Carbon monoxide concentrations in Santiago City at street levels and their vertical gradient

Carbon monoxide concentrations were measured at ground level (1 m) near heavy traffic streets in downtown Santiago de Chile in periods of low (November and December), intermediate (April) and high (May) ambient concentrations. Also, measurements were carried out at several heights (from 1 to 127 m) in Santiago’s main street during winter time. Measurements carried out at ground level show maximum values during the morning rush hour, with values considerably higher than those reported by the urban air quality network, particularly in summer time. However, the measured values are below air quality standards. Vertical CO profiles were measured in a tower located in the center of downtown. Below 40 m (average altitude of neighboring buildings), the profiles do not show a consistent vertical gradient, with CO concentrations increasing or decreasing with height, regardless of atmospheric stability. In this low altitude range, the observed vertical profiles are poorly predicted by a street canyon model, and the measured concentrations can not be described by a simple exponential decay. At higher altitudes (40 and 127 m) a negative gradient in CO concentrations is observed, both for stable and unstable atmospheric conditions. The values of CO measured at 127 m are relatively well described by an Eulerian dispersion model running with current CO emission inventories for Santiago, although this model tends to predict stepper CO gradients than the observed ones.     

Spatial distribution and quantification of endocrine-disrupting chemicals in Sado River estuary, Portugal

The important Portuguese Sado River estuary has never been investigated for the presence of potentially endocrine-disrupting chemicals (EDCs), such as natural estrogens (estradiol, estrone), pharmaceutical estrogens (17α-ethynylestradiol), phytoestrogens (daidzein, genistein and biochanin A), or industrial chemicals (4-octylphenol, 4-nonylphenol, and bisphenol A). Thus, the main objective of this study was to evaluate their presence at 13 sampling points distributed between both the industrial and the natural reserve areas of the estuary, zones 1 and 2, respectively. For that, water samples collected in summer and winter were processed by solid phase extraction and analyzed by high-performance liquid chromatography with photodiode array detection and gas chromatography–mass spectroscopy. Results showed that estrone, ethynylestradiol, all the aforementioned phytoestrogens as well as bisphenol A and 4-octylphenol were found in zone 1. In zone 2, neither estrogens nor 4-OP were found. However, in the same zone, daidzein (500 ng/L) and genistein (320 ng/L) attained their highest levels in summer, whereas biochanin A peaked in winter (170 ng/L). Furthermore, bisphenol A was also found in some areas of zone 2, but showed similar concentrations in both surveys (about 220 ng/L). This study demonstrated that the Sado River estuary had low EDCs levels, suggesting that the Sado’s high hydrodynamic activity may be involved in the dilution of local pollution. It was suggested that at the current levels of concentrations, all assayed EDCs are unlikely to individually cause endocrine disruption in local animals. However, under a continuous exposure scenario, an additive and/or synergistic action of the estrogenic chemicals load can not be excluded, and so, continuous monitoring is advisable.     

Climate adaptation in Australia’s resource-extraction industries: ready or not?

Australian resource-extraction industries—mining, fisheries and forestry—operate year-round in the natural environment with all three exposed to climate extremes and to long-term climatic change. However, the industries differ in terms of size, ownership and mobility. Although mining companies are ‘mobile,’ a commitment to a mine site makes them immobile at a location dictated by the presence of a mineral; forestry of natural and managed trees takes place in a specifically selected location that can be changed given a reasonably long time-frame and high financial investment; fishing is the last of the major hunting industries, and despite operating from fixed ports, fishers chase fish across the ocean. All three industries as employers and product providers seek a sustainable future under a changing climate but are subject to environmental variability that impacts on their activities. As each industry has historically dealt with and survived major climate impacts, they typically consider themselves to be resilient, although we illustrate in several case studies that recent climate variability significantly impacts productivity and current resilience is limited. Projected climate change and variability are likely to exacerbate impacts on these industries through new or intensified hazards. Although each industry performs risk management controls to minimize climate-related impacts, a new approach incorporating future climate projections in addition to historical experiences would better prepare each to reduce vulnerability to changing climate. We find that wholesale transformation may not be appropriate or necessary at this time for these industries, and in most cases anticipatory, incremental adaptation should be encouraged, while larger-scale changes are considered in the longer term. Additionally, to overcome some of the barriers and promote the drivers of adaptation, we suggest that a model of adaptive governance coupled with greater use of climate champions may be the most effective method for improving adaptation uptake in these industries.     

