环境科学
大都市区
大气科学
经济衰退
航程(航空)
回归分析
黄土
超细粒子
自然地理学
气象学
气候学
地理
统计
数学
化学
物理
地质学
材料科学
经济
复合材料
凯恩斯经济学
考古
有机化学
地貌学
作者
Mauro Masiol,David Chalupa,Mark J. Utell,David Q. Rich,Philip K. Hopke
标识
DOI:10.1016/j.scitotenv.2018.03.151
摘要
Significant changes in emission sources have occurred in the northeastern United States over the past decade, due in part to the implementation of emissions standards, the introduction and addition of abatement technologies for road transport, changes in fuel sulfur content for road and non-road transport, as well as economic impacts of a major recession and differential fuel prices. These changes in emission scenarios likely affected the concentrations of airborne submicron particles. This study investigated the characteristics of 11–500 nm particle number concentrations and their size spectra in Rochester, NY during the past 15 years (2002 to 2016). The modal structure, diurnal, weekly and monthly patterns of particle number concentrations are analyzed. Long-term trends are quantified using seasonal-trend decomposition procedures based on "Loess", Mann-Kendall regression with Theil-Sen slope and piecewise regression. Particle concentrations underwent significant (p < 0.05) downward trends. An annual decrease of −323 particles/cm3/y (−4.6%/y) was estimated for the total particle number concentration using Theil-Sen analysis. The trends were driven mainly by the decrease in particles in the 11–50 nm range (−181 particles/cm3/y; −4.7%/y). Slope changes were investigated annually and seasonally. Piecewise regression found different slopes for different portions of the overall period with the strongest declines between 2005 and 2011/2013, followed by small upward trends between 2013 and 2016 for most size bins, possibly representing increased vehicular traffic after the recovery from the 2008 recession.
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