As an aerosol, dust affects the Earth's radiation budget through direct and indirect effects. The degrees of both effects are dominated by chemical and physical properties of dust. Dust particles also provide reaction sites for many heterogeneous reactions involving SO₂, NO_y, HO_x, O₃, etc. and serve as conveyors carrying anthropogenic substances from the continents to the remote environments through the long-range transport. Those processes may alter the chemical and physical properties of dust (including aeolian iron solubility and then its bioavailability to the surface ocean biota). Characterization of dust properties is thus crucially important to quantify dust climate forcing and to understand its biological role in the ocean biogeochemical cycles. Our work in this direction includes field and laboratory efforts, reflected by selected publications below:

Dust is a source of iron, an essential micronutrient for phytoplankton growth in the surface ocean. Recent Fe fertilization experiments conducted in the HNLC ocean waters confirmed that Fe supplies strongly regulate phytoplankton growth in certain oceanic regions. The atmospheric Fe input may, in turn, regulate the global carbon cycle and thus affect climate. In particular, at present, climate warming has caused increased stratification in the upper ocean that may prevent the surface ocean from mixing with the deep ocean and decrease the nutrient fluxes from below, oceanic primary production could be more dependent on the nutrient input from external sources, such as atmospheric Fe deposition. Therefore, quantifying atmospheric iron deposition to the ocean is important. Our work in this direction has been made through modeling and data assimilations integrated with remote sensing; examples of our efforts are:

The coastal marine atmosphere adjacent to or downwind of large urban and industrial centers can be strongly impacted by pollution emissions, and high concentrations of pollutants in coastal air could result in enhanced air-to-sea deposition fluxes. One of the consequences is accelerated coastal primary production (or eutrophication) driven by excessive discharges of nutrient nitrogen (N) from both point and non-point sources, such as atmospheric deposition. With earlier work on the Asian coast, we recently have focused on quantifying atmospheric nitrogen over the US East Coast, in particular atmospheric nitrogen deposition to the New Jersey coastal ecosystems on the coast of the Mid-Atlantic Bight. Detailed results are in:

Urban air pollution has drawn increasing attention due to its impacts on air quality, human health, and regional and global climate change. Air pollutants, both primary and secondary, may exist in aerosol-, gas-, and precipitation- phases, functioning differently. Therefore air quality represents a result of interactions of different air components and environmental factors. Our efforts in the area of urban air pollution characterization are mainly based at Newark, the largest metropolitan center in New Jersey and adjacent to New York City. Examples of our efforts are as follows: