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Fine particle (PM 2.5 ) exposure is a public health issue affecting millions of people worldwide. In New York State, significant emission reductions occurred during the past decades due to fuel switching, increased renewable energy, and transformations in buildings and transportation. Between 2002 and 2018, anthropogenic emissions of CO, NO x , SO 2 , VOCs, and primary PM 2.5 declined by 58%, 61%, 89%, 47%, and 29%, respectively, in New York and three adjoining states. Ambient PM 2.5 mass concentrations decreased but contributions of source types to changes in PM 2.5 elemental carbon (EC) and organic carbon (OC) are incompletely understood. Receptor modeling was used to estimate changing source contributions to EC and OC in New York City (NYC) between 2007 and 2019. Source identification was facilitated by incorporating measurements of CO, NO, NO 2 , O 3 , SO 2, and speciated hydrocarbons (1,3-butadiene, n-butane, isobutane, n-pentane, isopentane, isoprene, benzene, toluene, xylenes, acetaldehyde, and formaldehyde). Hydrocarbon species identified mobile-source emissions, evaporative emissions, biogenics, and photochemical secondary organic aerosol. At three study locations, predicted reductions of TC (OC + EC) summed over all source types were 1.3 ± 0.2 μg m -3 , compared with a measured TC reduction of 1.5 ± 0.2 μg m -3 . Declining sulfate concentrations and cleaner mobile sources together reduced the predicted average TC by a combined 1 μg m -3 . Smaller changes occurred in other source contributions, e.g., 0.15 ± 0.01 μg m -3 reduction likely in response to NYC regulations related to heating fuel oil. Biomass burning PM 2.5 increased between 2007 and 2011, then declined between 2015 and 2019. Reductions contrast with a non-significant increase of 0.05 μg m -3 in photochemical TC. Further opportunities to decrease PM 2.5 concentrations include wood burning and photochemical-related OC. Continued temporal analysis and source apportionment will be needed to track changes in air quality and source contributions as jurisdictions expand renewable energy and energy efficiency goals. Implications : Large emission reductions that occurred in the eastern U.S. between 2002 and 2019 lowered average fine particle concentrations in New York City by a factor of two. Secondary organic aerosol concentrations declined as sulfate decreased but increased non-significantly with rising ozone. Cleaner mobile-source emissions lowered elemental and organic carbon concentrations. Opportunities for further reductions of PM 2.5 concentrations include biomass burning and photochemical secondary aerosol.

Unlabelled: Dry fly ash disposal involves dropping ash from a truck and the movement of a heavy grader or similar vehicle across the ash surface. These operations are known to produce fugitive particulate emissions that are not readily quantifiable using standard emission measurement techniques. However there are numerous situations--such as applying for a source air permit--that require these emissions be quantified. Engineers traditionally use emission factors (EFs) derived from measurements of related processes to estimate fly ash disposal emissions. This study near a dry fly ash disposal site using state-of-the-art particulate monitoring equipment examines for the first time fugitive emissions specific to fly ash handling at an active disposal site. The study measured hourly airborne mass concentrations for particles smaller than 2.5 microm (PM2.5) and 10 microm (PM10) along with meteorological conditions and atmospheric turbidity at high temporal resolution to characterize and quantify fugitive fly ash emissions. Fugitive fly ash transport and dispersion were computed using the on-site meteorological data and a regulatory air pollutant dispersion model (AERMOD). Model outputs coupled with ambient measurements yielded fugitive fly ash EFs that averaged 96 g Mg(-1) (of ash processed) for the PM(c) fraction (= PM10 - PM2.5) and 18 g Mg(-1) for PM2.5. Median EFs were much lower due to the strongly skewed shape of the derived EF distributions. Fugitive EFs from nearby unpaved roads were also characterized. Our primary finding is that EFs for dry fly ash disposal are considerably less than EFs derived using US Environmental Protection Agency AP-42 Emissions Handbook formulations for generic aggregate materials. This appears to be due to a large difference (a factor of 10+) between fugitive vehicular EFs estimated using the AP-42 formulation for vehicles driving on industrial roads (in this case, heavy slow-moving grading equipment) and EFs derived by the current study., Implications: Fugitive fly ash emission factors (EFs) derived by this study contribute to the small existing knowledge base for a type of pollutant that will become increasingly important as ambient particulate standards become tighter. In areas that are not in attainment with standards, realistic EFs can be used for compliance modeling and can help identify which classes of sources are best targeted to achieve desired air quality levels. In addition, understanding the natural variability in fugitive fly ash emissions can suggest methods that are most likely to be successful in controlling fugitive emissions related to dry fly ash storage.

Fine particle (PM2.5) exposure is a public health issue affecting millions of people worldwide. In New York State, significant emission reductions occurred during the past decades due to fuel switching, increased renewable energy, and transformations in buildings and transportation. Between 2002 and 2018, anthropogenic emissions of CO, NOx, SO2, VOCs, and primary PM2.5 declined by 58%, 61%, 89%, 47%, and 29%, respectively, in New York and three adjoining states. Ambient PM2.5 mass concentrations decreased but contributions of source types to changes in PM2.5 elemental carbon (EC) and organic carbon (OC) are incompletely understood. Receptor modeling was used to estimate changing source contributions to EC and OC in New York City (NYC) between 2007 and 2019. Source identification was facilitated by incorporating measurements of CO, NO, NO2, O3, SO2, and speciated hydrocarbons (1,3-butadiene, n-butane, isobutane, n-pentane, isopentane, isoprene, benzene, toluene, xylenes, acetaldehyde, and formaldehyde). Hydrocarbon species identified mobile-source emissions, evaporative emissions, biogenics, and photochemical secondary organic aerosol. At three study locations, predicted reductions of TC (OC + EC) summed over all source types were 1.3 ± 0.2 μg m−3, compared with a measured TC reduction of 1.5 ± 0.2 μg m−3. Declining sulfate concentrations and cleaner mobile sources together reduced the predicted average TC by a combined 1 μg m−3. Smaller changes occurred in other source contributions, e.g., 0.15 ± 0.01 μg m−3 reduction likely in response to NYC regulations related to heating fuel oil. Biomass burning PM2.5 increased between 2007 and 2011, then declined between 2015 and 2019. Reductions contrast with a non-significant increase of 0.05 μg m−3 in photochemical TC. Further opportunities to decrease PM2.5 concentrations include wood burning and photochemical-related OC. Continued temporal analysis and source apportionment will be needed to track changes in air quality and source contributions as jurisdictions expand renewable energy and energy efficiency goals. Implications: Large emission reductions that occurred in the eastern U.S. between 2002 and 2019 lowered average fine particle concentrations in New York City by a factor of two. Secondary organic aerosol concentrations declined as sulfate decreased but increased non-significantly with rising ozone. Cleaner mobile-source emissions lowered elemental and organic carbon concentrations. Opportunities for further reductions of PM2.5 concentrations include biomass burning and photochemical secondary aerosol. [ABSTRACT FROM AUTHOR]

Comprehensive techniques to describe the organic composition of atmospheric aerosol are needed to elucidate pollution sources, gain insights into atmospheric chemistry and evaluate changes in air quality. Fourier Transform Infrared absorption (FT-IR) spectrometry can be used to characterize atmospheric organic matter (OM) and its composition via functional groups on aerosol filter samples in air monitoring networks and research campaigns. We have built FT-IR spectrometry functional group calibration models that improve upon previous work. Laboratory standards that simulated the breadth of the absorbing functional groups in atmospheric OM were made: particles of relevant chemicals were first generated, collected, and analyzed. Challenges of collecting atmospherically relevant particles and spectra were addressed by including interferences of particle water and other inorganic aerosol constituents and exploring the spectral effects of inter-molecular interactions. Calibration models of functional groups were then constructed using partial least squares (PLS) regression and the collected laboratory standard data. These models were used to quantify concentrations of five organic functional groups and OM in eight years of ambient aerosol samples from the southeastern aerosol research and characterization (SEARCH) network. The results agreed with values estimated using other methods, including thermal optical reflectance (TOR) organic carbon (OC; R² = 0.74) and OM calculated as a difference between total aerosol mass and inorganic species concentrations (R² = 0.82). Comparisons with previous calibration models of the same type demonstrate that this new, more complete suite of chemicals has improved our ability to estimate oxygenated functional group and overall OM concentrations. Calculated characteristic and elemental ratios including OM/OC, O/C and H/C agree with those from previous work in the southeastern US, substantiating the aerosol composition described by FT-IR calibration. The median OM/OC ratio over all sites and years was 2.1 ± 0.2. Further results discussing temporal and spatial trends of functional group composition within the SEARCH network will be published in a forthcoming article. [ABSTRACT FROM AUTHOR]

This study assesses the potential impacts on emissions and air quality from the increased adoption of natural gas-fired distributed generation of electricity (DG), including displacement of power from central power generation, in the contiguous United States. The study includes four major tasks: (1) modeling of distributed generation market penetration; (2) modeling of central power generation systems; (3) modeling of spatially and temporally resolved emissions; and (4) photochemical grid modeling to evaluate the potential air quality impacts of increased DG penetration, which includes both power-only DG and combined heat and power (CHP) units, for 2030. Low and high DG penetration scenarios estimate the largest penetration of future DG units in three regions – New England, New York, and California. Projections of DG penetration in the contiguous United States estimate 6.3 GW and 24 GW of market adoption in 2030 for the low DG penetration and high DG penetration scenarios, respectively. High DG penetration (all of which is natural gas-fired) serves to offset 8 GW of new natural gas combined cycle (NGCC) units, and 19 GW of solar photovoltaic (PV) installations by 2030. In all scenarios, air quality in the central United States and the northwest remains unaffected as there is little to no DG penetration in those states. California and several states in the northeast are the most impacted by emissions from DG units. Peak increases in maximum daily 8-h average ozone concentrations exceed 5 ppb, which may impede attainment of ambient air quality standards. Overall, air quality impacts from DG vary greatly based on meteorological conditions, proximity to emissions sources, the number and type of DG installations, and the emissions factors used for DG units. [ABSTRACT FROM AUTHOR]