2014 Progress Report: Creating Building Blocks for a More Dynamic Air Quality Management Framework

EPA Grant Number: R835215
Title: Creating Building Blocks for a More Dynamic Air Quality Management Framework
Investigators: Demerjian, Kenneth L. , Beauharnois, Mark , Bielawa, Robert , Civerolo, Kevin , Hogrefe, Christian , Ku, Michael , Mao, Huiting , Yun, Jeongran
Institution: The State University of New York at Albany , New York State Department of Environmental Conservation , SUNY College of Environmental Science and Forestry , U.S. EPA
EPA Project Officer: Chung, Serena
Project Period: June 1, 2012 through May 31, 2015 (Extended to May 31, 2016)
Project Period Covered by this Report: June 1, 2014 through May 31,2015
Project Amount: $499,945
RFA: Dynamic Air Quality Management (2011) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Air

Objective:

The overall objectives of the proposed work are: 1) to develop a prototype system for providing real-time information on the contribution of short-term emission sources to air quality in relation to other source categories and the potential air quality benefits from episodic control measures; and 2) perform a comprehensive multi-pollutant air quality assessment that examine trends in pollutant concentrations versus emission controls, co-pollutant effects, and develop possible indicators that may aid in improved tracking of the effect of emission controls. 

Progress Summary:

In December of 2014, a no cost extension for the project was requested and granted. The revised end date for the grant is May 31, 2016. As previously outlined in our 2nd annual report, the CMAQ-DDM computations were delayed due to compiler issues with the CMAQ-DDM code. The requested extension allows us to complete CMAQ-DDM computations and perform the full range of data mining and sensitivity analyses identified in the proposal The request for a no cost extension did not modify or impact the milestones/deliverables identified in the subject project proposal. This 3rd annual report provides an overview of the progress made in CMAQ-DDM computations and related analyses as well as progress in the application of observation based analyses for multi-pollutant air quality assessments.

Status of the Direct Decoupled Method (DDM) with the Community Multiscale Air Quality (CMAQ) model production runs.

As discussed in our 2nd annual report, the DDM simulations with the introduction of the PGI compiled version of CMAQ-DDM v4.7.1 model running with 8 cores resolved the numerical instability problems and model simulations were completed for the 5/1/2007 to 9/30/2007 period.

CMAQ-DDM Sensitivity Simulation Results

CMAQ-DDM simulations to compute O3 sensitivity to NOx and VOC precursor emission changes in emission categories including: 1) all anthropogenic emission sources; 2) mobile source emissions; 3) combined area and nonroad emissions; 4) “peaking unit” electric generating unit (EGU) point sources emissions; 5) all EGU point sources emissions; 6) other point sources emissions; and 7) biogenic emissions were completed during this period as were the sensitivity to boundary conditions. The spatial sensitivity fields were calculated separately for the emission categories from the NYC only area (NYCONLY), the MANEVU region except NYC (MVNONYC), the southeastern US region (SESARM), and the rest of the modeling domain (LADCEN) to distinguish sensitivities from local vs. regional emissions. 

An example of the sensitivity analyses performed is provided for the Holtsville (NY) monitoring site. Figure 1 shows hourly average distributions of O3 sensitivity to NOX/VOC emissions from the four emission sensitivity regions for the 10 worst days of daily max 8 hour average ozone at the Holtsville site. Contributions of NOX/VOC emissions from each emission category: mobile sources; area and non-road sources; all EGU point sources; all other point sources; and biogenic sources are also shown in Figure 1. The major contributions of NOX to O3 concentrations at the Holtsville site come from mobile sources. VOC contributions to O3 concentrations come mainly from biogenic sources. The comparison O3 sensitivity to mobile source NOX emissions versus O3 sensitivity to all source NOX emissions indicates that up to 50% of O3 sensitivity to all source NOx emissions is from mobile sources emissions. While up to 20% of O3 sensitivity to all sources NOX emissions is from all EGU NOx source emissions.

Future analyses underway, calculate predicted ozone concentrations resulting from emissions reductions of each sector in each region based on percent reductions calculated from emissions estimates between 2007 and 2011 EPA emission inventories.


Figure 1: Hourly average distributions of O3 sensitivity to emissions/regions at the Holtsville site for 10 worst days of daily max 8 hour average O3: a) NOx from the MVNONYC region. b) VOC from the MVNONYC region. c) NOx from the NYCONLY region d) VOC from the NYCONLY region. 

Progress in the second objective of this project is proceeding on schedule. We have compiled the emissions and air quality concentration data resources for selected monitoring sites in the Northeast to track the comparability of emissions and concentration trends. We have conducted analyses of emission tracers and multi-pollutant relationships including CO, NOx, NOy, SO2, CO vs. O3, NOy vs. O3, CO vs. NOx, Hg0 vs. CO, Hg0 vs. SO2 and SO2 vs. NOx as well as analyses of their annual trends and factors impacting inter-annual variability. Analyses of observed trends in multi-pollutant relationships with DDM sensitivities are being explored and the results shared with air quality planners to identify avenues towards a more adaptive, dynamic air quality planning framework. 

Roles of Transport and Chemical Processes in Interannual Variability of Baseline Ozone and Carbon Monoxide in the Northeastern U.S. During 2001-2010

Interannual and seasonal variations of baseline CO and O3 were examined for seven rural sites in the Northeast US over varying periods in the 2000s decade. Baseline CO generally exhibited decreasing trends at most sites, except at Castle Spring (CS). Over April 2001 – December 2010, baseline CO at Thompson Farm (TF), Pinnacle State Park (PSP), and Whiteface Mountain (WFM) decreased at a rate between -4.3 -2.5 ppbv yr-1. Baseline CO decreased significantly at a rate of -2.3 ppbv yr-1 at Mt. Washington (MWO) over April 2001 – March 2009 and -3.5 ppbv yr-1 at Pack Monadnock (PM) over July 2004 – October 2010. 

Unlike baseline CO, baseline O3 did not exhibit a significant long term trend at any of the sites. The annual cycle of baseline O3 showed a maximum in spring and minimum in summer.  In spring and winter, baseline CO at MWO and WFM, the highest sites, did not exhibit a significant trend, which could probably be a result of decreasing CO emissions in the Northeast US and increasing CO emissions in Asia. Over 2001 – 2010, springtime and wintertime baseline O3 at TF increased significantly at a rate of 2.4 ppbv yr-1 and 2.7 ppbv yr-1, respectively. The increasing trends were most likely related to the decrease in nitrogen oxides (NOx) emissions over urban areas. It was also found that the variations of baseline CO and O3 were influenced by biomass burning emissions, cyclone activities related to Arctic Oscillation (AO), and North Atlantic Oscillation (NAO). In summer, ~38% of baseline CO variability at Appledore Island (AI), CS, MWO, TF, PSP, and WFM  could be explained by CO emissions from forest fires in Russia and ~22% by emissions from forest fires in Canada. Long-range transport of O3 and its precursors from biomass burning contributed to the highest baseline O3 in summer 2003 at AI, CS, MWO, TF, WFM. The lowest baseline CO at AI, PM, TF, PSP, WFM and the lowest baseline O3 at AI, PM, and PSP in summer 2009 were linked to the negative phase of AO, when more frequent cyclone activities brought more clean air masses from the Arctic region to midlatitudes. During springtime, a negative correlation was found between baseline O3 and the NAO index. During positive NAO years, low baseline O3 mixing ratios were linked to stronger moisture transport, stratosphere-troposphere exchange and continental export of O3 produced in North America. The findings of this study suggested impacts of increasing Asian emissions, NOx emissions from the urban corridor, biomass burning emissions, cyclone activities, and NAO should be considered when evaluating the air quality in the Northeast US. 

Impacts of Emission Reductions and Transport on Temporal Variability in Hg° in Bronx, NY During 2008 – 2015

Seasonal, annual, and interannual variability of Hgo and the potential mechanisms driving them were investigated at an urban site located in the borough of Bronx in New York City using continuous measurements data from 2008 – 2015.  The most discernible diurnal cycles occurred during the summer seasons, with a general peak of 193 – 211 ppqv between 2:00 and 5:00 AM and a trough of 134 – 158 ppqv between 12:00 and 16:00 PM, which is consistent with previous studies for urban locations, in large part linked to constant emissions and the diurnal variation of the planetary boundary layer height.  Large interannual variability was found in the seasonally averaged diurnal cycles of Hg0.  Of the seven cold seasons 2010 exhibited the lowest Hg0 levels whereas 2014 exhibited the highest Hg0 levels largely associated with the interannual variability in circulation patterns, i.e. more frequent and faster transport of relatively cleaner air from southern Canada via northwesterly flow in winter 2010 compared to more frequent and faster transport of polluted air masses via southerly flow in winter 2014.  The Hg°-CO, Hg°-SO2 and Hg°-NOx correlations suggested significant emission reductions in CO and SO2, especially the latter which resulted in scarce correlation between Hg° and SO2 albeit their shared common sources.  Seasonal HYSPLIT dispersion simulations suggested the important role of regional transport in Bronx Hg° concentrations, the region outside NYC contributing up to 75% of the total anthropogenic contribution.  Of the seven warm seasons, 2011 experienced the lowest concentrations, potentially caused by the most dynamic circulation that year with the strongest North American trough and the weakest subtropical high of all summers during the study period.  The low concentration of Hg° was also possibly a result of emission reductions, which was difficult to verify due to a lack of emission inventories for the corresponding time. 

Trends in Background Concentrations of Hg° in the Northeastern U.S.

An analysis of multi-year data sets suggested a decreasing trend of 3.8±0.9 ppqv yr-1 in background mixing ratios of gaseous elemental mercury (Hg°) at an elevated, rural site, Pack Monadnock, in New Hampshire, US.  It is in close agreement with the declining trends reported from Mace Head (3.1±1.1 ppqv yr-1), Cape Point South Africa (3.8±0.6 ppqv yr-1), and mid-latitude Canadian sites (~2.6-3.9 ppqv yr-1).  At a coastal, rural site, Thompson Farm, in southern New Hampshire, It was found that an abrupt increase in the fall of 2006 seemed to lead to no trends there during the period of 2003 – 2010.  At another rural site, Huntington Wildlife Forest in upstate New York, no trend was observed over February 2006 – August 2013 despite the three unusually large values in February, March, and December 2007. Further examination suggested a decreasing trend in the anthropogenic component at all three sites, which probably was the mechanism that drove the decline in the background concentrations observed at locations from previous studies.   However, near the surface, different from other years, there was abundant precipitation in the senescence months in 2006 followed by a lack of snow in the following winter in the northeastern U.S.  An examination of long-term soil moisture data for a northeastern site (Lye Brook, NY) suggested soils to be the driest in the year of 2007 during the decade of 2001 – 2011.  Drier soils had been observed to be closely linked to reduced Hg° evasion rates from soils.  It was thus hypothesized that near the surface, Hg° evasion from ecosystems in fall 2006 and the year of 2007 was significant enough to alter the declining trend in background Hg° in the northeastern US that appeared to be controlled primarily by decreasing anthropogenic emissions. 

Future Activities:

Complete CMAQ-DDM diagnostic analyses of sensitivity runs including the calculation of predicted ozone concentrations resulting from emissions reductions of each sector in each region based on percent reductions calculated from emissions estimates for years 2011 (EPA), 2018 (EPA), and 2020 (MARAMA). Complete analyses of air quality measurements in the northeast. Prepare peer reviewed publications for respective analyses performed. 

Journal Articles:

No journal articles submitted with this report: View all 12 publications for this project

Supplemental Keywords:

episodic emission controls, atmospheric modeling, emission trends, air quality trends, multi-pollutant analysis 

Progress and Final Reports:

Original Abstract
2012 Progress Report
2013 Progress Report
Final Report