OBJECTIVE To determine whether indoor air quality in schools is associated with the prevalence of allergic and respiratory diseases in children. METHODS We evaluated 1,019 students at 51 elementary schools in the city of Coimbra, Portugal. We applied a questionnaire that included questions regarding the demographic, social, and behavioral characteristics of students, as well as the presence o...

CO 2 forcing is defined as the initial change in heating rate, with no feedbacks included, that is the direct response to an increase in the CO2 concentration in the atmosphere. We have conducted a study of the effects of surface temperature and clouds on the CO2 forcing, based on use of the Colorado State University general circulation model. We report results from a pair of perpetual July sim...

forests as one of the most important terrestrial ecosystems provide many ecosystem services that almost there is no market to present their values. among this non market services, gas regulation has a significant importance. plants absorb co2 and use it in photosynthesis process. this process, in addition to producing plant biomass and releasing o2, has the effective role in reducing the greenh...

A dynamic numerical model was developed to predict the biomass concentration, pH, and carbon dioxide fixation rate in the continuous culture of cyanobacteria in a photobioreactor. The model is based on the growth rate equation of microalgae combined with mass transfer equations for gas and liquid phases in the photobioreactor as well as thermodynamic equilibrium of inorganic carbon ions in the ...

In this study, the solubility of CO2 in DEA in the presence and absence of choline chloride was reported at different temperatures of 276.15, 298.15, 313.15, and 333.15 K, and pressure range of 4-15 bar. The solubility of CO2 was evaluated using the pressure decay method in a batch isochoric stirred absorption cell. Also, the design of experiments performed with Qualitek-4 software using the Ta...

Measurement of total CO2 concentrations in bile from patients undergoing cholecystectomy because of gallstones has shown that the presence of calcium carbonate in the stones can be associated with a raised total CO2 concentration in the common duct bile. In bile from functioning and poorly-functioning gallbladders, total CO2 was nearly always related to pH irrespective of stone composition.

Recent advances in fossil fuel CO2 (FFCO2) emission inventories enable sensitivity tests of simulated atmospheric CO2 concentrations to sub-annual variations in FFCO2 emissions and what this implies for the interpretation of observed CO2. Six experiments are conducted to investigate the potential impact of three cycles of FFCO2 emission variability (diurnal, weekly and monthly) using a global t...

The NDIR gas detection method is based on the absorption of infrared radiation, which is shown by many polyatomic or heterodimer diatomic gases. For example CO2 gas absorbs IR radiation at 4.26μm wavelength. The detected radiation intensity at this wavelength decreases if the concentration of CO2 increases between source and detector. The extent of absorption mainly depends on the absolute numb...

We built a differential optical absorption spectroscopy system to measure near-surface CO2 absorption in the atmosphere using a nanosecond white light continuum. The white light laser can cover wavelengths ranging from 420 to 2400 nm, where the CO2 and H2O absorption lines are located. At an optical path length of 568 m, it was possible to evaluate atmospheric CO2 concentration from absorption ...

Experimental evidence indicates that the stomatal conductance and nitrogen concentration ([N]) of foliage decline under CO2 enrichment, and that the percentage growth response to elevated CO2 is amplified under water limitation, but reduced under nitrogen limitation. We advance simple explanations for these responses based on an optimisation hypothesis applied to a simple model of the annual ca...