Impact of Emissions from the Los Angeles Port Region on San Diego Air Quality during Regional Transport Events

Oceangoing ships emit an estimated 1.2−1.6 million metric tons (Tg) of PM10 per year and represent a significant source of air pollution to coastal communities. As shown herein, ship and other emissions near the Los Angeles and Long Beach Port region strongly influence air pollution levels in the San Diego area. During time periods with regional transport, atmospheric aerosol measurements in La Jolla, California show an increase in 0.5−1 μm sized single particles with unique signatures including soot, metals (i.e., vanadium, iron, and nickel), sulfate, and nitrate. These particles are attributed to primary emissions from residual oil sources such as ships and refineries, as well as traffic in the port region, and secondary processing during transport. During regional transport events, particulate matter concentrations were 2−4 times higher than typical average concentrations from local sources, indicating the health, environmental, and climate impacts from these emission sources must be taken into consideration in the San Diego region. Unless significant regulations are imposed on shipping-related activities, these emission sources will become even more important to California air quality as cars and truck emissions undergo further regulations and residual oil sources such as shipping continue to expand

Mass spectra of α-tocopherol and its oxidative products

Centroid mass spectra data for α-Tocopherol and its oxidative products separated by supercritical fluid extraction (SFE)/supercritical fluid chromatography (SFC)-proton transfer reaction (PTR) ionization time-of-flight (TOF) mass spectrometry.  SFE was carried out at 40°C 25 MPa of CO2.  One μL portion of extracts in the fluid was injected into an SFC system.  SFC was carried out at 40°C, 30 MPa of CO2, 1.0 mL/min isobaric using L-column3 (2.1 mm x 100 mm, 3μm).  The data file 'Not incubated (83.1)-0024-83.csv' and the 'Incubated (82.3 s)-82.3.csv' are both the mass spectrum of α-tocopherol obtained from non-incubated and incubated samples, respectively.   The number in a pair of parenthesis indicates the retention time for the data on an incubated α-tocopherol sample.</p

Negative ion mode SFE-PTR mass spectrum of a cell on the frit

Negative ion mode SFE-PTR mass spectrum of a cell on the frit.  Comma-separated arrays of m/z, intensity, and color code, where color code 15 suppose to be a sample-derived ion, and ten indicates a matched ion has been found in the non-HeLa cell control spectrum.</p

Negative ion mode SFE-PTR mass spectrum of 0.2 μL (20 cells equivalent) of the methanol-extract of a cell

Negative ion mode SFE-PTR mass spectrum of 0.2 μL (20 cells equivalent) of the methanol extract of a cell. Comma-separated arrays of m/z, intensity, and color code, where color code 15 suppose to be a sample-derived ion, and ten indicates a matched ion has been found in the non-HeLa cell control spectrum.</p

Positive ion mode SFE-PTR mass spectrum of 0.2 μL (20 cells equivalent) of the methanol-extract of a cell

Positive ion mode SFE-PTR mass spectrum of 0.2 μL (20 cells equivalent) of the methanol extract of a cell.  Comma-separated arrays of m/z, intensity, and color code, where color code 15 suppose to be a sample-derived ion, and ten indicates a matched ion has been found in the non-HeLa cell control spectrum.</p

Positive ion mode SFE-PTR mass spectrum of a cell on the frit.

Positive ion mode SFE-PTR mass spectrum of a cell on the frit.  Comma-separated arrays of m/z, intensity, and color code, where color code 15 suppose to be a sample-derived ion, and ten indicates a matched ion has been found in the non-HeLa cell control spectrum.</p

Direct Night-Time Ejection of Particle-Phase Reduced Biogenic Sulfur Compounds from the Ocean to the Atmosphere

The influence of oceanic biological activity on sea spray aerosol composition, clouds, and climate remains poorly understood. The emission of organic material and gaseous dimethyl sulfide (DMS) from the ocean represents well-documented biogenic processes that influence particle chemistry in marine environments. However, the direct emission of particle-phase biogenic sulfur from the ocean remains largely unexplored. Here we present measurements of ocean-derived particles containing reduced sulfur, detected as elemental sulfur ions (e.g., ³²S⁺, ⁶⁴S₂⁺), in seven different marine environments using <i>real-time</i>, single particle mass spectrometry; these particles have not been detected outside of the marine environment. These reduced sulfur compounds were associated with primary marine particle types and wind speeds typically between 5 and 10 m/s suggesting that these particles themselves are a primary emission. In studies with measurements of seawater properties, chlorophyll-<i>a</i> and atmospheric DMS concentrations were typically elevated in these same locations suggesting a biogenic source for these sulfur-containing particles. Interestingly, these sulfur-containing particles only appeared at night, likely due to rapid photochemical destruction during the daytime, and comprised up to ∼67% of the aerosol number fraction, particularly in the supermicrometer size range. These sulfur-containing particles were detected along the California coast, across the Pacific Ocean, and in the southern Indian Ocean suggesting that these particles represent a globally significant biogenic contribution to the marine aerosol burden

Development and Characterization of an Aircraft Aerosol Time-of-Flight Mass Spectrometer

Vertical and horizontal profiles of atmospheric aerosols are necessary for understanding the impact of air pollution on regional and global climate. To gain further insight into the size-resolved chemistry of individual atmospheric particles, a smaller aerosol time-of-flight mass spectrometer (ATOFMS) with increased data acquisition capabilities was developed for aircraft-based studies. Compared to previous ATOFMS systems, the new instrument has a faster data acquisition rate with improved ion transmission and mass resolution, as well as reduced physical size and power consumption, all required advances for use in aircraft studies. In addition, real-time source apportionment software allows the immediate identification and classification of individual particles to guide sampling decisions while in the field. The aircraft (A)-ATOFMS was field-tested on the ground during the Study of Organic Aerosols in Riverside, CA (SOAR) and aboard an aircraft during the Ice in Clouds Experiment-Layer Clouds (ICE-L). Initial results from ICE-L represent the first reported aircraft-based single-particle dual-polarity mass spectrometry measurements and provide an increased understanding of particle mixing state as a function of altitude. Improved ion transmission allows for the first single-particle detection of species out to ∼m/z 2000, an important mass range for the detection of biological aerosols and oligomeric species. In addition, high time resolution measurements of single-particle mixing state are demonstrated and shown to be important for airborne studies where particle concentrations and chemistry vary rapidly