Network Plan Part 13 - CO, NO2, PM, SO2
4. Criteria Contaminants
EPA is required to set National Ambient Air Quality Standards (NAAQS) for wide-spread pollutants from numerous and diverse sources considered harmful to public health and the environment. The Clean Air Act established two types of national air quality standards. Primary standards set limits to protect public health, including the health of "sensitive" populations such as asthmatics, children, and the elderly. Secondary standards set limits to protect public welfare, including protection against visibility impairment, damage to animals, crops, vegetation, and buildings. The Clean Air Act requires periodic review of the science upon which the standards are based and the standards themselves. Listed below are the NAAQS for six principal pollutants, which are called "criteria" pollutants.
(1) Not to be exceeded more than once per year.
(2) Effective 1/12/2009, replaces the previous quarterly average value of 1.5 µg/m3.
(3) Not to be exceeded more than once per year on average over 3 years.
(4) To attain this standard, the 3-year average of the weighted annual mean PM2.5 concentrations from single or multiple community-oriented monitors must not exceed 15.0 µg/m3.
(5) To attain this standard, the 3-year average of the 98th percentile of 24-hour concentrations at each population-oriented monitor within an area must not exceed 35 µg/m3 (effective December 17, 2006).
(6) To attain this standard, the 3-year average of the fourth-highest daily maximum 8-hour average ozone concentrations measured at each monitor within an area over each year must not exceed 0.075 ppm (effective May 27, 2008).
(7) (a) To attain this standard, the 3-year average of the fourth-highest daily maximum 8-hour average ozone concentrations measured at each monitor within an area over each year must not exceed 0.08 ppm. (b) The 1997 standard-and the implementation rules for that standard-will remain in place for implementation purposes as EPA undertakes rulemaking to address the transition from the 1997 ozone standard to the 2008 ozone standard.
(8) (a) The standard is attained when the expected number of days per calendar year with maximum hourly average concentrations above 0.12 ppm is < 1.
(b) As of June 15, 2005 EPA revoked the 1-hour ozone standard in all areas except the 8-hour ozone nonattainment Early Action Compact (EAC) Areas.
The following sections describe New York's effort in monitoring each of these criteria contaminants.
4.1 Carbon Monoxide
Carbon monoxide, a colorless and odorless gas, is produced as a primary pollutant during the combustion of fossil and biomass fuels. Vegetation also can emit CO directly into the atmosphere as a metabolic by-product. Sources such as motor vehicles, nonroad combustion engines or vehicles, and biomass burning can cause high concentrations of CO in the outdoor environment. Indoor sources include unvented, malfunctioning, or misused combustion appliances, combustion engines in garages or basements, and tobacco combustion. In both of these environments, CO is of direct concern because of the health effects that can result from human exposure to these high concentrations.
CO enters the bloodstream through the lungs and reduces oxygen delivery to the body's organs and tissues. The health threat from levels of CO sometimes found in the ambient air is most serious for those who suffer from cardiovascular disease such as angina pectoris. At much higher levels of exposure not commonly found in ambient air, CO can be poisonous, and even healthy individuals may be affected. Visual impairment, reduced work capacity, reduced manual dexterity, poor learning ability, and difficulty in performing complex tasks are all associated with exposure to elevated CO levels.
There are two primary NAAQS for ambient CO: a 1-hour average of 35 ppm and an 8-hour average of 9 ppm. These concentrations are not to be exceeded more than once per year. There currently are no secondary standards for CO.
Motor vehicle exhaust contributes about 60 percent of all CO emissions nationwide. High concentrations of CO generally occur in areas with heavy traffic congestion. Other sources of CO emissions include industrial processes, non-transportation fuel combustion, and natural sources such as wildfires. Peak CO concentrations typically occur during the colder months of the year when CO automotive emissions are greater and nighttime inversion conditions are more frequent.
Technological advancements in pollution control has brought about a downward trend for ambient CO concentrations over the past few decades. According to EPA estimates, annual CO emissions decreased from 197.3 million tons in 1970 to 89 million tons in 2005 nationally.
The number of monitors and concentration trends chart over the years in New York State are depicted in Figure 4.1. It clearly demonstrates that the current ambient levels of CO are well below the NAAQS, in spite of the continual increase in automobiles and vehicle-miles traveled in the State. As of 2002, all counties in the State have achieved attainment designation.
Figure 4.1 Carbon Monoxide Monitors and Concentration Trends
NYSDEC uses TEI Model 48C instruments that employ the NDIR gas filter correlation method for the continuous measurement of CO. Currently there are nine CO monitors in operation statewide as shown in Figure 4.2.
