New guidelines on air quality

The World Health Organization (WHO / WHO) has published the new guidelines on air quality (WHO global air quality guidelines 2021, PDF), which revise downwards the concentrations that the main air pollutants must not exceed, in order to to protect human health. Long awaited (the previous ones are from 2005), the indications are based on the last 15 years of studies, during which it was clear that air pollution is much more harmful than previously thought, even at much lower levels. of those considered dangerous at the beginning of the 2000s.

The WHO estimates speak of 7 million deaths a year, which make the damage related to smog comparable to that of cigarette smoking. In particular, the document reads, “there is very strong evidence of one causal relationship between exposure to PM2.5 dust and increased mortality from all causes and the risk of developing respiratory infections, chronic lung disease, heart attack, lung cancer and stroke. In addition, a growing number of studies indicate a relationship with type 2 diabetes, neonatal mortality, low birth weight and pre-term deliveries. Air pollution could also increase the incidence of a large number of other diseases, including Alzheimer’s and neurological diseases. ‘

The pollutants considered in the new guidelines are six: fine particles PM2.5 and PM10, ozone (O3), nitrogen (NO2) and sulfur (SO2) dioxides and carbon monoxide (CO).

For powders, the guidelines halve the annual limit relative to PM2.5, which goes from 10 to 5 micrograms per cubic meter (μg / m3) and reduces that of PM10 by a quarter (from 20 to 15 μg / m3). Even more drastic is the cut in NO2, the pollutant made famous by dieselgate (in 2015), whose threshold value goes from 40 to 10 μg / m3. Furthermore, a new limit for ozone is introduced, which in the summer period must not exceed daily average of 60 μg / m3. Carbon monoxide, a dangerous gas especially in closed places, is a “new entry”: the limit daily is set at 4 milligrams per cubic meter (mg / m3). Finally, SO2 is the only pollutant that sees the tolerance threshold rise, from 20 to 40 μg / m3. The values ​​indicated concern both outdoor air and indoor environments. The WHO estimates that compliance with the new limits would reduce the number of smog deaths by 80%.

The guidelines are not legally binding, but are intended to weigh on the guidelines of governments and authorities. Partly because the sensitivity of public opinion has increased, but also for very concrete economic reasons: on average, in OECD countries, the health costs of smog amount to 5% of GDP. Furthermore, the impact is destined to rise, not so much because pollution is increasing (indeed in high-income countries the concentrations of the main pollutants are almost all decreasing), but because the population is becoming more susceptible to damage from smog. As Hans Kluge, director of WHO Europe, explained at the conference presenting the report: “Pollution is an important risk factor for chronic non-communicable diseases, which continue to increase also due to the aging of the population and lifestyles”.

“We know that for many countries it will be difficult to achieve the objectives indicated in the guidelines”, declared Kluge: “we have therefore included intermediate targets, designed to favor a process that allows us to arrive at the result step by step.” Kluge refers in particular to middle and low-income countries, which often have very high levels of pollution, but it is not excluded that certain regions of the richest areas of the world must adopt a similar approach, starting from the Po Valley, which remains one of the most critical areas on the planet.

With regard to the European Union, then, it is possible that the new indications stimulate the adoption of limits that are more attentive to human health. The current ones, in fact, are even higher than those recommended by the WHO in 2005.

The presentation of the guidelines on air quality takes place a few weeks before the start of the work of the COP26 on climate to be held in Glasgow from 31 October to 12 November. It is no coincidence: the two issues are in fact closely linked, as explained by Maria Neira, director of the Department of Public Health, Environment and Social Determinants of Health at the WHO: “The World Health Organization is preparing a very extensive report to underline the importance of actions to mitigate the effect of climate change. These actions will in fact determine great benefits for health as well. And these benefits will come mainly from the reduction of pollution levels ».

In other words, actions that improve air quality also contribute to tackling climate change, and vice versa. «To reduce pollution globally, one of the key sectors is energy», concluded Neira: «with the guidelines we also underline the need to accelerate the energy transition, moving towards renewable and clean energies. Reducing greenhouse gases, the cause of climate change, and air pollution are two key pillars of policies to protect our health. “