The international study was conducted in 652 cities and confirms the relationship between urban air pollution and mortality risk.
The study figures show that a daily increase of 10 micrograms per cubic meter in airborne particles, emitted by the exhaust pipes of vehicles, is associated with an increase in mortality of 0.44% and 0, 68%
Exposure to this pollution may increase the risk of short-term mortality, as confirmed by an international epidemiological analysis in 652 cities around the world, led by the London School of Hygiene and Tropical Medicine, in the United Kingdom, and the University of Fudan, in China, in which researchers from the Institute for Environmental Diagnosis and Water Studies (IDAEA) of the Higher Council for Scientific Research (CSIC) have collaborated.
The study, published in the journalNew England Journal of Medicine, is the largest epidemiological evaluation to date of the short-term effects of air pollution. Researchers have collected time series data from 652 cities in 24 countries in the period 1986-2015, and have applied advanced statistical methods to compare daily mortality with urban airborne particulate (PM) pollution concentrations, emitted especially for the exhaust pipes of vehicles.
“It has been found that, on average, an increase of 10 micrograms / m3 in inhalable particles (PM10) –capable of penetrating to the lungs- and fines (PM2.5) -generated by combustion and that can penetrate to the bloodstream - It is associated with an increase in mortality of 0.44% and 0.68% ”, explains Aurelio Tobías, CSIC researcher at IDAEA, who participated in the study.
Dr. Antonio Gasparrini, coordinator of the MCC Collaborative Research Network, which has compiled the database, and one of the main authors of the article, points out: “Although the percentage increase in mortality seems small, this risk can lead to a significant excess in the number of deaths, given the widespread exposure and the large populations living in urban areas ”.
When the researchers examined the shape of the exposure-response relationship, they were unable to identify a threshold, finding significant increases in mortality even at exposures below threshold levels currently established in air quality guidelines.
“The absence of a discernible threshold means that a substantial increase in mortality is likely to occur even with low particulate matter exposure. These results should be taken into account when evaluating the potential benefits of interventions to reduce urban air pollution, and when reviewing existing threshold values for human health ”, says Dr. Gasparrini
The same methodology for different countries
Applying the same analytical methodology to this international dataset allows a critical comparison of risk between populations from different regions. Although the researchers identified some differences, they were able to establish a positive association in all 24 countries, regardless of pollution levels and socioeconomic background.
Professor Haidong Kan of Fudan University, the other lead author of the study, notes: “The consistency of the estimated risk across multiple countries and populations adds evidence about the possible causal link between exposure to air pollution and short-term increase term of mortality ”.
C. Liu, et. all “Ambient Particulate Air Pollution and Daily Mortality in 652 Cities”.The New England Journal of Medicine. DOI: 10.1056 / NEJMoa1817364