The Beijing Environmental Protection Bureau was interviewed by the Chinese press, and claimed the difference between its "light pollution" vs U.S embassy's "hazardous" rating is because the local rating does not measure particles less than 2.5 mm, which is the more harmful than the larger particles that they do measure. Regarding particles less than 2.5mm, they said they have the ability to measure it, and have the data, but they cannot make them public. (probably will come to the same result as U.S embassy's)