World Health Organisation (WHO) estimates that seven million deaths globally were attributed to the combined effects of the household and ambient air pollution in 2016.

About 94 per cent of these deaths occur in low- and middle-income countries. 

Based on the current scenario of pollutant emissions, projections indicate that the contribution of pollution to mortality globally will double by 2050.

WHO data shows that 9 out of 10 people breathe air containing high levels of pollutants that exceed levels established by WHO.

Air pollution, experts say, is the contamination of air by harmful gases, dust, and smoke; which affects the plants, animals, and humans drastically.

In other words, they say it is when air is contaminated by any chemical, physical or biological agent that modifies the natural characteristics of the atmosphere.

Dr  Christophe W. Ngendahayo, air and climate health expert, and founder of Air Health Now — working at Kibagabaga Hospital, says all these effects directly or indirectly pose a threat to planetary health, and cause a burden to the economies.

Health impact

Ngendahayo says air pollution is a major threat to health and the environment.

Studies have verified that there is an extensive body linking exposure to both indoor and outdoor air pollution and health effects. 

These effects, Ngendahayo says, are considered according to short-term exposures to pollutants, of hours, days or weeks, or long-term exposures, of months or years.

The effects of short-term exposure include exacerbation of pre-existing respiratory disease, especially asthma, and Chronic Obstructive Pulmonary Disease (COPD), and pre-existing cardiovascular disease, including ischemia, and cardiac failure.

The above effects, he says, come with increased hospitalisation and emergency department visits.

Whereas, he notes that long-term exposure to air pollution is associated with increased mortality, as well as increased incidence of lung cancer and pneumonia, and the development of atherosclerosis.

"Although previously it was understood that air pollution led only to exacerbation of asthma, there is now evidence from cohort studies that long-term exposure to air pollution might lead to the development of new asthma, and also delayed development of the lungs,” he says.

Ngendahayo goes on to explain that over the long term, the chronic health effects of air pollution are likely to affect "healthy” as well as susceptible populations.

"Over time, and despite the body’s defence mechanisms, some pollutants will still be deposited in the body and can cause irritation and lead to long-term illnesses including cardio-respiratory diseases, cancers, diabetes among other conditions,” he notes.

Vulnerable groups

Experts say some specific populations are more susceptible to the health effects of air pollution; these include children (infants and early childhood), pregnant mothers, and the elderly (65 years).

Also, individuals with pre-existing lung and  or heart disease, smokers (active and passive), workers occupationally exposed and socially vulnerable population, making up roughly 40 per cent of the population.

Studies have also demonstrated that pregnant women exposed to air pollutants may increase the risk of adverse birth outcomes such as premature birth or low birth weight.

Children and infants are particularly susceptible to adverse respiratory effects of air pollution, because they spend more time outdoors than adults; breathe in more air per kilogramme of body weight, and are more likely to breathe through their mouths, resulting in greater exposure.

For elderly individuals, Ngendahayo says they are more likely to have both recognised and unrecognised chronic disease.

"Individuals with diabetes are also identified as being at greater risk of air pollution-related mortality,” he says.

Additionally, the medic says that individuals with lower socioeconomic status may be more likely to reside in polluted cities and near roadways or other pollutant sources; are more likely to smoke or be exposed to environmental tobacco smoke.

They are also more likely to experience inadequate nutrition, as they may also experience increased risk factors for diseases that increase their susceptibility to air pollutants.

Besides, outdoor workers and those engaged in outdoor recreational activity are more highly exposed in relation to greater time spent outdoors, and for some individuals, higher levels of exertion which result in increased ventilation rate.

Studies also indicate that those with certain genotypes related to response to oxidative stress also appear to be at greater risk of experiencing respiratory adverse effects of air pollution.

In addition, the level and length of exposure, as well as conditions at home and work (both in- and outdoors) are also important considerations.

Preventions

There are general recommendations, irrespective of the geographical locations for reducing exposure in smoky areas.

Ngendahayo says paying attention and monitoring local air quality reports and smoke warnings from governments is vital.

It is also important to avoid over-hard working or prolonged work, especially outside or smoke/fire warning places.

"If the high-risk people are working outdoors, they should pay attention to symptoms and should be given attention - they are indicators that you need to reduce exposure and in this case wearing face masks is highly recommended,” he says.

He says, avoid activities that increase indoor pollution and try to avoid using anything that burns, like wood-burning fireplaces, cooking traditional stove - and even candles.

Avoid burning rubbish or other crop wastes products left after harvesting. Experts also say that it’s essential to always turn on the car’s air conditioning in re-circulation mode to prevent smoke from entering the car, despite the limitation of these filters.

For the governments, Ngendahayo says the important factor is how to implement the local capacity of the populations and personalise these recommendations.