A study published in the journal Environmental Pollution in 2018 found that lead levels in the air in Beijing exceeded the national air quality standard by a factor of 20, and that lead in the air was a major contributor to lead exposure in the population.
A report by the Beijing Municipal Environmental Protection Bureau in 2017 found that soil samples in urban areas of Beijing had lead levels above the national standard, with some samples exceeding the standard by as much as 10 times.
A study published in the journal Environmental Research in 2019 found that children living near a lead battery plant in Beijing had significantly higher levels of lead in their blood than children living in a control area.
Another study published in Environmental Pollution in 2019 found that workers in a lead acid battery recycling plant in Beijing had significantly higher levels of lead in their blood than a control group of workers.
According to a report by China's National Health Commission in 2019, the prevalence of lead poisoning among children in Beijing was higher than the national average, with some areas of the city reporting rates as high as 30%.
Update on Linear No-Threshold (LNT) Research-Chapter 2 by Prof. Edward Calabrese, PhD
This is a very technical objection to the toxicologists discussion of possible impacts of low level exposure.