Chicken manure increased concentration of organic sulfur compounds in field-grown onions

A field study was conducted at Kentucky State University (KSU) Research Farm. The soil in five plots was mixed with sewage sludge, five plots were mixed with yard waste compost, five plots were mixed with laying hen manure each at 15 t acre^?1, and five unamended plots that never received soil amendments were used for comparison purposes. Plots were planted with onion, Allium cepa L. var. Super Star-F1. The objectives of this investigation were to: 1) determine the concentrations of two organosulfur compounds (dipropyl disulfide and dipropyl trisulfide) in onion bulbs and 2) investigate the effect of mixing soil with three amendments (sewage sludge, yard waste, and chicken manure) on the concentration of dipropyl disulfide and dipropyl trisulfide in onion bulbs. Gas chromatographic/mass spectrometric (GC/MS) analyses of onion oil in chloroform extracts revealed the presence of two major fragment ions that correspond to dipropyl disulfide and – trisulfide. Concentration of these two organic sulfur compounds was greatest (1.5 and 0.8 mg 100 g^?1 fresh weight, respectively) in onion bulbs of plants grown in chicken manure and lowest (0.4 and 0.07 mg 100 g^?1 fresh weight, respectively) in onion bulbs of plants grown in yard waste compost treatments. We concluded that chicken manure could be exploited in growing onions with health-promoting properties.     

Application of a Chemical Mass Balance Receptor Model to Respirable Particulate Matter in Mexico City

Mexico City frequently experiences high levels of air pollution. This is due mainly to its topography and meteorology that suppress pollutant diffusion and dispersion. The atmospheric mixing is extremely poor, especially during the dry winter months. The levels of certain pollutants, such as particulate matter, are of concern since they have severe effects on public health. Visibility deterioration

is one of the most noticeable effects in large cities. Biological effects of particulate matter on man and animals, ranging from mild eye irritation to death, have been reported. The effects depend on the size of the particles, their solubility, and toxicity. The main objective of this paper is to present the results of a chemical mass balance receptor model applied to a well-characterized data set of particulate matter collected in the Mexico City Metropolitan Area (MCMA). Samples of particulate matter were collected using a denuder and a Hi-Vol system for the respirable fraction and total suspended particles, respectively.

In this paper the analysis of a database consisting of the chemical composition of 33 samples of respirable particulate matter (aerosols with diameter less than 2.5 μm) is presented. The 12-hour samples were acquired during day and night periods in a typical medium-income neighborhood from December 19, 1989 through February 5, 1990.

The results show that the main contributors to suspended particles are vehicles without catalytic converters and heavy-duty diesel vehicles. The contribution of refineries, smelters, cement plants, resuspended dust, natural sources, and secondary aerosols were taken into account. In particular, the vehicles without catalytic converters represent the major contribution to PM2.5. They contribute with 50% during the day and 38% at night. Most of the source profiles were taken from the model library SPECIATE EPA. However, native profiles for soil, vehicles, and refinery were designed.     

Association between Levels of Fine Particulate and Emergency Visits for Pneumonia and other Respiratory Illnesses among Children in Santiago,Chile

