Particulate matter (PM)
All the solid or liquid particles floating in the atmosphere can be seen as particulate matter, which can be created by natural processes, including the eruption of volcanoes, forest fires and dust storms. But human-created PM as a companion of economic growth is an absolutely major contributor to air pollution.
Particulate matter and gas can combine into aerosols. And PM can be divided into two categories based on its size. The first category refers to the fine particles that are under 10 microns or PM10. The other category is fine particles that are fewer than 2.5 microns or PM2.5. No matter what category the particulate matter belongs to, it can have harmful influences on the health of cardiopulmonary and respiratory systems. But PM2.5 is considered to be a higher risk factor to the health of humans since it can enter into lungs and bloodstreams.
Primary chemicals are just the start of air pollution. When primary pollutants and chemicals react with each other or other substances, the combination produced is called secondary pollutants, which are also a health hazard for living beings.
It is created by the reaction between smoke and pollutants, like sulfur dioxide, soot or black carbon. Some pollutants included in the smog will react with ultraviolet light released from the sun and generate some harmful secondary pollutants, such as VOCs, formaldehyde and others.
Ground level ozone
The ozone layer high above the atmosphere is critical protection for humans from ultraviolet light and other harmful radiation, but ground level ozone is a dangerous irritant which can intervene in respiratory systems and aggravate diseases, such as allergies and asthma. Sunlight can react with nitrous oxides and other chemicals and create secondary pollutant ground level ozone.
Indoor Air Pollution
Though exposure to the outdoor environment can make you susceptible to some dangerous diseases, it’s also not safe to stay inside homes or other enclosed spaces. Actually, indoor air pollution is more harmful and inevitable. According to the World Health Organization, among the premature deaths caused by air pollution, there are two million resulting from indoor air pollution. Just like outdoor air pollution, natural causes and human activities are the main reasons for indoor air pollution.
Building materials and artificial chemical products such as cleaners and solvents release VOCs, which can concentrate in homes or enclosed places, posing a high risk of respiratory issues and diseases. The burning of fossil fuels for cooking emits carbon monoxide, smoke and VOCs into the indoor air, which increase the rate of death resulting from lung cancers, pneumonia and lung-related diseases. In many developing countries, the poisonous substances and PM measured inside homes are ten times above the limit determined by the U.S. Environmental Protection Agency.
Air pollution has gained increasing attention around the world, especially in developed countries, where effective mitigation measures have been carried out. The ban on chlorofluorocarbons has been almost worldwide, even in some unregulated regions. The outcome is very inspiring. Programs initiated by the U.S. and EU with the aim of decreasing air pollution have achieved great successes. These cases have proven that air pollution is not an unsolvable problem. Governments, industrial organizations and the public all over the world should work together to fight against the monster called air pollution.