Air Quality Index (AQI) is a conventional value used by government institutions or private companies to inform the citizens about the level of air pollution. Different countries have their own indicators of air quality in accordance with national standards.
In general, it is considered that the less is the value of AQI, the higher is the quality of the air. If this value increases, the significant part of the population faces health risks caused by the air pollution.
Therefore, AQI is the value used by the international community to highlight the level of air pollution at a given moment (or how much it will be polluted in the nearest time). As a rule, its formula takes into consideration six basic pollutants (PM2.5, PM10, carbon monoxide, sulfur dioxide, nitrogen dioxide and ozone) and shows the respective health risk for each pollutant at a given time.
A common worldwide standardized approach to presentation of data on air quality has not yet been found. Therefore, the requirements to the admissible value of AQI, as a rule, vary from one country to another.
In YourAirTest, we use two standards: American and European (U.S.AQI and EAQI respectively)
All systems for the measurement of air quality index use the same formula. However, the difference is in the threshold values of AQI. The illustrations bellow will help explain this difference.
U.S.AQI
EAQI
Meaning
Air quality is considered satisfactory, and air pollution poses little or no risk.
Recommendations
The air is fresh and ideal for outdoor activities.
Meaning
Air quality is acceptable; however, for some pollutants there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.
Recommendations
Sensitive people should consider reducing durable or heavy outdoor physical activities.
Meaning
Members of sensitive groups may experience certain health effects. The generic public is not likely to be affected.
Recommendations
Members of sensitive groups may experience certain health effects. The generic public is not likely to be affected.
Meaning
Everyone may experience health effects; members of sensitive groups may experience more serious health effects.
Recommendations
The following groups of population should avoid endurance or heavy outdoor physical activities:
All other people should limit the scope of physical activities.
Meaning
Hazardous for your health! Everyone may experience more serious health effects.
Recommendations
The following groups of population should avoid any outdoor physical activities:
All other people should limit the scope of physical activities.
Meaning
Hazardous for your health (emergency conditions)! The entire population is more likely to be affected.
Recommendations
Everyone should avoid any outdoor physical activities.
Meaning
Polluted air does not affect health.
Recommendations
Enjoy outdoor activities and sports.
Meaning
There is a low health risk in chronic exposure.
Recommendations
You may have outdoor activities and sports as usual.
Meaning
There is a health risk in chronic exposure.
Recommendations
The adults and children with respiratory diseases and problems with their heart, in case of any symptoms of the disease, should think about the reduced level of physical activities, especially outdoor activities.
Meaning
There is a hazard to health. Sensitive groups of population may experience health effects. People suffering from asthma may need to use inhaler more frequently.
Recommendations
Everyone who feels uncomfortable, in particular eye pain, cough, tickle and sore throat, should think about the reduced level of physical activities, especially outdoor activities. The adults and children with respiratory diseases and problems with their heart, in case of any symptoms of the disease, should think about the reduced level of physical activities, especially outdoor activities. The elderly should reduce physical activities.
Meaning
High health risk. The generic public is likely to be affected. People suffering from asthma may need to use inhaler more frequently.
Recommendations
Reduce the outdoor physical activities, in particular if you have such symptoms as eye pain, cough, tickle and sore throat.
The adults and children with respiratory diseases and problems with their heart, in case of any symptoms of the disease, should think about the reduced level of physical activities, especially outdoor activities.
Meaning
Very hazardous for your health (emergency)! All the population may experience health effects.
Recommendations
Everyone should avoid physical and outdoor activities.
РМ – particulate matter (mg/m3)
PM2.5
PM10
PM (especially small particles called PM2.5) may have a harmful effect on the cardio-vascular system, including heart attacks and strokes. The exposure to small particles in the air may require urgent medical aid, hospitalization, and, in some cases, may lead to premature death. The severe respiratory diseases, including asthmatic attacks, are also associated with the effect of PM on the human organism.
О3 – Ozone (mg/m3)
Ozone negatively affects the lungs and causes respiratory symptoms like cough and dyspnea. It can also trigger asthma and lung disease (e.g., emphysema), leading to an increase in the use of medicines, visits to the hospital and even to rendering urgent medical aid. Ozone effects may increase the risk of premature mortality and respiratory diseases.
