The Network

Kentucky has operated an air-quality monitoring network since July 1967. The current network includes 143 monitors that are located in 31 counties. The locations of the monitoring stations are selected using U.S. EPA guidance and in general are established near populous areas or pollutant sources. Each year the station locations are reviewed to ensure that adequate coverage is being provided. Data from the network is used to demonstrate compliance with and/or progress toward meeting ambient air quality standards and to identify pollution trends. The data are also used to provide pollutant levels for daily air quality index reporting and to detect elevated pollutant levels for activation of emergency control procedures. Air monitoring stations may also be set up for special studies for limited time periods to address specific issues with air quality in areas where there are numerous complaints or where we feel that air quality in a small area is affected by a localized activity. The map below indicates past and present air monitoring activities in Kentucky.  The division compiles a Kentucky Air Quality Surveillance Network Report, which includes pertinent siting information for each monitor in Kentucky.  The Louisville Metro Air Pollution Control District operates their own air-monitoring network.

The bulk of the network is designed to measure the six criteria pollutants. These are pollutants that EPA has determined pose the greatest risk to public health in ambient air. They are ozone, sulfur dioxide, carbon monoxide, nitrogen dioxide, lead and particulate matter (PM10 and PM2.5). Under 40 CFR Part 50 national primary and secondary ambient air quality standards are established for each of these pollutants. Primary standards are defined as levels of air quality that EPA judges are necessary, with an adequate margin of safety, to protect the public health. Secondary standards are defined as levels of air quality that EPA judges are necessary to protect the public welfare from any known or anticipated adverse effects of a pollutant. These standards are reviewed on a periodic basis to determine if new scientific evidence warrants a change. Table 1 lists the six criteria pollutants and the primary and secondary standards associated with each.

Table 1

Pollutant	Average	Primary Standard	Secondary Standard
Carbon Monoxide	8-hour average	9 ppm	9 ppm
Carbon Monoxide	3-hour	35 ppm	35 ppm
Sulfur Dioxide	24-hour	0.14 ppm	--
Sulfur Dioxide	Annual	0.03 ppm	--
Sulfur Dioxide	3-hour	--	0.50 ppm
Nitrogen Dioxide	Annual	0.053 ppm	0.053 ppm
Lead	Calendar quarter	1.5 ug/m3	1.5 ug/m3
Ozone	1-hour average	0.12 ppm	0.12 ppm
Ozone	8-hour average	0.08 ppm	0.08 ppm
PM10	24-hour average	150 ug/m3	150 ug/m3
PM10	Annual average	50 ug/m3	50 ug/m3
PM2.5	24-hour average	65 ug/m3	65 ug/m3
PM2.5	Annual average	15 ug/m3	15 ug/m3

There are very strict guidelines that have to be followed when monitoring for criteria pollutants. The guidelines include specifications for siting monitors, use of only equipment that has demonstrated the capability, repeatability and reliability needed to collect accurate data and operation of the equipment within established methods. A tremendous amount of effort and money is expended to ensure that these guidelines are followed and that we operate the most accurate and reliable network possible.

A Typical Air Monitoring Station

Owensboro Primary Site

The rest of the network consists of sites and equipment designed to support the criteria pollutant network or to measure air pollutants for which a national ambient air quality standard does not exist. These usually include acid rain stations, meteorological stations and air toxics monitoring stations. Data collected from acid rain stations are used to assess the effectiveness of the acid rain reduction programs. Data collected from meteorological stations can be used for modeling, and for studying and flagging episodic events. Data collected from air toxics stations are typically used in risk assessments.

Table 2 lists the number of each monitor that is currently operated by the Division for Air Quality and the Louisville Metro Air Pollution Control District.

Table 2

Parameters	DAQ Monitors	Louisville Metro Monitors
Acid Rain	1	0
Carbon Monoxide	0	2
Nitrogen Dioxide	7	1
Ozone	26	3
Particulate Matter PM 10	20	2
Particulate Matter PM 2.5	19	5
Sulfur Dioxide	10	2
Lead	0	0
Meteorological	12	1
Air Toxics	14	0
TOTALS	109	16

The Instrumentation

The technology used for ambient air monitoring can be broken down into three categories. The first and most widely used are direct-reading instruments. These are monitors that run 24 hours per day, seven days a week, 365 days a year and provide a direct reading to a data system. Direct reading instruments pull in a sample of ambient air through a sampling manifold that is designed to not react or interfere with the whole air sample. The instruments will then use some type of light attenuation such as infrared or ultra violet absorption or a photochemical reaction may occur between the pollutant and a catalyst that results in a flash of light that can be measured. Through calibration techniques the degree of light attenuation or the intensity of the light created corresponds to a known level of air pollution. These instruments are typically very accurate, reliable and as one may guess expensive. Ozone, carbon monoxide, nitrogen dioxide and sulfur dioxide monitors are examples of direct reading instruments.

Examples of Direct Reading Instruments

The second type of instrument is typically referred to as a sampler. These instruments collect pollutants on a filter or on some type of media that is retrieved and analyzed by a laboratory. Usually these samplers run for a 24-hour period and the analysis represents a 24-hour average. PM10, PM2.5, lead, acid rain samplers and most air toxics samplers are examples of this type of instrumentation.

PM10 and PM2.5 Samplers
London Site

The third is actually a hybrid of the other two. In this instrument, a sample is collected over a short period of time and then is processed by additional instrumentation either included in or attached directly to the sampler. An example of this technology is the TEOM PM10 sampler that collects particulate matter on a filter and then determines mass using technology developed for NASA for weighing objects in zero gravity. Other examples are the MDA toxics gas monitors, total hydrocarbon analyzers. 

The Pollutants

Acid Rain

Acid rain includes precipitation in the form of snow, sleet, hail, rain or fog that has a low pH level resulting from emissions of pollutants into the atmosphere. Since 1986 Kentucky has participated in a national program to measure acid rain. Currently two sites are operated in Kentucky, one located at Grayson Lake State Park and the other at Mammoth Cave National Park. Samples are collected on a weekly basis and shipped to the Division of Environmental Services for analysis. Samples at the Mammoth Cave site are collected by the U.S. Park Service. Measurements include total rainfall, pH, conductivity, sodium, potassium, magnesium, calcium, chloride, ammonium, nitrate and sulfate.

Carbon Monoxide

Carbon monoxide is an odorless, colorless, poisonous gas that is produced by the incomplete combustion of carbon-containing fuels. The primary source of carbon monoxide is the exhaust from motor vehicles. Other sources include industrial processes and coal, kerosene, and wood-burning stoves in homes. Monitoring for carbon monoxide is accomplished by using direct reading instruments using infrared photometry. Carbon monoxide will absorb certain wavelengths of infrared light. A known intensity of infrared light is bounced through a detection chamber using a series of mirrors. If there is carbon monoxide present, some of the light will be absorbed. The attenuation of this light is proportional to the concentration of the pollutant. Statewide carbon monoxide levels show declining trends, primarily due to improved emission controls on motor vehicles.

Nitrogen Dioxide

Nitrogen dioxide is a reddish-brown gas that is produced during the high temperature combustion of fossil fuels. The primary sources of nitrogen dioxide are power plants, motor vehicles, incinerators, industrial boilers and some chemical processes. Monitoring is accomplished by using direct reading instruments that utilize the principle of photometric detection of a chemiluminescence reaction that occurs when nitric oxide is mixed with ozone. Statewide levels of nitrogen dioxide show a steady downward trend likely due to the use of pollution control devices on power plants, motor vehicles and industrial boilers.

Ozone

Ozone is a colorless gas that is not emitted directly into the atmosphere from sources but forms in the atmosphere from a photochemical reaction between volatile organic compounds and nitrogen oxides in the presence of sunlight. Sources of volatile organic compounds include motor vehicle exhaust, dry cleaning, paint solvents and gasoline evaporation. Because meteorological conditions play an important part in the formation of ozone, we only monitor for ozone between March 1 and Oct. 31. Monitoring is accomplished by using direct reading instruments that utilize ultraviolet photometry. Much like the upper ozone layer absorbs harmful UV rays; ground-level ozone absorbs UV light generated by the ozone monitor. The higher the absorption the higher the ozone level. Although ozone continues to be a problem in most areas of the state, there has been a general decline in ozone levels over the years. The decline is the result of control of VOCs and nitrogen oxides from industrial sources and vehicles.

Particulate Matter

Particulate matter is a broad classification of pollutants that consists of very fine solid particles, liquid droplets or aerosols. Particulates are produced from many sources, including electric utilities, wood-burning stoves, leaf burning, vehicle exhaust, incinerators, rock and coal processing, construction, smelting, farming and roadways. Common forms of particulates include fly ash, soot, soil, minerals, fibers, metals, oil aerosols and tire rubber. Particulates are categorized according to the particle diameter and the health impacts caused by particles of differing sizes. Particles of larger sizes typically settle out of the air rapidly and pose a limited health risk whereas particles of very small size may stay in the air for very long times and can penetrate deeply into the human respiratory system and cause harmful effects. There are generally three classifications of particulate matter.

• Total Suspended Particulates (TSP) are particles between 10 and 50 microns in diameter.
• PM10 are particles 10 microns or smaller in diameter.
• PM2.5 are particles 2.5 microns or smaller in diameter.

As one might guess PM10 and PM2.5 pose the biggest health risk due to their ability to penetrate deeply into the respiratory system. Particulate matter is typically measured by samplers. An air sample is drawn through a filter that traps the particles. The filters are removed and the filter is then gravimetrically analyzed to determine a concentration.  A recent addition to the Kentucky air monitoring network is the PM2.5 Speciation Sampler which is designed to collect particles 2.5 microns or smaller.  The samples are then sent to a laboratory for analysis of various chemical species.  Statewide levels of TSP and PM10 have declined over the years due to controls on industry and motor vehicles. Since we only began monitoring for PM2.5 in 1999 we do not have enough data on this pollutant to characterize ambient concentrations statewide.

