Before they mix with steam, dust and smoke, the constituent components of PM2.5 are toxic gases including nitrogen oxide (NOx) and sulphur dioxide (SO2), as well as heavy metals, such as mercury (Hg), cadmium (Cd), arsenic and lead (As). Moreover, there is a high likelihood that PM2.5 will also contain polycyclic aromatic hydrocarbons (PAHs), all of which are harmful to the human body. PAHs are a direct result of numerous human activities, including: the burning of crops and fields undertaken within the agricultural industry such as in the North of the country, which causes a toxic smog that spreads beyond borders; transport and vehicle use resulting in exhaust fumes created by the burning of diesel and gasohol fuels; industrial production of volatile organic compounds from chemicals and industrial sources; and electricity production which, despite producing less PM2.5 than burning vast swathes of crops and the transport industry, still plays a significant role in the release of sulphur dioxide (SO2) and nitrogen oxide (NOx) into the atmosphere.
Beginning in 2013, the presence of these toxic substances has led the World Health Organization (WHO) to classify PM2.5 as a group 1 carcinogen. Moreover, PM2.5 is one of the eight leading causes of early death worldwide. The fact that PM2.5 particles are so miniscule means that the nose cannot filter the substances effectively and the particulate matter finds its way into the respiratory and circulatory systems, where it negatively impacts various organs. PM2.5 can lead to a deterioration of lung function, while also increasing the risk of emphysema, respiratory inflammation resulting from allergy symptoms, and cardiovascular disease, especially coronary artery disease and myocardial infarctions.
Research has found that for every 10mg/m3 increase of PM2.5 in the bloodstream, there is a 5.9% increase in carotid intima-medial thickness. This increases the likelihood of narrowing or clogging of the heart’s arteries, thereby increasing a person’s risk of heart disease by up to 1.24 times and heightening their chance of suffering an early death due to heart disease by 1.76 times.