Temporal trends in the spatial-scale contributions to black carbon in a Middle Eastern megacity.

The analysis of high-resolution changes in black carbon (BC) concentrations was examined to distinguish and quantify various spatial-scale contributions to BC concentrations from nearby sources within 1 km distance to ranges of emission sources distributed over a larger city scale spanning tens of kilometers. Our analysis illustrated that BC emissions on the neighborhood scale only contribute a minor fraction (~15%) to total BC concentrations in the megacity of Tehran. Approximately 62% of the total black carbon is part of the city emissions, and around 23% is transported into the city from local nearby surroundings.

Secondary Organic Aerosol Formation of Fleet Vehicle Emissions in China: Potential Seasonality of Spatial Distributions.

Vehicle emissions are an important source of urban particular matter. To investigate the secondary organic aerosol (SOA) formation potential of real-world vehicle emissions, we exposed on-road air in Beijing to hydroxyl radicals generated in an oxidation flow reactor (OFR) under high-NO conditions on-board a mobile laboratory and characterized SOA and their precursors with a suite of state-of-the-art instrumentation. The OFR produced 10-170 μg m of SOA with a maximum SOA formation potential of 39-50 μg m ppmv CO that occurred following an integrated OH exposure of (1.

Chemical composition and health risk indices associated with size-resolved particulate matter in Pearl River Delta (PRD) region, China.

Size-resolved particulate matter (PM) was collected at the Heshan Super-Station in the Pearl River Delta (PRD) region, China, to evaluate their chemical characteristics and potential health risks. The chemical mass closures illustrate that the dominant fraction in coarse (2.5 μm < D < 10 μm) PM was dust, while organic matter made up a substantial portion of both fine (0.

Acute changes in a respiratory inflammation marker in guards following Beijing air pollution controls.

The adverse respiratory health effects of PM have been studied. However, the epidemiological evidence for the association of specific PM sources with health outcomes is still limited. This study investigated the association between PM components and sources with a biomarker of acute respiratory inflammation (FeNO) in guards.

Source apportionments of PM organic carbon during the elevated pollution episodes in the Ordos region, Inner Mongolia, China.

The Ordos region in the southwestern part of Inner Mongolia experiences frequent PM concentrations in excess of the national PM air quality standards. In order to determine the key sources of PM contributing to these pollution episodes, the main sources of PM OC during elevated PM episodes in the Inner Mongolia were analyzed and compared with non-polluted days. This will provide insight to the main sources of particulate matter pollution during the high-pollution episodes and the effective seasonal strategies to control sources of particulate matter during months and with the highest PM concentrations that need to be controlled.

Quantification of the sources of long-range transport of PM pollution in the Ordos region, Inner Mongolia, China.

The Ordos region of Inner Mongolia is rapidly developing and suffers from poor air quality and unhealthy levels of fine particulate matter. PM concentrations in the Ordos region were found to exceed 75 μg/m on average, annually, with peak pollution days in excess of 350 μg/m, but local air pollution emissions from surrounding sources are not sufficient to drive pollution levels to these concentrations. The current study was designed to quantify sources of PM and assess the local source contributions and effects of regional transport on local pollution.

An assessment of metal contamination risk in sediments of Hara Biosphere Reserve, southern Iran with a focus on application of pollution indicators.

The aim of this study was to assess the pollution status of metals in sediments of Hara Biosphere Reserve using pollution indicators. For this purpose, sediment samples from nine locations were collected and characterized for metal content (Pb, Cr, Zn, Cu, and Fe) using the total digestion technique. Comparison of metal concentrations with that of sediment quality guidelines (SQGs) demonstrated no association with negative biological effects for Cu and Zn, while the values of Pb and Cr mainly illustrated to have association with negative biological effects.

Evaluation of heavy metal contamination hazards in nuisance dust particles, in Kurdistan Province, western Iran.

The effects of natural and geochemical factors depending on heavy metal contamination in nuisance dust particles were evaluated. The nuisance dust particles were sampled using passive deposit gauge method for one year from April 2010 to March 2011 and the obtained samples were measured for the total contents and the contamination levels of Fe, Mn, Cu and As using geo-accumulation index (l(geo)), enrichment factor (EF) and the integrated pollution index (IPI). The results showed that, the contamination levels of Fe and Mn based on I(geo) values, were uncontaminated (I(geo) < 0) (variations of the I(geo) index was from -3.