Articles

Acid rain
Another effect of air pollution is acid rain. The phenomenon occurs when sulphur dioxide and nitrogen oxides from the burning of fossil fuels such as petrol, diesel and coal combine with water vapour in the atmosphere and fall as rain, snow or fog. These gases can also be emitted from natural sources like volcanoes. Acid rain causes extensive damage to water, forest, soil resources and even human health. Full article...

Activated carbon treatment of drinking water
Activated carbon filtration (AC) is effective in reducing certain organic chemicals and chlorine in water. It can also reduce the quantity of lead in water although most lead-reducing systems use another filter medium in addition to carbon. Full article...

What is air pollution?
Air is the ocean we breathe. Air supplies us with oxygen which is essential for our bodies to live. Air is 99.9% nitrogen, oxygen, water vapour and inert gases. Human activities can release substances into the air, some of which can cause problems for humans, plants and animals. Full article...

How can air pollution hurt my health?
Air pollution can affect our health in many ways with both short-term and long-term effects. Different groups of individuals are affected by air pollution in different ways. Some individuals are much more sensitive to pollutants than are others. Young children and elderly people often suffer more from the effects of air pollution. Full article...

Why should indoor air quality be of concern?
Environmental Protection Agency studies have shown that the air inside our homes and workplaces is often 10-100 times more polluted than outside air. Full article...

Worsening indoor air quality linked to increases in asthma & allergy problems
Does it seem like your asthma, or a family member's asthma, is giving you more and more problems? If so, it is not just your imagination. It is no coincidence that asthma cases have increased by more than 100% over the past 20 years. Full article...

CADR - Clean Air Delivery Rate
The AHAM seal (usually found on the back of an air cleaner's box) will list three CADR numbers - one for tobacco smoke, one for pollen and one for dust. The CADR indicates volume of filtered air delivered by an air cleaner. The higher the tobacco smoke, pollen and dust numbers, the faster the unit filters the air. Full article...

COMEAP advice: The health effects of air pollutants July 2000
Air pollution can worsen the condition of those with heart or lung disease. Air pollution can aggravate, but does not appear to cause, asthma. In the longer term, air pollution probably has additional effects on individuals, including some reduction in average life expectancy, though the extent of this is not fully understood at present. Full article...

Electrostatic air filters (electrostatic precipitator air cleaners)
Electrostatic precipitators are commonly used to remove particles from airstreams having large steady flow rates. Typical applications include coal-burning plants and cement kilns. Full article...

The plain English guide to the Clean Air Act
Although the 1990 Clean Air Act is a federal law covering the entire country, the states do much of the work to carry out the Act. For example, a state air pollution agency holds a hearing on a permit application by a power or chemical plant or fines a company for violating air pollution limits. Full article...

Filter pressure drop
Air filters are basic components of air handling systems and their life-cycle pressure drop significantly impacts a laboratory's energy consumption. Air filtration consumes energy in the way that conditioning coils do; however, the filters' energy consumption is greater because their resistance to air flow increases over time by definition. Full article...

Air pollution and noise: living and working in a healthy environment
Air: The endangered global commons - Sources of air pollution - Anthropogenic air pollutants and their sources. Full article...

EUROPEAN COMMISSION
Integrated Pollution Prevention and Control (IPPC) - Reference document on best available techniques in the large volume organic chemical industry. Full article...

Controlling VOC emissions in finishing operations
What technologies will help you control VOC emissions from your paint line? Full article...

Air pollution control
With environmental regulations becoming more and more stringent all over the world, companies have to continually monitor, log and control what is released into the atmosphere. Many different types of equipment are used, each dependent on many different factors. Full article...

Comparison between cartridge filters and bag filters
In a lot of filtering applications, the question derives whether to choose a cartridge filter or a bag filter. There are some differences between those two filter systems... Full article...

Dioxins and furans in the chemical industry
Dioxins is the general collective term for chlorinated aromatic compounds, consisting of a group called polychloro dibenzo-p-dioxins and polychloro dibenzofurans. The first group (PCDDs) consists of 75... Full article...

Basic concepts in environmental sciences
Air pollutants and control techniques - Dioxins and furans - Formation mechanisms. Full article...

Electrostatic precipitators
Electrostatic precipitators or ESPs have been used in industry for over 60 years. They can collect particles sized 0.1 to 10 microns very efficiently. They are generally more efficient at collecting fine particles than scrubbers or cyclones. Full article...

