Air quality
A mixture of oxygen and nitrogen and small amounts of carbon dioxide, argon and water vapour. This is the air we breathe. Breathing fresh air seems something no one should worry about. But last fifty years has seen a drastic change in the composition of air which we know as air pollution. You must have heard this resulting in increase in Earth’s temperature, making rains acidic, damaging our lungs.
Air quality is defined as a measure of the condition of air relative to the requirements of one or more biotic species and/or to any human need or purpose. Air quality indices (AQI) are numbers used by government agencies to characterize the quality of the air at a given location. As the AQI increases, an increasingly large percentage of the population is likely to experience increasingly severe adverse health effects. To compute the AQI requires an air pollutant concentration from a monitor or model. The function used to convert from air pollutant concentration to AQI varies by pollutant, and is different in different countries. Air quality index values are divided into ranges, and each range is assigned a descriptor and a color code. Standardized public health advisories are associated with each AQI range. An agency might also encourage members of the public to take public transportation or work from home when AQI levels are high.
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[edit] Why should you be concerned about air pollution?
Studies have shown that exposure to air pollution, particularly particulate matter, is harmful to your health. Exposure to air pollution has been linked to increases in hospital admissions and mortality related to respiratory illness and Disease. A World Health Organisation (WHO) study suggested that particular matter air pollution reduced the life expectancy of Europeans by 8.6 months, and that reducing this air pollution would save up to $161 billion euros.
[edit] Indoor Air pollution
Air pollution is usually measured outdoors and usually measures point sources of pollution, such as factories, or linear sources, such as high volume roads. Yet most of our time is spent indoors where our air quality is affected by other sources of pollution such as smoking, gas burners, mold, and VOC's.
Modern homes are far more air tight than earlier generations which can lead to additional air quality problems. To qualify as an energy efficient house under many programs a blower test must be conducted to certify the leaks in the home shell are within acceptable limits.
Indoor air pollution can be reduced using filter systems. One type of such system that also helps control heating/cooling costs is called Heat Recovery Ventilation (HRV). Air is picked up from certain rooms via ducting, goes the the central unit where it passes through a heat exchanger and is exhausted to the atmosphere. Fresh air comes in through the opposite side of the heat exchanger is is delivered through ducting to specified rooms.
The incoming air is heated/cooled in the heat exchanger to conserve energy spent in conditioning the air in the home. If the suction points are areas where mold may be a problem this system will assist in preventing mold growth.
Humidity can be controlled by a properly designed HRV system.
[edit] Air Pollution in Your Area
In the USA: The US Environmental Protection Agency (EPA) reports air pollution by State and County.
The US EPA and Google Earth have created a service that allows you to easily find out how air pollution affects your neighborhood. With this Google Earth feature, you are are able to find the sources of air pollution in your neighbourhood, as well as information about the type and quantity of air pollution from each source.
[edit] How Is Air Quality Monitored?
The air quality monitoring is a one day activity where four to eight hours are required for sampling the air. Schools begin with monitoring the air at the school premises and then move on to other critical sites in their zone like traffic junctions, market places or industrial areas. At sites outside the school, students also engage in other activities like surveying people directly exposed to air pollution like the traffic police and noting down numbers of polluting vehicles and further informing to the pollution control cell. Distributing material on introducing simple ways to reduce air pollution or conducting a street play to increase public awareness are also carried out enthusiastically.
