Effects of temperature on the formation of secondary organic aerosol from amine precursors

<p>Aerosol formation is directly influenced by meteorological properties such as temperature and relative humidity. This study examines the influence of temperature on the physical properties and chemical composition of the aerosol produced from radical oxidation of aliphatic amines. Aerosol formation for temperatures ranging from 10 to 40°C was investigated in dual 90 m³ indoor atmospheric chambers. Further, chemical and physical responses of aerosol formed at one temperature and then raised/cooled to another were investigated in detail. Around two to three times more aerosol formation occurred at 10°C than at 40°C. This has important implications for locations influenced by amine emissions during the winter months. Significant aerosol formation occurred with the oxidation of amines with nitrate radical (100–600 μg/m³) and consisted largely of amine nitrate salts. These reactions are important contributors to aerosol formation during the nighttime hours, when nitrate radical is the dominant oxidant and temperatures tend to be cooler. Solid/gas partitioning of amine nitrate salt aerosol was consistent with literature results. A novel, temperature dependent, mechanism describing peroxy and hydroperoxy radical reactions was observed in the trimethylamine with hydroxyl radical oxidation experiments.</p> <p>Copyright © 2016 American Association for Aerosol Research</p

Greenhouse Gas and Criteria Emission Benefits through Reduction of Vessel Speed at Sea

Reducing emissions from ocean-going vessels (OGVs) as they sail near populated areas is a widely recognized goal, and Vessel Speed Reduction (VSR) is one of several strategies that is being adopted by regulators and port authorities. The goal of this research was to measure the emission benefits associated with greenhouse gas and criteria pollutants by operating OGVs at reduced speed. Emissions were measured from one Panamax and one post-Panamax class container vessels as their vessel speed was reduced from cruise to 15 knots or below. VSR to 12 knots yielded carbon dioxide (CO₂) and nitrogen oxides (NO_<i>x</i>) emissions reductions (in kg/nautical mile (kg/nmi)) of approximately 61% and 56%, respectively, as compared to vessel cruise speed. The mass emission rate (kg/nmi) of PM_2.5 was reduced by 69% with VSR to 12 knots alone and by ∼97% when coupled with the use of the marine gas oil (MGO) with 0.00065% sulfur content. Emissions data from vessels while operating at sea are scarce and measurements from this research demonstrated that tidal current is a significant parameter affecting emission factors (EFs) at lower engine loads. Emissions factors at ≤20% loads calculated by methodology adopted by regulatory agencies were found to underestimate PM_2.5 and NO_<i>x</i> by 72% and 51%, respectively, when compared to EFs measured in this study. Total pollutant emitted (TPE) in the emission control area (ECA) was calculated, and emission benefits were estimated as the VSR zone increased from 24 to 200 nmi. TPE_CO2 and TPE_PM2.5 estimated for large container vessels showed benefits for CO₂ (2–26%) and PM_2.5 (4–57%) on reducing speeds from 15 to 12 knots, whereas TPE_CO2 and TPE_PM2.5 for small and medium container vessels were similar at 15 and 12 knots

Benefits of Two Mitigation Strategies for Container Vessels: Cleaner Engines and Cleaner Fuels

Emissions from ocean-going vessels (OGVs) are a significant health concern for people near port communities. This paper reports the emission benefits for two mitigation strategies, cleaner engines and cleaner fuels, for a 2010 container vessel. In-use emissions were measured following International Organization for Standardization (ISO) protocols. The overall in-use nitrogen oxide (NO_<i>x</i>) emission factor was 16.1 ± 0.1 gkW^–1 h^–1, lower than the Tier 1 certification (17 gkW^–1 h^–1) and significantly lower than the benchmark value of 18.7 gkW^–1 h^–1 commonly used for estimating emission inventories. The in-use particulate matter (PM_2.5) emission was 1.42 ± 0.04 gkW^–1 h^–1 for heavy fuel oil (HFO) containing 2.51 wt % sulfur. Unimodal (∼30 nm) and bimodal (∼35 nm; ∼75 nm) particle number size distributions (NSDs) were observed when the vessel operated on marine gas oil (MGO) and HFO, respectively. First-time emission measurements during fuel switching (required 24 nautical miles from coastline) showed that concentrations of sulfur dioxide (SO₂) and particle NSD took ∼55 min to reach steady-state when switching from MGO to HFO and ∼84 min in the opposite direction. Therefore, if OGVs commence fuel change at the regulated boundary, then vessels can travel up to 90% of the distance to the port before steady-state values are re-established. The transient behavior follows a classic, nonlinear mixing function driven by the amount of fuel in day tank and the fuel consumption rate. Hence, to achieve the maximum benefits from a fuel change regulation, fuel switch boundary should be further increased to provide the intended benefits for the people living near the ports