Figure 4.2 Location Map for Carbon Monoxide Monitoring Sites
Carbon monoxide in less polluted air is also of interest because of its importance to atmospheric chemistry. Carbon monoxide can affect the formation of ozone (O3) and other photochemical oxidants in the atmosphere. Carbon monoxide strongly influences the abundance of hydroxyl radicals (OH), thus affecting the global cycles of many biogenic and anthropogenic trace gases that affect the abundance of stratospheric O3 and the energy budget of the atmosphere. Changes in CO concentrations, therefore, may contribute to widespread changes in atmospheric chemistry and indirectly affect global climate. We anticipate the addition of low level CO monitors at the 3 NCore sites in the future (see section on NCore below).
4.2 Nitrogen Dioxide
Many chemical species of nitrogen oxides (NOx) exist, but the air pollutant species of most interest from the point of view of human health is nitrogen dioxide (NO2). Nitrogen dioxide is soluble in water, reddish-brown in color, and a strong oxidant.
Nitrogen dioxide is an important atmospheric trace gas, not only because of its health effects but also because (a) it absorbs visible solar radiation and contributes to impaired atmospheric visibility; (b) as an absorber of visible radiation it could have a potential direct role in global climate change if its concentrations were to become high enough; (c) it is, along with nitric oxide (NO), a chief regulator of the oxidizing capacity of the free troposphere by controlling the build-up and fate of radical species, including hydroxyl radicals; and (d) it plays a critical role in determining ozone (O3) concentrations in the troposphere because the photolysis of nitrogen dioxide is the only key initiator of the photochemical formation of ozone, whether in polluted or unpolluted atmospheres.
Natural sources include intrusion of stratospheric nitrogen oxides, bacterial and volcanic action, and lightning. The major source of anthropogenic emissions of nitrogen oxides into the atmosphere is the combustion of fossil fuels in stationary sources (heating, power generation) and in motor vehicles (internal combustion engines).
In most ambient situations, nitric oxide is emitted and transformed into nitrogen dioxide in the atmosphere. Oxidation of nitric oxide by atmospheric oxidants such as ozone occurs rapidly, even at the low levels of reactants present in the atmosphere. Consequently, this reaction is regarded as the most important route for nitrogen dioxide production in the atmosphere.
Other contributions of nitrogen dioxide to the atmosphere come from specific non-combustion industrial processes, such as the manufacture of nitric acid, the use of explosives and welding.
Indoor sources include tobacco smoking and the use of gas-fired appliances and oil stoves.
Nitrogen dioxide is the most widespread and commonly found nitrogen oxide and is a matter of public health concern. The most troubling health effects associated with short term exposures (i.e., less than 3 hours) to NOx at or near the ambient NOx concentrations seen in the United States include cough and increased changes in airway responsiveness and pulmonary function in individuals with preexisting respiratory illnesses, as well as increases in respiratory illnesses in children 5 to 12 years old.. Evidence suggests that long-term exposures to NOx may lead to increased susceptibility to respiratory infection and may cause structural alterations in the lungs.
Atmospheric transformation of NOx can lead to the formation of ozone and nitrogen-bearing particles (e.g., nitrates and nitric acid). As discussed in the ozone and particulate matter sections of this document, exposure to both PM and O3 is associated with adverse health effects.
Nitrogen oxides contribute to a wide range of effects on public welfare and the environment, including global warming and stratospheric ozone depletion. Deposition of nitrogen can lead to fertilization, eutrophication, or acidification of terrestrial, wetland, and aquatic (e.g., fresh water bodies, estuaries, and coastal water) systems. These effects can alter competition between existing species, leading to changes in the number and type of species (composition) within a community. For example, eutrophic conditions in aquatic systems can produce explosive algae growth leading to a depletion of oxygen in the water and/or an increase in levels of toxins harmful to fish and other aquatic life.
The level for both the primary and secondary NAAQS for NO2 is 0.053 ppm annual arithmetic average (mean), not to be exceeded. Figure 4.3 shows the number of monitoring sites and NO2 concentration trends over the years. The current ambient levels of NO2 observed in New York State are well below the NAAQS.
In New York, the TEI Model 42C instruments are deployed for continuous NO2 measurements using the gas phase chemiluminescence method. Currently there are seven NOx monitoring sites statewide as shown in Figure 4.4.
Although ambient NO2 levels are not expected to contravene the NAAQS, monitoring is necessary due to it being an ozone precursor, and to track the effectiveness of emission reduction programs.
4.3 Lead
Elemental lead (Pb) possesses an array of useful physical and chemical properties, making it among the first metals to be extracted and used by humankind. It has a relatively low melting point (327.5 °C), is a soft, malleable, and ductile metal, a poor electrical conductor, and is easily cast, rolled and extruded. Although sensitive to environmental acids, after exposure to environmental sulfuric acid (H2SO4), metallic Pb becomes impervious to corrosion due to weathering and submersion in water. This effect is due to the fact that Pb lead sulfate (PbSO4), the relatively insoluble precipitate produced by reaction of Pb with H2SO4, forms a protective barrier against further chemical reactions. This aspect of its chemistry made Pb especially convenient for protective surface coatings (e.g. paint), roofing, containment of corrosive liquids, and (until the discovery of its adverse health effects), construction of water supply systems.
Pb will only exist in the vapor phase at or above 1750°C. Therefore, at ambient atmospheric temperatures, elemental Pb will deposit to surfaces or exist in the atmosphere as a component of atmospheric aerosol.
Exposure to lead occurs through ingestion of lead in food, water, soil, or dust and through inhalation. It accumulates in the blood, bones, and soft tissues. Lead can also adversely affect the kidneys, liver, nervous system, and other organs. Excessive exposure to lead may cause neurological impairments such as seizures, mental retardation, and/or behavioral disorders. Even at low doses, Pb exposure is associated with changes in fundamental enzymatic, energy transfer, and homeostatic mechanisms in the human body. Additionally, even low levels of Pb exposure may cause central nervous system damage in fetuses and children. Recent studies show that neurobehavioral changes may result from Pb exposure during the child's first years of life and that lead may be a factor in high blood pressure and subsequent heart disease.
Airborne lead can also have adverse impacts on the environment. Wild and domestic grazing animals may ingest lead that has deposited on plant or soil surfaces or that has been absorbed by plants through leaves or roots. Animals, however, do not appear to be more susceptible or more sensitive to adverse effects from lead than are humans. Therefore, the secondary standard for lead is identical to the primary standard.
In November of 2008 EPA published the final rule for the revision of the NAAQS for lead. The primary lead standard was revised to 0.15 µg/m3 in total suspended particles (Pb-TSP). The averaging time was changed to a rolling 3-month period with a maximum (not-to-be-exceeded) form, evaluated over a 3-year period. The revised secondary standard was set to be identical in all respects to the new primary standard. These new standards became effective on January 12, 2009, superceding the old standard of quarterly average concentration not to exceed 1.5 µg/m3.
In the past, automotive sources were the major contributor of lead emissions to the atmosphere. As lead was phased out of gasoline, the contribution of air emissions of lead from transportation sources has greatly declined over the past two decades. Today, industrial processes, primarily metals processing, are the major source of lead emissions to the atmosphere. The highest air concentrations of lead are usually found in the vicinity of smelters and battery manufacturers.
Particulate lead samples are collected on glass fiber filters using a standard TSP high volume sampler which are subsequently analyzed by the laboratory using atomic absorption spectroscopy. Under the new rule, EPA is allowing Pb-PM10 in lieu of Pb-TSP where the maximum 3-month arithmetic mean Pb concentration is expected to be less than 0.10 µg/m3 (i.e., two thirds of the NAAQS) and where sources are not expected to emit ultra-coarse Pb.
Figure 4.5 depicts the number of monitoring sites and lead concentration trends for New York State over the years.
Currently there are five remaining Pb monitors in operation, four in Middletown, where a lead acid battery recycling facility is located, and one in New York City (JHS 126). It appears that the lead levels measured at the current monitoring sites are below the newly revised standards.
4.4 Particulate Matter
4.4.1 Total Suspended Particulate
Particulate matter is the generic term for a broad class of chemically and physically diverse substances that exist as discrete particles (liquid droplets or solids) over a wide range of sizes. Particles originate from a variety of anthropogenic stationary and mobile sources as well as natural sources. Particles may be emitted directly or formed in the atmosphere by transformations of gaseous emissions such as sulfur oxides, nitrogen oxides, and volatile organic compounds. The chemical and physical properties of PM vary greatly with time, location, meteorology, and source category, thus complicating the assessment of health and welfare effects.
EPA first established national ambient air quality standards for PM in 1971. The reference method specified for determining attainment of the original standards was the high-volume sampler, which collects PM up to a nominal size of 25 to 45 micrometers (µm), referred to as total suspended particles or TSP. The primary standards (measured by the indicator TSP) were 260 µg/m3, 24-hour average, not to be exceeded more than once per year, and 75 µg/m3, annual geometric mean. The secondary standard was 150 µg/m3, 24-hour average, not to be exceeded more than once per year. These standards were in place until 1987 when EPA changed the particle indicator from TSP to PM10, the latter referring to particles with a mean aerodynamic diameter less than or equal to10 µm.
4.6 Total Suspended Particulate Monitors and Concentration Trends
Figure 4.6 shows the number of monitoring sites and the composite annual geometric means of TSP over the years. Trace metal analysis was also performed on the TSP filters until 1998. NYSDEC terminated the TSP sampling program when DOH could no longer provide laboratory analysis support. The St. Regis Band of Mohawk Indians of New York continues to operate one remaining TSP monitor on tribal land in Hogansburg.
4.4.2 PM10
In 1987 EPA revised the 1971 standards in order to protect against adverse health effects of inhalable airborne particles that can be deposited in the lower (thoracic) regions of the human respiratory tract, with PM10 as the indicator. EPA established identical primary and secondary PM10 standards for two averaging times: 150 µg/m3 (24-h average, with no more than one expected exceedance per year) and 50 µg/m3 (expected annual arithmetic mean, averaged over three years). These standards remained in effect until 2002, when the courts finally upheld the 1997 revisions put forth by EPA as a result of the mandated periodic scientific review. After the most recent scientific review on PM, EPA issued the final rule in December, 2006 revising the PM2.5 standards, at the same time revoking the PM10 annual standard while retaining the 24 hr standard at 150 µg/m3.
Wedding & Associates PM10 Critical Flow High Volume Sampler (WED PM10 sampler) were employed for the NYSDEC network. The quartz filters were collected and submitted to the Department of Health for laboratory analysis until 2005, when support services were terminated. Figure 4.7 shows the number of monitors and the composite annual arithmetic mean for PM10.
Starting in 2004, the R&P Partisol 2025 samplers were used for manual PM10 collection by removing the PM2.5 size selective inlet. The filter cartridges are submitted to RTI (EPA contract laboratory) for mass analysis. Currently there are seven such sites in operation, as shown in Figure 4.8.
Figure 4.8 Location Map for PM10 Monitoring Sites
4.4.3 PM2.5
In July 1997, EPA Administrator promulgated significant revisions to the PM NAAQS, after taking into account scientific information and assessments presented by staff, Clean Air Scientific Advisory Committee advice and recommendations, and public comments. While it was determined that the PM NAAQS should continue to focus on particles less than or equal to 10 µm in diameter, it was also determined that the fine and coarse fractions of PM10 should be considered separately. New standards were added, using PM2.5 as the indicator for fine particles; and PM10 standards were retained for the purpose of regulating coarse-fraction particles. Two new PM2.5 standards were set: an annual standard of 15 µg/m3, based on the 3-year average of annual arithmetic mean PM2.5 concentrations from single or multiple community-oriented monitors; and a 24-h standard of 65 µg/m3, based on the 3-year average of the 98th percentile of 24-h PM2.5 concentrations at each population-oriented monitor within an area. To continue to address coarse-fraction particles, the annual PM10 standard was retained, and the form, but not the level, of the 24-h PM10 standard was revised to be based on the 99th percentile of 24-h PM10 concentrations at each monitor in an area. The secondary standards were revised by making them identical in all respects to the PM2.5 and PM10 primary standards.
After the most recent scientific review EPA issued the final rule in December, 2006 revising again the NAAQS for PM to provide increased protection of public health and welfare, respectively. EPA revised the level of the 24-hour PM2.5 standard from 65 to 35 micrograms per cubic meter (µg/m3) and retained the level of the annual PM2.5 standard at 15 µg/m3. With regard to PM10, the 24-hour standard was retained, but the annual PM10 standard was revoked.
The NYSDEC PM2.5 monitoring network deploys a combination of filter based Federal Reference Method (FRM) samplers, continuous mass monitors, filter based speciation samplers and continuous speciation samplers. The data from the FRM samplers are used to determine if the State's air quality meets the National Ambient Air Quality Standards (NAAQS). The continuous mass sampler data are used for the reporting of near real-time air quality data for health related warnings and forecasts. The speciation filter sampler data are used to determine the chemical constituents that make up PM2.5. The continuous speciation data are used to examine the short term fluctuations in the concentrations of individual species or components that make up PM2.5.
PM Monitoring Objectives
The principal objective of the PM2.5 monitoring network is to determine the exposure of the State's population to ambient PM2.5. This objective is the primary focus of the FRM filter based samplers as well as for the continuous mass monitoring network. The protocols and equipment used for the FRM network are meticulously specified in the Code of Federal Regulations (CFR) to insure that the measurements are consistent from one State to another. The continuous mass monitoring instruments cannot accurately provide data for direct comparison with the NAAQS but these instruments actually provide the most useful data for population exposure. The continuous PM2.5 data is updated every hour for near real-time health related warnings, PM2.5 forecasts and updates as to current pollution concentrations.
The NYSDEC has attempted to adjust the PM2.5 network in light of EPA expectations, updated regulations and prioritized funding. The FRM network consisted of 40 sites when it was fully established using the original design criteria from 1998. Since then the number of sites have been reduced because fewer sites were required to determine compliance with the Annual PM2.5 NAAQS. The latest revisions to the Federal regulations have reduced the number of required monitors even further. These new requirements base the number of required monitors on population and the expected PM2.5 concentration. The NYSDEC network exceeds these requirements in all areas that are expected to be near or above either the Annual or Daily PM2.5 standard.
The other monitoring objectives for the PM2.5 network include transport and background monitoring. Transport monitoring sites are sites that are situated so that the data are representative of the air masses moving into the State from areas upwind. These sites are important because the sources of PM2.5 that are outside of New York can contribute to New York's PM2.5 ambient concentration. Background monitoring sites are sites that are representative of PM2.5 concentrations that are generally not related to specific sources but impact wide areas. The concentrations measured at these background sites generally represent the lowest expected PM2.5 concentrations in New York State.
Monitoring Scale and Representativeness
The geography of New York State encompasses a lake shore to the west, plateaus and rolling hills in the center, mountains to the northeast and south and sea shores to the southeast. All of these areas have varying population densities and meteorology. The populations living in these areas are exposed to PM2.5 that is generated locally as well as from PM2.5 that is transported from areas outside of their region.
The actual design of the network is a compromise that minimizes the number of monitoring locations while ensuring that the measured concentrations for each area are indicative of actual population exposures. Each sampler is assigned a scale or "zone of representativeness" when it is installed. The scale determines how large a geographical area the resulting data will represent.
EPA has defined ambient monitoring scales as:
- Microscale: Represents (10 - 100 meters)
- Middle Scale: Represents (100 - 500 meters)
- Neighborhood Scale: Represents (500 meters - 4 km)
- Urban Scale: Represents (4 - 100 km)
- Regional Scale: Represents (100 to 1000 km)
The scale of the FRM monitoring sites that have population exposure as their objective is Neighborhood or Urban. The definitions of scale primarily serve to identify the site's sensitivity to individual sources. A monitoring site that is routinely impacted by a specific source has a much smaller "scale" than a site that only sees an effect from numerous widespread sources. The FRM sites in New York State are located in places that will likely have high concentrations and large monitoring scales. This ensures that the public is not exposed to higher ambient PM2.5 concentrations than the concentrations from the FRM network reported for their area.
The PM2.5 monitoring network works well for determining average ambient exposures for most of the State's population. The limitations of the network stem from the inability to monitor in smaller scales such as Middle and Microscale. An example of an urban microscale influence not addressed by the network would be PM2.5 emissions from traffic in a street canyon. Certainly if New York residents spent much of their time in this type of confined area, then their exposure to ambient PM2.5 would be considerably higher than that indicated by the closest neighborhood or urban scale monitor. Similarly, a person in a rural valley area subject to daily woodsmoke would also be exposed to higher PM2.5 concentrations than those measured at the nearest Neighborhood or Urban scale monitor.
The PM2.5 ambient monitoring network is also not able to determine the populations's overall exposure to PM2.5. Personal habits such as smoking and occupations such as mining, farming and construction can lead to much higher exposures to PM2.5 than that of the majority of the population. Other factors such as widely varying indoor PM2.5 concentrations can lead to uncertainty in overall PM2.5 exposures.
The locations of the PM2.5 monitoring sites are selected to measure ambient concentrations in representative populated areas statewide, and thus are suitable for annual standards comparisons with the exception of three sites: Whiteface, Potsdam, and Westfield. These sites are placed in sparsely populated locales for the purpose of background and regional transport determinations.
PM2.5 Monitoring Instrumentation
The filter based FRM samplers used in New York are the Model 2025 sequential samplers made by the Rupprecht and Patashnick Company. The sampler has been designated by EPA as a reference method instrument for PM2.5 particle collection. The designation is: RFPS-0498-118.
Currently there are 25 FRM monitors in operation statewide, as shown in Figure 4.9.
Figure 4.9 Location Map for PM2.5 Monitoring Sites
Figure 4.10 below shows the number of manual PM2.5 monitoring sites and the composite annual arithmetic means in New York State since the network was implemented in 1998.
Figure 4.10 PM2.5 Monitors and Concentration Trends
The continuous mass monitoring instruments used in New York are the TEOM 1400ab also made by the Rupprecht and Patashnick Company. These instruments have received designation by EPA for PM10 but not for PM2.5. PM2.5 is more difficult to measure than PM10 with automated samplers because PM2.5 contains a higher fraction of volatile components. The heated measurement sensor for the TEOM reduces the amount of volatile mass measured as compared to filter based FRMs. The NYSDEC utilizes non-linear data adjustments to make the TEOM data more comparable with the FRM data. The adjusted data are used for public reporting and forecasts of PM2.5 concentrations.
The NYSDEC uses eight MetOne SuperSass samplers and two IMPROVE samplers for the collection of samples for the speciation of PM2.5. The samplers collect 3 or 4 samples simultaneously every third day or sixth day for a period of 24 hours. The samples are then sent to an EPA contract laboratory for chemical analysis. There are over fifty species consisting of ions, metals and carbon species quantified by the analyses.
4.4.4 Continuous PM Monitoring
Continuous mass monitoring is performed primarily with a network of TEOM 1400ab instruments. This element of the PM2.5 monitoring network provides the data used for public reporting purposes including; the NYSDEC website, the AirNow website and for PM2.5 forecasting. The data from the TEOMs are polled and reported every hour to insure that the public has access to the most recent air quality information.
The TEOM data is compared to the filter based FRM data on an annual basis. The comparison allows the analysts to create non-linear correction factors that modify the TEOM data to more closely resemble FRM data. This is necessary because FRM data is not available for near real-time public reporting purposes. EPA has recently recognized the value of these data adjustments and has created new method codes so this adjusted data can be submitted to the AQS database. The NYSDEC now submits TEOM data from each site in its original unadjusted format as well as the adjusted data to match more closely with the FRM.
These 27 monitoring sites are depicted in Figure 4.11.
Figure 4.11 Location Map for Continuous PM2.5 Monitoring Sites
4.4.5 Speciation
Speciation monitoring is performed with a network of eight MetOne SuperSass samplers. There are eight sites in New York State operating with the Speciation Trends Network (STN) sampling protocol. Six operate on a 1/3 day schedule and two operate on a 1/6 day schedule. All of the these sites host collocated FRM and continuous mass monitoring instruments. A rural and an urban site also host collocated IMPROVE protocol samplers. The data from these sites is used to assist in the comparison between STN and IMPROVE data sets. The goal of the urban installation will be to further relate the mostly rural IMPROVE network to the mostly urban STN network.
In order to address inconsistencies in carbon sampling and analysis procedures used in urban STN/SLAMS and rural IMPROVE programs, EPA determined that the URG sampler would be used at all STN sites. The conversion was completed last year for all of the NY sites.
Figure 4.12 shows the eight STN sites currently in operation.
4.4.6 Continuous Speciation
The NYSDEC recognizes the value of semi continuous speciation monitoring. This data is useful for the examination of pollutant trends and can provide information necessary for identification of pollutant sources. This is critically important for areas facing non-attainment for the PM2.5 NAAQS. Identifying seasonality of species is necessary to develop control strategies.
The NYSDEC continuous speciation program is expanding and currently includes monitoring at urban and rural locations. Sulfate, nitrate, organic carbon, elemental carbon and black carbon species data are collected at hourly or higher frequency. In this manner both the regional and inter-urban variability of these species can be investigated. The NYSDEC uses instruments to examine the species of PM2.5 on a higher frequency than what is available from the filter based speciation sampling network. This continuous speciation data is useful in the examination of source strengths and the relationship between pollutant concentrations and meteorology. The operation of continuous speciation equipment is also less expensive than long term filter species measurements due to the high costs associated with filter lab analysis.
NYSDEC has been using the continuous speciation data in NYC to examine diurnal and day of week temporal patterns of aerosol species related to source strengths and meteorology. For example elemental carbon, black carbon and primary pollutant NOx in NYC track throughout the day with peak concentrations in the morning coincident with the early commute period. An elevation in boundary layer height during the day leads to a dispersion of pollutants and a less pronounced afternoon/evening peak. Concentrations of these species are also higher on weekdays compared to weekends indicating that local mobile emissions make a strong contribution to these species. During winter months organic carbon sometimes shows similar patterns to EC and NOx reflecting the primary organic component most likely from mobile emissions. Throughout the year however organic carbon does not track the primary pollutants but is more correlated with PM2.5 mass (and sulfate during summer months) indicating that there is a strong regional or non-local contribution to organic carbon measured in NYC. Our results show that in cooler months aerosol nitrate has a broader peak than EC which appears later in the morning, consistent with photochemical and secondary aerosol production. During the warm season aerosol nitrate concentrations are significantly lower because nitrate is sensitive to temperature. The late morning nitrate peak observed in winter is not observed in the warm season because as temperatures rise during the day aerosol nitrate reverts back to its precursors (nitric acid and ammonia). Nitrate exhibits no particular day of week pattern.
Continuous data can also be used to capture the full extent of regional plumes that would normally be missed by the 24-hr filter sampling network. It allows us to study plume events and how meteorology can affect measurements. One can also differentiate between plumes which are short term of a few hours long and likely driven by carbon versus those that are more regionally driven by sulfate in summer. High temporal pollutant data is also beneficial for public health effect studies that often require resolving confounding factors.
4.4.7 Additional Monitoring Initiatives
The NYSDEC has been active in additional research and monitoring beyond the mandated Federal requirements. Some of this work has been collaborative with goals ranging from collecting data with the newest technologies, to providing support for health studies to evaluating new monitoring instruments. Other projects undertaken by the NYSDEC such as adding additional monitoring after the World Trade Center attack or monitoring before and after the cap was installed on the Fresh Kills landfill could not have been undertaken by other Agencies.
4.4.7.1 PM2.5 Technology Assessment and Characterization Study-New York Supersite
The largest collaborative monitoring project undertaken by the NYSDEC and State University of New York 's Atmospheric Science Research Center (SUNYA-ASRC) was the Supersite program known as PMTACS. The 5 year monitoring initiative leveraged resources from EPA, NYSERDA and the NYS Environmental Bond Act to obtain detailed highly resolved pollutant measurements from NYC, Whiteface mountain and an upwind rural site south-west of Corning, NY. This monitoring project also involved participants from the NYDOH, Penn State University, Aerodyne Research Inc. and Clarkson University. The project's website lists many of the program details: http://www.asrc.cestm.albany.edu/pmtacsny/index.html
Some of the instrument method development work initiated under this program has continued after the conclusion of the PMTACS program. This shared effort includes method development work on trace gas monitors, continuous organic carbon monitors, continuous particulate sulfate instruments, continuous particulate nitrate and ammonia instruments. All of these instruments will be needed as NYSDEC designs PM control strategies for non-attainment areas within New York State.
The current research undertaken by this collaboration involves small particle and precursor gas concentration measurements from rural and urban locations in NY state. NYSERDA has provided funds for this work which includes an intensive monitoring campaign over several weeks this summer in New York City. The summer measurements will include a comparison between the measurements taken at an urban NYSDEC monitor and those from a mobile van traveling on nearby highways. These studies will help to determine the impacts of mobile sources at fixed neighborhood monitors.
4.4.7.2 Organic Carbon: Molecular Marker Characterization
The NYSDEC collaborated with Rutgers, Drexel, NESCAUM, NJDEP and CTDEP on a project called the Speciation of Organics for Apportionment of PM2.5 in the New York City Area (SOAP). The field portion of the project was conducted from May 2002 to May 2003. It operated at four sites: Queens, NYC (high density urban residential); Elizabeth, NJ (adjacent to the NJ Turnpike); Westport, CT (downwind NYC); and a regional background site in Chester, NJ (upwind NYC). The study's chief objectives were to expand the chemical characterization of organic compounds and to estimate the source contributions of carbonaceous fine particles at urban and background monitoring sites.
This project continued at a site in NYC and a rural site in Addison, south-west of Corning, NY during 2005 to 2007. Sampling for this project has been completed. The data from this project will provide information about the significance of sources of organic carbon particulate in both urban and rural areas in New York. This type of information will be used to assess the potential viability of local and wide range PM2.5 control strategies.
4.4.7.3 PM Coarse Monitoring
The NYSDEC is taking an active roll in advance of an upcoming EPA directive to monitor for PM Coarse (PM10 - PM2.5). Filter based monitoring was initiated in NYC and in Niagara Falls to determine approximate concentrations of PM Coarse. This information may assist EPA Office of Research and Development (ORD) in their effort to develop robust automated sampling technologies. The NYSDEC has also used this data to comment on the proposed PM Coarse standard and network design that were recently part of the draft CFR Parts 53 and 58.
The NYSDEC has supported the development of automated near real-time PM instruments. In fall 2006 the NYSDEC and the R&P/Thermo Co. installed two beta version automated PM Coarse instruments into one of the NYSDEC's NYC monitoring sites. Data from the filter based samplers already operating at the site will be used to evaluate the new technology. The benefit of this work for the NYSDEC is that it is much more likely that the new instrument when fully developed will work properly in the routine monitoring network.
4.4.8 Air Pollution and Environmental Conditions
4.4.8.1 NYC Micro-scale Street Canyon Monitoring
The NYSDEC responded to a request by EPA to install 2 street level monitors in an urban area in NYC. The areas are known as canyons due to the tall buildings on either side of the street. The PM10 data collected at the one remaining site is used to evaluate the differences between data collected at very low elevations, close to high traffic roadways, and the monitors that are properly sited in the rest of the monitoring network.
4.4.8.2 IMPROVE
The NYSDEC operates two samplers that are part of the Interagency Monitoring of Protected Visual Environments (IMPROVE) sampling network. These are collocated with samplers from EPA Speciation Trends Network (STN) at an urban (IS52) and a rural location (Addison) in New York. The data from these samplers will be compared so that the National IMPROVE database can be correlated with speciated PM2.5 data collected at the other STN protocol sites in New York.
4.4.8.3 Rochester PM Center Clarkson, Univ. of Rochester Medical Center
The NYSDEC collaborates with researchers from the University of Rochester Medical Center and Clarkson University who have been awarded a second PM health research grant from EPA. Their work focuses on the pathways and effects from PM pollution on the cardiovascular system. The NYSDEC provides data and support for a fine particle classifying instrument at a monitoring location near the University of Rochester. A second instrument provided by Clarkson University has been installed at IS52.
4.4.8.4 Ambient Mercury Monitoring in Rochester
The NYSDEC collaborates with researchers from Clarkson University and NYSERDA to perform measurements of ambient Elemental Hg, Reactive Gas Hg, and Particle Hg. The instrumentation for these measurements is being improved to make the measurements more consistent from site to site and to make the instrumentation more reliable. The measurements will be used to help establish a reference baseline for ambient air mercury concentrations in two urban areas in New York State. This baseline will be used in conjunction with other mercury monitoring measurements to track the overall progress of mercury reduction strategies for the two largest source categories, municipal waste combustors and coal fired electric steam generating utilities. The speciated mercury measurements along with other co-pollutants will be used to help understand the atmospheric transport and transformation processes of mercury which are required in order to understand the net impact of mercury on the environment.
4.4.8.5 Air Pollution Microscopy
In addition to performing toxics and acid deposition laboratory analyses, BAQS Monitoring Support Section at the Rensselaer facility operates a variety of analytical microscopes for particle analysis. These instruments include: Smiths Detection Inc. IlluminatIR Fourier Transform microscope; JEOL 6490LV Scanning Electron Microscope (SEM) with a Brucker Spirit Energy Dispersive Spectroscopy (EDS) System. Together with optical microscopes, staff can provide data on size, morphology, elemental, chemical, and other physical properties of particulate samples of size down to 1 µm in diameter. The information obtained is valuable for the understanding of source origin and provides important input for apportionment analysis.
Ultra fine particles (<0.1 µm), primarily generated from combustion processes, including stationary fossil-fuel electric power generation, industrial processes, boilers, and gasoline and diesel engines, are an important component of PM2.5. Scientists are becoming increasingly more interested in these ultra fine or "Nano" size particles. Recently NYSDEC acquired a VEECO Nanoscope Multimode Atomic Force Microscope (AFM) for the analysis of these extremely small particles. With the addition of this new instrument, we are now able to look at particulate an order of magnitude smaller than what the Scanning Electron Microscope (300,000X mag vs. 3,000,000x mag) can provide. Whereas the SEM specializes in particles in the 2.5 micron range, the Nanoscope is currently analyzing particles in the 25-50 nanometer range. Particle size, surface texture and roughness are now available on such particles as diesel exhaust, wood smoke, and other products of combustion.
Recently NYSDEC acquired the Olympus LEXT Laser Confocal Microscope (LCM). It is designed to obtain images of ultrafine particles at ranges smaller than what can be seen with our Scanning Electron Microscope (SEM) and larger than what we can see with Atomic Force Microscope (AFM). It is the perfect fit between these two pieces of instrumentation and will complement both the AFM and SEM. Each method can "see" in the size range that the other cannot. The LCM works on particles between 500 nm and 200 microns, so it works in between the two.
The intended use of this instrument will provide information:
- on the use of alternative fuels such as biodiesel and ethanol, as well as their use with different emission aftertreatment strategies. Little to no information is currently available on the effect of such fuels on particle morphology.
- to refine our methodologies for acquiring filter samples for microscopic examination and in performing these examinations. Future samples could potentially be taken both from direct mobile source emissions and also from ambient samplers deployed in the monitoring network.
- to re-evaluate our earlier ultrafine particle measurements. For example, earlier results suggest the presence of a secondary small particle mode in biodiesel emissions (smaller particles pose greater risks of health effects). Microscopic examination could provide evidence to either support or dismiss this finding.
Sulfur dioxide (SO2), a colorless, reactive gas, is produced during the burning of sulfur-containing fuels such as coal and oil, during metal smelting, and by other industrial processes. It belongs to a family of gases called sulfur oxides (SOx). Major sources include power plants, industrial boilers, petroleum refineries, smelters, iron and steel mills. Generally, the highest concentrations of sulfur dioxide are found near large fuel combustion sources.
High concentrations of SO2 can result in temporary breathing impairment for asthmatic children and adults who are active outdoors. Short-term exposures of asthmatic individuals to elevated SO2 levels while at moderate exertion may result in reduced lung function that may be accompanied by symptoms such as wheezing, chest tightness, or shortness of breath. Other effects that have been associated with longer-term exposures to high concentrations of SO2, in conjunction with high levels of PM, include respiratory illness, alterations in the lungs' defenses, and aggravation of existing cardiovascular disease. The subgroups of the population that may be affected under these conditions include individuals with cardiovascular disease or chronic lung disease, as well as children and the elderly.
Additionally, there are a variety of environmental concerns associated with high concentrations of SO2. Because SO2, along with NOx, is a major precursor to acidic deposition (acid rain), it contributes to the acidification of soils, lakes, and streams and the associated adverse impacts on ecosystems. Sulfur dioxide exposure to vegetation can increase foliar injury, decrease plant growth and yield, and decrease the number and variety of plant species in a given community. Sulfur dioxide also is a major precursor to PM2.5 (aerosols), which is of significant concern to human health, as well as a main pollutant that impairs visibility. Finally, SO2 can accelerate the corrosion of natural and man-made materials (e.g., concrete and limestone) that are used in buildings and monuments, as well as paper, iron-containing metals, zinc, and other protective coatings.
There are both short- and long-term primary NAAQS for SO2. The short term (24-hour) standard of 0.14 ppm (365 µg/m3) is not to be exceeded more than once per year. The long term standard specifies an annual arithmetic mean not to exceed 0.030 ppm (80 µg/m3). The secondary NAAQS (3-hour) of 0.50 ppm (1,300 µg/m3) is not to be exceeded more than once per year. The standards for SO2 have undergone periodic review, but the science has not warranted a change since they were established in 1972.
Figure 4.13 shows the number of SO2 monitors and the composite annual means in New York State over the years.
Figure 4.13 Sulfur Dioxide Monitors and Concentration Trends
There are 23 SO2 monitors in operation currently, as shown in Figure 4.14. TEI Model 43C instruments using the pulsed fluorescence method are deployed in the network.
Figure 4.14 Location Map for Sulfur Dioxide Monitoring Sites
