Recipe for Disaster – What Ails the Air Quality and Ways to Gauge It

In our previous blogs, we have discussed what constitutes air pollution, its quantified statistics, and the governmental regulations and measures to tackle the problem. However, such an effort can only be successful if we know the accurate methods to interpret these pollution statistics and pinpoint the precise reasons or things that cause such pollution. This blog thus attempts to uncover some of the components that together form a recipe for disaster related to the health and safety of people. Each comes with its set of causes, and each requires our attention and effort to prevent or minimize it.  

Air pollution is caused by solid and liquid particles called aerosols, suspended gases, and chemical reactions that make them worse pollutants than in their original form. Most air pollution comes from energy use and production. Certain gases in the atmosphere can also cause air pollution. In addition, EPA (United States Environmental Agency) has identified six pollutants as "criteria" air pollutants because it regulates them by developing human health-based and/or environmentally-based criteria (science-based guidelines) for setting permissible levels. These six pollutants are:

Carbon Monoxide (CO)

A colorless, odorless, and tasteless gas, it can be harmful when inhaled in large amounts. CO is released when something is burned. The outdoor sources of CO are cars, trucks, and other vehicles or machinery that burn fossil fuels. Indoor CO comes from home appliances such as unvented kerosene and gas space heaters, leaking chimneys and furnaces, and gas stoves.

Breathing air with a high CO concentration reduces oxygen transportation to the heart and brain. CO can cause dizziness, confusion, unconsciousness, and even death at very high levels in closed environments. When CO levels are highly elevated outdoors, they can be troublesome for heart disease patients since such people already have a reduced ability to get oxygenated blood to their hearts. In these situations, decreased oxygen to the heart can cause chest pain or angina, severe breathlessness, and choking. 

Lead (Pb)

At the national level, significant lead sources in the air are ore and metals processing and piston-engine aircraft operating on leaded aviation fuel. Other sources are waste incinerators, utilities, and lead-acid battery manufacturers. The highest air concentrations of lead are usually found near lead smelters.

Once taken into the body, lead distributes through blood and accumulates in the bones. Lead can adversely affect the nervous system, kidney function, immune system, reproductive, developmental, and cardiovascular systems depending on the exposure level. Lead exposure also affects the oxygen-carrying capacity of the blood. These can lead to neurological effects in children, behavioral problems, learning deficits, and lowered IQ in young learners. Elevated lead in the environment can also result in decreased growth and reproduction in plants and animals and neurological effects in vertebrates. 

Nitrogen Oxides 

Nitrogen Dioxide (NO2) is a known oxide highly reactive gas. Other nitrogen oxides include nitrous acid and nitric acid. NO2 primarily gets in the air from the burning of fuel, car emissions, trucks and buses, power plants, and off-road equipment. 

Breathing air with a high NO2 concentration can irritate the respiratory system's airways. This can aggravate respiratory diseases like asthma, accompanied by coughing, wheezing, or difficulty breathing, and necessitating hospital admissions. Longer exposures may contribute to the increased susceptibility to respiratory infections. NO2 and other NOx react with chemicals in the air to form ozone and acid rain, which harms sensitive ecosystems such as lakes, forests, and coastal waters. 

Ground Level Ozone 

Tropospheric, or ground-level ozone, is not emitted directly into the air but is created by chemical reactions between nitrogen oxides (NOx) and volatile organic compounds (VOC). This happens when pollutants emitted by cars, power plants, industrial boilers, refineries, chemical plants, and other sources chemically react in sunlight.

Ozone is most likely to reach unhealthy levels on hot sunny days in urban environments but can still get high levels during colder months. Ozone can also be transported over long distances by wind, so even rural areas can experience high ozone levels. Ozone in the air we breathe can harm our respiratory health. People with asthma are at greater risk from breathing air containing ozone. Elevated exposure to ozone can also affect sensitive vegetation and other ecosystems, including forests, parks, wildlife refuges, and wilderness areas. 

Particle Pollution

Particulate Matter (PM) or particle pollution is a mixture of solid particles and liquid droplets in the air. Some particles, such as dust, dirt, soot, or smoke, are large or dark enough to be seen with the naked eye. Others can only be detected using an electron microscope. Particle pollution includes PM10, inhalable particles with diameters of 10 micrometers and smaller, and PM2.5, fine inhalable particles with diameters of 2.5 micrometers and smaller. These particles are made up of hundreds of chemicals. Some are emitted directly from a source, such as construction sites, unpaved roads, fields, smokestacks, or fires. Others form in the atmosphere due to complex chemical reactions, such as sulfur dioxide and nitrogen oxides, which are pollutants emitted from power plants, industries, and automobiles.

Particulate matter causes serious health problems. Some particles can get deep into the lungs, and some may even get into the bloodstream, posing a severe health risk. 

Sulphur Oxides 

Sulfur dioxide (SO2), the most prominent indicator of pollution among sulfur oxides (SOx), poses the highest health risk for people. Other gaseous SOx, such as SO3, are found in concentrations much lower than SO2. The largest source of SO2 in the atmosphere is the burning of fossil fuels by power plants and other industrial facilities. Smaller sources of SO2 emissions include industrial processes such as extracting metal from ore; natural sources such as volcanoes; locomotives, ships, and vehicles; and heavy equipment that burn fuel with high sulfur content.  

Short-term exposures to SO2 can harm the human respiratory system and make breathing difficult. People with asthma, particularly children, are sensitive to the effects of SO2. Gaseous SOx can also harm trees and plants at high concentrations by damaging foliage and decreasing growth. SO2 and other sulfur oxides can further contribute to acid rain, which is harmful to sensitive ecosystems. Deposition of particles can also stain and damage stone and other materials, including culturally important objects such as statues and monuments. Control measures that reduce SO2 can reduce people's exposure to all gaseous SOx. This may have the critical co-benefit of reducing the formation of particulate sulfur pollutants, such as fine sulfate particles.

A conscious human effort to ensure industrial compliance with environmental norms, burning fossil fuel sustainably, regular checks of vehicles, and taking other measures to tackle outdoor and home appliances and equipment thus becomes a must in light of the above facts.