Smog is unnatural atmospheric phenomenon, which it is in the coexistence of chemical compounds and dust in our atmosphere. These substances threatens our health and our lives. The origin of the word smog has roots in two English words: smoke and fog.
One of it is types is London smog. It consists of sulfur oxide (IV), nitrogen oxides, carbon monoxide, soot and the already mentioned dust which staying just above the earth. It occurs during the heating season – usually from October to March, when in Poland temperatures are lower and the need for energy is the greatest. During these months we can observe a temperature inversion, which is an atmospheric phenomenon that increases the temperature of the air along with the altitude. A temperature inversion take place in the thin layer of the atmosphere where the normal decrease in temperature with height switches to the temperature increasing with height. An inversion acts like a lid, keeping normal convective overturning of the atmosphere from penetrating through the inversion.
In the situation when a temperature inversion doesn’t occur, in the lowest part of the atmosphere (troposphere), the air closer to the surface of the earth has a higher temperature than the air above. The air is heated by the surface of the earth which is warm from the sun. Then the heated air is lifted into higher parts of the atmosphere by convection. In the situation of inversion, we have to deal with the reverse temperature. It affects the co-occurrence in the atmosphere of such effects as fog accumulation or smog formation.
The second type is Los Angeles smog (photochemical smog). It exists mainly in the summer months, in subtropical zones. It’s composed of: carbon oxides, nitrogen oxides and hydrocarbons.
Below we present factors which are connected with London smog. It’s occurs on Polish territory during the heating season.
The air pollution consists of gases and aerosols – these are solids and liquids that float in the air and affect the natural composition of atmospheric air. The prevailing air pollutants are nitrogen oxides (NOx), sulfur oxide (SO2), carbon monoxide (CO) and hydrocarbons. volatile organic compounds. Their presence in the air can have dramatic effects. They affect not only the soil and water, but primarily the health of humans, animals and plants. Gases get into our atmosphere mainly by burning fossil fuels, except for volatile compounds that get into the atmosphere from natural sources. Contamination from natural sources are eg volcanic eruptions (ashes and volcanic gases); swamps (methane CH4, carbon dioxide); forest fires, savannas, steppes ( CO2, carbon monoxide); geysers (min hydrogen sulfide, arsenic); soils and erodible rocks; sandstorms; lightning discharge; bacteria and other organisms; as well as vegetation and mushrooms.
It should also be added that sources of pollution mustn’t necessarily have their sources in our country. It is possible that they will reach us from the … Sahara. In such cases air circulation is conducive and responsible for the influx of Saharan dust over other parts of the globe, including to Poland.
Typically, air pollution is associated with areas where large industrial plants are operating. Well … this is not the only source of pollution! In the forefront of some of the most poisonous and threatening substances in the smog are …
They are a mixture of solid, liquid particles. Due to their high degree of dispersion, they can stay in the atmosphere for a very long time. Why are they so dangerous to our health and life? Because they have micrometer size so can they penetrate the respiratory tract to our bloodstream and brain.
Taking into account the health hazard rating the size of the particles is evaluated (the so-called aerodynamic particle diameter). PM2.5 dust contains small particle with size up to 2.5 microns. It is thanks to this small size, they can easily and quickly enter the respiratory tract and then move further causing bloodstream intoxemia. In Poland, the main sources of such dust are fossil fuel heating systems and road transport.
In turn, PM10 consists of a grains that have a diameter of up to 10 microns. This size allows such particles to penetrate into our lungs. The main source of PM10 dust in the air in our cities is combustion emissions in individual solid fuel heating systems such as coal, wood and biomass and road traffic, especially from diesel vehicles without particle filters.
The health effects of exposure to contaminated air are primarily respiratory and cardiovascular illnesses and are also associated with increased hospitalization and reduced life expectancy.
Due to the current standards and stricter regulations, industry has significantly reduced the emission of dust (especially PM2.5). At present, low emissions play an important role in shaping the local level of air pollution. During the winter our map often showed that the inhabitants of large cities – here on the example of Cracow – are not the only people breathing such polluted air. For a very long time, in the consciousness of many people, Cracow used to be the so called Polish capital of smog. As it turns out, it is often that the inhabitants of the city outskirts as well as the inhabitants of small, charming towns inhale much worse air. Although there are no crowded streets and landscapes that represent industrial chimneys, air quality is often far worse than in the city center itself. Dusts are suspended by the incineration of low quality coal and all sorts waste (primarily plastics) in local boiler houses and individual households. Typically, the emission from these sources is associated with specific seasons throughout the year and lasts several months. Low emissions are also connected with transport, especially where congestion is high.
In order to simplify the presentation of air quality data, European cities use indexes to convert measurements into a single number. In our monitoring system, we use the hourly index – it describes the current air quality from the average hourly measurements.
Officially, this index has 5 levels, ranging from 0 (very low) to >100 (very high) – a relative measure of the amount of air pollution. In Airly, we use the CAQI index where we take into account PM10 and PM2.5 dust.
To highlight the differences in air pollution on our platform, there is a 6-level scale that informs you about the color of air pollution. From the green color that shows that the air quality is very good, to the burgundy color when the air pollution standards are repeatedly exceeded and it is advisable not to been leave the house!
In Poland, PM10 fine dust standards are set at three levels:
– Acceptable level 50 μg / m3 (daily)
– Information level 200 μg / m3 (daily)
– Alarm level 300 μg / m3 (daily)
On the other hand, the European Union for fine particulate matter PM10 and PM2.5 only set a permissible level, respectively suitable for PM10 – 50 μg / m3 (daily) and 40 μg / m3 (mean-year) and for PM2.5 – 25 μg / m3 (average-year).
Standards for permissible daily concentrations established by the World Health Organization are 25 μg / m3 for PM2.5 and 50 μg / m3 for PM10.
Direct measurement is the actual amount of air pollution that has been measured by our sensors. This measurement can be seen by directly clicking on the exact location of our sensor.
Interpolated measurement is the data we derive from the direct measurements of the closest sensors. Thanks to the algorithm, we can calculate the value of the CAQI index not only in the place where the device is installed but also in its surroundings!
Being able to read current data on our map is undoubtedly a very important step in taking care of our health and the health of our loved ones. From this idea came the conception of creating a forecast … air pollution for next 24h. Now, using it, you can plan the best time for outdoor activities such as walk with family.
For forecasting, we include weather data such as temperature, wind strength and its direction, pressure and humidity. Our forecast is burdened with an average error of 20μg / m³. To make the results more accurate, we use meteorological data from the site darkSky.
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