS monitor at 1 site	Operated by NDEQ
South Sioux City	1 TRS monitor at 1 site	Operated by NDEQ
Lexington	1 TRS monitor at 1 site	Operated by NDEQ
IMPROVE monitor sites for the study of regional haze Two Sites operated under contracts administered by the NDEQ: Nebraska National Forest In Thomas County Crescent Lake Wildlife Refuge in Garden County One site operated by the Omaha Tribe of Nebraska and Iowa and administered by USEPA: Omaha Indian Reservation in Thurston County

Highlights of Changes and Events Related to Nebraska’s Air Monitoring Network

Air Quality Monitoring Trends: Ozone and Fine Particulates – Nationally, EPA is reporting good progress at maintaining compliance with most standards. The most problematic areas seem to be compliance with ozone and PM2.5 in larger urban areas. Both of these pollutants are formed in the atmosphere from other pollutant precursors, which complicates their control. These pollutants are typically associated with urban smog.

EPA is placing an emphasis on the monitoring of these two pollutants in urban areas, including the use of advanced continuous monitors for PM2.5. These continuous monitors provide for real-time data that can be used as a basis for the issuance of health alerts (Note: the continuous monitors can be used for the issuance of health alerts, but are not EPA approved to demonstrate compliance with the national ambient air quality standards). Also anticipated is the use of “speciation” monitors that provide information on the make-up of the PM

2.5

material. Speciation data is useful in helping identify pollutant sources and to make more definitive public health impact analyses. There are standard PM2.5 monitors, as well as speciation and continuous PM2.5 monitors, located at 4102 Woolworth Street in Omaha. The continuous monitor was newly installed in 2004.

Nebraska is fortunate in that all areas of the state, including the Omaha and Lincoln, are in attainment with these standards.

Air Quality Monitoring Trends: Air Toxics - The potential impacts of airborne toxics is of increasing concern. Air toxics present monitoring challenges due to the great number of potential substances, sampling difficulties, testing expense, and the lack of promulgated standards. Typically, air toxics monitoring is conducted as part of a special study with recognized limitations and goals. A multi-disciplined team approach is required that includes expertise in sampling, constituent analysis, statistics, and risk analysis.

An air toxic study was conducted in the Dundee Neighborhood of Omaha from 2002 through 2004 (six days of sampling over a two year period). The Douglas County Health Department conducted the monitoring with assistance for Omaha Air Quality Program, EPA, the U.S. Agency for Toxic Substances and Disease Registry (ATSDR - an agency of the US Department of Health and Human Services), and the NDEQ. ATSDR analyzed the data obtained to evaluate public health risks, and determined that the data did not demonstrate the existence of a public health threat.
Network Modernization – A number of modernization efforts are ongoing:

PM2.5 Designation and Network – PM2.5 is the abbreviation for particulate matter with a diameter equal to or less than 2.5 micrometers. This pollutant is not only emitted from sources, but is also formed in the atmosphere from other precursors (also see Air Quality Monitoring Trends: Ozone and Fine Particulates above). These fine particulates are of a greater health concern than larger particulate matter because they can more easily reach the lungs. The NAAQS for PM2.5 is relatively new, with monitoring being initiated in 1999.
PM10 – PM10 is the abbreviation for particulate matter with a diameter equal to or less than 10 micrometers. It originates primarily from stationary and fugitive sources. Nebraska began monitoring PM10 in 1987. There are currently eight sites: four in Omaha, two in Weeping Water, and one each in Cozad and Gothenburg. The monitoring data from these sites is currently in compliance with the NAAQS, although significant levels of PM10 are being detected at several sites (See bullets on Broken Bow, Cozad, Gothenburg and Weeping Water below). It is anticipated that a new site will be added in the Weeping Water area in 2005; no reductions in sampling sites are anticipated.
Sulfur Dioxide - Sulfur dioxide is a gas formed from the combustion of fuels containing sulfur. It is emitted from both mobile and stationary sources. Natural gas, gasoline and diesel fuels have a relatively low sulfur-content (rules promulgated in the mid-1990’s lowered the sulfur content of gasoline and diesel fuel). The primary sources of sulfur dioxide are large coal-fired combustion sources, such as power plants.
Ozone – Ozone is a gas formed in the atmosphere from the photochemical reaction of other pollutant precursors (e.g., nitrogen oxides and volatile organic compounds). It typically only reaches problematic levels in or adjacent to larger metropolitan areas or in densely populated regional areas. There are currently four ozone monitors in Nebraska: three in the Omaha metro area and one in the Lincoln metro area. The data from these monitors is in compliance with the National Ambient Air Quality Standards. Changes in the ozone network are not anticipated.
Carbon Monoxide– Carbon monoxide is a gas that is emitted from combustion sources. There are currently three carbon monoxide monitors in Nebraska: two in the Omaha metro area and one in Lincoln. The data from these monitors is in compliance with the National Ambient Air Quality Standards. Changes in the carbon monoxide network are not anticipated.
Nitrogen Dioxide– Nitrogen dioxide is a gas formed during combustion from the reaction of oxygen and nitrogen in combustion air (i.e., it is not fuel-derived like sulfur dioxide). It is emitted from both mobile and stationary sources. Controls implemented over the last 30 years (e.g., auto emission controls and emission standards enforced through state and local air quality permits) have effectively controlled nitrogen dioxide emissions such that attainment with the National Ambient Air Quality Standards for nitrogen dioxide has been achieved. Thus, nitrogen dioxide monitoring was discontinued within the state, with USEPA approval, in 1984.
Lead – Lead levels at concentrations above the National Ambient Air Quality Standards were a problem in Omaha through 1997. Following the closure of the ASARCO lead refinery in July 1997, ambient air lead levels dropped more than ten-fold. This area has been determined to be in attainment with the standard since 1998 and monitoring for lead was discontinued in 2002. With the phase out of leaded gasoline in the 1980s, and in the absence of any new sources, lead is not anticipated to be an ambient air quality problem in the foreseeable future.
Total Reduced Sulfur (TRS) – Nebraska established a state ambient air quality standard for TRS in 1997 and monitoring was started that same year in the Lexington and Dakota City/South Sioux City areas. Monitoring initially demonstrated TRS levels well above that standard in both areas. Following the covering of the IBP wastewater lagoons in 2001, TRS levels dropped more than ten-fold in both areas, and came into compliance with the state’s TRS standards, except for some brief periods in the spring at Dakota City (47 minutes in April 2003 and 10 minutes in April 2004). In 2003, TRS monitoring was discontinued at two sites (one in Lexington and one in Dakota City). This reduction in the network was undertaken because the consistently low readings at these sites indicated that they were no longer needed. TRS monitoring was also conducted in Broken Bow from 2000 through 2002, and was discontinued after no exceedances were found. As of June 2004, the TRS network consists of two monitors in Dakota City/South Sioux City area and one in the Lexington area.
IMPROVE (Interagency Monitoring of Protected Visual Environments) – These monitors are operated to study nation-wide/regional air quality impacts related to visibility at national parks, wilderness areas and monuments. There are two IMPROVE monitors in Nebraska that are operated under EPA-funded, third-party contracts administered through the NDEQ. The monitors are located at the Crescent Lake National Wildlife Refuge in Garden County and the Halsey National Forest in Thomas County. There is also an IMPROVE monitor located on the Omaha Indian Reservation in Thurston County, which is operated by the Omaha Tribe of Nebraska and Iowa with oversight directly from USEPA.
Weeping Water Area – The limestone mining, processing, and trucking activities in this area are a significant source of PM10. From the 1998 through 2000, the air quality in the Weeping Water area was such that an exceedance of the National Ambient Air Quality Standards for PM10 appeared imminent. In December 2000, the NDEQ and local stakeholders (businesses, government, and interested citizens) initiated a cooperative program to reduce PM10 emissions and improve air quality in the region. Improved control measures were implemented in the area, initially on a voluntary basis and later as conditions in air quality permits. These efforts have improved the air quality in the area. However, PM10 levels remain relatively high and close to the National Ambient Air Quality Standards, which is why EPA is requesting more monitoring be conducted in the area. An additional monitoring site for PM10 (i.e., a second site) was established in Weeping Water in October 2003, and a third site, to be located west of Weeping Water, is anticipated in 2005. Both of these sites will be equipped with EPA-approved continuous monitors.
Cozad and Gothenburg Areas – PM10 monitors are located in these two communities to address particulate sources, including alfalfa processing facilities located there. These areas remain in compliance with the National Ambient Air Quality Standards. It is anticipated that the monitors in these two areas will remain because, although in compliance, significant PM10 levels are being detected.
Broken Bow Area – Monitoring for PM10 and TRS was initiated in 2000 in response to local concern over air quality in the region. This monitoring demonstrated that air quality in the area was meeting national and state air quality standards. Monitoring in the Broken Bow area was discontinued in the fall of 2002.

Ambient Air Quality Monitoring Data

Air Quality Publications, Forms and Applications

DEQ.NE.Gov Home Page

Security, Privacy & Accessibility Policy

�Nebraska.gov

Nebraska Department of Environmental Quality
1200 "N" Street, Suite 400
P.O. Box 98922
Lincoln, Nebraska 68509
(402) 471-2186