CO – Carbon monoxide (mg/m3)
While breathing the air with an increased level of CO, the amount of the oxygen brought to the organs and tissues is decreasing. Those who suffer from heart diseases may have chest pain and other symptoms, which require an urgent medical aid.
CO emissions contribute to production of CO2, ozone and greenhouse gases.
NO2 – nitrogen dioxide (mg/m3)
Short-term exposure to NO2 may cause respiratory diseases, which lead to respiratory symptoms and require an urgent medical aid. Long-term exposure to NO2 may cause asthma and susceptibility to respiratory infections.
SO2 – sulfur dioxide (mg/m3)
Short-term exposure to SO2 may cause respiratory diseases or breathing problems. This effect is especially hazardous to asthmatics, particularly in the course of physical exercises or games. Short-term exposure to SO2 may also increase the number of respiratory diseases that will require visiting a hospital or rendering urgent medical aid, particularly for high-risk groups, including children, the elderly and asthmatic patients.
It contributes to production of the particles with negative health effects.
РМ – particulate matter (mg/m3)
PM2.5
PM10
PM (especially small particles called PM2.5) may have a harmful effect on the cardio-vascular system, including heart attacks and strokes. The exposure to small particles in the air may require urgent medical aid, hospitalization, and, in some cases, may lead to premature death. The severe respiratory diseases, including asthmatic attacks, are also associated with the effect of PM on the human organism.
О3 – Ozone (mg/m3)
Ozone negatively affects the lungs and causes respiratory symptoms like cough and dyspnea. It can also trigger asthma and lung disease (e.g., emphysema), leading to an increase in the use of medicines, visits to the hospital and even to rendering urgent medical aid. Ozone effects may increase the risk of premature mortality and respiratory diseases.
CO – Carbon monoxide (mg/m3)
While breathing the air with an increased level of CO, the amount of the oxygen brought to the organs and tissues is decreasing. Those who suffer from heart diseases may have chest pain and other symptoms, which require an urgent medical aid.
CO emissions contribute to production of CO2, ozone and greenhouse gases.
NO2 – nitrogen dioxide (mg/m3)
Short-term exposure to NO2 may cause respiratory diseases, which lead to respiratory symptoms and require an urgent medical aid. Long-term exposure to NO2 may cause asthma and susceptibility to respiratory infections.
SO2 – sulfur dioxide (mg/m3)
Short-term exposure to SO2 may cause respiratory diseases or breathing problems. This effect is especially hazardous to asthmatics, particularly in the course of physical exercises or games. Short-term exposure to SO2 may also increase the number of respiratory diseases that will require visiting a hospital or rendering urgent medical aid, particularly for high-risk groups, including children, the elderly and asthmatic patients.
It contributes to production of the particles with negative health effects.
“PM” is related to airborne particulate matter. The figures “10” and “2.5” in the name of these pollutants are the particle size. PM may include organic dust, bacteria, construction dust, airborne coal particles from power plants, etc.
YourAirTest uses a unique real-time air quality monitoring system, which gathers, analyzes and verifies thousands of sources of data on the air quality, being mostly gathered by the ground monitoring stations provided by the government, non-governmental organizations and private persons.
Ground stations provide very precise and authentic data on the air quality. If a certain location lacks such stations and we get a request for information on the air quality in this area, we may use the data obtained as a result of satellite image processing and mathematical modelling as well as the data of weather forecast models.
Air pollution may pose significant risks to the environment, such as global warming, ozone layer depletion, increase in ultraviolet radiation or acid rain. It can also have negative effects on agriculture, water resources, forests, wildlife and coastal areas.
Further pollution of water leads to destruction of natural habitats of a number of species, inhabiting water bodies. Soil pollution affects plants and air crops. Of course, humans depend on plants and animals, and our existence on the planet depends on their existence. For example, consumption of fruits or vegetables grown on polluted soils may cause headache, nausea, damage to brain, liver, hormonal disorders and even damage to the nervous system.
The pollutants are emitted from a number of human-made and natural sources. They are the effects of the following processes:
Air pollutants may be transported over long distances and affect the areas, far away from the place of their origin. They may be carried by wind, causing a widespread uncontrolled pollution. Rain may remove pollutants from the air, but, thereby, it causes soil and water pollution. Sunlight may transform pollutants into other substances.