Sulfur Dioxide

Sulfur dioxide is a colorless gas that has a pungent odor at concentrations exceeding 0.5 parts-per-million. Sulfur dioxide is produced by the combustion of sulfur-containing fuels, ore smelting, petroleum processing and the manufacture of sulfuric acid. Coal-fired power plants are typically the largest sources of sulfur dioxide. Measurement is accomplished by utilizing direct reading instruments that operate on the ultraviolet fluorescence method. Portions of UV light generated by the analyzer is absorbed by the sulfur dioxide molecules which then re-emits the energy at specific wavelengths of light. The analyzer is filtered to only detect these wavelengths and the intensity is proportional to the concentration of sulfur dioxide present in the sample. Statewide levels of sulfur dioxide have shown a steady decline due in part to controls on power plants.

Lead

Lead is one of the naturally occurring metal elements that is classified as a heavy metal and is toxic if inhaled or ingested. The primary source of lead was from leaded fuels used in vehicles. During the 1970's legislation was adopted to gradually phase out the use of lead as a fuel additive. Today lead emissions from vehicles have been virtually eliminated. Currently smelters and battery plants are the major sources of lead emissions. Monitoring is accomplished by using a sampler that draws air through a filter. The filter is removed and sent to a laboratory for analysis. With the phase out of lead in fuels, ambient levels have fallen near to zero statewide. The division currently does not operate lead monitors but each year emission inventories are reviewed to look at industrial source emissions to determine if a network is needed.

Air Toxics

Air toxics include a wide variety of substances that are know or suspected to cause neurological, immunological, reproductive and respiratory disorders or are known or suspected human carcinogens. Sources include all types of industry, vehicle exhaust, gas stations, dry cleaners, pest control, painting and open burning. Currently the division has the capability to monitor for more than 168 air-toxic compounds and this list continues to grow as technology and methods improve. Air toxics can generally be divided into four distinct groups: volatile organic compounds, semi-volatile organic compounds, metals, and reactive acidic and caustic gases. Monitoring is typically accomplished by either collecting a whole-air sample in a nonreactive container, or by collecting a sample on some form of sample media. A laboratory using various analytical techniques then analyzes these samples. There are no national ambient air quality standards for air toxics so typically characterization involves a risk assessment. Historically Kentucky's approach to air toxics has been to concentrate monitoring near industrialized areas. Multi-year studies have been done near the Calvert City Industrial Complex in western Kentucky and in the northeastern portion of the state near Ashland, which is referred to as the Tri-State geographic area. These studies consumed most of our resources for air toxics sampling so the opportunity has not arisen to monitor elsewhere in the state. In 2000, a monitoring program was designed to characterize ambient air toxics levels in our most urban areas. Data from this network will give us a better indication of what air toxics levels are statewide and will assist us in designing programs to better address air toxics issues in the future.

The Data

Data from the air-monitoring network can be obtained in several ways. Each year the division issues the Kentucky Ambient Air Quality Annual Report which contains specifics onsite locations and a summary of data collected at these sites. More detailed data can be obtained from the EPA Aerometric Information Retrieval System through the EPA's Web site. Even more detailed information can be obtained from the Kentucky Air Monitoring System (KAMS) operated by the Technical Support Section. Maps indicating the formation of ozone during peak ozone months can be viewed from EPA's AIRNOW Web site. Air quality information for Lexington, Ashland, Owensboro, northern Kentucky and Paducah can be obtained by calling the division's Air Quality Index Reporting System at 800-AIR-INKY. Eventually we hope to get near-real time data from many of our sites available on our Web site.

The Players

The responsibility for designing and supporting the air-monitoring network mainly resides in the Technical Services Branch. Network design, budgeting, groveling for money, reporting and planning is initiated at the branch manager's level. The Technical Support Section is responsible for instrumentation repair, gravimetric analysis of particulate samples, training and data processing. Site audits, data validation and the development of Standard Operating Procedures Manuals are the responsibility of the Quality Assurance Section.

The responsibility for actually operating the network resides in the Field Operations Branch. Each regional office has personnel who are responsible for running the sites located within their regional boundaries. They make sure that the monitors are running correctly, attend to the basic maintenance of the monitors, perform calibrations, crunch data and collect samples.

The Kentucky Division of Environmental Services is responsible for analyzing air toxics samples and operates the mobile air toxics laboratory. The Air Toxics Section in this division handles the bulk of this workload.

Input from all the branches is used when evaluating the network to determine if their individual needs are being met. Data generated by the network is used on a daily basis by all of the programs in the division.