Air pollutant concentrations

About: Air pollutant concentrations is a research topic. Over the lifetime, 1652 publications have been published within this topic receiving 36138 citations.

Formation and Control of Air Pollutants

Abstract: Air pollutants are those substances—gases, mists, and particulate aerosols—which are present in the atmosphere in such concentrations that they can adversely affect man and his environment. Most of these substances—sulfur dioxide, the oxides of nitrogen, and many others—are naturally present in the atmosphere in low (background) concentrations. They are produced in nature, as well as from anthropogenic sources, and generally the natural background concentrations are such as to be harmless. Indeed, they may play a vital part in the natural cycles of growth and decay. Unusually high natural concentrations do occur; examples being methane (as “marsh gas”) and hydrogen sulfide from geothermal sources, but these are exceptional circumstances. So when we refer to air pollutants we consider these to be those in relatively high concentrations (compared with background values) which result from the chemical and biological processes used by man. Most notable among these are fuel combustion—for heating cooking and industrial processing—and the generation of electricity.

Simulations of short-term exposure to NO 2 and PM 2.5 to inform capture efficiency standards

Abstract: Author(s): Chan, Wanyu; Kumar, Sangeetha; Johnson, Alexandra; Singer, Brett | Abstract: The California building code requires all new or renovated residential dwelling units to have kitchen exhaust ventilation to manage air pollutants and moisture generated during cooking Current performance requirements are specified as a minimum airflow and maximum sound level This report presents an analysis to support consideration of adding a capture efficiency requirement to the code The analysis uses a physics-based simulation model to calculate air pollutant concentrations in homes that result from cooking and the inflow of outdoor air, mediated by loss and removal process including deposition, dwelling unit ventilation, and the use of a range hood with varying levels of capture efficiency Calculated pollutant concentrations are compared to relevant, health-based guidelines The analysis considers the highest 1-hour concentration of nitrogen dioxide (NO2), which is a product of natural gas combustion and the highest 24-hour concentrations of fine particulate matter (PM25) which is emitted in substantial quantities from frying, broiling and grilling among other cooking activities For NO2, the analysis considers cooking of a dinner for 3-4 persons consisting of pasta, meat sauce, a par-boiled vegetable, and baked garlic bread For PM25, the analysis considers a day in which breakfast emitted particles at the 80th percentile and lunch and dinner entailed particle emissions at the 50th percentile of cooking emission events reported in the literature Model simulations were performed to determine the level of range hood capture efficiency that will allow these cooking scenarios to occur in the vast majority (g99%) of new homes being built in California while maintaining pollutant concentrations below the health-based guidelines, if the range hood is used throughout cooking All homes were assumed to have dwelling unit ventilation at the rate required in the building code Simulation model input parameters were specified using a Monte Carlo approach to represent a range of housing characteristics, outdoor conditions, and indoor pollutant dynamics Simulation results suggest that requiring a minimum capture efficiency of at least 70% is needed to avoid unacceptably high NO2 (1-h average concentration of 100 ppb or higher) and at least 60% to avoid unacceptably high PM25 (24-h average of 25 ug/m3 or higher) These results were driven by multi-family homes, which have a smaller volume of air to dilute any pollutants not captured and removed at the cooking area, resulting in higher concentrations

Down in the dumps

Abstract: New EPA regulations may cause many landfill operators to install costly gas-collection systems and implement addition monitoring and control measures. Implementation of the regulations will force landfills to spend significant money and effort to satisfy design, operation and control requirements. The standards will address emissions of nonmethane organic compounds (NMOCs), including volatile organics, hazardous air pollutants, and odorous compounds, and methane from landfills. Topics covered in the article include applicability, major requirements, potential effects, and unresolved issues.

Emissions and Ambient Air Concentrations

Abstract: The impact of precursor emissions on oxidant formation in the atmosphere may in principle be assessed on the basis of emission inventories. In the assessment, a correlation must be found between emission rates and ambient air concentrations of precursors, which depend on transport, dispersion, and chemical conversion of the precursors in the atmosphere.