Technical articles
Before you design an inertial separator: Measuring your dust's aerodynamic particle size... Full article...

Persistent Organic Pollutants (POPs)
The term "Persistent Organic Pollutants" or POPs is used to describe a class of toxic chemical substances that can harm human health and environment. POPs are long-lasting toxic substances that are produced and released into the environment by human activity. Some POPs are produced for use as pesticides; some are for use as industrial chemicals; and some are produced as unwanted byproducts of certain chemical and/or combustion processes. Full article...

WHO | Dioxins and their effects on human health
Dioxins are environmental "repeat offenders". They have the dubious distinction of belonging to "dirty dozen club" - a special group of dangerous chemicals known as persistent organic pollutants. Full article...

Portable air cleaning devices
Research has suggested that schools tend to have poor indoor air quality (IAQ) for several reasons, including a concentration of classroom materials (such as art and science supplies), tight budgets that reduce maintenance and because of high occupant density (approximately four times as many people as office buildings). Full article...

Flyash
With the boom in population and industrial growth, the need for power has increased manifold. Nearly 73% of India's total installed power generation capacity is thermal, of which 90% is coal-based generation, with diesel, wind, gas and steam making up the rest. Thermal power generation through coal combustion produces minute particles of ash that causes serious environmental problems. Full article...

Health impacts of air pollution
Since the onset of the industrial revolution, there has been a steady change in the composition of the atmosphere mainly due to the combustion of fossil fuels used for the generation of energy and transportation. Air pollution is a major environmental health problem affecting the developing and the developed countries alike. Full article...

HEPA Filter - (High Efficiency Particulate Air Filter)
A HEPA filter is a "throw-away" dry type filter normally designed and manufactured within a rigid frame of metal or cardboard. The filtration media is normally paper, often has a pleated back. Close-pleating design is required for the smallest filter size design due to paper having a high resistance to air flow. Full article...

HEPA filter pressure drop
The pressure-drop for HEPA filtration is dependent on the types and amounts of media used in the filter, per unit area of the filter face. Full article...

How air filters work - A real breathe of fresh air!
Article description: Indoor air pollution, it can be filled with bacteria, moulds, dust and viruses. The best way to combat this is with air filters. Article explains how air filters work to help purifify the air. HEPA air filter information is included. Full article...

Indoor air pollution
It refers to the physical, chemical and biological characteristics of air in the indoor environment within a home, building, or an institution or commercial facility. Indoor air pollution is a concern in the developed countries, where energy efficiency improvements sometimes make houses relatively airtight, reducing ventilation and raising pollutant levels. Indoor air problems can be subtle and do not always produce easily recognized impacts on health. Full article...

Indoor air quality epidemic
Asthma cases have increased by more than 100% since 1976. About 1 in 9 children now have asthma. (See Asthma Fact Sheet.) Death rates due to asthma have tripled and quintupled in children ages 5 to 9, since 1976. Hospitalization rates and doctor visits are continuing to increase dramatically. Full article...

Air and its major pollutants
One of the formal definitions of air pollution is as follows - "The presence in the atmosphere of one or more contaminants in such quality and for such duration as is injurious, or tends to be injurious, to human health or welfare, animal or plant life". It is the contamination of air by the discharge of harmful substances. Full article...

Treatment systems for household water supplies
Activated carbon (AC) filtration is most effective in removing organic contaminants from water. Organic substances are composed of two basic elements, carbon and hydrogen. Because organic chemicals are often responsible for taste, odour and colour problems, AC filtration can generally be used to improve aesthetically objectional water. Full article...

ULPA and SULPA filters
As early as 1961, a filter with a higher efficiency than a HEPA filter was offered. It had a DOP efficiency of 99.999% and the 12 in. (304.8 mm.) deep version had a clean pressure drop of 1.1 in. w.g. (273.6 Pa) when operating at a face velocity of 250 fpm (1.27 m/s). This filter has helped meet the requirement for cleaner air in facilities needed for the manufacture of microelectronics. It is identified by the generic name ULPA (Ultra Low Penetration Air) filter. Full article...

Glossary of terms used when discussing air pollution
Aerosol: a gas that contains suspended solid particles or droplets of liquid able to stay suspended in air because of their very small size (usually less than one micrometer in diameter).
Air pollutant: an airborne substance occurring in the ambient air which has potential to cause harm to human health or welfare or to plant and animal life or materials. Full article...