link of the above image: https://www.apis.ac.uk/starters-guide-air-pollution-and-pollution-sources

A recent study suggested that outdoor air pollution is estimated to contribute to more than two and a half million deaths each year. Specifically, it calculated that each year, 470,000 people died due to ozone depletion, and 2.1 million deaths were linked to delicate particulate matter. Air pollution increases respiratory and heart disease risks, with the young, elderly, and infirm most vulnerable.

Epidemiological studies have shown that ozone and PM2.5 (particulates with a diameter of fewer than 2.5 microns – about 30 times thinner than the width of a human hair) significantly influence health, including premature mortality. However, some studies suggest we may overestimate PM2.5 mortality in regions with very high concentrations.

The WHO (World Health Organization) says it is challenging to identify the world’s most polluted areas because many cities with high levels of air pollution do not have monitoring systems. Further, the WHO adds that although most air pollution hot spots are located in developing nations, it says that developed countries are also at risk. The issue is a significant environmental risk globally. As air quality is largely beyond the control of an individual, the WHO says action needs to be taken by national and international bodies. In 2005, WHO published its Air Quality Guidelines that recommended limits for air pollutants, including PM2.5 and ozone. According to the WHO, continued exposure to particles contributes to the risk of developing cardiovascular and respiratory diseases and lung cancer. As a matter of fact the WHO adds that the mortality in cities with high pollution exceeds that observed in relatively cleaner cities by 15%-20%. Even in the EU, life expectancy is 8.6 months lower (due to) exposure to PM2.5 produced by human activities. Ozone pollution is linked to breathing problems, such as asthma, reduced lung function, and lung disease.

The research, conducted by an international team of scientists, also looked at how changes to the planet’s climatic system due to human activities could have affected the impact of air pollution, such as changes in temperature and humidity.

While contributing to climate change, previous studies had considered how the emissions could create conditions that exacerbated poor air quality, such as how an increased concentration of chemicals interacted with sunlight.

Another change is the way higher temperatures affect plants’ biochemical characteristics.  Trees use volatile organic compounds (VOCs) chemicals to attract pollinators and deter damaging attacks from insects and larger animals. However, higher temperatures can cause many tree species to emit more VOCs into the atmosphere, which reacts with sunlight to form ozone or more particulars.

Using a model of ozone and PM2.5 atmospheric concentrations from 1850 and 2000, the researchers concluded that changes to the climate since pre-industrial times accounted for only a tiny proportion of the current deaths related to air pollution. Specifically, they calculated that about 3,700 deaths each year could be attributed to the effects of past climate change on air quality.