Air pollution is one of the major challenges that the urban world today faces. Deteriorating outdoor air quality damages our health. It has the potential to decrease our average life span, increase the risk of respiratory diseases and induce cardiovascular diseases that might prove to be fatal. The common sources of outdoor air pollution are emissions caused by motor vehicles and factories. Other pollution sources include smoke from bushfires, windblown dust, and biogenic emissions from vegetation (pollen and mould spores).
Common Air Pollutants
The most common air pollutants of ambient air include:
Particulate matter (PM10 and PM2.5) - The phrase "particulate matter," also known as "particle pollution" or "PM," refers to very minute solid and liquid droplets hanging in the atmosphere. Numerous substances, such as nitrates, sulphates, organic compounds, metals, soil or dust particles, and allergies, can be found in particulate matter (such as fragments of pollen or mould spores). PM10 (particles with a diameter of 10 micrometres or less) are tiny particles that can get into the lungs by going through the nose and throat.
Once ingested, these particles can have detrimental effects on the heart and lungs as well as other vital organs. On other hand, PM2.5 (particles with a diameter of 2.5 micrometres or less) are particles that are so tiny, they can enter the circulation and reach the deepest parts of the lungs. There is enough proof to conclude that prolonged (year-long) exposure to PM2.5 can have harmful consequences on one's health. Note that PM2.5 is included in PM10.
Ozone (O3) - Our health is negatively impacted by ozone at ground level. Ground level ozone is a main component of smog. It is created when sunlight interacts with emissions from sources like motor vehicles and industries. Ozone can disperse widely and build up to high concentrations far from the initial polluting sources. Even at low concentrations, ground-level ozone can be dangerous to our health.
Nitrogen dioxide (NO2) - Nitrogen dioxide is a highly reactive gas that is created by emissions from gas stoves, unflued gas heaters, industry, and motor vehicles. High amounts can be observed indoors, especially in areas with unflued gas heaters and close to busy roadways.
Other indoor sources may include gas cooking or cigarette smoke. Outside, nitrogen dioxide helps to create particulate matter pollution and ground-level ozone (O3).
Carbon monoxide (CO) - Carbon monoxide (CO) is an odourless, colourless gas which forms when the carbon in fuels doesn’t entirely burn. It is mostly produced by industry and motor vehicles, but it can also occur during bushfires. Unflushed gas heaters, wood-burning heaters, and cigarette smoke all produce carbon monoxide indoors. Carbon monoxide levels are typically highest during winter, because cold weather makes combustion less complete and traps pollutants close to the ground.
Sulphur dioxide (SO2) - Sulphur dioxide is a gas with a strong, unpleasant odour that is extremely reactive. It is formed by fossil fuel combustion at power plants and other industrial facilities. Volcanic eruptions, the breakdown and burning of organic waste, and spray from the sea are some examples of natural processes that generate sulphur gases. It contributes to air pollution through enabling the formation of particulate matter.
Outdoor Air Pollution contributes to poor Indoor Air Quality
Our homes are not necessarily designed to protect us from harmful natural elements, such as outdoor air pollution. Since we spend most of our time indoors and frequently at home, exposure to air pollution is also a constant worry. Infiltration of outdoor air pollutants is a significant cause of air pollution in homes, in addition to indoor emissions from chores like cooking and cleaning. Open windows and doors, supply air ventilation systems, and other openings allow outdoor air pollution to enter buildings as a result of pressure and temperature changes.
Tackling Outdoor Air Pollution with Public Policy
It is difficult to overcome the challenge of outdoor air pollution without effective public policy. All stakeholders, both public and private, are required to join hands in introducing measures that will guarantee all safe air to breathe. For starters, it is important to improve public transport systems across all cities so that people prefer it over using private vehicles that cause carbon emission. Further, our cities should increasingly move towards green energy. Public spaces should be reoriented in order to adopt cleaner technologies instead of fossil powered generators. Construction work must be regulated well in order to control dust pollution. An important step to effectively implement such policies is to monitor and collect data about outdoor air pollutants. Both public and private institutions must use resources at their disposal and enhance their capacities in order to provide evidence which will inform policy and lead us to a safer and better future.