In Belgium we have very few outdoor ranges, the vast majority are indoor ranges (often with poor ventilation). Therefor I have my lead levels checked every 6 months. In September 2022 my doctor freaked out because I had 54. Before it was always betwen 11 and 25 (till then nothing to worry about), but 54 does pose issues on the long run. Reason for the increase: I switched IPSC clubs in April 2022, and obviously, the range itself is smaller, the ventilation less good and there is a steel back berm down range, which implies that the vast majority of rounds fired disintigrate into dust ... I started researching, take precautions (last check in february was 38 (so decreasing - measures work) and also made a video on it. Fyi: