Over the past several decades, several mitigation strategies have been adopted by federal and state agencies in the United States to improve air quality. These strategies were mostly targeted to reduce SO2 and NOx emissions from light- and heavy-duty vehicles and electric power generation. Between 2007 and 2009, the financial/economic crisis also lowered activity and reduced emissions. Simultaneously, changes in the prices of coal and natural gas drove a shift in fuels used for electricity generation toward natural gas. This study investigates the seasonal patterns, diel cycles, spatial gradients, and trends of gaseous and particulate pollutant concentrations and PM2.5 sources over New York State (NYS) between 2005 and 2016. Gaseous pollutants concentrations (SO2, O3, CO, and NOx) and PM2.5 mass and chemical speciation data (elements, major water soluble inorganic ions, EC, and OC) were retrieved from USEPA (https://aqs.epa.gov/api). The final dataset included 54 sites for PM2.5 mass and gases (26 for PM2.5, 37 for O3, 26 for SO2, 8 for NOx, 2 for NOy 11 for CO) and 6 urban sites (Albany, Bronx, Buffalo, Manhattan, Queens, and Rochester) and 2 rural sites (Pinnacle and Whiteface) for PM2.5 speciation data. EPA PMF 5.0 was applied to the speciation data to identify and apportion the major sources of PM2.5 across these sites. The relationships between ambient concentrations, changes in emissions retrieved from the national emission inventory (NEI), and economic changes were studied. Results show that the combined effects of the mitigation strategies, economic pressures, and the recession led to an overall decrease in PM2.5 and primary gaseous pollutants concentrations across New York State ultimately resulting in relatively homogeneous spatial distributions for PM2.5 and SO2. PM2.5 concentrations decreased significantly at all sites with slopes ranging from -8.6%/y and –2.2%/y. SO2 concentrations dropped significantly at all sites within this period, with the highest slopes observed at the urban sites (e.g., -8.5%/y at Queens, New York City). The reduction of NOx emissions contributed to the reduction of high ozone episodes during summer, but there was no reduction in spring maxima. Increases in autumn and winter ozone concentrations were estimated (e.g., 6.6 ± 0.4% y-1 on average in New York City). Statistically significant relationships were observed between PM2.5, primary pollutants, and economic indicators. Overall, the decrease in electricity generation with coal, and the simultaneous increase in natural gas consumption for power generation, led to a decrease in PM2.5 and gaseous pollutants concentrations. Seven main common sources of PM2.5 were identified across the state: (i) secondary sulfate; (ii) secondary nitrate; (iii) gasoline emissions; (iv) diesel emission; (v) road dust; (vi) biomass burning and (vii) OP-rich. A road salt source was identified at Albany, Buffalo, Rochester and Pinnacle and Whiteface. Additional sources at the New York City sites (Bronx, Manhattan, and Queens) were fresh sea salt, aged sea salt and residual oil combustion. Among the main PM2.5 sources, decreases of secondary sulfate, secondary nitrate, and diesel emissions were observed (-6.7±1.1%/y, -5.3±1.2%/y, -5.3±1.9%/y, respectively) across the state. Decreases can be associated to the mitigation strategies aimed at reducing emissions from light- and heavy-duty vehicles and electric power generation and to the shift from high sulfur to ultralow sulfur fuels. Beginning on July 1, 2012, New York State required that all No. 2 oil sold within the state for any purpose to have ultralow sulfur content. Gasoline emissions increased in Albany, Buffalo, and New York City with slopes higher than 7%/y reflecting the increase of registered vehicles in the area (e.g., New York City +9%, Buffalo +5%, and Albany +6% during 2007-2016).
|Data di pubblicazione:||2018|
|Titolo:||Impact of environmental policies and the economy on changes in criteria air pollutants concentrations and particulate matter compositions in New York State during 2005-2016|
|Titolo del libro:||Abstract Book|
|Appare nelle tipologie:||4.2 Abstract in Atti di convegno|