ABSTRACT

Recent evidence has implicated the fine fraction of particulate as the major contributor to the increase in mortality and morbidity related to particulate ambient levels. We therefore evaluated the impact of daily variation of ambient PM_2.5 and other pollutants on the number of daily respiratory-related emergency visits (REVs) to a large pediatric hospital of Santiago, Chile. The study was conducted from February 1995 to August 1996. Four monitoring stations from the network of Santiago provided air pollution data. The PM2.5 24-hr average ranged from 10 to 111 μg/m³ during September to April (warm months) and from 10 to 156 μg/m³ during May to August (cold months). Other contaminants (ozone (O₃), nitrogen dioxide (NO₂), and sulfur dioxide (SO₂)) were, in general, low during the study period. The increase in REVs was significantly related to PM₁₀ and PM_2.5 ambient levels, with the relationship between PM_2.5 levels and the number of REVs the stronger. During the cold months, an increase of 45 ìg/m³ in the PM_2.5 24-hr average was related to a 2.7% increase in the number of REVs (95% CI, 1.1–4.4%) with a two-day lag, and to an increase of 6.7% (95% CI, 1.7–12.0%) in the number of visits for pneumonia with a three-day lag. SO₂ and NO₂ were also related to REVs. We conclude that urban air pollutant mixture, particularly fine particulates, adversely affect the respiratory health of children residing in Santiago.     

Characterization of Activated Carbon Fiber Filters for Pressure Drop,Submicrometer Particulate Collection,and Mercury Capture

ABSTRACT

The use of activated carbon fiber (ACF) filters for the capture of particulate matter and elemental Hg is demonstrated. The pressure drop and particle collection efficiency characteristics of the ACF filters were established at two different face velocities and for two different aerosols: spherical NaCl and combustion-generated silica particles. The clean ACF filter specific resistance was 153 kg m^-2 sec^-1. The experimental specific resistance for cake filtration was 1.6 × 10⁶ sec^-1 and 2.4 × 10⁵ sec^-1 for 0.5- and 1.5-μm mass median diameter particles, respectively. The resistance factor R was approximately 2, similar to that for the high-efficiency particulate air filters. There was a discrepancy in the measured particle collection efficiencies and those predicted by theory. The use of the ACF filter for elemental Hg capture was illustrated, and the breakthrough characteristic was established. The capacity of the ACF filter for Hg capture was similar to other powdered activated carbons.     

Trends in primary particulate matter emissions from Canadian agriculture

Particulate matter (PM) has long been recognized as an air pollutant due to its adverse health and environmental impacts. As emission of PM from agricultural operations is an emerging air quality issue, the Agricultural Particulate Matter Emissions Indicator (APMEI) has been developed to estimate the primary PM contribution to the atmosphere from agricultural operations on Census years and to assess the impact of practices adopted to mitigate these emissions at the soil landscape polygon scale as part of the agri-environmental indicator report series produced by Agriculture and Agri-Food Canada. In the APMEI, PM emissions from animal feeding operations, wind erosion, land preparation, crop harvest, fertilizer and chemical application, grain handling, and pollen were calculated and compared for the Census years of 1981–2006. In this study, we present the results for PM₁₀ and PM_2.5, which exclude chemical application and pollen sources as they only contribute to total suspended particles. In 2006, PM emissions from agricultural operations were estimated to be 652.6 kt for PM₁₀ and 158.1 kt for PM_2.5. PM emissions from wind erosion and land preparation account for most of PM emissions from agricultural operations in Canada, contributing 82% of PM₁₀ and 76% of PM_2.5 in 2006. Results from the APMEI show a strong reduction in PM emissions from agricultural operations between 1981 and 2006, with a decrease of 40% (442.8 kt) for PM₁₀ and 47% (137.7 kt) for PM_2.5. This emission reduction is mainly attributed to the adoption of conservation tillage and no-till practices and the reduction in the area of summerfallow land.

Implications: Increasing sustainability in agriculture often means adapting management practices to have a beneficial impact on the environment while maintaining or increasing production and economic benefits. We developed an inventory of primary PM emissions from agriculture in Canada to better quantify the apportionment, spatial distribution, and trends for Census years 1981–2006. We found major reductions of 40% in PM₁₀ and 47% in PM_2.5 emissions over the 25-yr period as a co-benefit of increasing carbon sequestration in agricultural soils. Indeed, farmers adopted conservation tillage/no-till practices, increased usage of cover crops, and reduced summerfallow, in order to increase soil organic matter and reduce carbon dioxide emissions, which also reduced primary PM emissions, although the agricultural production increased over the period.