Air Pollution Sources

There are three types of air pollution sources: point, area, and line sources. A point source is a single facility that has one or more emissions points. An area source is a collection of smaller sources such as emissions from residential heating within a particular geographic area. A line source is a one-dimensional, horizontal configuration such as roadway. Most emissions emanate from a specific stack or vent. Emissions emanating from sources other than stacks, e.g., storage piles or unpaved lots, are classified as fugitive emissions.

EPA requires that each step develop emissions inventories for all primary pollutants and precursors to secondary pollutants that are classified as criteria or hazardous air pollutants. In clean, rural areas, country-wide emissions totals for individual pollutant species may be all that is needed as long as emissions from large point sources are inventoried separately. For urban areas having severe air pollution problems, gridded emissions inventories are required. An area is divided into grids, typically 5 to 10 km to a side, and area-and line- source emissions are calculated for each grid. Large point sources are listed individually. Such inventories are used as inputs to sophisticated air quality models, employed to develop air pollution control strategies.

Emissions rate for a specific source can be measured directly by inserting sampling probes into the stack or vent and this has been done for most large point sources. It would be an impossible task to do for every source in an area inventory, however. Instead, emission factors, based on measurements from similar sources or engineering mass-balance calculatios, are applied to most sources. An emissions factor is a statistical average or quantitative estimate of the amount of a pollutant emitted from a specific source type as a function of the amount of raw material processed, product produced, or fuel consumed. Emission factors for most sources have been compiled. Emission factors for motor vehicle are determined as a function of vehicle model year, speed, temperature, etc. The vehicles are operated using various driving patterns on a chassis dynamometer. Dynamometer-based emissions data are use in EPA's MOBILE 4 model to calculate total fleet emissions for a given roadway system.

Read more...

Alternative Energy Source: Ethanol

Ethanol, as we’ve already addressed is basically 85 percent grain alcohol and 15 percent gasoline. It is a cleaner burning fuel and provides more horsepower than gasoline alone. While ethanol burns cooler than gasoline, it doesn’t provide enough power to get an engine started on cold days which is why gasoline is added to the mixture.

With the rising popularity of E85 gasoline, more vehicles are being produced that can accommodate this new fuel. E85 fueling stations are currently available in 36 states (as of 2006), and over 6 million vehicles that can use E85 have been sold. The performance of E85 vehicles is potentially higher than that of gasoline vehicles because E85's high octane rating allows a much higher compression ratio, which translates into higher thermodynamic efficiency. However, the flex-fuel vehicles (FFVs) that retain the capacity to run on gasoline alone can't really take advantage of this octane boost since they also need to be able to run on pump-grade gasoline.

Read more...

How to Reduce The Use of Biocides

Buy organically grown food

Because organic farmers do not use biocides, buying their produce will ensure that an increasing area of land is farmed without the use of chemicals.

Buy fresh produce

Significantly more chemicals are used on food crops which are destinated to be packed and sold far away from their place of origin. Although fresh produce may take time to prepare, it does not encourage the use of biocides.

Ban biocides at home

It is not good insisting that farmers should not use chemicals if they are still used in and around home. Avoiding the use of garden biocides is an important part of reducing the general level of these poisons.

Read more...

Simple Ways to Save Water

Choose water-efficient appliances

There are large differences in the amount of water used by different brands of washing machines and dishwashers. Choosing appliances that are sparing with water will reduce your consumption.

Cut down on car-washing water

A large proportion of the domestic water that is used outside the home gets consumed in washing cars. Although a car that is regularly washed will generally last longer, nothing is to be gained by overdoing it: obsessive car-washing just wastes water

Recycle your kitchen water

Dirty washing-up water is generally harmless to plants. Using it to water your vegetable garden will save tap water in summer.

Read more...

Solar Energy Storage

Solar energy is an abundant source of energy. Solar energy fluctuation and its inconstant radiation intensity are important factors in the use of solar energy. For example, the radiation intensity in one place varies depending on season, weather, day or night. In general, it is difficult to reconcile energy needs with the availability solar energy. Therefore storage of solar energy is one of important issues of solar energy application study. Solar energy storage can be classified into three major groups:

1. Sensible Heat Storage

In the solar system with low and medium temperature, water and stone are type of storage medium give us the cheapest and the best performance. Solar energy collectors collect the heat so that the temperature of the medium increased. This temperature increase indicates that medium store heat energy. When needed, heat energy can be released from the medium. The weakness of this type of storage is in their short storage time.

2. Latent Heat Storage

For this type of storage, heat storage medium must be able to absorb heat in large, small variety of volume, little corrosion, and can be re-used. Currently, the medium used is sulphate, nitrate, and hydrate carbonates. The latent heat storage has high energy storing density and long storage period.

3. Chemical Reaction Energy Storage

On this type, endothermic chemical reaction is used to store heat energy. When the process reversed, heat can be released. Chemical materials used for this purpose are inorganic oxides. The advantages of this process is the large storage capacity and a long storage time. However, the high temperatures required for endothermic reaction takes the high cost.

Read more...

Biomass Convertion Systems

Biomass is one alternative source of energy that available abundantly on the earth. Using biomass as renewable energy source can reduce the use of fossil fuels that continue to decrease in number. To be used as a source of energy, biomass must be processed first. These processing technologies are:

1. Direct combustion. This is the easiest way to get energy from biomass. This has been used for centuries ever.
2. Biomass gasification. In this process, biomass is converted to gas products through pyrolysis. Pyrolysis is the process of heating or thermal degradation without the existence of oxygen or air. This process can convert almost all biomass into a product gas consisting of CO, CO2, H2 and CH4.
3. Liqudation of biomass. Results from the processing present usually in metanol form. This process includes biochemistry method through hydrolysis and digestion, mechanical processes such as the pressing and extraction, and chemical processes such as esterification.

Read more...