What’s happening? Consistently high levels of ozone pollution across Asia are causing estimated losses of $63bn per year in failed maize, rice and wheat crops in China, Japan and South Korea, according to an international study published in Nature Food. The mean figures of lost rice were 23% in China, 11% in South Korea and 5% in Japan. Asia supplies 90% of rice globally and 44% of all wheat. (Science X)

Why does this matter? Most people think of the countryside as a quiet place, where the air is still clean and the environment untouched. In other words: the opposite of the pollution and hectic that often comes with living in a big city. But, this isn’t entirely true – rural areas are dealing with their own forms of pollution.

The ozone paradox – When it comes to ozone, pollution levels actually tend to be higher in the countryside than in metropolitan areas. Ground-level zone (O3) is a secondary pollutant, the product of a complex reaction between nitrogen oxides and volatile organic compounds (VOC) under warm and sunny conditions. The primary sources of these precursors are combustion engines and fossil fuel power plants. The same pollutants that are forming ozone, however, can also degrade it – which means that urban pollution hotspots often end up reporting lower ozone levels than areas with less polluting activities.

Bad for humans and the environment – Exposure to ozone pollution is known to cause a range of health problems, including asthma attacks, respiratory infections, and even premature death. The oxidant is also highly damaging to plant tissues and reduces their growth. While certain crops – such as wheat, soyabeans and chickpeas – are naturally more sensitive to ozone than others, scientists have found that yield-enhancing measures, for example irrigation or targeted breeding, can further increase the vulnerability of plants.

Air pollution in rural areas, however, is not just limited to ground-level ozone. Intensive farming practices emit significant amounts of ammonia and bioaerosols, which are proven to be harmful to rural communities. On top of that, air pollution has many negative impacts on ecosystems – from direct health issues and acid rain to increased eutrophication and harmful haze.

Climate action can help – Luckily, ozone and ammonia have a short atmospheric lifetime, which means that targeted measures can improve the situation of local communities very quickly. Climate change mitigation – such as a switch to sustainable farming or the adoption of electric vehicles – also comes with the added benefit of cutting air pollution.

One last thing – Of course, air pollution is also a major problem in metropolitan areas, where it can be a driver of socio-economic segregation. A classic example of that is the east-west divide in English cities. Scientists found that the east ends of London, Manchester and Bristol are poorer than neighbourhoods in the west because the wind tends to blow from the southwest – and wealthy people fled from the east when levels of industrial air pollution started to rise there in the 19th century.