Skip to main navigation

Network Plan Part 14 - Ozone, NATTS, Toxics, PAMS

4.6 Ozone

Ozone is a molecule made up of three oxygen atoms (O₃), a very reactive gas, and even at low concentrations it is irritating and toxic. It occurs naturally in small amounts in the earth's upper atmosphere, and in the air of the lower atmosphere after a lightning storm. In the stratosphere, between 10km and 50km above the earth's surface it forms the Ozone Layer. This is an important protective layer which filters out most of the high energy ultra-violet radiation from the sun which would damage much of the life on earth. When ozone is present at ground level and in the troposphere (10-18 km above earth's surface) it is considered a pollutant and a greenhouse gas. Ozone is used both industrially and commercially due mainly to its reactivity. It is used as a clean way of purifying water both in industry and in the home in hot-tubs and fish tanks. It is also used to disinfect laundry both in hospitals and in the home.

Ground-level O₃ remains a pervasive pollution problem in the United States. Ozone is readily formed in the atmosphere by the reaction of volatile organic compounds (VOCs) and NO_x in the presence of heat and sunlight, which are most abundant in the summer. VOCs are emitted from a variety of sources, including motor vehicles, chemical plants, refineries, factories, consumer and commercial products, other industries, and natural (biogenic) sources. Nitrogen oxides (a precursor to ozone) are emitted from motor vehicles, power plants, and other sources of combustion, as well as natural sources including lightning and biological processes in soil. Changing weather patterns contribute to yearly differences in O₃ concentrations. Ozone and the precursor pollutants that cause O₃ also can be transported into an area from pollution sources located hundreds of miles upwind.

Ozone occurs naturally in the stratosphere and provides a protective layer high above the earth. However, at ground level, it is the prime ingredient of smog. Short-term (1- to 3-hour) and prolonged (6- to 8-hour) exposures to ambient O₃ concentrations have been linked to a number of health effects of concern. For example, increased hospital admissions and emergency room visits for respiratory causes have been associated with ambient O₃ exposures.

Exposures to O₃ result in lung inflammation, aggravate preexisting respiratory diseases such as asthma, and may make people more susceptible to respiratory infection. Other health effects attributed to short-term and prolonged exposures to O₃, generally while individuals are engaged in moderate or heavy exertion, include significant decreases in lung function and increased respiratory symptoms such as chest pain and cough. Children active outdoors during the summer when O₃ levels are at their highest are most at risk of experiencing such effects. Other at-risk groups include adults who are active outdoors, such as outdoor workers, and individuals with preexisting respiratory disorders such as asthma and chronic obstructive lung disease. Within each of these groups are individuals who are unusually sensitive to O₃. In addition, repeated long-term exposure to O₃ presents the possibility of irreversible changes in the lungs, which could lead to premature aging of the lungs and/or chronic respiratory illnesses.

Ozone also affects sensitive vegetation and ecosystems. Specifically, O₃ can lead to reductions in agricultural and commercial forest yields, reduced survivability of sensitive tree seedlings, and increased plant susceptibility to disease, pests, and other environmental stresses such as harsh weather. In long-lived species, these effects may become evident only after several years or even decades. As these species are out-competed by others, long-term effects on forest ecosystems and habitat quality for wildlife and endangered species become evident. Furthermore, O₃ injury to the foliage of trees and other plants can decrease the aesthetic value of ornamental species as well as the natural beauty of our national parks and recreation areas.

EPA initially established primary and secondary NAAQS for photochemical oxidants on April 30, 1971. Both primary and secondary standards were set at an hourly average of 0.08 parts per million (ppm), total photochemical oxidants, not to be exceeded more than one hour per year.

On February 8, 1979, EPA completed its first periodic review of the criteria and standards for O₃ and other photochemical oxidants and made significant revisions to the original standard: the level of the primary and secondary NAAQS was changed to 0.12 ppm; the indicator was changed to O₃; and the form of the standards was changed to be based on the expected number of days per calendar year with a maximum hourly average concentration above 0.12 ppm (i.e., attainment of the standard occurs when that number is equal to or less than one).

