Section 3.0 Air Quality Data and Trends
Ozone and ozone precursor monitoring stations in the New York Consolidated Metropolitan Statistical Area (New York CMSA) 8-hr ozone non-attainment area are listed in Table 1 in Appendix A.
Table 2 in Appendix A lists ozone measurements for a total of 24 stations, of which 9 are in New York, 8 in Connecticut and 7 in the New Jersey portions of the non-attainment area for the 2000 to 2006 period. There are some monitors which have blanks indicating that either they were not operational during the entire period or were discontinued during this period. The data listed for each monitor consists of the four highest 1-hr and 8-hr concentrations and the corresponding number of exceedance days that had occurred at that monitor. Table 3 in Appendix A lists the calculated design values for the period of 2000 to 2004 that are averaged to yield the base year design value (DVC) at each monitor.
Following the Photochemical Assessment Monitoring Station (PAMS) network design, there are three sites within the New York CMSA that measure non-methane organic compounds (NMOC) during the ozone season. The locations are identified as upwind, center city and downwind under PAMS network configuration (PAMS 1995). The three sites are:
|New Brunswick||Middlesex, NJ||340230011||upwind|
|Botanical Gardens||Bronx, NY||360050083||center city|
|Sherwood Island||Fairfield, CT||090019003||downwind|
Hereafter, we refer the upwind site as RU, center city site as NY, and downwind site as SI. In this analysis, we examined the seasonal averages of the Total NMOC and some selected species at the three PAMS sites for the period 1995 to 2006. The following provides a brief assessment on the measured NMOC levels in New York CMSA, along with the following species (AQS = Air Quality System):
|Species||AQS Parameter||Species||AQS Parameter|
Figure 3-1 displays the seasonal average of total NMOC concentrations at NY, RU, and SI from 1995 through 2006. There is no surprise that the center city site (NY) measures the highest total NMOC concentrations, follow by the upwind site (RU) and downwind site (SI). Unfortunately no data were available for 2006 for the NY site. The center city (NY) shows a downward trend except for a sudden increase in year 2003, while no clear trend emerges for the upwind (RU) and downwind (SI) stations, respectively.
Figures 3-2 to 3-8 display the seasonal average concentrations for ethane, propane, isoprene, benzene, toluene, ethylbenzene, and o- xylene, respectively. A majority of these species represent motor vehicle exhaust, natural gas-based hot water heating, industrial coatings, and natural sources. The center city site (NY), reports higher concentrations than the upwind (RU) or the downwind (SI) sites for ethane, benzene, ethylbenzene and o-xylene, indicating the localized nature of these compounds. Similar to the total NMOC, in general there is a downward trend in these compounds, but with occasional exceptions. Figure 3-3 displays the average concentrations of propane, which appears to show a decrease in the center city (NY) with levels similar to those at upwind (RU) or downwind (SI). For toluene (Figure 3-6), attributable to the industrial coating usage, there seems to be a general decrease in the levels at NY and RU, reaching to those similar to the downwind (SI) site. In the case of isoprene (Figure 3-4), the measurements show year-to-year variability associated with changes in meteorological conditions.
Seasonal averages (June, July, and August) were calculated for CO, NO, and NO2 for monitors in New York CMSA for the period 1995 to 2006. The averaging was performed using hourly data from 6 to 9 AM that is reflective of the morning rush-hour traffic. For each pollutant the mean concentration and the standard deviation are listed in Table 4 in Appendix A. Examination of the NO and NO2 data shows that these are associated with high standard deviations suggesting higher variability in these measurements. The CO concentration shows a clearly declining trend for most of the locations in the CMSA. From the limited data, the NO average concentrations also show a slight decline, while NO2 concentrations are so varied that no clear trend can be ascribed.
The 2002 base year emissions inventory has been compiled as part of the regional modeling effort and the details are reported in TSD- 1c (2007), and in Pechan (2006). Tables 5a and 5b in Appendix A list the 2002 emissions by major source category and summary, respectively, and in Figure 3-9 are displayed in graphical form. The 2009 projected year emissions inventories for on-the-way (OTW) and beyond-on-the-way (BOTW) have been compiled as part of the regional modeling effort and the details are reported in TSD-1d (2007), TSD-1f (2007), TSD-1j (2007) and MACTEC (2007). The emissions were projected based on growth and control, and in the case of point sources they are provided as 3 distinct sectors, namely as emissions from electric generation units (EGUs), emissions from other point sources (Non-EGU), and emissions from non-fossil fuel units (Non. Foss.). Tables 6a and 6b in Appendix A list the 2009OTW emissions by county and by source sector, while Figures 3-10 and 3-11 display the 2009OTW and 2009BOTW, respectively. In addition to the 2009 scenario, emissions are also estimated for 2012BOTW and these are listed in Table 7a in Appendix A by county and summarized in Table 7b in Appendix A and displayed in Figure 3-12. The emissions identified as 2009BOTW reflect additional emissions reduction measures being undertaken by the Ozone Transport Commission (OTC) states. In this case, emissions changes were limited to the non- EGU and Area sectors only. It should be noted that these emissions data are then processed using SMOKE for use as input to the photochemical model, CMAQ, to simulate ozone over the domain.
Biogenic emissions over the modeling domain were calculated using SMOKE2.1 that incorporated Biogenic Emissions Inventory System (BEIS) v3.1.2. Details of the approach are described in TSD-1b (2007). Briefly, the method utilized surface temperatures generated by the mesoscale meteorological model (TSD-1a 2007) and gridded land use and emissions factors data provided in SMOKE. These estimated emissions were used in all photochemical model (CMAQ) applications. Table 8 in Appendix A lists the annual emissions by county for the New York CMSA.
The 2002 annual meteorology using MM5 was developed as input data for photochemical model CMAQ. Details of MM5 setup and assessment can be found in TSD-1a (2007).
3.7.1 Base Year 2002
The five month period covering May 15 through September 30, 2002 was examined explicitly for ozone. The model assessment on a regional basis can be found in TSD-1e (2007) in Appendix A, which shows that the simulation can be considered satisfactory in reproducing the observed ozone distribution. Eder et al (2003) suggested that overall normalized mean bias (NMB) should be less than 10% and normalized mean error (NME) of 20% as possible indicators of acceptable model performance for ozone. The statistical measures applied in this analysis are
Observed average, in parts per billion (ppb):
Predicted average, in ppb (only use Pi when Oi is valid):
Correlation coefficient, R2:
Normalized mean error (NME), in %:
Root mean square error (RMSE), in ppb:
Fractional error (FE), in %:
Mean absolute gross error (MAGE), in ppb:
Mean normalized gross error (MNGE), in %:
Mean bias (MB), in ppb:
Mean normalized bias (MNB), in %:
Mean fractionalized bias (MFB), in %:
Normalized mean bias (NMB), in %:
In particular for this non-attainment area, the assessment is performed with measurements based on the ozone monitors listed in Table 1 in Appendix A and the results of the statistical measures are listed in Table 9a and 9b in Appendix A for two observed daily maximum 8-hr ozone threshold levels of 40 and 60 ppb, respectively. Results listed suggest that the estimated NME and NMB at most of these monitors is at an acceptable level suggested by Eder et al (2003).
Table 10 in Appendix A lists the comparison between measured and predicted ozone precursor concentrations including selected NMOC species provide an overall view of the application of SMOKE/CMAQ system.
3.7.2 Future Year 2009 and 2012
Photochemical modeling was performed in a manner similar to that of base year. The intent of this modeling is to use the predicted ozone concentrations relative to the base year and estimate the future design value at the monitored locations as well as other areas of the nonattainment area. The approach to be used has been documented in EPA Guidance documents (EPA 2005, 2006) and how it is applied is described in TSD-1g (2007) and in TSD-1h (2007). Table 11a and 11b in Appendix A summarizes the information on the estimated relative reduction factor (RRF) and the projected future design values for 2009BOTW and 2012BOTW scenarios, respectively. Examination of Table 11a in Appendix A indicates that the projected DVF is above the 8-hr ozone NAAQS level of 84 ppb as well as outside the weight of evidence (WOE) range for several monitors in the CMSA. Examination of Table 11b in Appendix A shows that all monitored stations are below the 8-hr ozone NAAQS except for the Stratford, CT location (AQS ID 090013007) which is within the WOE range, thus demonstrating modeled attainment of the area.
3.7.3 Unmonitored Area Analysis
As per EPA guidance (2005, 2006a), the potential occurrence of a projected exceedence at an unmonitored location was investigated. The procedure examined all grid cells for all counties within and immediately surrounding the non-attainment area using the spatial interpolation and gradient adjustment techniques implemented in the EPA- MATS (Model Attainment Test System) software (Timin, 2006).
In this application, MATS was utilized to spatially interpolate base year observed design values. MATS was also utilized to estimate gradient adjustment factors that were based on the CMAQ predictions of the top-30 daily maximum 8-hr ozone concentrations at each grid cell for the 2002 base case. The relative effect of the emission reduction under the 2009BOTW scenario on daily maximum 8-hr concentrations was then estimated by calculating a gridded field of RRF by treating each grid cell as a monitor location. Two approaches were used for calculating the RRF. Use MATS to provide RRF at each grid cell, and the other approach is based on 9- grid cells as described in TSD-1g and TSD-1h. Finally, Future design value (DVF) for each grid cell is estimated by multiplying the spatially interpolated Base Design Values (DVB) from MATS with the gridded gradient adjustment factors (from MATS) and with the gridded RRF fields estimated by the two methods.
The New York CMSA 8-hr ozone non-attaiment is abutted by the Philadelphia, Poughkeepsie, and Greater Connecticut 8- h ozone nonattainment areas, and as such are not considered in this analysis and discussed elsewhere (New York CMSA, 2007).
Table 12a and 12b in Appendix A lists all the counties pertaining to the nonattainment area and some of the surrounding counties identified by their FIPS code and location of the grid cells in the CMAQ modeling domain for the 2009BOTW and 2012BOTW scenarios, respectively. The Tables also provide information as to whether or not the grid cell is associated with an ozone monitor and the percent of the grid area located over water based upon the land classification used in the meteorological modeling with MM5. This analysis shows that for the 2009BOTW scenario, there are several other grid cells that are not associated with a monitor but a percent of the grid cell is over water that are above the 84 ppb threshold both under the hybrid MATS or MATS methodology. In particular, a grid cell that is not associated with water in Bergen County, NJ is at 92ppb or 91ppb depending upon the MATS methodology used. Considering the 2012BOTW scenario (see Table 12b in Appendix A) again the Bergen county grid cell that is not associated with water is projected at 88ppb or 87ppb depending upon the MATS methodology, while other grid cells above the 84 ppb threshold are found to be associated with water. Thus the unmonitored area analysis suggests the potential exists for projected 8-h ozone levels to be above the 8-h ozone NAAQS level under the 2009BOTW scenario, but are essentially absent under the 2012 scenario.
The model projects that the 8-hr ozone design values for 2009 for the New York CMSA are well above the 8-hr ozone NAAQS, but are below for 2012. The current design values (DV) from 2002 through 2007 are listed in Table 13 in Appendix A. While all monitors show that the 2006 DV levels are lower compared to 2002 DVs, several of the monitors continue to be above the 8-hr ozone NAAQS level. There was a slight upturn in measured ozone levels for 2007. For the monitors in New York State, the only appreciable upward changes were found at the White Plains monitor in Westchester County and the Riverhead monitor in Suffolk County. The changes in DVs from 2006 to 2007 is mostly attributable to the loss of a low 4th highest value (0.078 ppm at White Plains and 0.069 ppm at Riverhead) for 2004. Since the long term trends at these locations show declining ozone, data from these sites will need to be examined carefully in the future.
The EPA recommended method of estimating the base year design value (DVC) for the period of 2000 to 2004 is a weighted average approach that weighs 2002 measurements much more than the other years. Another method is to estimate the base year design value as the average of the five year period of 2000 to 2004. For this approach the 4th highest concentration listed in Table 2 in Appendix A are utilized and average DVC is listed in Table 14 in Appendix A for each of the monitors. The projected design values are estimated using the RRF values from Table 11a in Appendix A and are included in Table 14 in Appendix A. The estimated design values by this method are well below the 8-hr ozone NAAQS, suggesting that this area may be in attainment of the 8-hr ozone NAAQS in 2009. The Department chose not to use this approach to demonstrate attainment since it did not believe, especially given the measured ozone levels for 2007, it had the evidence to indicate that such dramatic drops in measured ozone levels were achievable.
In addition, the trends in the hourly ozone concentrations at some of the monitoring stations (TSD-aa 2007) were examined and the results are listed in Table 15 in Appendix A. The estimated trend is found to be strongly dependent upon the time period that is being considered in the analysis. The estimated trend (percent per year) at a majority of the monitors is downward (with and without meteorological adjustment) for the overall monitoring time period, with some exceptions for the longer time period. However, if consideration is given to the 2000 to 2005 period during which there were targeted reductions in ozone precursor emissions through the state and federal programs, all monitors in the CMSA show a downward trend.
The Department, as a result of the above referenced attainment projection modeling, is requesting under separate cover, that EPA reclassify the NY-NJ-CT ozone nonattainment area as "serious" in accordance with CAA Section 181(a)(3). The completed modeling shows that the nonattainment area will attain the ozone NAAQS by 2012 considering weight-of-evidence. The critical monitoring location (Fairfield (Stratford), CT) has a predicted 2012 design value of 0.086 ppm which is within the weight-of-evidence range as allowed pursuant to EPA's "Guidance on the Use of Models and Other Analyses for Demonstrating Attainment of Air Qulaity Goals for Ozone, PM2.5 , and Regional Haze." The Department anticipates that the nonattainment area will measure attainment by 2012 (equal to or less than 0.084 ppm) as a result of additional emissions reduction measures that are not accounted for in the model-based attainment predictions.
A number of control programs are being adopted or implemented that are not represented in the projection inventories for 2012. These include:
- Part 222, Distributed Generation
- Part 227-2, NOx RACT (High Electric Demand Day Units)
- PlaNYC (New York City emission reduction initiatives)
- Governor Spitzer's "15 by 15" Initiative
These measures will reduce NOx and VOC emissions by significant amounts. The regulations being adopted by the Department will yield quantifiable, enforceable NOx emissions reductions on the order of 50 tons per day. When compared to those measures included in the modeling and the base and projected NOx inventories, it is apparent that reductions of this magnitude (9 percent of the 2012 projected NOx inventory) have the ability to reduce ozone levels substantially. Given that New Jersey and Connecticut as well as other northeastern states (Delaware, Maryland and Pennsylvania) are committing to similar measures that will also yield substantial reductions in NOx emissions (Memorandum of Understanding Among the States of the Ozone Transport Commission Concerning the Incorporation of High Electrical Demand Day Emission Reduction Strategies into Ozone Attainment State Implementation Planning), it is expected that NOx emissions on days of high electricity demand (which typically track with days of high ozone) will be reduced substantially throughout the Northeast corridor.
3.8.1 Part 222, Distributed Generation
This regulation will set limits on small generators that are not currently controlled. As minor sources, these sources need only to stay below the major source threshold to avoid reasonably available control technology (RACT). Most of these sources (generally diesel-fired stationary internal combustion engines) tend to operate on days of high electricity demand and when called upon to address reliability concerns. This regulation will place NOx and PM limits on existing sources as well as restrict the number of megawatts that can be called to operate under demand response. It will also set strict emission standards for new units. It is expected that NOx emissions on High Electricity Demand Days (HEDD) could be reduced by 10 to 15 tons per day in 2012 through the implementation of this regulation.
3.8.2 Part 227-2, NOx RACT (High Electricity Demand Day Units)
This regulatory revision will set new more stringent NOx limits on electricity generating units. On High Electricity Demand Days (HEDD) base loaded, load following and peaking units all increase operations to meet demand. HEDD are generally those days when the potential for ozone formation is highest (hazy, hot and humid weather). The Department is specifically moving to revise the NOx emission limits for all very large boilers and combustion turbines. These emission limits are expected to result in the reduction of 35 to 40 tons per day of NOx emissions.
PlaNYC is a compilation of initiatives intended to make the City of New York "the model for cities in the 21st Century." PlaNYC is a holistic vision that focuses on five key elements of the city's environment - land air, water, energy and transportation recognizing that choices in one area have unavoidable impacts on the other areas. The air quality goal of PlaNYC is to "achieve the cleanest air quality of any big U. S. city." We laud the City of New York for this ambitious goal and will partner with the City to help it achieve this goal. While much of PlaNYC has an outlook beyond the attainment date of this plan (2012) and is focused on pollutants that are not causing ozone, many initiatives within PlaNYC will help reduce emissions of NOx and VOCs in time to assist with the 2012 attainment of the ozone NAAQS. It should be noted that the Department is not committing to adopting any of these measures as part of the SIP, but is instead providing these programs as information to further its weight-of-evidence demonstration. If the Department chooses to include these measures in a future SIP revision, it will first evaluate each measure resulting from this initiative individually to determine if it is appropriate to be included in the SIP. The Department will need to consider among other things whether the measure is quantifiable, enforceable, and include emissions reductions that are additional to other adopted SIP measures. The PlaNYC measures include:
Improving the fuel efficiency of private cars by waiving New York City's sales tax on the cleanest, most efficient vehicles and working with the MTA, the Port Authority, and the State DOT to promote hybrid and other clean vehicles. Pilot new technologies and fuels, including hydrogen and plug-in
Reducing emissions from taxis and other for-hire vehicles by reducing idling and increasing fleet efficiency. This will be accomplished by working with the Taxi and Limousine Commission, the industry and other stakeholders.
Retrofit ferries and mandate the use of cleaner fuels. Retrofit the Staten Island Ferry fleet to reduce emissions. Work with private ferries to reduce their emissions.
Replace, retrofit and refuel diesel trucks. Introduce biodiesel into the City's truck fleet, go beyond compliance with local laws, and further reduce emissions. Accelerate emissions reductions of private fleets through existing Congestion Mitigation and Air Quality (CMAQ) programs. Work with stakeholders and the State to create incentives for the adoption of vehicle emission control and efficiency strategies. Improve compliance of existing anti-idling laws through targeted educational campaign.
Reduce emissions from buildings by improving energy efficiency, decreasing fuel consumption, promoting the use of cleaner burning heating fuels, and facilitating the repowering, replacement and retirement of out-of-date equipment at older power plants.
Implement more efficient construction management practices. Accelerate adoption of technologies to reduce construction related emissions.
Partner with Port Authority to reduce emissions from port marine vehicles, port facilities and airports.
Reduce emissions from boilers in 100 city public schools.
Reforest 2,000 acres of parkland. Increase tree planting on lots. Through MillionTreesNYC plant and care for one million new trees across the City's five boroughs over the next decade.
3.8.4 Governor Spitzer's "15 by 15" Initiative
"15 by 15" is a comprehensive plan for reducing energy costs and curbing pollution in New York. It calls for the reduction of electricity use by 15 percent from forecasted levels by the year 2015 through new energy efficiency programs in industry and government. It also calls for the creation of new appliance efficiency standards and the setting of more rigorous energy building codes. The Department is not committing to the inclusion of any of these measures as part of the SIP at this time, The Department will evaluate each measure resulting from this initiative individually to determine if it is appropriate to be included in the SIP. The Department will need to consider among other things whether the measure is quantifiable, enforceable, and include emissions reductions that are additional to other adopted SIP measures.
This study shows that based upon the projected emissions inventory and the photochemical modeling the New York CMSA shows modeled attainment for 8-hr ozone NAAQS in 2012 based upon the EPA guidance method.
Eder, B., and S. Yu (2003) An evaluation of the 2003 release of Models-3/CMAQ, presented at the 2003 Annual CMAS Workshop, Research Triangle Park, NC.
EPA (2005) Guidance on the Use of Models and Other Analyses in Attainment Demonstrations for the 8-hour Ozone NAAQS. EPA-454/R-05-002.
EPA (2006a) Guidance on the use of Models and Other Analyses for Demonstrating Attainment of Air Quality Goals for Ozone, PM2.5 and Regional Haze. Draft 3.2-September 2006.
EPA (2006b) http://www.epa.gov/air/airtrends/2006/ozonenbp/
MACTEC (2007) Development of Emission Projection for 2009, 2012, and 2018 for nonEGU point, area, and nonroad sources in the MANE-VU region. www.marama.org/reports
PAMS 1995. See http://www.epa.gov/air/oaqps/pams/
Pechan: (2006) Technical Support document for 2002 MANE-VU SIP Modeling inventories, version 3. Prepared by E. H. Pechan & Associates, Inc. 3622 Lyckan Parkway, Suite 2005, Durham, NC
Timin, Brian (2006) Communication (e-mail) of release of beta version of MATS
TSD-1a (2007) Meteorological modeling using Penn State/NCAR 5th generation mesoscale model (MM5)
TSD-1b (2007) Processing of Biogenic Emissions for OTC/MANE- VU Modeling
TSD-1c (2007) Emissions processing for the revised 2002 OTC Regional and Urban 12km base case Simulation
TSD-1d (2007) 8hr ozone modeling using the SMOKE/CMAQ system
TSD-1e (2007) CMAQ model performance and assessment 8-hr OTC Ozone Modeling
TSD-1f (2007) Future Year Emissions Inventory for 8-h OTC Ozone Modeling
TSD-1g (2007) Relative response factor (RRF) and "modeled attainment test"
TSD-1h (2007) Projected 8-h ozone air quality over the ozone transport region
TSD-1j (2007) Emission Processing for OTC 2009 OTW/OTB 12km CMAQ simulations
TSD-aa (2007) Trends in Measured 1-hr Ozone Concentrations over the OTR modeling domai