Gasoline Particulate Filters as an Effective Tool to Reduce Particulate and Polycyclic Aromatic Hydrocarbon Emissions from Gasoline Direct Injection (GDI) Vehicles: A Case Study with Two GDI Vehicles

We assessed the gaseous, particulate, and genotoxic pollutants from two current technology gasoline direct injection vehicles when tested in their original configuration and with a catalyzed gasoline particulate filter (GPF). Testing was conducted over the LA92 and US06 Supplemental Federal Test Procedure (US06) driving cycles on typical California E10 fuel. The use of a GPF did not show any fuel economy and carbon dioxide (CO₂) emission penalties, while the emissions of total hydrocarbons (THC), carbon monoxide (CO), and nitrogen oxides (NOx) were generally reduced. Our results showed dramatic reductions in particulate matter (PM) mass, black carbon, and total and solid particle number emissions with the use of GPFs for both vehicles over the LA92 and US06 cycles. Particle size distributions were primarily bimodal in nature, with accumulation mode particles dominating the distribution profile and their concentrations being higher during the cold-start period of the cycle. Polycyclic aromatic hydrocarbons (PAHs) and nitrated PAHs were quantified in both the vapor and particle phases of the PM, with the GPF-equipped vehicles practically eliminating most of these species in the exhaust. For the stock vehicles, 2–3 ring compounds and heavier 5–6 ring compounds were observed in the PM, whereas the vapor phase was dominated mostly by 2–3 ring aromatic compounds

More unsaturated, cooking-type hydrocarbon-like organic aerosol particle emissions from renewable diesel compared to ultra low sulfur diesel in at-sea operations of a research vessel

<p>The aerosol particle emissions from R/V <i>Robert Gordon Sproul</i> were measured during two 5-day research cruises (29 September–3 October 2014; 4–7 and 26–28 September 2015) at four engine speeds (1600 rpm, 1300 rpm, 1000 rpm, and 700 rpm) to characterize the emissions under different engine conditions for ultra low sulfur diesel (ULSD) and hydrogenation derived renewable diesel (HDRD) fuels. Organic aerosol composition and mass distribution were measured on the aft deck of the vessel directly behind the exhaust stack to intercept the ship plume. The ship emissions for both fuels were composed of alkane-like compounds (H/C = 1.94 ± 0.003, O/C = 0.04 ± 0.001, C<i>_n</i>H₂<i>_n</i>) with mass spectral fragmentation patterns consistent with hydrocarbon-like organic aerosol (HOA). Single-particle mass spectra from emissions for both fuels showed two distinct HOA compositions, with one HOA type containing more saturated alkane fragments (C<i>_n</i>H₂<i>_n</i>₊₁) and the other HOA type containing more monounsaturated fragments (C<i>_n</i>H₂<i>_n</i>₋₁). The particles dominated by the C<i>_n</i>H₂<i>_n</i>₋₁ fragment series are similar to mass spectra previously associated with cooking emissions. More cooking-type organic particles were observed in the ship emissions for HDRD than for ULSD (45% and 38%, respectively). Changes in the plume aerosol composition due to photochemical aging in the atmosphere were also characterized. The higher fraction of alkene or aromatic (C<i>_n</i>H₂<i>_n</i>₋<i>_m</i>_, <i>m</i> ≥ 3) fragments in aged compared to fresh plume emissions suggest that some of the semivolatile alkane-like components partition back to the vapor phase as dilution increases, while alkene or aromatic hydrocarbons contribute more mass to the particle phase due to continuing photochemical oxidation and subsequent condensation from the vapor phase.</p> <p>Copyright © 2017 American Association for Aerosol Research</p