In July, 1997 EPA revised the primary and secondary O₃ standards on the basis of the then latest scientific evidence linking exposures to ambient O₃ to adverse health and welfare effects at levels allowed by the 1-hr average standards. The O₃ standards were revised by replacing the existing primary 1-hr average standard with an 8-hr average O₃ standard set at a level of 0.08 ppm. The form of the primary standard was changed to the annual fourth-highest daily maximum 8-hr average concentration, averaged over three years. The secondary O₃ standard was changed by making it identical in all respects to the revised primary standard. These standards were challenged in the courts and the litigation lasted until March, 2002 when the D.C. Circuit Court issued its final decision, finding the 1997 O₃ NAAQS to be "neither arbitrary nor capricious," and denying the remaining petitions for review. As of June 15, 2005 EPA revoked the 1-hour ozone standard in all areas except the fourteen 8-hour ozone nonattainment Early Action Compact (EAC) Areas (none in NY).

After the most recent review of the ozone NAAQS, EPA revised the 8 hr ozone standard (primary and secondary) to 0.075 ppm, which went into effect on May 27, 2008.

The number of ozone monitors and concentration trends for both the 1 hr, and 8 hr standards in New York State for the past three decades are shown in Figures 4.15 and 4.16, respectively.

At present NYSDEC operates 34 TEI Model 49C ozone monitors statewide, which use the UV photometric method for detection. The site locations are depicted in Figure 4.17 below.

Figure 4.15 Ozone Monitors and 1 hr Concentration Trends

Figure 4.16 Ozone Monitors and 8 hr Concentration Trends

Figure 4.17 Location Map for Ozone Monitoring Sites

5. EPA's National Toxics Program

In general, EPA plans to use ambient air toxics monitoring to support the air toxics program's efforts to reduce human exposure and health risks from air toxics. The monitoring data provided by the ambient air toxics monitoring program is intended to support four major objectives:

• Establish trends and evaluate the effectiveness of air toxics emissions reduction strategies.
• Characterize ambient concentrations (and deposition) in local areas. Air toxics originate from local sources and can concentrate in relatively small geographical areas, producing the greatest risks to human health.
• Provide data to support, evaluate, and improve air quality models. Air quality models are used to develop emission control strategies, perform exposure assessments, and assess program effectiveness.
• Provide data to support scientific studies to better understand the relationship between ambient air toxics concentrations, human exposure, and health effects from these exposures.

EPA's national air toxics monitoring program is comprised of four different monitoring efforts:
1. National Air Toxics Trends Stations (NATTS)
2. EPA funded local-scale projects to assess conditions at the local level
3. Existing State and local program monitoring
4. Persistent bio-accumulative toxics monitoring

The objective for the NATTS network is to provide long-term monitoring data for certain priority air toxics across representative areas of the country in order to establish overall trends for these pollutants. Currently there are 23 NATTS established in 22 cities. The two New York NATTS sites are located in the Bronx, and Rochester, respectively.

EPA's initial ambient air toxics monitoring pilot studies disclosed that significant variations in pollutant concentrations occurred across a city and that these variations cannot be characterized by a single monitoring site. As a result, EPA decided that local-scale projects consisting of several monitors operated for a period of 1 to 2 years should be incorporated into the national air toxics monitoring strategy. In 2006 New York was awarded a grant for a community air quality air study in Tonawanda which began in July 2007. Hazardous air pollutans (HAPs) and fine particulate matter are measured at 4 locations in the Tonawanda community to address citizen concerns. The field sampling portion of this study was completed in July 2008. A final report on the findings will be released shortly.

New York State has been operating a toxics monitoring network since 1990, funded entirely by State monies. Currently there are 12 sites statewide collecting 24 hr canister samples for VOC analysis in a 1 in 6 days interval. See section on NY Toxics Monitoring Network.

