Air pollution in the atmosphere in modern day is like the monster Medusa, affecting almost all the aspects directly or indirectly related to human life, with its head having many venomous snakes, sometimes impacting human health by elevating risks of heart diseases, lung cancer and chronic respiratory diseases, disturbing sensitive terrestrial and aquatic ecosystems through acid rains, loss of fish biodiversity, damaging forests and soil fertility resulting in agricultural losses, eutrophication of waters and soils. Such direct impacts have been responsible for the climate to change slowly in the past and now pacing up rapidly, resulting in episodes of frequent and devastating floods and droughts, shifting weather patterns, highlighted by intense cold and heat waves, consequently impacting the socioeconomic thread of sustainable development by dragging the economies down with reduced crop yields and increased spread of diseases. If air pollution, quickly becoming an atmospheric monster, is not beheaded with intellectual, academic and scientific approaches, coming generations might not be breathing in fresh air.
The air column encompassing Pakistan, is unfortunately ranked as one of the most polluted in the world. In our country, this menace of pollution has many dimensions. One of the main contributors include anthropogenic localised emissions from automobiles, industries, crops-residue burning, fossil-fuelled power plants, unmanaged solid waste and disposal sites, unplanned expansion in urban areas and transboundary air pollution. Transboundary air pollution (TAP) brings the subject of pollution in the limelight, from local to global scales, making the whole world a stakeholder for any atmospheric ill-happening in any part of the world. Pollutants through TAP may be transported, at hemispheric, intercontinental, or regional scales, over distances of hundreds to thousands of kilometres from their sources, subsequently hurting, affecting, and felt by some other countries. Events that are globally responsible for TAP include, industrial accidents (like the Chernobyl nuclear plant explosion, 1986), forest fires (like the California forest fire, 2020), volcanic eruptions (like the eruption of Mount Tambora, 1815), dust storms (like the Trans-Atlantic dust storm, 2020), megacity emissions (like Delhi, Mexico City, etc.), and large scale crop-residue burning events (Like Punjab on the Pakistan and Indian sides, Myanmar, etc.)
Rising trends of air pollution in Pakistan are posing serious environmental threats and are caused both, by the local emissions and by transboundary transport of air pollutants. In the recent past, severe episodes of very high concentrations in air columns of various pollutants including, sulphur dioxide, nitrogen dioxide, carbon monoxide, ozone, heavy metals, dust storms and smoke have been observed and documented, caused and transported by the transboundary air pollution. Such unusual environmental occurrences in various parts of the world including, the Middle East, Africa, Europe and India through TAP have created a huge burden on the air quality of Pakistan. For example, pollutants emitted during the volcanic eruptions from Jabal Al-Tair (Yemen), Dalaffilla (Ethiopia), Nabro (Eritrea) and Mt Etna (Italy) loaded the air quality of the western regions of Pakistan through TAP for several days during 2007-2011, and in these episodes, sulphur dioxide values over some of the regions were observed to be elevated to 1000 percent of the average values. Similarly, NO2, CO, and smoke from large scale crops-residue burning events in north-western India severely contribute to a transboundary phenomenon of wintertime smog episodes over northern Punjab in Pakistan, causing the shut down of schools, affecting the overall daily life and putting pressure on economic activity and the health system of Pakistan. Similarly, during March 2012, a dust storm originated from the Middle East and southwest Asia, hit most of the regions of Pakistan leading to a suspension of flight operations at airports due to poor visibility, and people were even hospitalised with elevated respiratory problems.
Pakistan is a signatory of the Malé Declaration on Control and Prevention of Air Pollution and Its Likely Transboundary Effects for South Asia (1998). It is unfortunate that these aforementioned transboundary air pollution episodes were detected after years of their occurrence, due to a lack of real time and prior information systems for detection of such events.
The issue of TAP must be dealt with a multi-pronged approach, including the quantification of the exported and imported pollution load, characterisation of hotspots, identification of sensitive and high deposition areas and impacts on different ecosystems. Also, there is a need for regular monitoring of cross-border air pollution to quantify the amount of pollutants and a mapping activity, identifying their pathways, so that responsibility could be fixed, and damage could be compensated with each other under the “polluter pays” principle. Real-time monitoring and regulating the emissions of pollutants should be made one of the top priorities for environmental regulation agencies. The Remote Sensing, GIS and Climatic Research Lab (RSGCRL), (National Center of GIS and Space Applications), University of the Punjab, Lahore has started to conceptualise an early warning system, the first of its kind in the region for real-time monitoring of transboundary air pollution, in collaboration with the National Disaster Management Authority (NDMA) of Pakistan for effective preparedness and early response to protect people, save local ecology and realise the dream of sustainable development for Pakistan.