Scientists have reported a link between air pollution and lung function in children

Children in Denmark who were exposed to higher concentrations of pollutants before birth and in the first years of life had lower lung function at the age of six on average. According to researchers from the University of Copenhagen and their colleagues, repeated examinations of participants under the age of 18 also showed a link between air quality and the development of respiratory function. For more information, see the Izvestia article.

How was the air pollution at home calculated?

The researchers used data from 846 children from two Danish COPSAC observation groups. The first group recruited children of mothers with asthma, the second group invited pregnant women from the general population. The researchers took into account relocations and calculated concentrations of pollutants at the addresses where mothers lived during pregnancy and where children lived after birth.

The team studied nitrogen dioxide and suspended PM2.5 particles up to 2.5 micrometers in diameter. These pollutants enter the air, in particular, during fuel combustion. For PM2.5, both vehicle exhaust and smoke from stove heating can be a source. During the examinations, the scientists measured how much air the child can exhale after a deep breath and how much volume falls on the first second of this exhalation. The resistance of the respiratory tract to air flow was assessed separately.

What changed with a difference of two micrograms

When the estimated concentration of PM2.5 during pregnancy was higher by 2 micrograms/m3, in six—year-olds, the volume of forced exhalation in the first second was on average 2.14% lower, and the forced vital capacity of the lungs was 1.92% lower. These are group assessments. According to the authors, such a difference may not be noticeable for an individual child, whereas a shift in averages is important for assessing the health of the population.

For the period from birth to six years, the relationship was more pronounced. At the calculated concentration of PM2.5 higher by 2.2 micrograms/m, the exhalation volume for the first second was 2.7% lower, and the airway resistance was 7.3% higher. The calculations took into account, among other things, the height and weight of the child, the mother's smoking during pregnancy and contact with tobacco smoke after birth.

Scientists called for recognizing climate change as a threat to human health

During repeated examinations from the age of three to 18, the researchers compared the indicators with air pollution a year before each measurement. At higher concentrations of PM2.5, airway resistance increased faster with age, and the air flow rate increased more slowly in the middle of exhalation. For another indicator, exhalation volume in the first second, the association of pollution with the rate of change was statistically uncertain.

Why reduce pollution if the air has already become cleaner?

The concentrations of PM2.5 and nitrogen dioxide in Denmark decreased during the observations. Nevertheless, the average concentration of PM2.5 at the addresses of the participants in the year before their sixth birthday was 9.6 micrograms/m3. The guideline recommended by the World Health Organization for the average annual level is 5 mcg/m.

Air pollution in a particular city depends, among other things, on emissions far beyond its borders. According to the Danish Environmental Protection Authority, approximately 75% of the country's particulate air pollution comes from foreign sources. The lead author of the study, Associate Professor of Public Health at the University of Copenhagen, Marie Pedersen, believes that measures to improve air quality should be strengthened throughout Europe.

The scientists assessed the pollution on the street near the house. According to these data, it is impossible to determine how many pollutants the child inhaled indoors, on the way to school or in other places. Pedersen emphasizes that the findings of the study relate primarily to air quality.