Molecular chlorine (Cl2) is an important yet poorly understood trace constituent of the lower atmosphere. Although a number of mechanisms have been proposed for the conversion of particle-bound chloride (Cl-) to gas-phase Cl2, the detailed processes involved remain uncertain.

The effect of anthropogenic aerosols on clouds is one of the most important and least understood aspects of human-induced climate change. Small changes in the amount of cloud coverage can produce a climate forcing equivalent in magnitude and opposite in sign to that caused by anthropogenic greenhouse gases, and changes in cloud height can shift the effect of clouds from cooling to warming.

Atmospheric aerosols play a substantial role in climate change through radiative forcing. Combustion-produced carbonaceous particles are the main light-absorbing aerosols; thus, quantifying their optical properties is essential for determining the magnitude of direct forcing.

The simultaneous determination of heavy metals associated with airborne particulate matter in the atmosphere of the city of Isfahan (Iran) was performed by inductively coupled plasma atomic emission spectrometry (ICP-AES) after pre-concentration with sodium diethyldithiocarbamate.

Biomarkers of systemic inflammation have been associated with risk of cardiovascular morbidity and mortality. The researchers aimed to clarify associations of particulate matter (PM) air pollution with systemic inflammation using models based on size-fractionated PM mass and markers of primary and secondary aerosols.

Between 2001 and 2003, public transport vehicles in New Delhi were required to switch their fuel to natural gas in an attempt to reduce their air pollution impacts. This study examines the climatic impacts of New Delhi’s fuel switching policy, and outlines implications for such efforts in rapidly industrializing countries.

Dust aerosols can suppress rainfall by increasing the number of cloud condensation nuclei in warm clouds and affecting the surface radiation budget and boundary layer instability. The extent to which atmospheric dust may affect precipitation yields and the hydrologic cycle in semiarid regions remains poorly understood. We investigate the relationship between dust aerosols and rainfall in the West African Sahel where the dust-rainfall feedback has been speculated to contribute to sustained droughts.

The Amazon rainforest plays a crucial role in the climate system, helping to drive atmospheric circulations in the tropics by absorbing energy and recycling about half of the rainfall that falls on it. This region (Amazonia) is also estimated to contain about onetenth of the total carbon stored in land ecosystems, and to account for one-tenth of global, net primary productivity.

Nitryl chloride, an active halogen, can be produced through the night-time reaction of dinitrogen pentoxide with chloride-containing aerosol in the polluted marine boundary, and has been measured at levels that are sufficient to affect the photochemistry of oxidants off the southwestern US coast and near Houston, Texas.

In densely populated coastal areas, reactions of polluted air with sea salt aerosol from the ocean can lead to high surface ozone levels that affect air quality.