The monitoring program for persistent bio-accumulative toxics primarily consists of deposition monitoring, not ambient air monitoring. Several monitoring programs operated by various Federal agencies have been established to measure the presence of toxics in various media. Recently New York has been awarded an EPA grant for "New York State Ambient Mercury Baseline Study"for the measurement of speciated mercury in ambient air, as well as mercury in wet deposition. This project is began in early 2008, and instrument deployment is under way.

In addition to air toxic-specific monitoring activities, several other monitoring programs that are primarily intended to address other air pollution concerns incorporate some aspects of air toxics monitoring. For example, the Photochemical Assessment Monitoring Stations (PAMS) collect data on certain volatile organic compound and carbonyl air toxics. Further, the results of some particulate matter monitoring is speciated (i.e., the individual compounds comprising the particulate matter are analyzed) to identify certain air toxics compounds.

5.1 National Air Toxics Trends Stations (NATTS)

EPA's Urban Air Toxics Program identified 33 high-priority urban air toxics. From these 33 air toxics EPA developed a list of 19 "core" air toxics representing the pollutants for which EPA eventually wants to develop trends information. However, because of limitations in available methodologies, EPA decided that at a minimum, in starting the network, each of the NATTS should monitor for at least 6 of these 19 pollutants. These six pollutants are considered national air toxics "drivers" (i.e., pollutants of concern in all areas of the country).

For the two NATTS sites, New York will perform analysis of 42 VOCs (Table 5.2), and 12 carbonyls (Table 5.6). More details on the sampling and analysis are provided in the NY Toxics Monitoring, and Photochemical Assessment Monitoring Stations sections, respectively. In addition, low volume PM10 teflon filters are collected for trace metals analysis using ICP-MS. The targeted metals include: arsenic, beryllium, cadmium, lead, manganese, nickel, antimony, cobalt, and selenium, with the last three being potential future HAPs. Hexavalent chromium sampling commenced in November 2007 at the Rochester and Bronx sites. The cellulose filter samples are shipped to EPA/ERG for laboratory analysis.

Polycyclic Aromatic Hydrocarbons (PAHs) sampling at the Rochester and IS 52 sites began in July 2008. The collection media consists of one 110mm diameter glass microfiber filter and a tubular glass cartridge containing a combination of Polyurethane Foam (PUF) and XAD-2 resin. The exposed samples are shipped to an EPA contract laboratory (ERG) for analysis.

5.2 NY Toxics Monitoring Network

The NY ambient air toxics monitoring program was first established in 1985 as part of the Governor's Air Monitoring Modernization Capital Budget Program. This monitoring network measures Volatile Organic Compounds (VOCs) across the State. The initial development of the network and analytical capabilities was part of a joint Staten Island/New Jersey Urban Air Toxics Assessment Project (SI/NJ Study) coordinated with U.S. EPA Region II from 1987 through 1989. The network expanded in 1990 to a statewide network.

The goal is to monitor air quality related to toxics in the State's urban, industrial, residential, and rural areas. Implementation of this program starts the development of a long-term toxics air quality database for New York State. The database will be used to define, attain, and preserve good air quality in New York State. The data defines actual air quality impacts of the VOCs. The data is used in the design and management of New York's air quality, including risk assessment, modeling, planning and trend analysis.

Initially only seventeen VOCs were monitored until 1995, when the number of analytes was increased to nineteen. In 2002 the list of VOCs was expanded to include 42 compounds as shown in Table 5.2 below:

Volatile organic compounds are collected in stainless steel canisters contained in a sampler known as an ambient air canister sampler. The sampler is an air flow calibrated sampling device that pumps ambient air into the canister. A special stainless steel diaphragm pump provides a constant pressure to push the sample through the sampler. A relief valve is used to maintain a steady pressure for the sample flow controller. Samples are collected at a one in six days frequency and shipped back to the Rensselaer laboratory facility for analysis.

The analysis methodology is a modified version of EPA method TO-15. An aliquot of air sample is taken from the canister at a controlled flow and temperature onto an Entech Model 7100A preconcentrator. The preconcentration process involves a series of steps. The first trap consists of glass beads/Tenax held at -110 °C which is then heated to room temperature in order to remove water/moisture in the sample. The next trap in line consists of Tenax held at - 30 °C. The contaminants of interest are then desorbed at 150 °C and collected on the cryofocuser held at -150 °C. The sample is then rapidly heated for column injection using a Varian GC coupled with a Saturn MS detection. This method of analysis allows positive identification by retention time and molecular mass.

Concentration trends charts for some ubiquitous VOCs are provided below.

Figure 5.1 Annual Averages for 1,3-Butadiene

Legend:
AGC Annual Guideline Concentration
LK Lakawanna
WF Whiteface
NF Niagara Falls
NYBG New York Botanical Gardens
FKW Fresh Kills West
FKG La Tourette Golf Course

Figure 5.2 Annual Averages for Methyl Tertiary-Butyl Ether

Legend:
AGC Annual Guideline Concentration
LK Lakawanna
WF Whiteface
NF Niagara Falls
NYBG New York Botanical Gardens
FKW Fresh Kills West
FKG La Tourette Golf Course

Figure 5.3 Annual Averages for 1,1,1-Trichloroethane


Legend:
AGC Annual Guideline Concentration
LK Lakawanna
WF Whiteface
NF Niagara Falls
NYBG New York Botanical Gardens
FKW Fresh Kills West
FKG La Tourette Golf Course

Figure 5.4 Annual Averages for Methylene Chloride


Legend:
AGC Annual Guideline Concentration
LK Lakawanna
WF Whiteface
NF Niagara Falls
NYBG New York Botanical Gardens
FKW Fresh Kills West
FKG La Tourette Golf Course

Figure 5.5 Annual Averages for Trichloroethylene


Legend:
AGC Annual Guideline Concentration
LK Lakawanna
WF Whiteface
NF Niagara Falls
NYBG New York Botanical Gardens
FKW Fresh Kills West
FKG La Tourette Golf Course

Figure 5.6 Annual Averages for Chloroform

Legend:
AGC Annual Guideline Concentration
LK Lakawanna
WF Whiteface
NF Niagara Falls
NYBG New York Botanical Gardens
FKW Fresh Kills West
FKG La Tourette Golf Course

Figure 5.7 Annual Averages for Benzene


Legend:
AGC Annual Guideline Concentration
LK Lakawanna
WF Whiteface
NF Niagara Falls
NYBG New York Botanical Gardens
FKW Fresh Kills West
FKG La Tourette Golf Course

Figure 5.8 Annual Averages for Toluene


Legend:
AGC Annual Guideline Concentration
LK Lakawanna
WF Whiteface
NF Niagara Falls
NYBG New York Botanical Gardens
FKW Fresh Kills West
FKG La Tourette Golf Course

Figure 5.9 Annual Averages for Tetrachloroethene

Legend:
AGC Annual Guideline Concentration
LK Lakawanna
WF Whiteface
NF Niagara Falls
NYBG New York Botanical Gardens
FKW Fresh Kills West
FKG La Tourette Golf Course

Figure 5.10 Annual Averages for m/p-Xylene

Legend:
AGC Annual Guideline Concentration
LK Lakawanna
WF Whiteface
NF Niagara Falls
NYBG New York Botanical Gardens
FKW Fresh Kills West
FKG La Tourette Golf Course

Figure 5.11 Annual Averages for o-Xylene

Legend:
AGC Annual Guideline Concentration
LK Lakawanna
WF Whiteface
NF Niagara Falls
NYBG New York Botanical Gardens
FKW Fresh Kills West
FKG La Tourette Golf Course

Figure 5.12 Annual Averages for 1,4-Dichlorobenzene

Legend:
AGC Annual Guideline Concentration
LK Lakawanna
WF Whiteface
NF Niagara Falls
NYBG New York Botanical Gardens
FKW Fresh Kills West
FKG La Tourette Golf Course

Currently there are 11 toxics monitoring sites in operation for the measurement of VOCs statewide. These locations are shown in Figure 5.13 below.

Figure 5.13 Location Map of Toxics Monitoring Sites